% # % # % # % # %

Stages of skeletal maturation

Total

Coefficient Kappa = 0,964 p=0,000 n=75

**5. Discussion** 

single phalanx.

maturation of the middle phalanx of the third finger.

indicator of the level of an individual's bone maturation.

evaluation of the orthodontist patient.

There were a positive, very significant correlation (p <0,010) among the bone age (TW2) and the stages of skeletal maturation in both sexes (rho = 0,855 for the females and rho = 0,903 for the males). These results coincide with other carried out studies (Moore et al., 1990; Uysal et al., 2006).

In the analysis of the stages of maturation of the half phalange of the third finger it was found that the females were earlier in their maturation stages than the males. These results belong together with those obtained in other methods analyzed in this investigation and they coincide with those of Hägg and Taranger (Hägg & Taranger, 1980a, 1980b, 1982) who they find that, the females mature early, that which is important to consider in the planning of the orthodontist treatment.

The coefficient of correlation of Spearman among the bone age (TW2) and the stages of maturation of the middle phalanx of the third finger showed positive, very significant correlations (p <0,010); in both sexes (0,888 in the feminine one and 0, 921 in the masculine one). These results coincide with other studies that analyze the bone maturation through the development of the phalanges: Leite et al. (Leite et al., 1987) they carry out a longitudinal study, through which value the age skeletal analyzing the first one, second and third fingers of the hand, in a sample of 19 males radiographies and 20 females whose radiographic of the annual hand-wrist had taken from the 10 to the 16 years for the girls and of 12 to 18 years for the males and they find that although differences exist between the analysis of the total hand and that of the three fingers, the method of the three fingers never strays of that of the hand-wrist for more than 2.89 months for the males with a minimum deviation of 0.32 months and for the females, the maximum deviation was of 4.45 months with a minimum of 1.55 months. They also find that the maximum deviations happen during the time of coalition of the epiphysis with the diaphysis when the growth is coming closer to their finalization and consequently they are not of clinical importance. These authors conclude that the advantage of the use of the method of the three fingers is that they can incorporate in the lateral teleradiography, eliminating this way the necessity of other radiographies.

Shigemi Goto et al. (Shigemi Goto & Yamada Miyazawa, 1996) carry out a study in which analyze the ossification of the distal phalanx of the first finger like an indicator of maturity for the initiation of the orthodontist treatment in 2 Japanese women with Class III malocclusion, where they conclude that the determination of the phases of maturation skeletal of the distal phalanx of the first finger, it can be a quick and useful clinical method, to evaluate the potential of residual growth in the cases of Class III.

Rossi et al. (Rossi et al., 1999) carry out a study in 72 feminine patients with ages understood between 8 and 13 years of age, where they analyze the proximal phalanx of the first finger and they find that in the patients that were in the epiphysis stage C, they were next to the peak of maximum speed of growth pubertal.

In relation of the concordance between the stages of skeletal maturation and the stages of maturation of the middle phalanx of the third finger, in the studied sample a high concordance existed, very significant (p <0,010) in both sexes, being perfect in the feminine sex (1,000). That which coincides with other carried out studies: Rajagopal and Sudhanshu (Rajagopal & Sudhanshu, 2002) carry out a study with the objective of determining the dependability of using radiographic of the middle phalanx of the third finger as an indicator of skeletal maturation, in a sample of 75 girls and 75 children, between the 9 and 17 years of age; where they compare the stages of maturation of the cervical vertebras, and the stages of maturation of the middle phalanx of the third finger and they conclude that the assessment of the growth puberal based on the observations of the middle phalanx of the third finger observed by means of standard X-rays, is an useful method and it has as advantages: the smallest exhibition to the X rays and that X rays supplementary machine is not needed.

Madhu et al. (Madhu et al., 2003) carry out a study with the objective of obtaining a unique and simple method to determine the skeletal maturation using the stages of development of the middle phalanx of the third finger that one observes in a radiographic, taken with a conventional X ray dental machine; in a sample of 67 patients, 35 males between 10 and 18 years of age and 32 females between 8 and 16 years. To the patients they carry out them lateral teleradiographies of skull and an X-ray of the area of the middle phalanx of the third finger, where they determine the stages of maturation of the cervical vertebras of the patients in previous stages to the peak puberal, patient that were in the peak of growth puberal and patient in those that it had already happened the peak of growth puberal and the stages of the middle phalanx of the third finger are classified in 3 stages: patient in the previous period to reach the peak pubertal of growth, patient that are in the period of growth pubertal and those patients that the period of growth pubertal had passed. These authors find agreement among the results obtained in the analysis of the cervical vertebras and of the middle phalanx of the third finger and they conclude that the analysis of the maturation of the middle phalanx of the third finger, is an alternative method that can be used to determine the skeletal maturation of the children in growth.

Ozer et al. (Ozer et al., 2006) carry out a study in 150 masculine patients, with ages understood among 9 and 19 years that were in orthodontist treatment, with the purpose of determining the correlation between the index of maturation of the cervical vertebras and the stages of maturation of the middle phalanx of the third finger, for that which they carry out lateral teleradiography of skull and X-rays of the middle phalanx of the third finger of the left hand, finding high correlation coefficients between the stages of vertebral maturation and those of the phalanges. They conclude that the middle phalanx of the third finger can be used in the evaluation of the skeletal maturation of the patients.

From the clinical point of view in the planning of an orthodontist treatment, we should consider if the patient has begun the spurt of pubertal growth, if this is happening in that moment or if it has concluded (Tedaldi, 2007). With the analysis of the stages of maturation of the middle phalanx of the third finger, visualized in an X-ray of 41 x 31 mm., is possible to determine: if the patient has not reached the spurt of pubertal growth (Stage A), if it is next or this event already began (B), if it is in its maximum peak (C) or if it is in the descending curve of growth pubertal (D and E) (Toledo Mayarí & Otaño Lugo, 2010).

Due to the high correlation coefficient found in this sample, between the stages of maturation of the middle phalanx of the third finger and the bone age in both sexes, as well as to the high concordance found in this study, among the evaluation of the maturation through the left hand and the analysis of the middle phalanx of the third finger, which was perfect in the feminine sex, and considering the current tendency in Orthodontics of reducing the number of radiations, we propose inside the diagnosis for the evaluation of the potential growth of the patients, the realization of an X-ray of 41 x 31 mm. of the middle phalanx of the third finger of the left hand (Fig. 3), with the following requirements:

An auxiliary table will be used, where the radiography of 41x31 mm. will be placed, with the vertical bigger axis coinciding with the same position of the phalanx and with the active face in front of the focus. The radiograph will be located on the union between the middle and proximal phalanx of the third finger of the left hand, with the coincident located reference point with the proximal phalanx. The focus will be centered in perpendicular sense to the table, with an angle of 90 °, at a distance focus film, using short cone, of 11 cm. with a time of exhibition of 0,5 second. The calibration of the machine will be of 110 volt / 10 MA / seg. They will take all the measures of protection radiological established (Ugarte et al., 2004) and a dental machine of X rays and dental films standard of 41x31mm., Kodak marks. The one revealed will be executed looking for soft revealed low contrasts.

Fig. 3. Radiographic of middle phalanx of the third finger.

The author considers that, in the patients, it is not necessary to carry out a lateral teleradiography of skull, the evaluation of the potential of growth, inside the diagnosis in Orthodontics, one can make through the stages of maturation of the middle phalanx of the third finger of the left hand, which contributes the following benefits:

It constitutes a simplified method that can be applied in any service of Orthodontics and it allows planning for the treatment of orthodontics in dependence of the potential of growth which the patient presents that makes more efficient therapy.

It allows bigger efficiency and decrease of the costs and it can be carried out in the dental X rays machine, for what includes relative savings to the depreciation of the machine of X-rays and the energy consumption.

They diminish the quantity from radiations to those that are exposed to the patients and the auxiliary personnel (technicians in radiology), as well as, the radiations in the local where the radiographies were taken.

#### **6. Conclusions**

168 Orthodontics – Basic Aspects and Clinical Considerations

age; where they compare the stages of maturation of the cervical vertebras, and the stages of maturation of the middle phalanx of the third finger and they conclude that the assessment of the growth puberal based on the observations of the middle phalanx of the third finger observed by means of standard X-rays, is an useful method and it has as advantages: the smallest exhibition to the X rays and that X rays supplementary machine is not needed.

Madhu et al. (Madhu et al., 2003) carry out a study with the objective of obtaining a unique and simple method to determine the skeletal maturation using the stages of development of the middle phalanx of the third finger that one observes in a radiographic, taken with a conventional X ray dental machine; in a sample of 67 patients, 35 males between 10 and 18 years of age and 32 females between 8 and 16 years. To the patients they carry out them lateral teleradiographies of skull and an X-ray of the area of the middle phalanx of the third finger, where they determine the stages of maturation of the cervical vertebras of the patients in previous stages to the peak puberal, patient that were in the peak of growth puberal and patient in those that it had already happened the peak of growth puberal and the stages of the middle phalanx of the third finger are classified in 3 stages: patient in the previous period to reach the peak pubertal of growth, patient that are in the period of growth pubertal and those patients that the period of growth pubertal had passed. These authors find agreement among the results obtained in the analysis of the cervical vertebras and of the middle phalanx of the third finger and they conclude that the analysis of the maturation of the middle phalanx of the third finger, is an alternative method that can be

Ozer et al. (Ozer et al., 2006) carry out a study in 150 masculine patients, with ages understood among 9 and 19 years that were in orthodontist treatment, with the purpose of determining the correlation between the index of maturation of the cervical vertebras and the stages of maturation of the middle phalanx of the third finger, for that which they carry out lateral teleradiography of skull and X-rays of the middle phalanx of the third finger of the left hand, finding high correlation coefficients between the stages of vertebral maturation and those of the phalanges. They conclude that the middle phalanx of the third

From the clinical point of view in the planning of an orthodontist treatment, we should consider if the patient has begun the spurt of pubertal growth, if this is happening in that moment or if it has concluded (Tedaldi, 2007). With the analysis of the stages of maturation of the middle phalanx of the third finger, visualized in an X-ray of 41 x 31 mm., is possible to determine: if the patient has not reached the spurt of pubertal growth (Stage A), if it is next or this event already began (B), if it is in its maximum peak (C) or if it is in the descending

Due to the high correlation coefficient found in this sample, between the stages of maturation of the middle phalanx of the third finger and the bone age in both sexes, as well as to the high concordance found in this study, among the evaluation of the maturation through the left hand and the analysis of the middle phalanx of the third finger, which was perfect in the feminine sex, and considering the current tendency in Orthodontics of reducing the number of radiations, we propose inside the diagnosis for the evaluation of the potential growth of the patients, the realization of an X-ray of 41 x 31 mm. of the middle

phalanx of the third finger of the left hand (Fig. 3), with the following requirements:

used to determine the skeletal maturation of the children in growth.

finger can be used in the evaluation of the skeletal maturation of the patients.

curve of growth pubertal (D and E) (Toledo Mayarí & Otaño Lugo, 2010).

The evaluation of the potential of growth that the patients of Orthodontics present can be made by means of the realization of radiography of the middle phalanx of the third finger of the left hand.

In the three certain methods, it was found that the females mature before the males of their same age.

It existed a high correlation and concordance among the studied methods of determination of the potential growth.

The substitution of the radiography of the left hand, for the radiography of the middle phalanx of the third finger, allows the realization of that in the own service of Dentistry, with the benefits that it reports as for the patient's better attention.

The results of this study prove the hypothesis formulated and constituted part of the Thesis in option to PhD degree in Dentistry of the author.

#### **7. Acknowledgment**

This research project would not have been possible without the support of many people. The author wishes to express her gratitude to her mother Dr. Zoila Gúdula Mayarí Cano, who introduced her into Dentistry, her tutor, Prof. PhD. Rigoberto Otaño Lugo of blessed memory who was abundantly helpful and offered invaluable assistance, support and guidance. Deepest gratitude also goes to all the members of the investigation team, without whose knowledge and assistance this study would not have been successful.

#### **8. References**


It existed a high correlation and concordance among the studied methods of determination

The substitution of the radiography of the left hand, for the radiography of the middle phalanx of the third finger, allows the realization of that in the own service of Dentistry,

The results of this study prove the hypothesis formulated and constituted part of the Thesis

This research project would not have been possible without the support of many people. The author wishes to express her gratitude to her mother Dr. Zoila Gúdula Mayarí Cano, who introduced her into Dentistry, her tutor, Prof. PhD. Rigoberto Otaño Lugo of blessed memory who was abundantly helpful and offered invaluable assistance, support and guidance. Deepest gratitude also goes to all the members of the investigation team, without

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## **Three-Dimensional Imaging and Software Advances in Orthodontics**

Ahmed Ghoneima1,2, Eman Allam1, Katherine Kula1 and L. Jack Windsor1 *1Indiana University School of Dentistry, Indianapolis, 2Faculty of Dental Medicine, Al-Azhar University, Cairo 1USA 2Egypt* 

#### **1. Introduction**

The technological advances and innovations of imaging systems for orthodontic practice require a continuous update of their applications and assessments of their strength and weakness, as well as guidelines for utilization. Orthodontists are challenged by the increasing number and complexity of these systems and softwares. Accurate diagnostic imaging is an essential requirement for the optimal diagnosis and treatment planning of orthodontic patients. In addition, it is a critical tool that allows the clinician to monitor and document the treatment progress and outcome. The purpose of this chapter is to update orthodontists about the current options and applications of the latest imaging techniques in orthodontic practice and to review the existing software advances.

#### **2. Cone beam technology in orthodontics**

The cone-beam computed tomography (CBCT) scanners were introduced in the late 1990s. Shortly after, the US Food and Drug Administration (FDA) approved the first CBCT unit in 2001. Since then, there has been an enormous interest in this new technology for its clinical and research applications. The CBCT is an imaging acquisition technique that utilizes a volumetric scanning machine. This technology is based on a cone-shaped X-ray beam directed at a flat two-dimensional (2D) detector. As both rotate around the patient's head, a series of 2D images are generated. The software then reconstructs the images into threedimensional (3D) data set using a specialized algorithm (De Vos et al., 2009; Molen, 2011).

Currently, there are more than 43 CBCT systems from 20 different companies available commercially. The most commonly used of these CBCT imaging aquistion systems are the 3D Accuitomo (J. Morita, Kyoto, Japan), CB MercuRay (Hitachi Medical Corporation, Osaka, Japan), iCAT (Imaging Sciences International, Hatfield, PA), Galileos (Sirona Dental Systems LLC, Charlotte, NC), New-Tom 3G (QR srl, Verona, Italy), Scanora 3D (SOREDEX, Milwaukee, WI), and Kodak 9500 (Kodak Dental Systems, Rochester, NY). There are big variations in the quality and characteristics of the images or the reconstructed volumes and the radiation doses between most of these CBCT systems. Machines with reduced radiation doses and less powerful tubes are often associated with poor image quality, low contrast resolution and increased noise. The exposure parameters, the source-detector distance, the field of view (FOV), the data reconstruction algorithm, and the software used are among the major factors responsible for those variations. The currently available CBCT units utilize radiation doses ranging from 87 to 206 μSv for a full craniofacial scan. These radiation doses are slightly higher than the conventional radiographic techniques such as the lateral cephalograms or the panoramic radiographs and markedly lower than that of multi-slice CT. The scan time varies between 10 to 75 seconds, depending on the FOV and the CBCT unit used (Molen, 2011; Kapila et al., 2011).

Craniofacial imaging is a crucial component of an orthodontic patient's record. The gold standard for orthodontic records is the attempt to achieve an accurate replication of the real anatomical structures or the "anatomic truth". Although the use of the traditional imaging views in orthodontics has been adequate, the achievement of the ideal imaging goal of replicating the anatomic truth has been limited by the available technology such as the 2D frontal and lateral cephalograms, panoramic radiographs, and intraoral/extraoral photographs. Recently, more emphasis has been placed on the CBCT technology, the 3D images, and virtual models. The main advantage for the use of CBCT is that the clinician can get more accurate data from one scan than from the many 2D radiographs traditionally used with less radiation exposure (Mah & Hatcher, 2005) (Figure 1).

The 3D CBCT data can greatly expand the orthodontist's diagnostic capabilities. It offers a comprehensive evaluation of the dentition and is very useful for identifying abnormalities such as missing teeth, supernumerary teeth, eruption disturbances, teeth malpositions, and/or root irregularities that could delay or prevent tooth movement. CBCT can be considered the technique of choice for examining and localizing impacted teeth. The exact position of impacted tooth and its relations to the adjacent roots or important anatomical structures such as the maxillary sinus or the mandibular canal when planning surgical exposure and subsequently orthodontic management can be precisely assessed by 3D CBCT (Mah et al., 2011)(Figures 2 and 3).

Using CBCT scans, alveolar bone can be assessed from all aspects not only on the mesial and distal surfaces of the tooth. This allows for the assessment of the width of available bone for buccolingual movement of teeth during orthodontic management especially in cases requiring arch expansion or labial movement of incisors. Fenestrations, dehiscence, and/or external apical root resorption can be precisely visualized on the 3D images. Evaluation of alveolar bone volume, which is especially important in periodontally compromised adult orthodontic patients, is one of the beneficial uses of CBCT in orthodontics. The width of alveolar ridges for placement of implants is another variable that can be investigated (Halazonetis, 2005; Valiathan et al., 2008).

Preoperative implant site assessment is probably one of the most useful applications of CBCT in orthodontics. In the orthodontic field, osseo-integrated implants are either used for anchorage or as a prosthetic replacement of missing teeth. The accurate determination of root angulations and the available space are essential for successful placement of the implant. CBCT can be used to accurately assess the space availability and root angulation, as well as the 3D quantification of the alveolar bone at the implant site (Mah & Hatcher, 2005) (Figure 4).

resolution and increased noise. The exposure parameters, the source-detector distance, the field of view (FOV), the data reconstruction algorithm, and the software used are among the major factors responsible for those variations. The currently available CBCT units utilize radiation doses ranging from 87 to 206 μSv for a full craniofacial scan. These radiation doses are slightly higher than the conventional radiographic techniques such as the lateral cephalograms or the panoramic radiographs and markedly lower than that of multi-slice CT. The scan time varies between 10 to 75 seconds, depending on the FOV and the CBCT

Craniofacial imaging is a crucial component of an orthodontic patient's record. The gold standard for orthodontic records is the attempt to achieve an accurate replication of the real anatomical structures or the "anatomic truth". Although the use of the traditional imaging views in orthodontics has been adequate, the achievement of the ideal imaging goal of replicating the anatomic truth has been limited by the available technology such as the 2D frontal and lateral cephalograms, panoramic radiographs, and intraoral/extraoral photographs. Recently, more emphasis has been placed on the CBCT technology, the 3D images, and virtual models. The main advantage for the use of CBCT is that the clinician can get more accurate data from one scan than from the many 2D radiographs traditionally used

The 3D CBCT data can greatly expand the orthodontist's diagnostic capabilities. It offers a comprehensive evaluation of the dentition and is very useful for identifying abnormalities such as missing teeth, supernumerary teeth, eruption disturbances, teeth malpositions, and/or root irregularities that could delay or prevent tooth movement. CBCT can be considered the technique of choice for examining and localizing impacted teeth. The exact position of impacted tooth and its relations to the adjacent roots or important anatomical structures such as the maxillary sinus or the mandibular canal when planning surgical exposure and subsequently orthodontic management can be precisely assessed by 3D CBCT

Using CBCT scans, alveolar bone can be assessed from all aspects not only on the mesial and distal surfaces of the tooth. This allows for the assessment of the width of available bone for buccolingual movement of teeth during orthodontic management especially in cases requiring arch expansion or labial movement of incisors. Fenestrations, dehiscence, and/or external apical root resorption can be precisely visualized on the 3D images. Evaluation of alveolar bone volume, which is especially important in periodontally compromised adult orthodontic patients, is one of the beneficial uses of CBCT in orthodontics. The width of alveolar ridges for placement of implants is another variable that can be investigated

Preoperative implant site assessment is probably one of the most useful applications of CBCT in orthodontics. In the orthodontic field, osseo-integrated implants are either used for anchorage or as a prosthetic replacement of missing teeth. The accurate determination of root angulations and the available space are essential for successful placement of the implant. CBCT can be used to accurately assess the space availability and root angulation, as well as the 3D quantification of the alveolar bone at the implant site (Mah & Hatcher,

unit used (Molen, 2011; Kapila et al., 2011).

(Mah et al., 2011)(Figures 2 and 3).

(Halazonetis, 2005; Valiathan et al., 2008).

2005) (Figure 4).

with less radiation exposure (Mah & Hatcher, 2005) (Figure 1).

Fig. 1. CBCT data can be easily reconstructed into traditional panoramic, lateral, or posteroanterior cephalometric images, as well as cross section views. In this way, the clinician can get more information from the scan than from multiple 2D radiographs with less radiation exposure. Images created by the Dolphin and InVivoDental softwares from a single CBCT scan.

Fig. 2. A 15 years old female with impacted canine that was initially diagnosed on the panoramic radiograph, but could not be precisely located in relationship to the present teeth. Using the axial and sagittal sections of the CBCT data, the labial location could be confirmed. In addition, the 3D volume allowed for viewing the impacted canine from any angle.

Fig. 3. Cross section view for the impacted canine allowed for the evaluation of its location and relationship to other structures slice by slice in 1 view (slice thickness 0.5 mm).

Fig. 2. A 15 years old female with impacted canine that was initially diagnosed on the panoramic radiograph, but could not be precisely located in relationship to the present teeth. Using the axial and sagittal sections of the CBCT data, the labial location could be confirmed.

In addition, the 3D volume allowed for viewing the impacted canine from any angle.

Fig. 3. Cross section view for the impacted canine allowed for the evaluation of its location and relationship to other structures slice by slice in 1 view (slice thickness 0.5 mm).

Fig. 4. Axial and sagittal sections showing the buccal and lingual bone thickness, as well as the relationship between the implant and the inferior alveolar nerve (labeled in red color). The 3D view is important in the evaluation of space availability.

Orthodontic patients with temporomandibular joint (TMJ) disorders are common. When these disorders occur during development, they may alter the facial growth pattern and may also affect the growth of the ipsilateral part of the mandible with compensations in the maxilla, tooth position, occlusion, and cranial base. CBCT allows the clinicians to assess and quantify these changes associated with TMJ disorders more accurately than the 2D images as these changes occur in the vertical, horizontal, and transverse directions. CBCT is especially indicated when more information about the morphology and internal structure of the osseous components of the TMJ is required. Studies have shown that CBCT images provide higher reliability and accuracy than CT and panoramic radiographs in the detection of condylar cortical erosion. CBCT images also allow for the visualization of the TMJs from different views and efficient evaluation of its relationship to the dentition and occlusion (Huang, et al., 2005; Hilgers et al., 2005; Honey et al., 2007) (Figure 5).

Fig. 5. 3D CBCT volume allows for better visualization and provides more details about the morphology and position of the TMJ and the condyles from different views. In addition, the TMJ cross-section view permits complete and thorough examination of the joint through a group of cross section slices.

Digital study models have been introduced as the digital alternative to the traditional stone cast record. A gradual transition from the plaster models decade to the digital models is expected to occur in the near future. The rapid growth and acceptance of these digital models among the orthodontists has been driven by many factors. They are easier and faster to obtain, to store, transfer, and retrieve. Patients benefit from shorter appointment time when impressions are not needed, and the clinicians benefit from the superior diagnosis and treatment simulation provided by better presentation of the dentition and manipulation of the images (Enciso et al., 2003).

Fig. 5. 3D CBCT volume allows for better visualization and provides more details about the morphology and position of the TMJ and the condyles from different views. In addition, the TMJ cross-section view permits complete and thorough examination of the joint through a

Digital study models have been introduced as the digital alternative to the traditional stone cast record. A gradual transition from the plaster models decade to the digital models is expected to occur in the near future. The rapid growth and acceptance of these digital models among the orthodontists has been driven by many factors. They are easier and faster to obtain, to store, transfer, and retrieve. Patients benefit from shorter appointment time when impressions are not needed, and the clinicians benefit from the superior diagnosis and treatment simulation provided by better presentation of the dentition and manipulation of

group of cross section slices.

the images (Enciso et al., 2003).

The digital models allow the clinician to obtain additional diagnostic information that are not available with the use of the plaster models such as root shape, position, and angulations. The relationship of the roots to anatomic structures such as the mandibular nerve, as well as quantitative bone density information, can also be evaluated. Crown to root ratios can be estimated and other different dental measurements can be performed easily. Several studies have proved that the digital models created from CBCT scans or obtained from laser scanning of a dental impression or study model are as accurate and as reliable as plasters models (Dalstra & Melsen, 2009; Hernandez-Soler et al., 2011). Perhaps a major advantage of the digital models is the virtual setup capability with complete 3D anatomy by including the roots and the alveolar bone. The virtual setup provides superior case presentation, treatment simulation, aesthetic predictions, and results visualization. It also allows for including the torque and labiolingual inclination calculations in the dental setup (Hernandez-Soler et al., 2011) (Figures 6 and 7).

Fig. 6. Computer-generated models reconstructed from the digital imaging and communications in medicine (DICOM) data using the InVivoDental software showing not only the crowns of the teeth but also the roots.

Fig. 7. Dual volume superimposition: the digital model superimposed on a 3D skull volume and a 3D facial photograph provides an excellent tool for treatment simulation and for the evaluation of the anatomical relationships between the teeth, the skeletal, and the soft tissues.

#### **3. Cone beam computed tomography and airway analysis**

Airway disorders are a common cause of malocclusions and might result in the classical appearance of adenoid facies. The results of a retrospective review of 500 orthodontic patients showed that 18.2 percent of the patients had airway-related problems. Variations in airway morphology and dimensions are commonly related to hereditary or functional disorders. Despite the cause or the effect, any airway problem has to be properly diagnosed and treated as soon as it is identified. Methods that are traditionally used to assess the airway include cephalometry, rhinoendoscopy, and tomography (Subtenley & Baker, 1965; Fujiki & Rossato, 1999; Filho et al., 2001; Abramson et al., 2010).

Mandibular advancement device, tongue retraining device, and a continous positive airflow pressure appliance are the most common orthodontic therapeutic options for patients with breathing disorders. The assessment of the patient's airway plays a primary role in planning the management strategy, especially in patients suffering from mouth breathing, adenoid hypertrophy, or sleep apnea. The 2D lateral cephalograms offer limited information due to the difficulty in identifying the soft tissue contour in the third dimension thus restricting evaluation of areas and volumes. Currently, there appears to be no better way to assess the airway than by using CBCT imaging (Halazonetis, 2005; Aboudara et al., 2009).

3D CBCT images offer accurate representation of the airway. The CBCT data with the use of different software systems allows better visualization, volumetric measurements, and patency assessment of the airway, as well as the precise distinction between the soft tissues and the airway space. Several studies questioned the reliability of the 3D methods and indicated high reliability and accuracy of area and volume measurements using this technique. Clinicians can more easily perform the volumetric measurements and also calculate the cross-sectional areas of the airway in 3 planes of space: coronal, sagittal, and axial. In addition, the option provided by some softwares for detecting and measuring the most constricted area in the airway provides essential diagnostic clinical information especially in obstructive sleep apnea patients (Ogawa et al., 2007; Aboudara et al., 2009; Abramson et al., 2010) (Figures 8 and 9).

#### **4. 3D cephalometry**

184 Orthodontics – Basic Aspects and Clinical Considerations

Fig. 7. Dual volume superimposition: the digital model superimposed on a 3D skull volume and a 3D facial photograph provides an excellent tool for treatment simulation and for the evaluation of the anatomical relationships between the teeth, the skeletal, and the soft

Airway disorders are a common cause of malocclusions and might result in the classical appearance of adenoid facies. The results of a retrospective review of 500 orthodontic patients showed that 18.2 percent of the patients had airway-related problems. Variations in airway morphology and dimensions are commonly related to hereditary or functional disorders. Despite the cause or the effect, any airway problem has to be properly diagnosed and treated as soon as it is identified. Methods that are traditionally used to assess the

**3. Cone beam computed tomography and airway analysis** 

tissues.

Cephalometric analysis in orthodontics is an important diagnostic tool for the assessment of craniofacial morphology. The lateral cephalograms enable orthodontists to determine the size and shape of the jaws, their position in sagittal and vertical relation to the anterior base of the skull, and their position in relation to each other. An analytical method is used to identify and analyze the necessary parameters. It involves determining hard tissue and soft tissue landmarks, and making angular and linear measurements. The information provided by the lateral cephalogram about the vertical and sagittal structure of the facial skull cannot be obtained by any other diagnostic measure. However, cephalometric measurements on the 2D images suffer from several limitations such as the difficulty in locating some reference points and landmarks, image distortion, differences in magnifications, superimposition of the bilateral craniofacial structures, and measurement errors. Another important drawback of lateral and frontal cephalograms is the lack of information about cross-sectional area and volume (Adams et al., 2004; Lenza et al., 2010).

CBCT provide a 3D method for cephalometric analysis (Figure 10). Compared with the traditional cephalometric radiographs, the CBCT produces images that are anatomically true (real-size 1:1 scale) with accurate volumetric 3D depiction of hard and soft tissues of the skull and lack of superimposition of the anatomical structures. Other advantages of this method over the 2D cephalometric analysis include the reduced radiation exposure (as the 3D visualization software generates a 2D lateral image from the 3D data set) and the high precision of the linear and angular measurements obtained. Reliability studies demonstrated that cephalograms reconstructed from CBCT data have no statistically significant differences in linear and angular measurements relative to traditional cephalograms, whereas measurement error from CBCT images are lower than those from cephalograms (Kumar et al., 2007; Moshiri et al., 2007; Kumar et al., 2008).

Fig. 8. Volumetric measurements of the airway can be done using different softwares each with a different way of performing the calculations. A) using the InVivoDental software (Anatomage Inc, San Jose, CA), the operator first manually trace the airway passage and then the software will calculate it selectively, B) total airway volume can be calculated by filling in the airway space automatically using the Dolphin software (Dolphin Imaging & Management solutions, Chatsworth, CA), and C) using 3dMD software (3dMD LLC, Atlanta, GA), segmentation for the airway is done first and then the selected areas to be measured will be automatically turned up to a multiple axial slices and the software will calculate the height and width of each slice and give the total airway volume.

in linear and angular measurements relative to traditional cephalograms, whereas measurement error from CBCT images are lower than those from cephalograms (Kumar et

Fig. 8. Volumetric measurements of the airway can be done using different softwares each with a different way of performing the calculations. A) using the InVivoDental software (Anatomage Inc, San Jose, CA), the operator first manually trace the airway passage and then the software will calculate it selectively, B) total airway volume can be calculated by filling in the airway space automatically using the Dolphin software (Dolphin Imaging & Management solutions, Chatsworth, CA), and C) using 3dMD software (3dMD LLC, Atlanta, GA), segmentation for the airway is done first and then the selected areas to be measured will be automatically turned up to a multiple axial slices and the software will

calculate the height and width of each slice and give the total airway volume.

al., 2007; Moshiri et al., 2007; Kumar et al., 2008).

Fig. 9. Volume-rendered CBCT images for the airway in either color enhanced form (A, B, and C) or shaded form (D) where the colors or the shadow are used to aid better visualization and assessment of the airway, as well as correlations with the surrounding head and neck structures. Images generated using the Dolphin software (A), 3dMD (B and D), and InVivoDental (C).

For 3D cephalometry, the anatomical landmarks are identified on 3D surface-rendered volumes or models obtained from CBCT data. In the tracing step, cephalometric planes are defined using either three or four landmarks instead of the two landmarks traditionally used in 2D cephalometry. Beside the elimination of the superimposition of bilateral structures and unequal enlargement artifacts, this also allows for the evaluation of the right and the left sides of the skull independently. The quality and the visibility of the 3D cephalometric landmarks and parameters vary among the different scanners and depend mainly on the scan field of view (FOV) selection, the 3D model segmentation threshold, and image artifacts (Swennen & Schutyser, 2006; Halazonetis, 2005).

Fig. 10. Linear and angular parameters used for 3D cephalometric analysis (InVivoDental software).

#### **5. 3D superimposition**

One of the main advantages of the CBCT is that it allows superimposition of serial images to evaluate the growth and treatment changes. This is an efficient way for showing areas of bone displacement and remodeling, as well as demonstrating the changes in size, shape, and shift in positions of skeletal and soft tissues as a result of either orthodontic or surgical treatments. The 2D cepahalograms have been traditionally used to evaluate these growth or treatment changes based on stable reference structures or anatomical landmarks. The traditional approach to lateral cephalometric superimposition is based on using the most stable anatomical landmarks. For example, the sella turcica for the cranial base registration, the lingual curvature of the palate for the maxillary bony structures, the internal cortical outline of the symphysis, and the mandibular canal for the mandible. However, a major limitation of the 2D representation of a 3D structure with the difficulty in identification of the landmarks is due to the superimposition of multiple structures. In contrast, 3D images provided easier and more accurate anatomical landmark registration (Cevidanes et al., 2005; Lagravere et al., 2006).

The available software tools and options allow optimal alignment of the 3D CBCT datasets at different time points with high precision and accuracy after identification of specific anatomical landmarks and structures. The computed registration is then applied to the segmented structures to measure changes due to orthodontic treatment or surgery. Surface distance calculations are then used for the purpose of accurate quantification of the changes or displacement due to either growth or treatment. Color mapping can show surface area distance differences between two 3D objects or 3D facial photographs (Cevidanes et al., 2005) (Figures 11, 12, and 13).

Fig. 10. Linear and angular parameters used for 3D cephalometric analysis (InVivoDental

One of the main advantages of the CBCT is that it allows superimposition of serial images to evaluate the growth and treatment changes. This is an efficient way for showing areas of bone displacement and remodeling, as well as demonstrating the changes in size, shape, and shift in positions of skeletal and soft tissues as a result of either orthodontic or surgical treatments. The 2D cepahalograms have been traditionally used to evaluate these growth or treatment changes based on stable reference structures or anatomical landmarks. The traditional approach to lateral cephalometric superimposition is based on using the most stable anatomical landmarks. For example, the sella turcica for the cranial base registration, the lingual curvature of the palate for the maxillary bony structures, the internal cortical outline of the symphysis, and the mandibular canal for the mandible. However, a major limitation of the 2D representation of a 3D structure with the difficulty in identification of the landmarks is due to the superimposition of multiple structures. In contrast, 3D images provided easier and more accurate anatomical landmark registration (Cevidanes et al., 2005;

The available software tools and options allow optimal alignment of the 3D CBCT datasets at different time points with high precision and accuracy after identification of specific anatomical landmarks and structures. The computed registration is then applied to the segmented structures to measure changes due to orthodontic treatment or surgery. Surface distance calculations are then used for the purpose of accurate quantification of the changes or displacement due to either growth or treatment. Color mapping can show surface area distance differences between two 3D objects or 3D facial photographs (Cevidanes et al.,

software).

**5. 3D superimposition** 

Lagravere et al., 2006).

2005) (Figures 11, 12, and 13).

Fig. 11. Demonstration of superimposition of the pre- (brown) and post - (blue) treatment skull models of a 12 years old patient treated with rapid maxillary expansion for a constricted maxillary arch. The use of different colors highlights the changes between the two scans.

Fig. 12. Three-dimensional facial photograph of a trumpet player: in the rest position (A), during blowing (B), and color mapping (C) used to demonstrate the differences between the two positions.

Fig. 13. The changes and shift in position of skeletal structures resulting from orthognathic surgery for correction of mandibular prognathism in 23 years old female patient demonstrated by superimposition of serial 3D images of skull volumes using 2 different color codes.

### **6. 3D facial photographs**

With the introduction of a new system and software, the applicability of 3D photographs in daily orthodontic practice became possible. Photographic soft tissue profile analysis, evaluation of the craniofacial growth and development, orthodontic diagnosis, and measurements of the aesthetic facial parameters can all be professionally performed on these photographs.

One of the gold standard diagnostic tools in orthognathic surgery and preoperative orthodontic treatment is the 2-D facial photographs that consequently reveal limitations in describing the 3D structures of a patient's face. CBCT and the newly introduced imaging techniques such as the 3D stereophotogrammetry (3D photographs) allows exploring the human face 3-dimensionally with multiple useful applications that ranges from using the facial scans to measure all the aesthetic facial parameters to orthodontic diagnosis and evaluation of the craniofacial growth and development (Lane & Harrell, 2008).

Stereophotogrammetry is a method of obtaining an image by means of one or more stereo pairs of photographs being taken simultaneously. The 3D photo camera is used to capture the soft tissue surface of the face with correct geometry and texture information. The technique is based on the triangulation and fringe projection method. Image fusion (i.e., registration of a 3D photograph upon a CBCT) results in an accurate and photorealistic digital 3D data set of a patient's face (Maal et al., 2008).

Fig. 13. The changes and shift in position of skeletal structures resulting from orthognathic

With the introduction of a new system and software, the applicability of 3D photographs in daily orthodontic practice became possible. Photographic soft tissue profile analysis, evaluation of the craniofacial growth and development, orthodontic diagnosis, and measurements of the aesthetic facial parameters can all be professionally performed on

One of the gold standard diagnostic tools in orthognathic surgery and preoperative orthodontic treatment is the 2-D facial photographs that consequently reveal limitations in describing the 3D structures of a patient's face. CBCT and the newly introduced imaging techniques such as the 3D stereophotogrammetry (3D photographs) allows exploring the human face 3-dimensionally with multiple useful applications that ranges from using the facial scans to measure all the aesthetic facial parameters to orthodontic diagnosis and

Stereophotogrammetry is a method of obtaining an image by means of one or more stereo pairs of photographs being taken simultaneously. The 3D photo camera is used to capture the soft tissue surface of the face with correct geometry and texture information. The technique is based on the triangulation and fringe projection method. Image fusion (i.e., registration of a 3D photograph upon a CBCT) results in an accurate and photorealistic

evaluation of the craniofacial growth and development (Lane & Harrell, 2008).

digital 3D data set of a patient's face (Maal et al., 2008).

demonstrated by superimposition of serial 3D images of skull volumes using 2 different

surgery for correction of mandibular prognathism in 23 years old female patient

color codes.

these photographs.

**6. 3D facial photographs** 

The registration of pre- and post-operative 3D photographs has many important applications, which mainly include the evaluation of treatment outcomes in orthognathic surgery or orthodontic treatment. After registration or matching of the 3D photographs, the differences between the pre- and post-photographs can be visualized by a color scale or map. In this way, results of the treatment can be evaluated quantitatively and objectively. Other useful applications of comparing different 3D photographs are the evaluation of pathological lesions or swelling such as abscess or tumors over time, cross-sectional growth changes, and the establishment of databases for normative populations. For clinical use, the registration process of pre- and post-treatment 3D photographs has to be very accurate (Metzger et al., 2007; Maal et al., 2010).

One of the recently introduced software features allow the facial photograph to be morphed onto a digital imaging and communications in medicine (DICOM) dataset where the 3D volume can generate a simulated 3D projection of the face in any frontal, lateral, or userdefined view of the face. By changing the translucency of the image, the correlation between the facial soft tissues to the skeleton can be determined. This has great implications in planning orthognathic surgery, orthodontic treatment, or other craniofacial therapies that could affect the facial appearance (Harrell, 2009; Schendel & Lane, 2009) (Figure 14).

Fig. 14. Facial photographs morphed onto 3D skeletal volume can be used for measurements of the aesthetic facial parameters and soft tissue profile analysis, as well as treatment simulation.

#### **7. Conclusion**

CBCT has become widely available and acceptable by the orthodontic community especially as the radiation exposure and cost decreases. The continuous advancements in the imaging machines, techniques, and softwares have added valuable improvement in its diagnostic capabilities. In addition, the ease of image manipulation and its relevancy to the clinical setting offers orthodontists and clinicians the chance for improved diagnosis. Craniofacial imaging is expected to become totally digital in the near future. The orthodontic community needs to increase their knowledge, and evaluate its clinical relevancy and reliability, as well as consider its other applications.

#### **8. References**


CBCT has become widely available and acceptable by the orthodontic community especially as the radiation exposure and cost decreases. The continuous advancements in the imaging machines, techniques, and softwares have added valuable improvement in its diagnostic capabilities. In addition, the ease of image manipulation and its relevancy to the clinical setting offers orthodontists and clinicians the chance for improved diagnosis. Craniofacial imaging is expected to become totally digital in the near future. The orthodontic community needs to increase their knowledge, and evaluate its clinical relevancy and reliability, as well

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beam computed tomography. Am J Orthod Dentofac Orthop 135:468-479. Abramson, Z., Susarla, S., August, M., Troulis, M. & Kaban, L. (2010). Three-dimensional

Adams, G., Gansky, S., Miller, A., Harell, W. & Hatcher D. (2004). Comparison between

Cevidanes, L., Bailey, L. & Tucker, GR.(2005). Superimpositon of 3D cone-beam CT models of orthognathic surgery patients. Dentomaxillofac Radiol 34:369-375. Cevidanes, L., Oliveira, A., Grauer, D., Styner, M. & Proffit, W. (2011). Clinical application of 3D imaging for assessment of treatment outcomes. Semin Orthod 17:72-80. Dalstra, M. & Melsen, B. (2009). From alginate impressions to virtual digital models. J

De Vos, W., Casselman, J. & Swennen, G. (2009). Cone-beam computerized tomography

Enciso, R., Memon, A. & Fidaleo, D. (2003). The virtual craniofacial patient: 3D jaw

Filho, D., Raveli, D., Raveli, R., De Castro, L. & Gandin, L. (2001). A comparison of

Halazonetis, D. (2005). From 2-dimensional cephalograms to 3-dimensional computed

Harrell, W. (2009). 3D diagnosis and treatment planning in orthodontics. Semin Orthod

Hernandez-Soler, V., Enciso, R. & Cisneros, G. (2011). The virtual patient specific-model and

Hilgers, M., Scarfe, S. & Scheetz, J. (2005). Accuracy of linear temporomandibular joint

measurements with cone beam computed tomography and digital cephalometric

modeling and animation. Stud Health Technol Inform 94:65-71.

tomography scans. Am J Orthod Dentofac Orthop 127: 627–637

radiography. Am J Orthod Dentofacial Orthop 128:803-811.

desenvolvimento craniodentofacial. Ortodontia 32:70-79.

the virtual dental model. Semin Orthod 17:46-48.

(CBCT) imaging of the oral and maxillofacial region: A systemic review of the

nasopharyngeal endoscopy and lateral cephalometric radiography in the diagnosis of nasopharyngeal airway obstruction. Am J Orthod Dentofac Orthop 120:348-352. Fujiki, P. & Rossato, C. (1999). Influencia da hipertrofa adenoideana no crescimento e

sleep apnea. J Oral Maxillofac Surg 68:354-362.

dry skull. Am J Orthod Dentofac Orthop 126:397-409.

literature. Int J Oral Maxillofac Surg 38(6):609-25.

conventional lateral headfilms and three-dimensional reconstruction from cone-

computed tomographic analysis of airway anatomy in patients with obstructive

traditional 2-dimensional cephalometry and a 3-dimensional approach on human

**7. Conclusion** 

**8. References** 

as consider its other applications.

Orthod 36:36-41.

15:35-41.


## **The Use of Mini-Implants (Temporary Anchorage Devices) in Resolving Orthodontic Problems**

P. Salehi, S. Torkan, S.M.M. Roeinpeikar *Orthodontic Research Center, Shiraz University of Medical Sciences, Shiraz Iran* 

#### **1. Introduction**

194 Orthodontics – Basic Aspects and Clinical Considerations

Subtelney, J. & Baker, H. (1956). The significance of adenoid tissue in velopharyngeal

Swennen, G. & Schutyser, F. (2006). Three-dimensional cephalometry: spiral multi-slice vs cone-beam computed tomography. Am J Orthod Dentofac Orthop 130: 410–416 Valiathan, A., Dhar, S. & Verma, N. (2008). 3D CT imaging in orthodontics: Adding a new

dimension to diagnosis and treatment planning. Trends Biomater Artif Organs

function. Plastic and Reconstructive Surgery 17:235-250.

21(2):116-120.

In orthodontic treatment, the final goal is to achieve the desired tooth movement and to reduce the number of unwanted side effects and eventually to improve patient's esthetics.[1] Therefore, different methods for anchorage control has been suggested, such as using the opposing arch, extraoral anchorage, increasing the number of teeth in the anchorage unit or circum-oral musculature.

Nowadays, with the advent of mini-implants, maximum anchorage has become possible and unwanted side effects have been reduced to a minimum. Mini-implants which are also known as Temporary Anchorage Devices (TADs) are small titanium bone screw or stainless steel bone screws which are placed either in buccal alveolar bone or the palatal side. These bone screws can be placed on the paramedian areas of the palate in growing children. [2, 3] The use of TADs can ensure a rigid intra-oral anchorage through which different tooth movements in all three planes of space can be provided. This might as well serve as an alternative to orthognathic surgery, especially in those instances where changes in the vertical dimension are required.[4] They can vary in size form 5-12 mm in length and from 1.2-20 mm in diameter. [5]

Among the pioneers in this field, Linkow was one of the first to use blade implants as an anchorage method for cl II elastics, [6] Later, in 1983, Creekmore and Eklund used vitallium screws placed in the anterior nasal spine region to intrude maxillary incisors as much as 6 mm. [7] it was until later in 1997, that Kanomi described the intrusion of mandibular anterior teeth using mini-implants. [8] Gelgor et al. reported as much as 88% success in molar distalization when the first and second molars were present following immediate loading. [9]

It has been reported that mini-implants can be further divided into two group: 1) those that provide mechanical retention and 2) those that osseointegrate. [10] The process of osseointegration is a histological phenomenon through which the bony tissue is formed around the implant without the presence of fibrous tissue at the interface of implant-bone, [11- 13] however, in mechanical retention, those areas which are in direct contact with the bone are in charge of providing the primary stability; while there might be gaps in other areas between the mini-implant and the bone. [10] Osseointegrated devices need a healing period during which they should not be loaded. Anyhow, it has been reported that immediate loading up to 5 N does not affect the stability of miniscrew or loss of anchorage. [14, 15]

The decision making based on which the site for mini-implant placement is determined depends on the quality and quantity of bone in a particular region as well as interdental root space and the type of malocclusion. [5] The recommended anatomic sites for placement of mini-implant in maxilla include the interdental alveolar process , maxillary tuberosity, palate or anterior nasal spine.[16] As for mandible, the proper anatomic places are symphysis and parasymphysial area, interdental alveolar process and retromolar area. [16]

Correction of vertical problems has become easier with the advent of mini-implants. The envelope of orthodontic tooth movement has well increased and less emphasis needs to be placed upon patient's compliance. Treatment of different patients addressing their orthodontic problems (specially vertical problems) are presented in this chapter.

### **2. Patients and methods**

#### **2.1 Case 1: T.P.**

The patient is a 15 year old male who was suffering from crowding both in the upper and lower arches. In order to alleviate the crowding, the patient had extracted the four first premolars based on an old myth that this will resolve the crowding. The spaces did not obviously close following extraction and the patient was referred to the orthodontist due to deep bite and the presence of spacing both in the upper and lower arches. (Figure 1-a to 1-c and 2-a to 2-f) The patient's chief complaint was the presence of spaces in both the maxillary and mandibular arches.

Clinical examination of patient show a slightly retrusive mandible and a nice posed smile. The intraoral photographs exhibit increased overbite, mild maxillary anterior crowding and a class II canine and molar relationship on both sides.

Fig. 1. Figure 1-a to 1-c, patient T.P, pretreatment facial photographs. The patient exhibits a nice social or posed smile, but a convex profile. An analysis of the E-line and S-line of the patient shows that the lips are retruded and therefore, the teeth cannot be further retracted.

which they should not be loaded. Anyhow, it has been reported that immediate loading up to

The decision making based on which the site for mini-implant placement is determined depends on the quality and quantity of bone in a particular region as well as interdental root space and the type of malocclusion. [5] The recommended anatomic sites for placement of mini-implant in maxilla include the interdental alveolar process , maxillary tuberosity, palate or anterior nasal spine.[16] As for mandible, the proper anatomic places are symphysis and parasymphysial area, interdental alveolar process and retromolar area. [16] Correction of vertical problems has become easier with the advent of mini-implants. The envelope of orthodontic tooth movement has well increased and less emphasis needs to be placed upon patient's compliance. Treatment of different patients addressing their

The patient is a 15 year old male who was suffering from crowding both in the upper and lower arches. In order to alleviate the crowding, the patient had extracted the four first premolars based on an old myth that this will resolve the crowding. The spaces did not obviously close following extraction and the patient was referred to the orthodontist due to deep bite and the presence of spacing both in the upper and lower arches. (Figure 1-a to 1-c and 2-a to 2-f) The patient's chief complaint was the presence of spaces in both the maxillary

Clinical examination of patient show a slightly retrusive mandible and a nice posed smile. The intraoral photographs exhibit increased overbite, mild maxillary anterior crowding and

Fig. 1. Figure 1-a to 1-c, patient T.P, pretreatment facial photographs. The patient exhibits a nice social or posed smile, but a convex profile. An analysis of the E-line and S-line of the patient shows that the lips are retruded and therefore, the teeth cannot be further retracted.

5 N does not affect the stability of miniscrew or loss of anchorage. [14, 15]

orthodontic problems (specially vertical problems) are presented in this chapter.

**2. Patients and methods** 

**2.1 Case 1: T.P.** 

and mandibular arches.

a class II canine and molar relationship on both sides.

Fig. 2. Figs 2-a to 2-f, the patient had already extracted his four first premolars hoping that this would alleviate the mild crowding present. This had only led to a deep bite and four extraction spaces which looked unaesthetic.

Fig. 3. Figs 3-a to 3-c, pretreatment lateral cephalograms, cephalometric tracing and panoramic radiograph.

Correction of deep bite can be achieved through different methods: extrusion of posterior teeth, upper incisors flaring, upper or lower incisors intrusion. Factors such as lower face height and upper incisor display dictate the technique through which deep bite can be addressed.[17]

Intrusion of anterior teeth has always been challenging and more difficult to attain than extrusion. [18] For intrusion to be successful and efficient, light, continuous forces are desired. [17, 19] This method can be successfully carried out in patients with an increased interlabial gap, increased vertical dimension and excessive gingival display.[20]

Case T.P exhibits acceptable posed smile at rest and upon smiling, therefore, intrusion of the upper incisors would not be a wise choice. Extrusion of posterior teeth, even though easier to achieve has a higher tendency for relapse but it tends to rotate the mandible backward and downward and thus aggravate the convex profile.[21] Based on the aforementioned factors, intrusion of lower incisors is the logical treatment approach.

Lower and upper arch were set up with 0.018-in slot standard edgewise braces. In the lower arch, segmented technique was used to intrude anterior teeth. Two mini-implants, 1.6 mm in diameter and 8.0 mm in length were placed between the roots of mandibular lateral incisors and canines for en masse intrusion of lower incisors by chain elastics. In the rest of treatment the lower anterior teeth were tied to the miniscrews in order to prevent them from

x

Fig. 3. Figs 3-a to 3-c, pretreatment lateral cephalograms, cephalometric tracing and

interlabial gap, increased vertical dimension and excessive gingival display.[20]

factors, intrusion of lower incisors is the logical treatment approach.

Correction of deep bite can be achieved through different methods: extrusion of posterior teeth, upper incisors flaring, upper or lower incisors intrusion. Factors such as lower face height and upper incisor display dictate the technique through which deep bite can be

Intrusion of anterior teeth has always been challenging and more difficult to attain than extrusion. [18] For intrusion to be successful and efficient, light, continuous forces are desired. [17, 19] This method can be successfully carried out in patients with an increased

Case T.P exhibits acceptable posed smile at rest and upon smiling, therefore, intrusion of the upper incisors would not be a wise choice. Extrusion of posterior teeth, even though easier to achieve has a higher tendency for relapse but it tends to rotate the mandible backward and downward and thus aggravate the convex profile.[21] Based on the aforementioned

Lower and upper arch were set up with 0.018-in slot standard edgewise braces. In the lower arch, segmented technique was used to intrude anterior teeth. Two mini-implants, 1.6 mm in diameter and 8.0 mm in length were placed between the roots of mandibular lateral incisors and canines for en masse intrusion of lower incisors by chain elastics. In the rest of treatment the lower anterior teeth were tied to the miniscrews in order to prevent them from

x

panoramic radiograph.

addressed.[17]

relapse after their intrusion and to prepare anchorage for upper and lower posterior teeth to protract.

After intrusion the lower arch was replaced by a continuous arch wire. The mini-implants were used in this stage of treatment for upper and lower posterior segment protraction. Lower posterior teeth were protracted one by one. Protraction of upper posterior teeth was done by class III elastics. So, the miniscrews were used as an indirect anchorage to close the spaces in the upper arch. In addition, As the upper anterior teeth were not retracted and the canine relationship was class II it was necessary for the lower anterior teeth to be protracted by increased lower arch wire and use of miniscrews. (Figures 4-a to 4-c)

Fig. 4. Figs 4-a to4-c, progress intraoral photographs, Protrusion of upper and lower anterior teeth along with intrusion of lower incisors was needed to achieve the optimal overbite.

At 12 months, treatment was completed (figure 5-a to 5-h and figures 6-a to 6-c). Fixed retainers extending from premolar to premolar were bonded in maxilla and mandible.

Fig. 5. Figs 5-a to 5-h at 11 months, treatment is completed. Notice the marked improvement in the facial profile and overbite.

Fig. 6. Figs 6-a to 6-c, posttreatment cephalogram and panoramic radiograph.

#### **2.2 Case 2: J.V.**

200 Orthodontics – Basic Aspects and Clinical Considerations

Fig. 5. Figs 5-a to 5-h at 11 months, treatment is completed. Notice the marked improvement

in the facial profile and overbite.

The patient is a 16-year-old girl with a class II canine relationship on both sides and a very deep overbite. Her chief complaint was irregular teeth.

The pretreatment facial photographs show a retrsuive mandible and moderate crowding of the maxillary anterior teeth. The pretreatment intraoral photographs exhibited full class II molar and canine relationship on both sides, severe deep bite along with retroinclination of maxillary central incisors (fig 7-a to 7-I)

Cephalometric analysis showed a class II skeletal relationship due to mandibular deficiency ( SNB angle, 71°), A-point was also retruded (SNA angle, 75°). The FMA was within the normal range (26°). Maxillary incisor to SN plane was 87° which is much smaller than the normal range. IMPA was 94° which is within the normal range. In other words, the maxillary incisors were linguoversion and mandible is slightly retruded.

The ideal treatment was to create a normal overbite and overjet relationship, reduce the anteroposterior skeletal discrepancy and obtain a class I canine and molar relationship.

Fig. 7. Fig 7-a to 7-i, pretreatment facial and intraoral photographs. Notice the retruded mandible and marked retroinclination of maxillary central incisors.

Fig. 7. Fig 7-a to 7-i, pretreatment facial and intraoral photographs. Notice the retruded

mandible and marked retroinclination of maxillary central incisors.

Fig. 8. Figs 8-a to 8-c, pretreatment cephalogram, cephalometric tracing and panoramic radiograph.

The ideal treatment approach would be orthognathic surgery during which maxillary anterior teeth are proclined forward to obtain some overjet and move the mandible forward. However, the patient is past the age of growth modification and is not willing to undertake surgery as well. The treatment alternative would be distalization of maxillary dentition to provide space for leveling and aligning of maxillary incisors. However, distalizing the teeth tends to extrude them which makes the mandible to rotate backward and downward and thus worsen the facial profile. Therefore, it is essential that distalization of maxillary molars be carried out without extrusion.

Missing of mandibular third molars permitted the second upper molars to be extracted. Therefore, Initially maxillary second molars were extracted and it was decided that the maxillary third molars would eventually replace the extracted teeth . Then, a segmented arch technique ( o.o18-in slot) was fabricated in the maxillary arch to prevent protrusion of the maxillary incisors while distalization of maxillary molars was being carried out. Two mini-implants 2mm in diameter and 10 mm in length were placed in paramedian midsagittal raphe. A transpalatal bar (0.38-in) was fabricated which was soldered to the bands cemented on maxillary molars. Anchorage was provided from the mini-implants to distalize the maxillary molars and at the same time prevent extrusion of maxillary molars. (figure 9-a to 9-f)

Fig. 9. Figs 9-a to 9-f, A modified version of transpalatal bar is fabricated in the maxillary arch to help distalize maxillary molars. As you see first upper molars have started to rotate.

Retraction of all posterior maxillary teeth were intended during the course of distalization, maxillary first molars started to rotate(mesial in and distal out) due to the location of miniimplants and the resultant untoward moment on them, therefore two other miniscrews were inserted in the buccal vestibule in the position of extraction of the second upper molars. The position where the miniscrews were to be inserted was critical in this case because if they were inserted too far mesially, distal root of the first molar could be cut off while they were being retracted. On the other hand, if they were inserted too far distally the third molars could not be repositioned mesially to replace the extracted second molars.

While retracting upper posterior teeth lower teeth and upper anterior teeth were not set up since it was not necessary and also the patient was sensitive on her appearance And wanted to reduce the time during which she had to bear braces in the anterior area to a minimum. Therefore, for the major part of her treatment process which included the retraction of upper posterior teeth she was free of braces in the esthetic zone. Once a class I canine and molar relationship was attained, the transpalatal bar was removed to minimize the irritation in the palatal mucosa (figures 10-a to 10-f).

 Fig. 9. Figs 9-a to 9-f, A modified version of transpalatal bar is fabricated in the maxillary arch to help distalize maxillary molars. As you see first upper molars have started to rotate.

could not be repositioned mesially to replace the extracted second molars.

palatal mucosa (figures 10-a to 10-f).

Retraction of all posterior maxillary teeth were intended during the course of distalization, maxillary first molars started to rotate(mesial in and distal out) due to the location of miniimplants and the resultant untoward moment on them, therefore two other miniscrews were inserted in the buccal vestibule in the position of extraction of the second upper molars. The position where the miniscrews were to be inserted was critical in this case because if they were inserted too far mesially, distal root of the first molar could be cut off while they were being retracted. On the other hand, if they were inserted too far distally the third molars

While retracting upper posterior teeth lower teeth and upper anterior teeth were not set up since it was not necessary and also the patient was sensitive on her appearance And wanted to reduce the time during which she had to bear braces in the anterior area to a minimum. Therefore, for the major part of her treatment process which included the retraction of upper posterior teeth she was free of braces in the esthetic zone. Once a class I canine and molar relationship was attained, the transpalatal bar was removed to minimize the irritation in the

Fig. 10. Figs 10-a to 10-f, progress intraoral photographs at 6 months. A class I molar and canine relationship is maintained. Notice the miniscrews in the buccal vestibule. The transpalatal bar is removed to eliminate the irritation of soft tissue.

Upper lateral incisors were small-sized and had thus resulted in anterior Bolton discrepancy. The patient was referred for composite build up of lateral incisors to gain normal tooth size. Total treatment time was 15 months. The mini-implant and the transpalatal bar were well tolerated by the patient. The post treatment intraoral photographs show a class I canine and molar relationship. Overbite is corrected. Facial harmony is very good. The pretreatment and posttreatment superimposition of lateral cephalograms shows no backward or downward rotation of mandible. Fixed canine to canine retainers were bonded in the maxilla and mandible (figures 11-a to 11-I and figures 12-a to 12-c)

Fig. 11. Figs 11-a to 11-I, posttreatment facial and intraoral photographs. Correction of increased overbite and class II molar and canine relationship.

Fig. 12. figs 12-a to 12-c, post treatment cephalogram, superimposition of pretreatment (red) and post treatment (black) cephalometric tracings, and panoramic radiograph.

#### **2.3 Case R.R.**

206 Orthodontics – Basic Aspects and Clinical Considerations

Fig. 11. Figs 11-a to 11-I, posttreatment facial and intraoral photographs. Correction of

increased overbite and class II molar and canine relationship.

The next patient is a 31-year-old female who was once referred to a maxillofacial surgeon with a chief complaint of gummy smile. The surgeon had performed a maxillary impaction and an advancement genioplasty on the patient without presurgical orthodontic treatment. The patient eventually was not satisfied with the results and was therefore, referred to the orthodontist. Her chief complaints were gummy smile and the present spacing.

The pretreatment facial photographs exhibit facial asymmetry along with a cant of maxillary occlusal plane. Clinical examination revealed a deviated midline (2mm). Spacing could be noticed at different areas both in maxillary and mandibular dentition. The four first premolars had already been extracted in earlier years to help alleviate crowding, but no further orthodontic treatment was carried out on the patient to consolidate the arches (figures 13-a to 13-j)

Cephalometric analysis revealed a retrusive mandible (ANB angle 7°) and an increased IMPA angle (94°). The SNA angle was within the normal limits (82º); however, SNB angle was decreased (75º). In other words, patient had a skeletal class II profile accompanied with mandibular dental compensation ( figures 14-a to 14-c). The patient was not willing to undergo another orthognathic surgery to correct the existing problems and since the four first premolars had already been extracted, extracting yet another tooth was out of question.

Fig. 13. Figs 13-a to 13-j pretreatment facial and intraoral photographs, the four first premolars had already been extracted; notice the canted maxillary occlusal plane and excessive gingival display.

Fig. 13. Figs 13-a to 13-j pretreatment facial and intraoral photographs, the four first premolars had already been extracted; notice the canted maxillary occlusal plane and

excessive gingival display.

Fig. 14. figs 14-a to 14-c, pretreatment cephalogram, cephalometric tracing and panoramic radiographs.

The treatment goals were to address the patient's chief complaints, i.e correct the canted occlusal palne and close the spaces. Two mini-implants of 1.4 in diameter and 6.0 mm in length were placed between the roots of maxillary lateral incisors and canines. Initially a continuous 0.016 NiTi arch wire was placed as the initial arch wire. With the progress in the size of the arch wire, after 2 months, a 0.016×0.022-in stainless steel segmented arch wire was placed extending from left to right maxillary lateral incisors. In order to decrease the gummy smile, the patient was asked to wear <sup>3</sup> <sup>16</sup> - in latex elastics from the anterior segment to the mini-implants. Since, the equal use of both mini-implants would not correct the canted occlusal plane, the patient was asked to wear the latex elastic to the left mini-implant two days in a row and to the right mini-implant once every three days (figure 15-a to 15- f)

Consecutive use of latex elastics in the anterior region has the disadvantage of irritating the labial frenum, thus, decreasing the patient cooperation. After 1 month, in lieu of latex elastics, elastomeric chains were used. After intrusion of the upper anterior teeth and correction of its cant, continuous 0.016 SS arch wire was inserted in the upper and lower arches. Midline correction and space closure was carried out in both arches at this stage. Meanwhile, the upper anterior teeth were tied to the miniscrews to prevent their relapse after intrusion.

Fig. 15. Figs 15-a to 15-f, progress facial and intraoral photographs, mini-implants are placed between the roots of lateral incisor and canine to address gummy smile and canted occlusal plane.

After 13 months, the treatment was completed. The patient was very well satisfied with the changes in her appearance. The gummy smile and canted occlusal plane had resolved significantly. Fixed retainers extending from second premolar to second premolar were bonded in the maxilla and mandible (figures 16-a to 16-h). Post treatment cephalometric tracing revealed 6 mm intrusion of maxillary incisors without a significant difference in the inclination of upper incisors (upper incisors to SN angle, pretreatment : 106º, post treatment: 105º) ( figures 17-a to 17-d).

Fig. 15. Figs 15-a to 15-f, progress facial and intraoral photographs, mini-implants are placed between the roots of lateral incisor and canine to address gummy smile and canted occlusal

After 13 months, the treatment was completed. The patient was very well satisfied with the changes in her appearance. The gummy smile and canted occlusal plane had resolved significantly. Fixed retainers extending from second premolar to second premolar were bonded in the maxilla and mandible (figures 16-a to 16-h). Post treatment cephalometric tracing revealed 6 mm intrusion of maxillary incisors without a significant difference in the inclination of upper incisors (upper incisors to SN angle, pretreatment : 106º, post treatment:

plane.

105º) ( figures 17-a to 17-d).

Fig. 16. Figs 16-a to 16-h, post treatment facial and intraoral photographs, notice the correction of the canted occlusal plane and gummy smile.

Fig. 17. Figs 17-a to 17-d. post treatment cephalogram, superimposition of pretreatment (red) and post treatment (black) cephalometric tracings and panoramic radiograph.

#### **2.4 Case R.T.**

This patient was a 31-year-old female with a class I molar and canine relationship. Her chief complaints were protrusion of her teeth and inability to bring her lips together.

Clinical examination revealed bimaxillary dentoalveolar protrusion with excessive gingival display upon rest and lip incompetence. She exhibited slight facial asymmetry with her chin deviated to the left and also a class I molar and canine relationship and spacing distal to both maxillary lateral incisors (figures 18-a to 18-h )

Cephalomettric analysis showed the A-point and B-point to be protruded (SNA angle 89° and SNB angle 85°). The upper incisor angle was increased (126°) and IMPA was also much larger than normal (105°).The interincisal angle was 97°. The ANB angle was 4°. In other words, the patient showed bimaxillary dentoalveolar protrusion (figures 19-a to 19-c).

Fig. 17. Figs 17-a to 17-d. post treatment cephalogram, superimposition of pretreatment (red)

This patient was a 31-year-old female with a class I molar and canine relationship. Her chief

Clinical examination revealed bimaxillary dentoalveolar protrusion with excessive gingival display upon rest and lip incompetence. She exhibited slight facial asymmetry with her chin deviated to the left and also a class I molar and canine relationship and spacing distal to

Cephalomettric analysis showed the A-point and B-point to be protruded (SNA angle 89° and SNB angle 85°). The upper incisor angle was increased (126°) and IMPA was also much larger than normal (105°).The interincisal angle was 97°. The ANB angle was 4°. In other words, the patient showed bimaxillary dentoalveolar protrusion (figures 19-a to 19-c).

and post treatment (black) cephalometric tracings and panoramic radiograph.

complaints were protrusion of her teeth and inability to bring her lips together.

both maxillary lateral incisors (figures 18-a to 18-h )

**2.4 Case R.T.** 

Fig. 18. Figs 18-a to 18-h, Pretreatment facial and intraoral photographs of the patient R.T.

Fig. 19. Figs 19-a to 19-c, pretreatment cephalogram, cephalometric tracing and panoramic radiographic.

The best treatment approach in bimaxillary dentoalveolar protrusion is extraction of four first premolars. However, since the patient is suffering from excessive upper incisor display upon rest, extraction of premolars and retraction of anterior teeth would only exacerbate the gummy smile. In this case, the best treatment approach would probably be orthognathic surgery. The patient, however, was reluctant to undertake any type of surgery due to financial issues. The treatment alternative was to intrude the teeth and reduce the excessive gingival display with the use of mini-implants.

Two mini-implants of 1.6 in diameter and 8.0 in length were placed between the roots of maxillary lateral incisors and canines. 0.018-in slot standard edgewise brackets were bonded on the patients teeth. The four first premolars were extracted. Anchorage preparation was extremely important in this case and therefore, maxillary and mandibular second molars were added to the anchorage unit. Anterior teeth retraction was carried out in two separate stages. Initially, maxillary and mandibular canines were retracted using pull coil spring and then T-loop on 0.016×0.022-in stainless steel was used to retract the incisors during the second phase of anterior teeth retraction. Elastic chain was applied to the upper anterior teeth from miniscrews to intrude them during retraction. 0.016-in and 0.016×0.022-in stainless steel wires were inserted after space closure as ideal arch wires. Interdigitation of the teeth was achieved by a short duration of interarch elastics. [22]

After 17 months, treatment is completed. Even though the bimaxillary dentoalveolar protrusion is resolved, excessive tooth display was also corrected. Fixed retainers were bonded from the left to the right second premolars in both maxilla and mandible (figure 20 a to 20-f). cephalometric tracing revealed significant improvement in the inclination of the

Fig. 19. Figs 19-a to 19-c, pretreatment cephalogram, cephalometric tracing and panoramic

The best treatment approach in bimaxillary dentoalveolar protrusion is extraction of four first premolars. However, since the patient is suffering from excessive upper incisor display upon rest, extraction of premolars and retraction of anterior teeth would only exacerbate the gummy smile. In this case, the best treatment approach would probably be orthognathic surgery. The patient, however, was reluctant to undertake any type of surgery due to financial issues. The treatment alternative was to intrude the teeth and reduce the excessive

Two mini-implants of 1.6 in diameter and 8.0 in length were placed between the roots of maxillary lateral incisors and canines. 0.018-in slot standard edgewise brackets were bonded on the patients teeth. The four first premolars were extracted. Anchorage preparation was extremely important in this case and therefore, maxillary and mandibular second molars were added to the anchorage unit. Anterior teeth retraction was carried out in two separate stages. Initially, maxillary and mandibular canines were retracted using pull coil spring and then T-loop on 0.016×0.022-in stainless steel was used to retract the incisors during the second phase of anterior teeth retraction. Elastic chain was applied to the upper anterior teeth from miniscrews to intrude them during retraction. 0.016-in and 0.016×0.022-in stainless steel wires were inserted after space closure as ideal arch wires. Interdigitation of

After 17 months, treatment is completed. Even though the bimaxillary dentoalveolar protrusion is resolved, excessive tooth display was also corrected. Fixed retainers were bonded from the left to the right second premolars in both maxilla and mandible (figure 20 a to 20-f). cephalometric tracing revealed significant improvement in the inclination of the

radiographic.

gingival display with the use of mini-implants.

the teeth was achieved by a short duration of interarch elastics. [22]

maxillary and mandibular incisors ( upper incisors to SN angle; pretreatment: 126º and post treatment: 91º, IMPA; pretreatment: 105º and post treatment 94º, Figures 21-a to 21-e).

Fig. 20. Figs 20-a to 20-f, post treatment facial and intraoral photographs, notice the marked improvement in the patient's profile. Lip incompetence is resolved with no increase in upper incisor display upon rest or posed smile.

Fig. 21. Figs 21-a to 21-e, post treatment cephalogram, superimposition of pretreatment (red) and post treatment cephalometric tracings and panoramic radiograph. Notice the miniscrews in the upper arch that are not explanted yet.

#### **3. Conclusion**

The introduction of mini-implants has improved the practice of orthodontics. Treatment approaches have become available that can be an alternative to orthognathic surgery and provide acceptable results. Duration of treatment becomes shorter significantly and simpler. The envelope of tooth movement has increased to an extent that more versatile movements in three planes of space can be carried out with more success.

#### **4. References**

216 Orthodontics – Basic Aspects and Clinical Considerations

Fig. 21. Figs 21-a to 21-e, post treatment cephalogram, superimposition of pretreatment (red)

The introduction of mini-implants has improved the practice of orthodontics. Treatment approaches have become available that can be an alternative to orthognathic surgery and

and post treatment cephalometric tracings and panoramic radiograph. Notice the

miniscrews in the upper arch that are not explanted yet.

**3. Conclusion** 


## **Management of Dental Impaction**

Farid Bourzgui, Mourad Sebbar, Zouhair Abidine and Zakaria Bentahar *Faculty of Dentistry, University of Hassan II Ain Chok Morocco*

#### **1. Introduction**

218 Orthodontics – Basic Aspects and Clinical Considerations

[21] Levin, R.I., *Deep bite treatment in relation to mandibular growth rotation.* Eur J Orthod, 1991.

[22] Burstone, C.J., *The segmented arch approach to space closure.* Am J Orthod, 1982. 82(5): p.

13(2): p. 86-94.

361-78.

Practitioners are frequently faced with tooth eruption anomalies during the gradual emergence of complete adult dentition, and notably disorders related to tooth impaction (Hurme et al. 1949). This process, which affects deciduous, permanent and supernumerary teeth, is thought, apart from more general causes, to stem from a breakdown in the dynamics of eruption as a result of numerous different factors (Rajic et al. 1996) among whchi we can cite the following:


Agenesia of proximal teeth sometimes gives rise to tooth impaction as a result of loss of the eruption guidance function. In particular, this can affect the upper lateral incisors. And, lastly, the poorly-documented phenomenon of ankylosis occurs following the more or less total disappearance of the dental ligament associated with hypercementosis and root resorption which obstruct all physiological or provoked dental development at various stages (Chambas, 1997).

The unerupted or impacted tooth will trigger some major esthetic and/or functional disorders (Le Breton, 1997) depending on which tooth is affected; hence, the need to reposition in the arch, particularly if the impaction is located in the anterior region. With this in mind, and to achieve maximum results, treatment of tooth retention requires collaboration between surgeons and orthodontists. Consequently, the introduction of surgical-orthodontic techniques in our clinical practice has made it easier to manage dental impaction.

This chapter aims to review the current state of knowledge on management of impacted teeth in order to establish a standard protocol and thus codify the treatment of this anomaly.

#### **2. Definition**

Impacted teeth are classically defined as retained in the jaw beyond their normal date of eruption, surrounded by their coronary bag and without communication with the oral cavity (Favre, 2003).

For Izard (Izard, 1950), there is total retention tooth when the tooth is kept inside the jaw beyond the normal period of its eruption, and no tendency to make its vertical migration.

According to Lacoste (1988): a tooth that remains within bone or submucosa after the normal date of its rash is most often referred to as tooth retention.

According Bordais (1980), a tooth is said to be retained when its evolutionary potential is preserved, while a tooth is said to be included when it its evolutionary potential is lost.

Vigneul (1974) speaks of a tooth completely embedded in the bone and whose coronary bag remains unscathed. He maintains that there are two types of inclusions:


A new classification of Dentistry Teeth (Favre, 2003) integrates data from major international reference classifications. The clinicopathological and pathophysiological classification distinguishes:


#### **3. Epidemiology**

The results of different studies show variable numbers, which are not necessarily contradictory. These discrepancies come from the non-homogeneity of the samples studied. All are unanimous on the fact that the mandibular third molars are most frequently included, followed by their counterparts of maxillary and maxillary canines.

The classic distribution in order of frequency of impaction of permanent teeth can be summarized as follows : lower third molars, upper third molars, upper canines, upper and lower premolars, upper incisors, lower canines, lower incisors, upper and lower first molars and upper and lower second molars [Ericsson, 2000; Quirynen, 2000).

The position of the canines is palatal in 50% of the cases, buccal in 30%of the cases, while it occupies an intermediate position in 20% of the cases (Chambas, 1997). Its frequency is 10 times higher in Caucasians than in Chinese, while the variability in gender shows a slight prevalence in girls.

#### **4. Etiology**

**Primary reasons:** genetics (Vichi, 1996), endocrinologic deficiency, irradiation, palatal clefts, developmental abnormities of germs, supernumerary tooth or tooth fragments , dento-maxillary disharmony (mostly for bucal impactions), late or missing root development, growth disharmony between pre-maxilla and maxilla (concerns maxillary canines only), maxillary brachygnatia, transversal growth deficiency of the anterior maxilla (Mc Connelt, 1996).

**Secondary reasons:** loss of guidance of the lateral incisor (microdontia or tooth absence) (Sasakura, 1984; Ericsson, 1987; Peck, 1996), trauma, premature extraction causing space problems by mesialisation of the anterior sector (second mandibular premolar moving mesialy after extraction of the second deciduous molar), root malformation, pericoronary pathology, ectopic germ position, thick fibrous tissue (Goho, 1987), mesio-distal dimension of the nasal fossae, unerupted canine at the borderline of a palatal cleft (Benoit, 1989).

#### **5. Diagnosis**

220 Orthodontics – Basic Aspects and Clinical Considerations

For Izard (Izard, 1950), there is total retention tooth when the tooth is kept inside the jaw beyond the normal period of its eruption, and no tendency to make its vertical migration.

According to Lacoste (1988): a tooth that remains within bone or submucosa after the

According Bordais (1980), a tooth is said to be retained when its evolutionary potential is preserved, while a tooth is said to be included when it its evolutionary potential is lost.

Vigneul (1974) speaks of a tooth completely embedded in the bone and whose coronary bag


A new classification of Dentistry Teeth (Favre, 2003) integrates data from major international reference classifications. The clinicopathological and pathophysiological

The results of different studies show variable numbers, which are not necessarily contradictory. These discrepancies come from the non-homogeneity of the samples studied. All are unanimous on the fact that the mandibular third molars are most frequently

The classic distribution in order of frequency of impaction of permanent teeth can be summarized as follows : lower third molars, upper third molars, upper canines, upper and lower premolars, upper incisors, lower canines, lower incisors, upper and lower first molars

The position of the canines is palatal in 50% of the cases, buccal in 30%of the cases, while it occupies an intermediate position in 20% of the cases (Chambas, 1997). Its frequency is 10 times higher in Caucasians than in Chinese, while the variability in gender shows a slight

**Primary reasons:** genetics (Vichi, 1996), endocrinologic deficiency, irradiation, palatal clefts, developmental abnormities of germs, supernumerary tooth or tooth fragments , dento-maxillary disharmony (mostly for bucal impactions), late or missing root development, growth disharmony between pre-maxilla and maxilla (concerns maxillary

included, followed by their counterparts of maxillary and maxillary canines.

and upper and lower second molars [Ericsson, 2000; Quirynen, 2000).

normal date of its rash is most often referred to as tooth retention.

remains unscathed. He maintains that there are two types of inclusions:

intraosseous or submucosa.

tooth included in the way of normal eruption;

tooth disimpaction,in its proper sense;

impacted teeth, proper, or retained tooth included;

classification distinguishes:

enclosed tooth retention;

tooth disimpaction at large.

tooth retention;

**3. Epidemiology** 

prevalence in girls.

**4. Etiology** 


The diagnosis of any tooth impaction should be established as early as possible in order to monitor its development and implementation of appropriate therapy in time. In the absence of a maxillary central incisor, the parents consult early for the appearance of the lateral incisor reducing the median space, thus creating an asymmetric and unsightly situation. For canines, as a rule, no functional sign would lead the patient to consult early; the discovery is almost always casual in a screening or radiological examination (presence of a late primary cuspid)**.** 

The diagnosis is based on clinical and radiographic examination. Three positions of impaction are generally possible: buccal, intermediary and palatal (in the maxilla) or lingual (in the mandible). But a very strict attitude in this subject can lead to errors in the appreciation of the precise position. Thus we know that canines whose crowns are positioned buccaly often have their root reaching out palataly behind the root-tips of the neighbouring teeth (Korbendeau, 2005).

#### **5.1 Clinical diagnosis**

#### **5.1.1 Anamnesis**

The interview will allow collecting any family predisposition to inclusions or other hereditary factors such as agenesis. The medical history should identify pathological antecedents and any counter-indications for surgical-orthodontic treatment. The patient's motivation is also an important point to consider, facing a long and difficult treatment.

#### **5.1.2 Clinical examination**

The clinical examination often allows establishing a presumption of inclusion. Two methods are used:

#### **Inspection**


#### **Palpation**


#### **5.1.3 Radiological examination**

In addition to clinical assessment, the protocol begins with a dental panoramic X-ray around which the complementary techniques revolve. Emphasis should be placed on simple conventional sophisticated methods and keep modern imagery to circumstances where simple tests are insufficient.

#### **The dental panoramic X-ray or orthopantomogram (OPT)**

The OPT allows practionners to:


Fig. 1. The panoramic screening to determine the dental formula, which must be performed at the age of 8-9 years.

#### **Periapical radiograph**

222 Orthodontics – Basic Aspects and Clinical Considerations



In addition to clinical assessment, the protocol begins with a dental panoramic X-ray around which the complementary techniques revolve. Emphasis should be placed on simple conventional sophisticated methods and keep modern imagery to circumstances where



Fig. 1. The panoramic screening to determine the dental formula, which must be performed

hands is recommended to estimate the position of the teeth changing.

X-ray examination can establish with certainty the diagnosis of inclusion**.** 

**Palpation** 

**5.1.3 Radiological examination** 

simple tests are insufficient.

ectopic;

at the age of 8-9 years.

The OPT allows practionners to:



**The dental panoramic X-ray or orthopantomogram (OPT)** 


relationship, but it cannot locate buccal or palate position. - Identify an obstacle that blocks the development of the tooth; Any x-ray is a two-dimensional representation of structures that are actually three dimensional. Therefore, it is essential to achieve at least two shots as different impacts to be able to determine the position of the canine, bothmesiodistally and vestibulo-buccally. Thus, the technique of "tubeshift" or as the "rule of Clark" is based on achieving two to three shots. The first shot is made as mesial eccentric projection, for the second shot, the central beam is positioned perpendicular to the alveolar process, the effect corresponding to the ideal axis of the canine and the third shot is made as eccentric projection distal. When the dog moves in the same direction as the source of X-rays, it is included in palatal position. It moves in the opposite direction, it is in position buccal (Crisman, 2000).

Fig. 2. a) Periapical radiograph: with an orthocenter incidence. b) Periapical radiograph with a distocentric incidence. These two shots are needed to determine if the crown of the tooth is in position vestibular or buccal compared to others teeth.

#### **Occlusal check-bit**

The occlusal radiograph is very easy to use in young children because of the narrowness of the palate. Three types of effects can be used:


This exploration technique differentiates the position of the buccal or palatine impacted teeth by providing essential data on the transverse plane, the location of the tooth compared to the apex. It is full of orthopantomography (Korbendeau, 2005).

Fig. 3. a) The orthoocclusal incidence reveals the palatal dystopia of 23. It allows visualizing the orientation of the impacted tooth, but it does not show the apical third of the root. The relationship with the roots of the incisors cannot be interpreted. b) The dysocclusal side to 60 ° can view the impacted tooth as a whole, and its relation with the anteroposterior incisor.

#### **Lateral cephalometric radiographs**

Orthodontic part of the record, this examination provides information in the vertical and sagittal - position - direction - height of inclusion. The superimposition of teeth from left and right arch limits the accuracy of the images (Korbendeau, 2005).

Fig. 4. the direction of the crown and the angle of the root are well highlighted in this lateral cephalometric radiograph.

#### **CT or scanner**

224 Orthodontics – Basic Aspects and Clinical Considerations

Fig. 3. a) The orthoocclusal incidence reveals the palatal dystopia of 23. It allows visualizing the orientation of the impacted tooth, but it does not show the apical third of the root. The relationship with the roots of the incisors cannot be interpreted. b) The dysocclusal side to 60 ° can view the impacted tooth as a whole, and its relation with the anteroposterior

Orthodontic part of the record, this examination provides information in the vertical and sagittal - position - direction - height of inclusion. The superimposition of teeth from left and

Fig. 4. the direction of the crown and the angle of the root are well highlighted in this lateral

a b

right arch limits the accuracy of the images (Korbendeau, 2005).

incisor.

**Lateral cephalometric radiographs** 

cephalometric radiograph.

We realize, in the maxillary, a fine axial parallel to the palate bone; documents are provided full-scale, enabling a study and direct measurements on the photographs:


With modern software reconstruction from cuts made in all three planes of space, we will obtain three-dimensional reconstructions. These images will allow to study the position of the teeth and their relationship to adjacent anatomical structures from any angle desired and to perform distance measurements between the various structures (Nabbout, 2004; Treil, 1997).

Fig. 5. a) Native axial b) The panoramic curve reconstruction.

CT allows a precise localization of the germ of the impacted tooth and guide the surgical approach safely. In addition, it allows the examination of the anatomical structures of neighborhood (nasal cavity, adjacent tooth), the ability to view dental resorptions, the location of a potential barrier (supernumerary teeth, follicular cyst)

b

Fig. 6. a) b) 3D reconstruction provides a relief image of the orientation and position of teeth, and their relationship with the roots of permanent teeth. These images are very useful in the choice of operating procedures when clearing of impacted teeth deep.

### **6. Surgical-orthodontic management of dental impaction**

After diagnosis, four types of attitudes are possible, facing impaction or missing eruption of teeth: abstention (mandibular canines close to the alveolar nerve); extraction; etiologic therapy if a deciduous tooth blocks the evolution; surgical exposure.

#### **6.1 Abstention**

226 Orthodontics – Basic Aspects and Clinical Considerations

CT allows a precise localization of the germ of the impacted tooth and guide the surgical approach safely. In addition, it allows the examination of the anatomical structures of neighborhood (nasal cavity, adjacent tooth), the ability to view dental resorptions, the

a

b Fig. 6. a) b) 3D reconstruction provides a relief image of the orientation and position of teeth, and their relationship with the roots of permanent teeth. These images are very useful in the

choice of operating procedures when clearing of impacted teeth deep.

location of a potential barrier (supernumerary teeth, follicular cyst)

The grounds for abstention may come from the patient who refuses orthodontic treatment when the impacted tooth does, by its position, represent no threat to the environment. This decision may also be related to the inability to establish the impacted tooth, because of its position or its ankylosis and the desire to avoid a too avulsion decaying in bone or adjacent teeth. In all cases, regular monitoring will be necessary to intercept any active disease of the teeth left in place.

#### **6.2 Etiological treatment**

The age of the patient is decisive when setting up preventive measures against risks of inclusion. Suspicion of impacted teeth will lead the practitioner to implement early treatment.


#### **6.3 Technologies to promote spontaneous eruption of impacted teeth**

#### **6.3.1 Preventive guidance**

It includes all actions necessary for the removal of barriers, but it also serves to create space for a normal development of tooth retention (Al Hussain, 1988). The goal is to awaken the potential eruption as soon as possible by lifting these barriers to have a spontaneous eruption. The avulsion of permanent or temporary teeth may be indicated to allow eruption of the impacted tooth physiological (Altounian, 1997, Langlade, 1986) but only if three conditions are met: inclusion bit old, apex not closed and canine well oriented.

#### **6.3.2 Conductive alveolectomy**

This technique, also called alveolectomy induction was established by Chatellier in 1957 (Chatellier, 1962). It creates a path of surgical eruption by releasing obstacles bone and removing the fibrous tissue periodontal (pericoronal bag). For the potential of eruption to be maximized, the conductive alveolectomy must be completed before the construction of the apical third and the apex overhangs the desired axis of extrusion (Durival, 1979). This technique has the advantage of enjoying the natural and physiological potential eruption of the tooth, however, the risk of ankylosis and / or bone resorption due to trauma of the periodontal ligament in the bone resection is not insignificant.

#### **6.3.3 Directional osteotomy**

It corrects the position of the tooth without moving its apex. It is indicated when the canine is raised, with an apex close to its normal place. A flap of the lateral incisor to first molar can expose the portal up to two thirds and a root mobilization syndesmotome is performed with a minimal apical displacement and thus a decreased risk of secondary mortification. But the risk of ankylosis still exists and the position of the canine often limits the indication of this process (Baron, 2001).

#### **6.3.4 Autotransplantation**

It is a resettlement in a newly formed alveolar at the level of the physiological eruption site of the extracted tooth. This technique is indicated when surgical-orthodontic treatment is impossible or when the impacted tooth threatens the roots of adjacent teeth. It requires sufficient space in the arch as well as mesiodistal vestibulopalatine and should be reserved for immature teeth. The major risk of this intervention is the process of ankylosis-root resorption resulting in the total resorption of the root variable within 7 to 10 years. To inhibit this process, it is necessary to follow a very strict operating procedure preserving the integrity of the periodontal ligament, and there is a differentiation of a functional periodontal ligament stable over time, putting the root transplanted immune to ankylosis phenomena (Garcia 1990).

#### **6.4 Treatment of selected central incisors**

In the absence of a maxillary central incisor, the parents consult most often after the emergence of the lateral incisor. The reduction of space further underscores the absence of the plant, because the asymmetry created is unattractive. Sometimes an early screening radiographic examination reveals the existence of inclusion**.** 

#### **6.4.1 Extraction of the permanent central incisor**

This decision is based on therapeutic and complementary clinical examinations. The lack of a permanent central incisor is revealed after the fall of the deciduous tooth, a more or less pronounced collapse of the alveolar process in its vestibular part. Surgical-orthodontic treatment usually ensures the building of the thickness and height of the alveolar bone. Avulsion is reserved for cases of ankylosis and cases of laceration of interest to the crown or the top third root (Wong-Lee, 1985).

#### **6.4.2 Implementation surgical-orthodontic**

This is the technique of choice for positioning function of impacted teeth; it offers the best results and longevity of the tooth over time. A space to recreate the arcade is almost always necessary and this often lengthy treatment is possible at any age but requires motivation and impeccable cleanliness on the part of the patient. Several phases of treatment will succeed.

apical third and the apex overhangs the desired axis of extrusion (Durival, 1979). This technique has the advantage of enjoying the natural and physiological potential eruption of the tooth, however, the risk of ankylosis and / or bone resorption due to trauma of the

It corrects the position of the tooth without moving its apex. It is indicated when the canine is raised, with an apex close to its normal place. A flap of the lateral incisor to first molar can expose the portal up to two thirds and a root mobilization syndesmotome is performed with a minimal apical displacement and thus a decreased risk of secondary mortification. But the risk of ankylosis still exists and the position of the canine often limits the indication of this

It is a resettlement in a newly formed alveolar at the level of the physiological eruption site of the extracted tooth. This technique is indicated when surgical-orthodontic treatment is impossible or when the impacted tooth threatens the roots of adjacent teeth. It requires sufficient space in the arch as well as mesiodistal vestibulopalatine and should be reserved for immature teeth. The major risk of this intervention is the process of ankylosis-root resorption resulting in the total resorption of the root variable within 7 to 10 years. To inhibit this process, it is necessary to follow a very strict operating procedure preserving the integrity of the periodontal ligament, and there is a differentiation of a functional periodontal ligament stable over time, putting the root transplanted immune to ankylosis phenomena (Garcia 1990).

In the absence of a maxillary central incisor, the parents consult most often after the emergence of the lateral incisor. The reduction of space further underscores the absence of the plant, because the asymmetry created is unattractive. Sometimes an early screening

This decision is based on therapeutic and complementary clinical examinations. The lack of a permanent central incisor is revealed after the fall of the deciduous tooth, a more or less pronounced collapse of the alveolar process in its vestibular part. Surgical-orthodontic treatment usually ensures the building of the thickness and height of the alveolar bone. Avulsion is reserved for cases of ankylosis and cases of laceration of interest to the crown or

This is the technique of choice for positioning function of impacted teeth; it offers the best results and longevity of the tooth over time. A space to recreate the arcade is almost always necessary and this often lengthy treatment is possible at any age but requires motivation and impeccable cleanliness on the part of the patient. Several phases of treatment will succeed.

periodontal ligament in the bone resection is not insignificant.

**6.3.3 Directional osteotomy** 

process (Baron, 2001).

**6.3.4 Autotransplantation** 

**6.4 Treatment of selected central incisors** 

radiographic examination reveals the existence of inclusion**.** 

**6.4.1 Extraction of the permanent central incisor** 

the top third root (Wong-Lee, 1985).

**6.4.2 Implementation surgical-orthodontic** 

#### **6.4.2.1 Presurgical orthodontic preparation**

It aims to provide an anchor to pull the impacted tooth from its release position and to develop a surgical site on receiving the arch with an excess of up to 2 mm. This action may be obtained either by a removable appliance with resin base plate equipped with an active device (cylinder, spring ...) but it is more often preferred as a fixed multi-attachments with various accessories (coil spring, intermaxillary traction ...). This anchoring is most often offered by the entire arcade, but it can also be provided by implants or mini implants.

#### **6.4.2.2 Surgical phase: Principle of surgical release**

More than two decades ago, the surgeon used to perform a "comprehensive exhibition of the crown" of the tooth retained by making a buttonhole opening through the alveolar mucosa or attached gingiva (Archer, 1996). Other authors (Eiholtz, 1979) prepared a wider path by raising a mucoperiosteal flap to remove the bony wall, and the entire follicle to relate the crown to the anatomical neck. The mucous membrane covering the crown was then removed and the flap sutured in its original position.

#### **Mucoperiosteal flap replaced**

When the inclusion is deep, bonding intraoperatively is often difficult, so a rectangular flap provides extended release, conducive to good hemostasis. This flap is delimited by two vertical incisions, away from the impacted tooth, and a horizontal incision.

The two vertical incisions - discharge - leave the bottom of the vestibule, through the alveolar mucosa and reach the gum interdental papilla. The horizontal incision placed in the gingival sulcus, the lateral incisor, crosses the top of the edentulous ridge and follows the gingival sulcus of the contralateral central incisor to the line of the vertical incision.

This is a flap that provides a comprehensive surgery, with good visibility, and allows access to large vestibular ectopic teeth, the cystic lesions, the odontoma, ect. When the incisions are removed, hemostasis is ensured. The flap returned to its original position and ensures a rapid closure of the wound sealed. The post-operative care is reduced (Korbendeau, 1998).

a b

Fig. 7. a) Preparation of a rectangular mucoperiosteal flap. The horizontal incision is placed at the top of the ridge, so that the pull wire reaches the axis of the arcade. b) The tissue flap is replaced in its original position. (Korbendeau, 1998).

#### **Apically positioned flap**

The apical fragment of translation is to place the gingival tissue on the labial crown of the impacted tooth to achieve a surgical emergence. The flap is delimited by two vertical incisions and a horizontal incision.


Apical displacement of the bottom edge of the flap provides a surgical emergence of the crown. This protocol has the advantage of seeing the crown, of picking a clip, of moving an anchor point in the weeks after surgery, and finally of leading the tooth, from the start of the pull toward eruption. Finally, the migration of the tooth, following emergent surgerical trajectory occurs spontaneously and is usually faster than if the flap is replaced (Korbendeau, 1998).

Fig. 8. The apically positioned flap is defined by three incisions: a, b and c. (Korbendeau, 1998).

#### **6.5 Treatment of retained canines**

#### **6.5.1 Surgical techniques**

Surgical exposure is undertaken only after orthodontic pre-treatment. Orthodontic preparation concerns mostly space management for the final position of the tooth. The extraction of the deciduous canine or of the premolar should only be planned after the impacted tooth has been mobilised without any sign of ankylosis (particularly in adults).

The apical fragment of translation is to place the gingival tissue on the labial crown of the impacted tooth to achieve a surgical emergence. The flap is delimited by two vertical




Apical displacement of the bottom edge of the flap provides a surgical emergence of the crown. This protocol has the advantage of seeing the crown, of picking a clip, of moving an anchor point in the weeks after surgery, and finally of leading the tooth, from the start of the pull toward eruption. Finally, the migration of the tooth, following emergent surgerical trajectory occurs spontaneously and is usually faster than if the flap is replaced

Fig. 8. The apically positioned flap is defined by three incisions: a, b and c. (Korbendeau,

Surgical exposure is undertaken only after orthodontic pre-treatment. Orthodontic preparation concerns mostly space management for the final position of the tooth. The extraction of the deciduous canine or of the premolar should only be planned after the impacted tooth has been mobilised without any sign of ankylosis (particularly in adults).

**Apically positioned flap** 

the central incisor.

(Korbendeau, 1998).

1998).

**6.5 Treatment of retained canines** 

**6.5.1 Surgical techniques** 

positioned on the crown.

tooth.

incisions and a horizontal incision.

The preservation of the deciduous canine is usually not only an important question for the patients' aesthetics, but also for biomechanics and space maintenance. Nevertheless, to permit spontaneous eruption or orthodontic repositioning, disposing of sufficient keratinized tissue, extraction of the deciduous tooth may sometimes be necessary (Monnet-Corti, 2003).

Premolar extraction for space management has to be delayed until the probability of success is evaluated, and the duration of treatment and patient's motivation established (Thomine, 1995). The extraction has to be conducted to maintain the integrity of the osseous structures and particularly the bucal cortical plate, often being lost and thus reducing the buco-palatal dimension of the residual bone.

The access flaps are derived from the papers of Korbendau and Guyomard 1980 and 1998. The following techniques of surgical exposure are described: on the bucal side, gingivectomy, repositioned bucal flap, apically positioned flap and the laterally and apically repositioned flap, and the palatal side, the palatably repositioned flap in its fenestrated or not fenestrated version.

#### **6.5.2 Gingivectomy**

Gingivectomy is indicated when a big amount of keratinised tissue is found at the level of the impacted tooth. Between one third and one half of the tooth can be uncovered with a simple excision, leaving imperatively at least 3 mm of keratinised tissue on the apical side. From a periodontal point of view the application of such an excision is not indicated if only the oral mucosa is present (Archer, 1996).

#### **6.5.3 Repositioned buccal flap**

This flap is indicated when the tooth is positioned centrally to the alveolar crest or very high into the vestibulum (under the nasal spine) (Hunter, 1983; Magnusson 1990). In these very special situations apical and/or lateral translation of the keratinised tissue is impossible. It allows bone exposure and the bonding of the orthodontic device. For Boyd et al. it represents the technique of choice for any type of impaction.

#### **6.5.4 Apically repositioned flap**

This type of flap is the treatment of choice in many situations (Borghetti, 2000). It aims to create or to maintain keratinised tissue around the tooth by displacing the pre-existent keratinised tissue into the apical direction. The technique of the apically positioned flap (APF) is based on a mucosal flap (or partial thickness flap), the preservation of the existing keratinised tissue, its displacement into an apical position and its immobilisation by periostal sutures which remain in place. Access to the impacted tooth is obtained by a full thickness flap.

The dimension of the tissue to be displaced is decided according to the quality and quantity of periodontal tissue of the adjacent teeth (39). The horizontal width of the flap depends on the width of the crown of the impacted tooth (~ 7, 5-8 mm for an impacted maxillary canine) to which 1-2 mm are added if possible.

Fig. 9. The apically positioned flap is defined by three incisions a, b and c.

#### **6.5.5 Laterally and apically positioned flap**

The indications for this flap are the same as for the APF but the position of the tooth is more lateral in relation to the keratinised tissue on the crest or at the level of the adjacent teeth (Kokich, 1993).

The donor site can be the edentulous ridge (the simplest case) or the bucal tissue of the adjacent teeth. If the donor site is above a lateral or a central incisor, at least 2-3 mm of keratinised tissue have to remain over the teeth. At least 3 mm of tissue have to be displaced. Thus the donor site has to present with at least 6 mm of keratinized tissue to make sure that no dehiscence or recessions are created above the donor tooth (Kokich, 1993). The incisions permit to access the crown and to recreate a healthy periodontal environment).

Fig. 10. Schematic drawing of laterally and apically positioned flap (from Borghetti and Monet Corti, 2000).

(a) Incision design 1: horizontal incision; 2-3: vertical incisions connecting to the first incision to remove the alveolar mucosa over the canine; 4: crestal horizontal incision and 5: vertical incision delimiting the distal part of the flap, dissected in partial thickness.

(b) Discontinuons flap sutures

Fig. 9. The apically positioned flap is defined by three incisions a, b and c.

The indications for this flap are the same as for the APF but the position of the tooth is more lateral in relation to the keratinised tissue on the crest or at the level of the adjacent teeth

The donor site can be the edentulous ridge (the simplest case) or the bucal tissue of the adjacent teeth. If the donor site is above a lateral or a central incisor, at least 2-3 mm of keratinised tissue have to remain over the teeth. At least 3 mm of tissue have to be displaced. Thus the donor site has to present with at least 6 mm of keratinized tissue to make sure that no dehiscence or recessions are created above the donor tooth (Kokich, 1993). The incisions permit to access the crown and to recreate a healthy periodontal environment).

Fig. 10. Schematic drawing of laterally and apically positioned flap (from Borghetti and

incision delimiting the distal part of the flap, dissected in partial thickness.

(a) Incision design 1: horizontal incision; 2-3: vertical incisions connecting to the first incision to remove the alveolar mucosa over the canine; 4: crestal horizontal incision and 5: vertical

**6.5.5 Laterally and apically positioned flap** 

(Kokich, 1993).

Monet Corti, 2000).

(b) Discontinuons flap sutures

#### **6.5.6 Palatably repositioned flap**

This technique is recommended for palatal inclusions. Because of the difficulties in determining the precise dimension and position of the tooth, direct access to the impacted tooth by cutting a little window into the soft tissue cannot be recommended.

Eliminating the bone, managing the bleeding and bonding the orthodontic device may present further difficulties. The intra-sulcular incisions are extending from the first premolar to the central incisor when the tooth is not deeply impacted. In cases of deep impaction near the palatal median line, the incisors can reach down to the contra-lateral premolar. No vertical incisions are made.

A full thickness flap is raised. The position of the tooth can mostly be determined by a typical convexity of the cortical bone, allowing the crown to expose. After the flap is replaced, a little window is prepared (using a new blade N° 15). The window has to be big enough to contain the rapid connective tissue proliferation, tending to close the wound (Monnet-Corti, 2003).

Fig. 11. Osteotomie and peri-coronary curettage disengaging the clinical crown.

#### **7. Study conducted at the faculty of dentistry, Casablanca**

The Department of Dentofacial Orthopaedics of the Faculty of Dentistry at Casablanca conducted an internal survey to review the current state of knowledge on management of impacted teeth in order to establish a standard protocol and thus codify the treatment of this anomaly (Bourzgui et al. 2009).

Our sample comprised 30 patients (24 females, 6 males) aged between 9 and 40 years. Mean age was 17 with a standard deviation of 8.141. These patients were all treated for impacted teeth by both the Surgical Dentistry Department and the Dentofacial Orthopaedics Department in Casablanca (Morocco). The clinical files included in the study comprised a clinical examination, X-rays and an iconography.

In our sample, the main reason for consultation was esthetics (54%). The discovery was made for esthetic reasons in 56.7% of the cases, for clinical examination in 16.7% of the cases, for X-ray examination and totally fortuitously in 23.3% of the cases, and delayed eruption unsuspected by the patient, but revealed by the practitioner in 3.3% of the cases.

The clinical examination was followed by X-ray examinations comprising not only a panoramic and slide-view headfilm but also a periapical radiograph and an occlusal checkbite in 36.7% of the cases, a periapical image combined xith a CT scan in 16.7% of the cases and a check-bite combined with a CT scan in 6.7% of the cases.

The number of impacted teeth varied from 1 to 6. Most often, however, only one tooth was involved (56.7%). In 66% of cases, canines were implicated, of which 9% were mandibular, 22% were incisal (all maxillary) and 12% were premolars. The impacted tooth was vestibular in 43.3% of cases, palatal in 33.3%, and in an intermediary position in 20% with 1 case with 2 impacted teeth; one vestibular, the other palatal. Level wise, distribution of dental impaction was divided into two groups: high impaction 63.3% and low impaction 36.7%.

Twenty-four patients (80%) were treated orthodontically prior to surgery. This stage aimed to prepare traction anchorage in 29.2% of cases or to open up space in 70.8%, occasionally with the assistance of extractions (41.2%). It should be noted that in 1 patient out of 30, the impacted tooth erupted spontaneously after 6 months of orthodontic preparation without course to surgery as the orthodontist had direct access to the tooth and was able to blond a bracket to it.

The surgical approach was vestibular in 17 cases, palatal in 9 cases and both vestibular and palatal in 3 cases. A replaced flap was used in 27 cases, a displaced flap in 1 case. In 1 case, a replaced flap was used on one side and a displaced flap on the other. Osteotomy was also performed to free the impacted tooth in 75.9% of cases.

An obstacle was found in 5 cases. Surgical elimination was performed in only 4 cases and the fifth case, involving a cyst, was marsupialized. Bonding was done during surgery in 27 cases and later in 2 cases. In 8 cases, a second procedure was needed following complications occurring during orthodontic traction. Treatment duration ranged from 3 to 24 months, with a mean of 11.4 months.

Twenty-one of 30 impacted teeth were correctly positioned in the arch, representing 70% success rate. Among the teeth which were not positioned, 66.6% were upper canines, 22.2% were upper central incisors and 11.1 were upper first premolars.

#### **8. Discussion**

The diagnosis of tooth impaction is made at different stages in the clinical examination and is then confirmed by radiological documents. In the course of our study, we looked most

Our sample comprised 30 patients (24 females, 6 males) aged between 9 and 40 years. Mean age was 17 with a standard deviation of 8.141. These patients were all treated for impacted teeth by both the Surgical Dentistry Department and the Dentofacial Orthopaedics Department in Casablanca (Morocco). The clinical files included in the study comprised a

In our sample, the main reason for consultation was esthetics (54%). The discovery was made for esthetic reasons in 56.7% of the cases, for clinical examination in 16.7% of the cases, for X-ray examination and totally fortuitously in 23.3% of the cases, and delayed eruption

The clinical examination was followed by X-ray examinations comprising not only a panoramic and slide-view headfilm but also a periapical radiograph and an occlusal checkbite in 36.7% of the cases, a periapical image combined xith a CT scan in 16.7% of the cases

The number of impacted teeth varied from 1 to 6. Most often, however, only one tooth was involved (56.7%). In 66% of cases, canines were implicated, of which 9% were mandibular, 22% were incisal (all maxillary) and 12% were premolars. The impacted tooth was vestibular in 43.3% of cases, palatal in 33.3%, and in an intermediary position in 20% with 1 case with 2 impacted teeth; one vestibular, the other palatal. Level wise, distribution of dental impaction

Twenty-four patients (80%) were treated orthodontically prior to surgery. This stage aimed to prepare traction anchorage in 29.2% of cases or to open up space in 70.8%, occasionally with the assistance of extractions (41.2%). It should be noted that in 1 patient out of 30, the impacted tooth erupted spontaneously after 6 months of orthodontic preparation without course to surgery as the orthodontist had direct access to the tooth and was able to blond a

The surgical approach was vestibular in 17 cases, palatal in 9 cases and both vestibular and palatal in 3 cases. A replaced flap was used in 27 cases, a displaced flap in 1 case. In 1 case, a replaced flap was used on one side and a displaced flap on the other. Osteotomy was also

An obstacle was found in 5 cases. Surgical elimination was performed in only 4 cases and the fifth case, involving a cyst, was marsupialized. Bonding was done during surgery in 27 cases and later in 2 cases. In 8 cases, a second procedure was needed following complications occurring during orthodontic traction. Treatment duration ranged from 3 to

Twenty-one of 30 impacted teeth were correctly positioned in the arch, representing 70% success rate. Among the teeth which were not positioned, 66.6% were upper canines, 22.2%

The diagnosis of tooth impaction is made at different stages in the clinical examination and is then confirmed by radiological documents. In the course of our study, we looked most

unsuspected by the patient, but revealed by the practitioner in 3.3% of the cases.

was divided into two groups: high impaction 63.3% and low impaction 36.7%.

and a check-bite combined with a CT scan in 6.7% of the cases.

performed to free the impacted tooth in 75.9% of cases.

were upper central incisors and 11.1 were upper first premolars.

24 months, with a mean of 11.4 months.

clinical examination, X-rays and an iconography.

bracket to it.

**8. Discussion** 

specifically into the reason for consulting which, in some cases, can lead the orthodontist to suspect the presence of an impacted tooth.

Dental impaction can be associated with various accidents, whether infectious, mechanical, or other, or with clinical silence. In the latter case, the practitioner should look carefully for revelatory clinical signs such as diastemas, swelling, teeth loss, etc. which can confirm any suspicion the patient may have had during the pretreatment history-taking (Roberts-Harry et al. 2004). Apart from the fairly uncommon cases of impaction which are easily detected from symptoms, the orthodontist should also use X-ray in order to localize unerupted teeth. According to the British body which deals with the use of radiographic imagery for orthodontic diagnosis, any tooth which has not yet erupted and which has not been felt on palpation should necessarily be X-rayed (Isaacson and Thom 2001)

A number of potential complications can occur and disrupt treatment leading inevitably to failure. Some of these complications may require a second surgical procedure. This is the case, for instance, when soft tissue covers the site which is deliberately left open and thus prevents clinical access to the impacted tooth (Burden et al. 1999) or when the orthodontic attachment detaches during traction mechanics (Pearson et al.1997).

Other complications can occur in which no second procedure can be of assistance, notably resorption (Blair et al. 1998), necrosis and ankylosis (Roberts-Harry et al. 2004). This last instance presents the worst scenario. Encountered in one of our patients, it was treated by extraction.

Enhanced management of impacted teeth can be achieved in daily practice by implementing the dental impaction charter which we submit in conclusion to our study. The charter comprises three items:


If surgical-orthodontic treatment is scheduled, it is essential to coordinate the appointments with both the orthodontist and the surgeon. The following considerations should be taken into account:


Furthermore, the practitioner should consider the benefit/risk ratio as well. In some instances, it is advisable to refrain from treatment.

### **9. Clinical cases**

#### **Clinical case 1**

Fig. 12. a, b, c, d: Views buccal, right, front and left at the start of treatment. We note the absence of 13 and 23 with persistence of their spaces on the arcade. On palpation, we note the presence of palatal voussoirs.

Fig. 13. The panoramic photograph shows the presence of 13 and 23 which have an inclination mesially and whose images are superimposed with those of the roots of the maxillary incisors.

a b

c d

the presence of palatal voussoirs.

maxillary incisors.

Fig. 12. a, b, c, d: Views buccal, right, front and left at the start of treatment. We note the absence of 13 and 23 with persistence of their spaces on the arcade. On palpation, we note

Fig. 13. The panoramic photograph shows the presence of 13 and 23 which have an inclination mesially and whose images are superimposed with those of the roots of the

**9. Clinical cases** 

**Clinical case 1** 

Fig. 14. The Occlusal check-bit shows the palatal position of 13 and 23.

a b

c

Fig. 15. a, b, c: a palatal flap ranging from 14 to 24 is off. After the release bone, the palatal surfaces of 13 and 23 are exposed. The clip provided with a tie wire is attached during surgery.

Fig. 16. The traction of 13 and 23 is made using elastic. A window gum can be achieved to facilitate the orthodontic traction.

Fig. 17. The panoramic photograph shows the favorable axis of 13 and 23.

#### **Clinical case 2**

238 Orthodontics – Basic Aspects and Clinical Considerations

Fig. 16. The traction of 13 and 23 is made using elastic. A window gum can be achieved to

Fig. 17. The panoramic photograph shows the favorable axis of 13 and 23.

facilitate the orthodontic traction.

a

b

c

Fig. 18. a; b ;c : Views of buccal, right, front and left at the start of treatment. We note the absence of the 23 with persistence of 63 on the arcade.

Fig. 19. The panoramic photograph shows the presence of 23 which is inclined mesially and whose axis is favorable for an attempt to orthodontic traction.

Fig. 20. The Occlusal check-bit shows an intermediate position of 23, the crown appears in buccal position and the root in palatal position.

Fig. 21. Apically positioned flap was performed. The clip was bonded to the buccal surface of 23.

Fig. 19. The panoramic photograph shows the presence of 23 which is inclined mesially and

Fig. 20. The Occlusal check-bit shows an intermediate position of 23, the crown appears in

Fig. 21. Apically positioned flap was performed. The clip was bonded to the buccal surface

whose axis is favorable for an attempt to orthodontic traction.

buccal position and the root in palatal position.

of 23.

a

b

c

Fig. 22. a; b ;c : Views of buccal, right front and left at the end of treatment. We note the establishment of 23 that seems built on both the aesthetic and functional.

#### **Clinical case 3**

Fig. 23. Intraoral labial view of right at the start of treatment. We note the absence of the 13 with persistence of 53 on the arcade.

Fig. 24. The Occlusal check-bit shows palatal position of the 13.

Fig. 25. The panoramic photograph shows the presence of 23 which is inclined mesially and whose axis is favorable for an attempt to orthodontic traction.

Fig. 23. Intraoral labial view of right at the start of treatment. We note the absence of the 13

Fig. 25. The panoramic photograph shows the presence of 23 which is inclined mesially and

**Clinical case 3** 

with persistence of 53 on the arcade.

Fig. 24. The Occlusal check-bit shows palatal position of the 13.

whose axis is favorable for an attempt to orthodontic traction.

a b

c

Fig. 26. a, b, c: a palatal flap is lifted off. The palatal surface of 13 is exposed. The clip provided with a tie wire is attached during surgery.

Fig. 27. a; b: View vestibular intraoral right, and view of occlusal jaw at the end of treatment. We note the establishment of 13.

#### **10. Conclusion**

Dental impaction confronts the practitioner with a serious challenge. Failure of the various approaches can be highly frustrating.

Treatment for dental impaction is a complex procedure on account of the wide range of cases encountered and the difficulty involved in making a precise and, most importantly, an early diagnosis and adequate treatment plan. Nevertheless, the treatment of choice for the placement of the unerupted tooth in the arch will involve close collaboration between orthodontists and surgeons.

The 70% success rate achieved on the 30 cases treated in our study is the result of a close partnership between the two specialties. Nevertheless, this figure can be improved still further by following the threefold strategy described above for the management of impacted teeth.

#### **11. Acknowledgment**

I would like to express my gratitude to my colleague Pr. Samir Diouny for his big help with the translations.

#### **12. References**


Treatment for dental impaction is a complex procedure on account of the wide range of cases encountered and the difficulty involved in making a precise and, most importantly, an early diagnosis and adequate treatment plan. Nevertheless, the treatment of choice for the placement of the unerupted tooth in the arch will involve close collaboration between

The 70% success rate achieved on the 30 cases treated in our study is the result of a close partnership between the two specialties. Nevertheless, this figure can be improved still further by following the threefold strategy described above for the management of impacted

I would like to express my gratitude to my colleague Pr. Samir Diouny for his big help with

Al Hussain I. Contribution à l'étude de la canine maxillaire incluse. [these 3e cycle],

Altounian G. Mise en place de la canine maxillaire en ectopie palatine. Orthod Fr 1997; Vol

Blair GS, Hobson RS, Leggat TG. Posttreatment assessment of surgically exposed and

Bordais P. ET AL. Les dents incluses. Encycl. Med. Chir. Paris, Odontologie ; 22032 G10, 10-

Chatellier J, Chateau M, Kolf J, Landart L. Notes sur le traitement chirurgico-orthodontique

Crismani AG, Freudenthaler JW, Weber, Bantleon RH. Canines supérieures incluses –

Dupont S, Durand B.Approche préventive et orthopédique des canines maxillaires incluses

Durivaux S, Viennet D, Demetz P. Alvéolectomie conductrice de la canine supérieure

dans les cas de brachygraphie maxillaire. J Edge 2001;Vol 43:85-99.

permanente. Rev Odontostomatol (Paris) 1979; Vol 8:91-3.

des dents retenues et incluses. Actual Odontostomatol (Paris) 1962; Vol 59:293-318.

méthodes conventionnelles de diagnostic radiologique et de traitement. Rev Mens

Borghetti A., Monnet-Corti V. Chirurgie Plastique Parodontale. Ed: CdP Paris, 2000. Bourzgui F, Belhaj S, Tazi H, Hamza M, Khazana MM. Int Orthod. 2009 Sep;7(3):257-67 Burden DJ, Mullally BH, Robinson SN. Palatally ectopic canines: closed eruption versus open eruption. Am J Orthod Dentofacial Orthop. 1999;Vol 115:640-4. Chambas C. Désinclusion et mise en place des dents retenues. Encycl Méd Chir (Elsevier

en place des canines en bordure des fentes labio-alvéolaires. J Parodont 1989; Vol

orthodontically aligned impacted maxillary canines. Am J Orthod Dentofacial

Baron P. Désinclusion orthodontico-magnétique des canines. J Edge 2001; Vol 43:59-71. Benoit R., Leduc J.P., Genon P. Considérations orthodontiques et parodontales pour la mise

Archer WH. Oral surgery. 4th ed. Philadelphia: WB Saunders Co, 1996.

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68:291-6.

8:139-154.

1980.

Strasbourg, 1988. 128p.

Orthop. 1998; Vol 113:329-32.

SAS, Paris), Odontologie, 23-492-A-10,1997.

Suisse Odontostomatol 2000,Vol 110:1264-1268.

the translations.

**12. References** 

teeth.


## **Uprighting of the Impacted Second Mandibular Molar with Skeletal Anchorage**

Stefano Sivolella, Michela Roberto, Paolo Bressan, Eriberto Bressan, Serena Cernuschi, Francesca Miotti and Mario Berengo *University of Padua, Departments of Oral Surgery and Orthodontics Italy* 

#### **1. Introduction**

246 Orthodontics – Basic Aspects and Clinical Considerations

Quirynen M, Opheij DG, Andriasens A, Opdebeek HM, Van Steenberghe D. Periodontal

Rajic S, Muretic Z, Percac S. Impacted canine in a prehistoric skull. Angle

Roberts-Harry D, Sandy J. Orthodontics. Part 10: Impacted teeth. Br Dent J. 2004; Vol

Sasakura H., Xoshida T., Murxama S., Hamadak., Makajima T. Root resorption of upper

Thomine F., Korbendau J.M., Martineau C. - Mise en place chirurgico-orthodontique des

Treil J, Casteigt J, Madrid C, Borianne P. Une nouvelle construction céphalométrique

Vichi M., Franchi L. Eruption anomalies of the maxillary permanent cuspids in children

Vigneul J.C. Extraction chirurgicale des canines incluses Act. Odonto-Stomatol. 1974; Vol

Wong-Lee TK, Wong FC. Maintaining an ideal tooth-gingiva relationship when exposing

with cleft lip and or palate. J Clin Pedia Dent 1996; Vol 20:149-53.

and aligning an impacted tooth. Br J Orthod. 1985; Vol 12:189-92.

evaluation. J Periodontol 2000; Vol 71:1708-14.

dents retenues. Réalités Clin 1995;6:351-369.

Orthod. 1996;66:477 -80.

Surg 1984; Vol 13:299-306.

196:319-27; quiz 362.

68:171-81.

105 :53-78

health of orthodontically extruded impacted teeth. Asplit mouth, long-term clinical

permanent incisor caused by impacted canine. An analysis of 23 cases. Int J Oral

tridimensionnelle. Un nouveau paramétrage d'analyse tridimensionnelle : les axes d'inertie. Un nouveau concept de l'équilibre maxillo-facial. Orthod Fr 1997; Vol

> Eruption disorder of the mandibular second permanent molars is quite rare, but it does need to be treated early.

> There are many functional, periodontal, hygienic and prosthetic reasons which justify retrieving a second molar with eruption problems.

> In terms of occlusion, the patient is assured of the proper arch length, with obvious functional and masticatory advantages, and any extrusion of the antagonist is avoided, especially when the eruption of third molars is unpredictable. (McAboy et al., 2003)

> Oral hygiene at home becomes more straightforward and effective, thanks to the elimination of the pseudo-pocket. The incidence of caries is much higher in impacted teeth, and there is often radiographic evidence of severe damage to the crown or root of the first permanent molar. (Shellhert & Oesterle, 1999)

> Adult and elderly patients often present with molars which are over-erupted and mesially inclined. Tipping of the first molar may initiate a vicious cycle of traumatic occlusion and periodontal problems mesial to the tipped tooth.

#### **1.1 Epidemiology and causes**

The permanent teeth most often affected by eruption problems are the mandibular and maxillary third molars, maxillary canines, central incisors and, more rarely, second mandibular premolars. (Aitasalo et al., 1972)

The incidence of eruption disorder involving the second molars is quite rare, ranging in the literature between 0.03-0.04% of all impacted teeth. (Mead, 1930), (Grover & Norton, 1985). The problem is encountered more frequently in the mandible, often only on one side, and with a predilection for the female gender. (Frank, 2000)

Because second-molar impaction is a relatively rare clinical problem, there is only a limited amount of literature regarding case management.

The main cause of second molar eruption anomalies is shortage of space. (Mead, 1930) The space required for the second molar to erupt in the mandible derives from resorptionapposition processes typical of normal growth, which lead to remodeling of the anterior border of the mandibular ramus. During the normal growth and development of the lower jaw, the molar tooth buds distal to the first permanent mandibular molar have a mesial inclination, which is usually self-correcting as the anterior border of the mandibular ramus resorbs. In addition to this, the mesial drift of the first permanent molar creates approximately 2.7 mm of space per side for angular adjustment. (Majourau & Norton, 1995)

Functional impairment of this natural process leads to molar eruption problems, due to inadequate arch length. A further increase in the available space stems from the mesial migration of the first mandibular molar into the leeway space. (Majourau & Norton, 1995) Orthodontic treatment designed to prevent such migration, e.g., using the lingual arch or lip bumper, may increase the risk of eruption anomalies. (Kokich & Mathews, 1993)

Other important iatrogenic factors include an incorrectly tted band cemented on the rst mandibular molar, or of the first maxillary molar previous orthodontic sagittal expansion. (Eckhart, 1998)

Another reason for impaction is sometimes an excessive amount of space, because the eruption of the second molar needs to be guided by the roots of the first molar. (Shapira et al., 1998) This may give rise to eruption problems even though there is too much space between the two teeth, g.e. when orthodontic expansion of the maxillary arch occurs. The molar may also sometimes undergo spontaneous eruption anomalies, due to excessive mesioversion of the tooth germ or the presence of the third molar. Other problems may be due to premature extraction of the first permanent molar, molar ankylosis, odontogenic cysts, or odontomas. (Frank, 2000)

#### **1.2 Surgical options**

Extraction of an impacted mandibular second molar which appears to have no chance of uprighting itself may allow the third molar to erupt into the second molar position. This requires precise manipulation by the oral surgeon, who must carefully consider the unpredictability of these eruption patterns. (Tinerfe & Blakey, 2000)

Surgical methods vary from simply uncovering the tooth to third molar extraction and surgical second molar repositioning, with or without bone grafts in the medullar space. Surgical uprighting and repositioning of the mandibular second molar, with or without extraction of the third molar, is a possible option.

When a molar tooth is severely impacted, surgical uprighting may provide a quick and easy solution, particularly when orthodontic treatment is contraindicated. (Johnson & Quirk, 1987)

Typical orthodontic treatment for these molars may not be an option if patient commitment is minimal, or if the position of the tooth does not provide the proper environment for bonding a bracket.

When the decision has been made to perform surgical uprighting and repositioning second molars, Tinerfe and Blakey (Tinerfe & Blakey, 2000) recommend that certain criteria be considered.

These include ascertainment of root length/form, available space within the dental arch, arc of rotation, occlusion, periodontal status and jaw development. The optimal root length should be one-third to half of the eventual length of the fully formed root, to enhance revascularization after tipping and bodily movement. As adequate space must be available in the arch, third molars may need to be prophylactically removed.

Ideally, the tooth to be uprighted should not be buccally or lingually inclined, since the buccal and lingual cortical plates are needed for primary stabilization once the second molar is surgically uprighted.

The angle of rotation for uprighting the second molar should not exceed 90° because, as Pogrel suggested (1995), uprighting teeth by more than 90° causes them to behave like transplants, thus diminishing the chance of future vitality.

Once the molar has been uprighted, any occlusion should be carefully checked for interferences which may lead to occlusal trauma. The uprighted tooth also should be positioned in a manner which allows healthy soft tissue attachment and ease of access for appropriate hygiene. Careful handling and positioning of the keratinized gingiva during the procedure are critical for the long-term periodontal health of uprighted molars.

It is also important that vertical jaw growth should be nearly complete, to achieve ideal occlusion and prevent tooth submersion during growth. If these criteria are met, surgical second molar uprighting has been shown to be a predictable procedure and a viable option when other types of treatment are not possible. (McAboy et al., 2003)

#### **1.3 Orthodontic treatment**

248 Orthodontics – Basic Aspects and Clinical Considerations

apposition processes typical of normal growth, which lead to remodeling of the anterior border of the mandibular ramus. During the normal growth and development of the lower jaw, the molar tooth buds distal to the first permanent mandibular molar have a mesial inclination, which is usually self-correcting as the anterior border of the mandibular ramus resorbs. In addition to this, the mesial drift of the first permanent molar creates approximately 2.7 mm of space per side for angular adjustment. (Majourau & Norton, 1995) Functional impairment of this natural process leads to molar eruption problems, due to inadequate arch length. A further increase in the available space stems from the mesial migration of the first mandibular molar into the leeway space. (Majourau & Norton, 1995) Orthodontic treatment designed to prevent such migration, e.g., using the lingual arch or lip

Other important iatrogenic factors include an incorrectly tted band cemented on the rst mandibular molar, or of the first maxillary molar previous orthodontic sagittal expansion.

Another reason for impaction is sometimes an excessive amount of space, because the eruption of the second molar needs to be guided by the roots of the first molar. (Shapira et al., 1998) This may give rise to eruption problems even though there is too much space between the two teeth, g.e. when orthodontic expansion of the maxillary arch occurs. The molar may also sometimes undergo spontaneous eruption anomalies, due to excessive mesioversion of the tooth germ or the presence of the third molar. Other problems may be due to premature extraction of the first permanent molar, molar ankylosis, odontogenic

Extraction of an impacted mandibular second molar which appears to have no chance of uprighting itself may allow the third molar to erupt into the second molar position. This requires precise manipulation by the oral surgeon, who must carefully consider the

Surgical methods vary from simply uncovering the tooth to third molar extraction and surgical second molar repositioning, with or without bone grafts in the medullar space. Surgical uprighting and repositioning of the mandibular second molar, with or without

When a molar tooth is severely impacted, surgical uprighting may provide a quick and easy solution, particularly when orthodontic treatment is contraindicated. (Johnson & Quirk, 1987) Typical orthodontic treatment for these molars may not be an option if patient commitment is minimal, or if the position of the tooth does not provide the proper environment for

When the decision has been made to perform surgical uprighting and repositioning second molars, Tinerfe and Blakey (Tinerfe & Blakey, 2000) recommend that certain criteria be

These include ascertainment of root length/form, available space within the dental arch, arc of rotation, occlusion, periodontal status and jaw development. The optimal root length

unpredictability of these eruption patterns. (Tinerfe & Blakey, 2000)

extraction of the third molar, is a possible option.

bumper, may increase the risk of eruption anomalies. (Kokich & Mathews, 1993)

(Eckhart, 1998)

cysts, or odontomas. (Frank, 2000)

**1.2 Surgical options** 

bonding a bracket.

considered.

The best timing for treating impacted second molars is between 11 and 14 years of age, when the root is still not fully developed. The type of treatment depends on the slant of the tooth and the amount of orthodontic movement required.

Minor malpositioning can be corrected by placing an elastic separator between the two teeth. (Moro et al., 2002)

More severe malpositioning demands the use of surgical methods or orthodontically assisted eruptions, with or without surgical disinclusion of the tooth.

Mesially inclined molars should be differentiated not only by degree of impaction, but also by the types of tooth movement required for correction in all three spatial planes. For any particular tooth movement, it is very difficult to plan a correct force system with respect to the center of resistance. In the sagittal plane, the appropriate combination of vertical movement and uprighting must be determined. (Melsen et al., 1996)

A good treatment option is orthodontically assisted eruption, with or without surgical uncovering. The general approach is an attachment bonded to the surgically uncovered buccal or distobuccal surface of the second mandibular molar, followed by application of an uprighting force delivered by tip-back cantilever (Melsen et al., 1996), (Sawicka et al., 2007), NiTi-coil spring (Aksoy & Aras 1998), super-elastic NiTi wire (Going & Reyes-Lois, 1999), a variety of uprighting springs (Shapira & Borell 1998), (Park, 1999), (Majourau & Norton 1995), a fixed appliance (Carano et al. 1996), (Miao & Zhong, 2006) or a sectional arch wire (Alessandri Bonetti et al., 1999), (Kogod M & Kogod HS.,1991).

Molar uprighting may be secured by pure rotation obtained by applying a couple force system with a high moment-to-force ratio (so that the center of rotation is very close to the center of resistance). A long cantilever gives a high moment-to-force ratio, which results in a clinical effect very close to that of pure rotation. The magnitude of the moment required to rotate a molar has been suggested to be 800–1500 g/mm. (Romeo & Burstone, 1977)

The cantilever produces effects on the tooth in three planes, mainly in the mesiodistal (distal crown tipping) and vertical directions (molar extrusion). Determining the forces on teeth also requires dening the forces delivered to the cantilever inserted in the molar tube. The activation force is directed to the occlusal plane and is opposed by the apically directed force which the molar tube exerts on the wire. Mesial and distal aspects of the molar tube also exert forces on the wire which oppose the counterclockwise rotation resulting from activation forces. The forces acting on the teeth are of the same magnitude as, but of opposite direction to, those acting on the wire. Thus, the intrusive force is on the anterior segment and the extrusive force on the molar, and the couple distally rotates. (Sawicka et al., 2007)

In traditional orthodontic biomechanics, when the molar is to be extruded, uprighting is often performed with simple tipback mechanics. If significant extrusion is needed, the force delivered to the bracket should be relatively large compared with the moment. If little or no extrusion is desired, the moment should be larger and the cantilever as long as possible. (Melsen et al., 1996)

Melsen et al. believe that, when molar intrusion is required, the biomechanics become more complex. The law of equilibrium states that the moment added to the molar must be smaller than the moment added to the anterior unit. This force system corresponds to what Burstone and Koenig defined as a geometry V, and can be obtained by proper activation of a root spring, as described by Roberts and colleagues. (Roberts et al., 1982)

It is also important to consider the force system generated in the horizontal plane. Although both the root spring and the V bend act parallel to the dental arch, in close proximity to the center of resistance, the cantilevers may have their point of force application on either side of the center of resistance, and thus generate tipping in either the buccal or the lingual direction. (Melsen et al., 1996)

The difficulty of managing these complex biomechanics has led many authors to seek easier alternative solutions, such as appliance design specifications.

The distal jet appliance, modified for use in the lower arch (uprighter-jet), is an example of a fixed appliance associated with an open-coil spring for proper lower molar uprighting. (Carano et al., 1996) The appliance design involves soldering an 0.036" tube to the premolar band, parallel to the occlusal plane but below the level of the edentulous ridge, so as not to interfere with the occlusion. The tube is oriented so that a wire with a bayonet bend can be slid into the tube from the distal end. A loop is bent into the distal end of this wire and attached to the molar band with a screw. Thus, wire and molar band are held together but are free to rotate around a common axis.

An adjustable screw-clamp and a 150g nickel titanium open-coil spring is placed over the tube. The two premolars are connected with a soldered lingual wire to form the anchorage unit. As the clamp is moved distally, the coil spring is compressed and a distalizing force is applied. Because the connection of the molar band to the wire is not rigid, the line of action of this force is at the molar crown and the point of force application is at the screw. The molar crown will therefore be tipped distally.

Often, however, these stages of treatment are impossible, due to the severe mesio-inclination angle and the gingival position of the element which does not permit proper bonding. Many techniques have therefore been proposed involving, for example, segmented TMA (Majourau & Norton 1995) to avoid the problem or for pre-positioning the element.

Miao et al. (Miao & Zhong, 2006) proposed using a fixed appliance composed of a minihook and a push-spring (arrow) to move the crown of an impacted molar distally.

The mini-hook is made of 0.014" stainless steel wire and is conventionally bonded to the distal surface of a horizontally impacted molar or the occlusal surface of a mesially impacted molar, so that the hook opens mesially. Surgical exposure is needed only if horizontal impaction is so severe that the molar has not erupted at all. In such a case, the distal surface of the impacted tooth should be exposed just enough to bond the mini-hook.

A stainless steel wire, about 60 mm long, is soldered to the middle of the lingual surface of the mesially adjacent molar band. The wire is bent at the distolingual corner of the band, extended 2-3 mm buccally, and then turned distally, making a double- or triple-bend pushspring. The band with the push-spring is cemented to the mesially adjacent molar. The spring is stretched 4-5 mm distally and attached to the open mesial end of the mini-hook. The push-spring will then exert a distalizing and uprighting force. It should be reactivated monthly until the impacted molar is upright.

All these techniques present complex biomechanics which require careful evaluation to avoid side-effects such as extrusion or loss of anchorage.

Placing placing titanium miniscrews in the retromolar area for molar uprighting has been recommended as the most predictable and easiest method to manage. (Park et al., 2002), (Giancotti et al, 2003, 2004), (Nęcka et al., 2010)

#### **2. Skeletal anchorage**

250 Orthodontics – Basic Aspects and Clinical Considerations

center of resistance). A long cantilever gives a high moment-to-force ratio, which results in a clinical effect very close to that of pure rotation. The magnitude of the moment required to

The cantilever produces effects on the tooth in three planes, mainly in the mesiodistal (distal crown tipping) and vertical directions (molar extrusion). Determining the forces on teeth also requires dening the forces delivered to the cantilever inserted in the molar tube. The activation force is directed to the occlusal plane and is opposed by the apically directed force which the molar tube exerts on the wire. Mesial and distal aspects of the molar tube also exert forces on the wire which oppose the counterclockwise rotation resulting from activation forces. The forces acting on the teeth are of the same magnitude as, but of opposite direction to, those acting on the wire. Thus, the intrusive force is on the anterior segment and the extrusive force on the molar, and the couple distally rotates.

In traditional orthodontic biomechanics, when the molar is to be extruded, uprighting is often performed with simple tipback mechanics. If significant extrusion is needed, the force delivered to the bracket should be relatively large compared with the moment. If little or no extrusion is desired, the moment should be larger and the cantilever as long as possible.

Melsen et al. believe that, when molar intrusion is required, the biomechanics become more complex. The law of equilibrium states that the moment added to the molar must be smaller than the moment added to the anterior unit. This force system corresponds to what Burstone and Koenig defined as a geometry V, and can be obtained by proper activation of a root

It is also important to consider the force system generated in the horizontal plane. Although both the root spring and the V bend act parallel to the dental arch, in close proximity to the center of resistance, the cantilevers may have their point of force application on either side of the center of resistance, and thus generate tipping in either the buccal or the lingual

The difficulty of managing these complex biomechanics has led many authors to seek easier

The distal jet appliance, modified for use in the lower arch (uprighter-jet), is an example of a fixed appliance associated with an open-coil spring for proper lower molar uprighting. (Carano et al., 1996) The appliance design involves soldering an 0.036" tube to the premolar band, parallel to the occlusal plane but below the level of the edentulous ridge, so as not to interfere with the occlusion. The tube is oriented so that a wire with a bayonet bend can be slid into the tube from the distal end. A loop is bent into the distal end of this wire and attached to the molar band with a screw. Thus, wire and molar band are held together but

An adjustable screw-clamp and a 150g nickel titanium open-coil spring is placed over the tube. The two premolars are connected with a soldered lingual wire to form the anchorage unit. As the clamp is moved distally, the coil spring is compressed and a distalizing force is applied. Because the connection of the molar band to the wire is not rigid, the line of action

spring, as described by Roberts and colleagues. (Roberts et al., 1982)

alternative solutions, such as appliance design specifications.

rotate a molar has been suggested to be 800–1500 g/mm. (Romeo & Burstone, 1977)

(Sawicka et al., 2007)

(Melsen et al., 1996)

direction. (Melsen et al., 1996)

are free to rotate around a common axis.

The most common problem of classical distalization techniques is the frequent loss of anchorage and adverse effect on adjacent teeth.

Anchorage is a direct consequence of Newton's Third Law, i.e., "For every action there is an equal and opposite reaction", and is defined as the resistance to unwanted tooth movement. (Daskalogiannakis, 2000)

Orthodontic anchorage can also be defined as the "amount of movement allowed to the reactive unit", where the latter is composed of tooth/teeth acting as anchorage units during movement of the active unit, and the active unit is composed of tooth/teeth undergoing movement. (Cope, 2007)

Orthodontists often have inadequate mechanical systems to control anchorage, which leads to loss of anchorage in the reactive unit and thus incomplete correction of malocclusion. To avoid this kind of side-effect, clinicians often associate acrylic or extraoral appliances which, when combined with the ever-challenging problem of uncooperative patients, are often futile attempts at best. As even a small reactive force can cause undesirable movements, it is important to ensure that anchorages are solidly based. (Pilon et al., 1996)

Absolute or innite anchorage is dened as no movement of the anchorage unit (zero anchorage loss) as a consequence to the reaction forces applied to move teeth. (Daskalogiannakis, 2000)

This kind of anchorage can only be obtained with ankylosed teeth or dental implants as anchors, both of which rely on bone to inhibit undesired movement.

The need to check anchorage during orthodontic treatment has led clinicians to develop many types of Temporary Anchorage Devices (TAD). These may be defined as devices which are temporarily fixed to bone for the purpose of enhancing orthodontic anchorage by supporting the teeth of the reactive unit (indirect anchorage) or by obviating the need for the reactive unit altogether (direct anchorage) and are subsequently removed after use. (Cope, 2007).

The idea of using screws fixed to bone to obtain absolute anchorage goes back to 1945, when Gainsforth and Higley (Gainsforth & Higley, 1945) placed Vitallium screws in the ascending ramus of six dogs to retract their canines. The first clinical use reported in the literature came in 1983, when Creekmore and Eklund (Creekmore & Eklund,1983) used a Vitallium bone screw inserted in the anterior nasal spine to treat a patient with a deep overbite. However, miniscrew implants for orthodontic anchorage were not immediately popular. Thereafter, a number of papers focused on other means of obtaining skeletal anchorage for orthodontic tooth movement, such as dental implants, onplants and palatal implants. (Papadopulos et al., 2009)

In 1997, Kanomi (1997) described a mini-implant specifically made for orthodontic use and, in 1998, Costa et al. (1998) presented a screw with a bracket-like head requiring a simplified procedure: only local anesthesia, placement of a drill-free screw, and immediate loading.

Labanauskaite et al. (2005) suggested the following classication of implants for orthodontic anchorage:

	- conical (cylindrical)
	- miniscrew implants
	- palatal implants
	- prosthodontic implants
	- mini-plate implants
	- disc implants (onplants);
	- bone-integrated
	- not bone-integrated;
	- used only for orthodontic purposes (orthodontic implants)
	- used for prosthodontic and orthodontic purposes (prosthodontic implants).

With the exception of the Orthodontic Mini-Implant, which is made of stainless steel, all other above-mentioned systems are made of medical type IV or type V titanium alloy.

futile attempts at best. As even a small reactive force can cause undesirable movements, it is

Absolute or innite anchorage is dened as no movement of the anchorage unit (zero anchorage loss) as a consequence to the reaction forces applied to move teeth.

This kind of anchorage can only be obtained with ankylosed teeth or dental implants as

The need to check anchorage during orthodontic treatment has led clinicians to develop many types of Temporary Anchorage Devices (TAD). These may be defined as devices which are temporarily fixed to bone for the purpose of enhancing orthodontic anchorage by supporting the teeth of the reactive unit (indirect anchorage) or by obviating the need for the reactive unit

The idea of using screws fixed to bone to obtain absolute anchorage goes back to 1945, when Gainsforth and Higley (Gainsforth & Higley, 1945) placed Vitallium screws in the ascending ramus of six dogs to retract their canines. The first clinical use reported in the literature came in 1983, when Creekmore and Eklund (Creekmore & Eklund,1983) used a Vitallium bone screw inserted in the anterior nasal spine to treat a patient with a deep overbite. However, miniscrew implants for orthodontic anchorage were not immediately popular. Thereafter, a number of papers focused on other means of obtaining skeletal anchorage for orthodontic tooth movement, such as dental implants, onplants and palatal implants.

In 1997, Kanomi (1997) described a mini-implant specifically made for orthodontic use and, in 1998, Costa et al. (1998) presented a screw with a bracket-like head requiring a simplified procedure: only local anesthesia, placement of a drill-free screw, and immediate loading.

Labanauskaite et al. (2005) suggested the following classication of implants for orthodontic



With the exception of the Orthodontic Mini-Implant, which is made of stainless steel, all other above-mentioned systems are made of medical type IV or type V titanium alloy.

altogether (direct anchorage) and are subsequently removed after use. (Cope, 2007).

important to ensure that anchorages are solidly based. (Pilon et al., 1996)

anchors, both of which rely on bone to inhibit undesired movement.

(Daskalogiannakis, 2000)

(Papadopulos et al., 2009)

1. according to shape and size: - conical (cylindrical) - miniscrew implants - palatal implants - prosthodontic implants - mini-plate implants - disc implants (onplants); 2. according to implant bone contact


anchorage:

Miniscrew implants can be used as anchorages for tooth movements which could not otherwise be achieved, as in patients with insufcient teeth for conventional anchorages to be applied, when the forces on the reactive unit would generate adverse side-effects, in patients requiring asymmetrical tooth movements in all spatial planes and, in some cases, as an alternative to orthognathic surgical procedures. (Melsen B. 2005)

Using the retromolar area to position orthodontic implants was proposed by Roberts et al. in 1990. The authors used an experimental titanium bone-integrated implant to obtain absolute anchorage for second and third molar protraction after a first extracted molar replacement.

The retromolar area is particularly suitable for screw insertion, due to the presence of compact cortical bone tissue which immediately provides excellent primary stability (Figures 1 and 2).

The side-effects of positioning screws in this area are the risk of inflammation and hypertrophy of the movable mucosa, which may coverthe screw entirely, resulting in difficult case management and the need for additional gingivectomy. Care must be taken in evaluating the position of the mandibular canal, in order to avoid neurological complications (e.g., damage to the inferior alveolar nerve).

Fig. 1. Example of screw positioning in retromolar area. Lateral view.

Fig. 2. Example of screw positioning in retromolar area. (A) Retromolar area. (B) Screw and device in place. (C) Third molar extraction socket. (D). Impacted second molar. (E) First molar. (F) Oblique external line.

Using implants as a method of skeletal anchorage for second lower molar uprighting was first proposed by Shellhart et al. These Authors placed a bone-integrated implant in an edentulous site, from which the first molar had previously been extracted. (Shellhart et al., 1996)

Park, first proposed the use of orthodontics implants for uprighting of the second molar by placing miniscrews in retromolar area. (Park H.S., 2002) The distalizing force is exerted through the use of elastomeric threads using perhaps rather low forces, about 50-80g. Other authors (Giancotti, 2003, 2004), (Nęcka et al., 2010) propose a very similar method, involving elastomeric chains, with monthly reactivations, or 50g-force closed Ni-Ti coil springs. The average treatment time in all these case reports was 7-9 months.

In an adolescent patient with a developing third molar, however, it is difficult to insert a miniscrew in the retromolar area unless the third molar is extracted. Thick overlying soft tissue and poor accessibility of the insertion site can also hinder miniscrew insertion. In such cases, the miniscrew can be inserted into the buccal alveolar bone on the mesial side to generate a "pushing" force. Lee et al. proposed to position the microscrew in interradicular area between second premolar and first molar and the use of a 0.016" or 0.016"x0.022" stainless steel wire with welded hook and open-coil spring for force delivery. (Lee et al., 2007)

Other Authors (Sohn et al., 2007) proposed a mesial positioning, using the screw as an anchor for the indirect stabilization of the first molar and second premolar. A 0.016''x0.022'' stainless steel wire directly bonded with composite on teeth surface was used to connect dental elements and microscrews.

#### **3. Combined surgical and orthodontic treatment using a distal screw as skeletal anchorage**

This chapter describes a multidisciplinary surgical and orthodontic procedure for the treatment of second lower molar impaction.

#### **3.1 Materials and methods**

254 Orthodontics – Basic Aspects and Clinical Considerations

Fig. 2. Example of screw positioning in retromolar area. (A) Retromolar area. (B) Screw and device in place. (C) Third molar extraction socket. (D). Impacted second molar. (E) First

Using implants as a method of skeletal anchorage for second lower molar uprighting was first proposed by Shellhart et al. These Authors placed a bone-integrated implant in an edentulous

Park, first proposed the use of orthodontics implants for uprighting of the second molar by placing miniscrews in retromolar area. (Park H.S., 2002) The distalizing force is exerted through the use of elastomeric threads using perhaps rather low forces, about 50-80g. Other authors (Giancotti, 2003, 2004), (Nęcka et al., 2010) propose a very similar method, involving elastomeric chains, with monthly reactivations, or 50g-force closed Ni-Ti coil springs. The

In an adolescent patient with a developing third molar, however, it is difficult to insert a miniscrew in the retromolar area unless the third molar is extracted. Thick overlying soft tissue and poor accessibility of the insertion site can also hinder miniscrew insertion. In such cases, the miniscrew can be inserted into the buccal alveolar bone on the mesial side to generate a "pushing" force. Lee et al. proposed to position the microscrew in interradicular area between second premolar and first molar and the use of a 0.016" or 0.016"x0.022" stainless steel wire with welded hook and open-coil spring for force

Other Authors (Sohn et al., 2007) proposed a mesial positioning, using the screw as an anchor for the indirect stabilization of the first molar and second premolar. A 0.016''x0.022'' stainless steel wire directly bonded with composite on teeth surface was used to connect

site, from which the first molar had previously been extracted. (Shellhart et al., 1996)

average treatment time in all these case reports was 7-9 months.

molar. (F) Oblique external line.

delivery. (Lee et al., 2007)

dental elements and microscrews.

A brief and schematic description of the materials and methods is given in this section.


Fig. 3. Patient MF, aged 14 at the beginning of the therapy, had the following Orthodontic characteristics: I skeletal class with a normal vertical dimension, mild II molar and canine class, increased overjet, moderate anterior-inferior and anterior-superior crowding, cross bite 1.6-4.6, 2.6-3.6, eruption disorder of the right second lower molar with complete gingival inclusion.

Fig. 4. Intraoral frontal view before treatment. The patient was treated by the use of crisscross elastic for the correction of XB and EOT for the correction of molar Class II.

Fig. 5. Upper dental arch after distalization.

Fig. 4. Intraoral frontal view before treatment. The patient was treated by the use of criss-

cross elastic for the correction of XB and EOT for the correction of molar Class II.

Fig. 5. Upper dental arch after distalization.

Fig. 6. Lower dental arch before surgical-orthodontic treatment. Patient simultaneously underwent the procedure for the surgical-orthodontic disinclusion of the element 47, during the last phase of interceptive treatment.

Fig. 7. The screw used in the proposed case has the following features: 2.0mm screws, 8- 12mm thread lengths, made of 316L extra-hard stainless steel for maximum strength; selfdrilling, self-tapping for one-step insertion; groove under screw-head secures wires or elastics; cruciform head design; two cross-holes with align cruciform head slots; a 4-mm capstan-style head to hold the wire away from the mucosa (Synthes, West Chester, Pennsylvania).

Fig. 8, 9 and 10. Surgical phases. The left mandibular third molar was extracted (germectomy), and a skeletal anchorage (2.0mm diameter/12mm length screw, Synthes, West Chester, Pennsylvania) was immediately applied. Two brackets, Roth Prescription slots 0.22, were positioned on the second molar (vestibular and occlusal) to optimize traction direction. Second molar was immediately connected to the screw by means of two metal ligatures with eyelets to attach intermediate traction elastic module. Eyelet to anchor the screw was modeled with 0.010" metallic ligature wire.

Fig 11. Immediately post operatively ortopantomography.

Fig. 8, 9 and 10. Surgical phases. The left mandibular third molar was extracted

screw was modeled with 0.010" metallic ligature wire.

Fig 11. Immediately post operatively ortopantomography.

(germectomy), and a skeletal anchorage (2.0mm diameter/12mm length screw, Synthes, West Chester, Pennsylvania) was immediately applied. Two brackets, Roth Prescription slots 0.22, were positioned on the second molar (vestibular and occlusal) to optimize traction direction. Second molar was immediately connected to the screw by means of two metal ligatures with eyelets to attach intermediate traction elastic module. Eyelet to anchor the

Fig. 12. Radiological check taken approximately 11 months later. The second left mandibular molar is in the correct position, the screw is still in place with no signs of bone inflammation. The time of treatment to achieve uprighting: about 9 months.

Fig. 13. Intraoral frontal view after treatment. The periodic checks to reactive the elastic traction, performed monthly at patient's request, rather than twice a week, caused a lengthening of time required to achieve the therapeutic effects. The patient was often advised to maintain good oral hygiene to prevent hypertrophy of the mucosa in the area of screw insertion.

Fig. 14. Intraoral right lateral view after treatment. Passive ligature metallic wire still anchored on element 46. Only one gingivectomy was necessary during treatment, to set bracket in better position.

Fig. 15. Lower dental arch after treatment. Case will conclude with fixed orthodontic treatment to correct and finalize the occlusion.

#### **4. Cases presentation**

Until now, the Authors successfully treated five cases of eruptive disorder of the second lower molar with the described technique (table 1).

Patients' mean age was 15.8 years; only one was female. When present, the third molar was always extracted. No damage to the inferior alveolar nerve or other major complications were encountered. Patients' compliance was crucial: oral hygiene at home and relatively frequent clinical checks (about every 3 weeks) were important to prevent inflammation, hypertrophy of soft tissues and pain. When present, these minor complications did not affect the outcome of the procedure. The average duration of treatment for uprighting was 10.4 months. Results remained stable over 5 year follow-up.


Table 1. Patients treated with Combined Surgical and Orthodontic treatment using a distal screw as skeletal anchorage.

### **5. Discussion and conclusions**

260 Orthodontics – Basic Aspects and Clinical Considerations

Fig. 14. Intraoral right lateral view after treatment. Passive ligature metallic wire still anchored on element 46. Only one gingivectomy was necessary during treatment, to set

Fig. 15. Lower dental arch after treatment. Case will conclude with fixed orthodontic

Until now, the Authors successfully treated five cases of eruptive disorder of the second

Patients' mean age was 15.8 years; only one was female. When present, the third molar was always extracted. No damage to the inferior alveolar nerve or other major complications

treatment to correct and finalize the occlusion.

lower molar with the described technique (table 1).

**4. Cases presentation** 

bracket in better position.

This chapter discusses the application of a skeletal anchorage device to achieve a very complex orthodontic movement such as second lower molar uprighting, an issue relatively little discussed in the literature due to the low prevalence of this kind of malocclusion.

The method described is minimally invasive, as the surgery needed to expose the impacted tooth and emplace the screw is quite simple and can be completed in a single session, together with extraction of the third molar, which is necessary in most cases. It also seems that the creation of a cortico-medullar void distal to the second molar, after third molar extraction or appositely surgically performed (Finotti et al, 2009), is important in shortening treatment time.

The dimensions of the device are minimal. It only requires one miniscrew and a single bracket or button attachment, and is more comfortable for the patient than complex segmental biomechanics.

Miniscrew insertion, preparation of the appliance and delivery can all be done during a single appointment, unlike conventional treatment which requires impressions and laboratory work. The simple design reduces chair time compared with more complex indirect anchorages. This system guarantees the utmost respect of periodontal tissues, soft tissues and bone. The method allows absolute control of the anchorage and no unwanted movement of adjacent teeth. (Park et al., 2002), (Giancotti et al, 2003, 2004), (Nęcka et al., 2010)

The direct application of force to the target tooth eliminates any unwanted movement of the anchorage unit, which may occur even with indirect miniscrew anchorage as a result of technical errors in passive bracket placement or weak attachment between miniscrew and anchor tooth.

Removing the anchoring screw is straightforward, with negligible risks and consequences for the patient. The use of miniscrews and their success rate are predictable. (Degichi et al., 2003), (Motoyoshy et al., 2007), (Yanosky & Holmes, 2008), (Moon et al., 2008), (Manni et al., 2010).

Temporary skeletal anchorage devices enable orthodontic movements that were previously considered difficult, if not impossible, without consequences for the other teeth (e.g., anchorage loss, unwanted extrusion). Treatment involving skeletal anchorage requires interdisciplinary collaboration and planning with regular interaction, ongoing education, improvement of materials and continual reviews of the latest literature.

#### **6. References**


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Removing the anchoring screw is straightforward, with negligible risks and consequences for the patient. The use of miniscrews and their success rate are predictable. (Degichi et al., 2003), (Motoyoshy et al., 2007), (Yanosky & Holmes, 2008), (Moon et al., 2008), (Manni

Temporary skeletal anchorage devices enable orthodontic movements that were previously considered difficult, if not impossible, without consequences for the other teeth (e.g., anchorage loss, unwanted extrusion). Treatment involving skeletal anchorage requires interdisciplinary collaboration and planning with regular interaction, ongoing education,

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## **Guidelines for "Surgery First" Orthodontic Treatment**

Jeong Hwan Kim1, Niloufar Nouri Mahdavie2 and Carla A. Evans2 *1Private Practice, Seoul 2University of Illinois at Chicago, Chicago 1Korea 2USA* 

#### **1. Introduction**

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Pre-surgical orthodontic preparation was uncommon for patients requiring orthognathic surgery until the 1960's. However, as surgical techniques advanced and the number of patients choosing an orthognathic approach increased, the patients' and clinicians' desire for optimal esthetic and occlusal results led to the most common current treatment approach. This approach involves pre-surgical orthodontic decompensation of the occlusal relationships and attainment of normal dental alignment. As most orthognathic treatment is planned now, there are two phases of orthodontic tooth movement, namely before and after orthognathic surgery. The disadvantages of having orthodontic interventions both before and after orthognathic surgery include a long treatment time and temporary worsening of facial appearance. Many patients become discouraged.

In recent years, a trend toward implementing treatment plans that achieve immediate facial change has arisen. In "Surgery First" treatment plans, the presurgical orthodontic treatment phase is eliminated or greatly reduced, the jaws are surgically repositioned into the desired locations, and orthodontic tooth movement follows. Patients appreciate the immediate improvement in facial appearance while the orthodontist can utilize the increased bone turnover to achieve accelerated tooth movement.

Caution is important when embarking on a "Surgery First" course of treatment. Even for the highly experienced orthodontist and surgeon, it is difficult to identify the occlusal relationship that will accompany an ideal facial and functional result. The planning process is time-consuming and requires choosing the desired appearance and skeletal relationships, mounting the casts in the position determined by the skeletal change, and then planning the post-operative orthodontic tooth movements. The surgical movement must be sufficient to allow dental decompensation after the surgical procedure. Surgical splints are fabricated on the articulated study models. Generally, the teeth are bonded/banded and a passive archwire is placed pre-surgically. Active orthodontic tooth movement begins within a relatively short period of time after the jaw(s) are repositioned to capitalize on the potential for accelerated tooth movement.

This chapter illustrates step-by-step concepts for "Surgery First" treatment with case records of increasing complexity. Surgical fixation and skeletal anchorage are discussed as well.

#### **1.1 Background**

Ever since the first orthognathic surgery procedure was performed by Hullihen in 1848, many new techniques and methods have been introduced. The introduction of orthognathic surgery widened the possibilities for treatment of severe malocclusions which could not be treated by orthodontics alone. As shown by Kondo and her colleagues (2000, 2005), the limits of orthodontic treatment alone for severe malocclusions are broadening, but the underlying skeletal imbalances remain. Until the 1960's, orthognathic surgeries were usually performed without any pre-surgical orthodontic treatment. In fact, when Hullihen performed the first mandibular sub-apical osteotomy on a burn victim, he was able to correct the prognathism but created an edge-to-edge occlusion anteriorly (Aziz, 2004).

The three stage philosophy of orthognathic surgery was later adapted and is still valid today in the majority of cases. These stages involve pre-orthognathic orthodontic treatment to relieve the dental compensations followed by the orthognathic surgical procedure and finally post-surgical orthodontics to finish the case and settle the occlusion.

#### **1.2 Challenges associated with conventional orthognathic surgery cases**

The pre-surgical orthodontic treatment of patients requiring orthognathic surgery has been criticized to be the most time consuming stage of treatment (O'Brien et al., 2009). The mean length of this stage has been reported anywhere between 7 to 47 months (Luther et al., 2003). The longer pre-operative treatment phase can potentially aggravate the dental caries and periodontal problems and negatively influence patient compliance.

The worsening of facial profile prior to surgery which results from dentoalveolar decompensation is also a great disadvantage. This is even more so noticeable in Class III patients. The removal of natural dental compensation in these patients often results in advancement of the lower lip as well as retrusion of the upper lip which together accentuate the soft tissue disharmony. Considering the fact that patients who desire to undergo orthognathic surgery are often very concerned about facial esthetics, the long pre-surgical orthodontic preparation delays addressing the patient's chief complaint.

#### **1.3 "Surgery First" orthognathics**

The challenges involved with the conventional three stage model of orthognathic surgery have given rise to new concepts such as what is known as "Surgery First" orthognathics. In 1991 Brachvogel proposed this approach with the goal of reducing some of the disadvantages and inconveniences of pre-surgical orthodontics (Brachvogel et al., 1991). In that article the advantages of post-surgical orthodontics are outlined as follows: 1) Orthodontic movement does not interfere with compensatory biological responses, 2) Dental movements can be based on an already corrected skeletal pattern, and 3) Some surgical relapse can be managed during treatment. Informative case reports have been published by Tsuruda et al. (2003) and Sugawara et al. (2008).

This chapter illustrates step-by-step concepts for "Surgery First" treatment with case records of increasing complexity. Surgical fixation and skeletal anchorage are discussed as well.

Ever since the first orthognathic surgery procedure was performed by Hullihen in 1848, many new techniques and methods have been introduced. The introduction of orthognathic surgery widened the possibilities for treatment of severe malocclusions which could not be treated by orthodontics alone. As shown by Kondo and her colleagues (2000, 2005), the limits of orthodontic treatment alone for severe malocclusions are broadening, but the underlying skeletal imbalances remain. Until the 1960's, orthognathic surgeries were usually performed without any pre-surgical orthodontic treatment. In fact, when Hullihen performed the first mandibular sub-apical osteotomy on a burn victim, he was able to correct the prognathism but created an edge-to-edge occlusion anteriorly (Aziz, 2004).

The three stage philosophy of orthognathic surgery was later adapted and is still valid today in the majority of cases. These stages involve pre-orthognathic orthodontic treatment to relieve the dental compensations followed by the orthognathic surgical procedure and

The pre-surgical orthodontic treatment of patients requiring orthognathic surgery has been criticized to be the most time consuming stage of treatment (O'Brien et al., 2009). The mean length of this stage has been reported anywhere between 7 to 47 months (Luther et al., 2003). The longer pre-operative treatment phase can potentially aggravate the dental caries and

The worsening of facial profile prior to surgery which results from dentoalveolar decompensation is also a great disadvantage. This is even more so noticeable in Class III patients. The removal of natural dental compensation in these patients often results in advancement of the lower lip as well as retrusion of the upper lip which together accentuate the soft tissue disharmony. Considering the fact that patients who desire to undergo orthognathic surgery are often very concerned about facial esthetics, the long pre-surgical

The challenges involved with the conventional three stage model of orthognathic surgery have given rise to new concepts such as what is known as "Surgery First" orthognathics. In 1991 Brachvogel proposed this approach with the goal of reducing some of the disadvantages and inconveniences of pre-surgical orthodontics (Brachvogel et al., 1991). In that article the advantages of post-surgical orthodontics are outlined as follows: 1) Orthodontic movement does not interfere with compensatory biological responses, 2) Dental movements can be based on an already corrected skeletal pattern, and 3) Some surgical relapse can be managed during treatment. Informative case reports have been

finally post-surgical orthodontics to finish the case and settle the occlusion.

periodontal problems and negatively influence patient compliance.

orthodontic preparation delays addressing the patient's chief complaint.

published by Tsuruda et al. (2003) and Sugawara et al. (2008).

**1.3 "Surgery First" orthognathics** 

**1.2 Challenges associated with conventional orthognathic surgery cases** 

**1.1 Background** 

Fig. 1. Various approaches to the treatment of severe skeletal disharmonies. A. Historical methods. B. Conventional orthognathics. C. "Surgery First" sequence.

A major driving motive for performing surgery first orthognathics has been the reduced treatment time reported in the literature (Yu et al., 2010; Villegas et al., 2010; Liou et al., 2011a, 2011b). Traditionally, a number of studies have focused on accelerated orthodontics as a result of corticotomy procedures with or without bone augmentation. It has been shown that orthodontic treatment time decreases by using alveolar osteotomy procedures (Wilcko et al., 2001; Wilcko et al., 2009). The proposed mechanism for this decrease in treatment time is the increase in cortical bone porosity which translates to decreased resistance to tooth movement (Wilcko et al., 2009). The same concept can be applied to performing orthognathic surgery before orthodontic treatment begins, but actual supporting data are sparse.

It has been shown that during the healing process after orthognathic surgery, there is an increase in blood flow above the pre-surgical levels (Justus et al., 2001). The increase in blood flow facilitates the healing process and stimulates bone turnover which can potentially speed up orthodontic tooth movement. Despite the postulated hypothesis, there is very limited information about the molecular basis for accelerated tooth movement. Moreover, the decrease in treatment time has only been documented as case reports. As knowledge becomes available about the reasons for increased bone turnover after osteotomies of the jaws (Iliopoulos et al., 2010), new surgical techniques will improve treatment options for the patients.

In recent years, more attention has been given to the subject and more and more cases are being treated with the "Surgery First" approach. The basic concept that underlies surgery first orthognathics is the elimination of the pre-surgical orthodontic phase and elimination of soft tissue imbalance accompanying the dentofacial deformity. The most important consideration in using this technique is the fact that it is a complicated approach that requires close cooperation of a highly experienced orthodontist and the orthognathic surgeon. Prediction of the desired final occlusion is a very difficult task. Also, the surgeon must be able to arrange the skeletal components to match the predicted skeletal positions and occlusion precisely. More importantly, the advent of rigid fixation was the key which allowed the surgery first approach to be implemented. With the conventional wire fixation, the mobility of the bony segments would not allow for a stable position of bone post surgically. Hence, any attempted movement could potentially result in movement of the skeletal components. Skeletal relapse caused by occlusal instability can be partially overcome with rigid fixation (Liao et al., 2010). In a series of case studies, it seems that the postoperative skeletal changes are similar between surgery first and conventional treatment of Class III malocclusions (Baek et al, 2011; Liao et al, 2010). Postoperatively in both types of treatment there was some forward superior movement of the mandible, but overall the needed posterior movement of the mandible was achieved and preserved.

The following segmental osteotomy case demonstrates the concepts of surgery first technique before getting into conventional one or two-jaw orthognathic surgery cases. Figure 2 shows the initial presentation of a patient with a chief complaint of unattractive smile and broken front teeth. On examination it was revealed that the bimaxillary protrusion could be resolved by extraction of upper and lower first premolars and segmental osteotomy procedures to retract the maxillary and mandibular dentoalveolar segments. After model surgery was performed (Figure 3), it was decided to remove the teeth at the time of surgery and utilize the surgery first approach. Maxillary and mandibular first

A major driving motive for performing surgery first orthognathics has been the reduced treatment time reported in the literature (Yu et al., 2010; Villegas et al., 2010; Liou et al., 2011a, 2011b). Traditionally, a number of studies have focused on accelerated orthodontics as a result of corticotomy procedures with or without bone augmentation. It has been shown that orthodontic treatment time decreases by using alveolar osteotomy procedures (Wilcko et al., 2001; Wilcko et al., 2009). The proposed mechanism for this decrease in treatment time is the increase in cortical bone porosity which translates to decreased resistance to tooth movement (Wilcko et al., 2009). The same concept can be applied to performing orthognathic surgery before orthodontic treatment begins, but actual supporting data are

It has been shown that during the healing process after orthognathic surgery, there is an increase in blood flow above the pre-surgical levels (Justus et al., 2001). The increase in blood flow facilitates the healing process and stimulates bone turnover which can potentially speed up orthodontic tooth movement. Despite the postulated hypothesis, there is very limited information about the molecular basis for accelerated tooth movement. Moreover, the decrease in treatment time has only been documented as case reports. As knowledge becomes available about the reasons for increased bone turnover after osteotomies of the jaws (Iliopoulos et al., 2010), new surgical techniques will improve

In recent years, more attention has been given to the subject and more and more cases are being treated with the "Surgery First" approach. The basic concept that underlies surgery first orthognathics is the elimination of the pre-surgical orthodontic phase and elimination of soft tissue imbalance accompanying the dentofacial deformity. The most important consideration in using this technique is the fact that it is a complicated approach that requires close cooperation of a highly experienced orthodontist and the orthognathic surgeon. Prediction of the desired final occlusion is a very difficult task. Also, the surgeon must be able to arrange the skeletal components to match the predicted skeletal positions and occlusion precisely. More importantly, the advent of rigid fixation was the key which allowed the surgery first approach to be implemented. With the conventional wire fixation, the mobility of the bony segments would not allow for a stable position of bone post surgically. Hence, any attempted movement could potentially result in movement of the skeletal components. Skeletal relapse caused by occlusal instability can be partially overcome with rigid fixation (Liao et al., 2010). In a series of case studies, it seems that the postoperative skeletal changes are similar between surgery first and conventional treatment of Class III malocclusions (Baek et al, 2011; Liao et al, 2010). Postoperatively in both types of treatment there was some forward superior movement of the mandible, but overall the

needed posterior movement of the mandible was achieved and preserved.

The following segmental osteotomy case demonstrates the concepts of surgery first technique before getting into conventional one or two-jaw orthognathic surgery cases. Figure 2 shows the initial presentation of a patient with a chief complaint of unattractive smile and broken front teeth. On examination it was revealed that the bimaxillary protrusion could be resolved by extraction of upper and lower first premolars and segmental osteotomy procedures to retract the maxillary and mandibular dentoalveolar segments. After model surgery was performed (Figure 3), it was decided to remove the teeth at the time of surgery and utilize the surgery first approach. Maxillary and mandibular first

sparse.

treatment options for the patients.

premolars were extracted at the time of surgery and the anterior dentoalveolar segments were set back before any orthodontic treatment was initiated. An advancement genioplasty was done simultaneously; bony continuity between the right and left sides of the mandible could be maintained because the vertical dimension of the mandibular symphysis was large.

Fig. 2. Initial Presentation.

Fig. 3. A) Initial Models B) Model Set-up.

Fig. 3. A) Initial Models B) Model Set-up.

Figure 4 shows the patient immediately following the procedure. The occlusion immediately following surgery shows the same occlusion as was predicted in the model surgery. Orthodontic treatment was initiated 3 weeks after surgery and case was finished in 15 months. The treatment time in this case was longer than typical anterior segmental osteotomy cases due to the need for Class II correction. Subsequently the maxillary anterior teeth were restored for better esthetics. The final intra-oral and extra-oral pictures are shown in Figure 5.

Fig. 4. Records immediately after surgery.

Fig. 5. Final Presentation.

By performing surgery first, patient was very satisfied with the reduction in protrusion as soon as the surgery was performed. The reduced treatment time also was an advantage.

#### **2. Surgery first orthognathics indications**

The surgery first approach can be used to treat a variety of cases depending on the specific characteristics of the malocclusion and the dentofacial deformity. Nonetheless, there are certain criteria which can make a case the ideal surgery first case.

By performing surgery first, patient was very satisfied with the reduction in protrusion as soon as the surgery was performed. The reduced treatment time also was an advantage.

The surgery first approach can be used to treat a variety of cases depending on the specific characteristics of the malocclusion and the dentofacial deformity. Nonetheless, there are

Fig. 5. Final Presentation.

**2. Surgery first orthognathics indications** 

certain criteria which can make a case the ideal surgery first case.

In the ideal situation, the malocclusion accompanying the skeletal deformity represents mild to moderate crowding, normal to mild proclination and retroclination of upper and lower incisors, and minimal transverse discrepancies (Liou et al., 2011a, 2011b).

Even though the surgery first technique can be applied to Class II as well as Class III malocclusions, the majority of cases treated using this approach have been cases with Class III malocclusion meeting the above criteria. A possible explanation is that a Class III skeletal relationship results in a more pronounced soft tissue imbalance. Often, Class II skeletal deformities can be masked as the patient shifts the mandible forward, but the equivalent backward shift of the mandible to mask Class III deformities is physically impossible. In the traditional approach, decompensation of the arches results in an even more disfiguring profile for Class III patients. Hence, these patients seem to see the benefit of the surgery first approach to a greater extent than Class II cases and possibly seek this new approach more. It is also likely that for Class II patients, advancing a retrognathic mandible into the correct position will create an anterior crossbite temporarily worsening the patient's appearance until orthodontic treatment can upright and retract the lower incisors; this occurrence doesn't fit with surgery first concepts.

Figure 6 illustrates an ideal case which was treated using the surgery first approach. Patient presented at the age of 22. After the case was treatment planned and the model surgery was performed, the surgery first approach was indicated. Teeth were bonded and passive stainless steel arch wires were placed a few days prior to surgery. A two-jaw orthognathic surgery was performed and the patient returned five weeks after surgery for the initiation of orthodontic treatment. As it will be discussed later in this chapter, immediately after surgery there was a lateral open bite as can be seen in Figure 7. This transitional malocclusion was predicted during the model surgery procedure. Since the skeletal discrepancy was no longer present, the case could subsequently be treated as a Class I skeletal case. Figure 7 shows the occlusion at the start of orthodontic treatment followed by settling of the bite and improvement of overbite and overjet after eight months of orthodontic movement. The case was finished after a total treatment time of 20 months (19 months of orthodontic treatment) with lateral incisor restorations and satisfactory results in terms of facial aesthetics and occlusion as evident in the final records (Figure 8).

#### **3. Advantages of surgery first orthognathics**

In most cases, patients who receive orthognathic surgery in order to correct a dento-skeletal deformity present to the orthodontist's office with a chief complaint that includes dissatisfaction with their facial appearance. Hence, the main concern of the patient must be addressed during the course of treatment. The conventional three-stage approach in orthognathic surgery requires decompensation of the teeth which often results in worsening of the facial profile especially in patients with Class III malocclusion. The improvement in facial aesthetics in these patients does not occur until months later when the actual surgery is performed. Having surgery first eliminates the unsightly pre-surgical profile and allows the chief complaint of the patient to be addressed at the beginning of treatment. With the conventional approach, it is very difficult for the patient and the orthodontist to predict the exact time of surgery. Since the surgical procedure precedes orthodontic treatment, the patient has the opportunity to choose the timing of surgery to allow for the postoperative healing period.

Fig. 6. Initial Presentation.

Fig. 7. A) Model Surgery B) Progress records at the start of orthodontic treatment and C) Progress records 8 months into orthodontic treatment.

Fig. 7. A) Model Surgery B) Progress records at the start of orthodontic treatment and C)

Progress records 8 months into orthodontic treatment.

Fig. 6. Initial Presentation.

Fig. 8. Final Presentation.

The total treatment time in surgery first cases is reduced. Treatment times as short as seven months have been reported in the literature (Villegas et al., 1997). The pre-surgical orthodontic phase in conventional three-step orthognathic surgery cases is the most time consuming step. Bypassing this step results in an overall shortened treatment time to 1 to 1.5 years or less (Liou et al., 2011a, 2011b). The treatment time varies depending on the treating orthodontist's experience and the orthodontist's standard for finishing.

Immediate resolution of the soft tissue and skeletal imbalance is an added advantage in surgery first approach (Baek et al, 2010; Nagasaka et al, 2009). Dentoalveolar decompensation which is performed in conventional pre-surgical orthodontics works against the physiological compensatory dentoalveolar processes. In other words, the orthodontist tries to achieve a preoperative occlusion which is against what the soft tissue and skeletal components dictate. This has been thought of as one of the challenges in decompensating the arches prior to surgery. When surgery is completed first, the skeletal and soft tissue discrepancy is relieved and the teeth can be aligned without the need to fight with the physiological limitations.

#### **3.1 Reduced treatment time in surgery first orthodontics**

The reduced treatment time in surgery first approach can be attributed to two main factors: 1) the resolution of skeletal and soft tissue imbalance prior to initiation of tooth movement and 2) the regional acceleratory phenomenon.

As mentioned previously, the resolution of skeletal and soft tissue imbalance through surgery allows the orthodontist to move the teeth in a normal skeletal and soft tissue envelope which facilitates the orthodontic movement. For example, in a Class III skeletal pattern, the relationship between the upper and lower jaw is not ideal. The imbalance between the two jaws results in dentoalveolar compensation which throughout an individual's lifetime, attempts to minimize and mask the skeletal deformity by maintaining contact between the teeth. This often results in proclination of upper incisors and retroclination of lower incisors in an attempt to minimize the negative overjet.

Figure 9 illustrates the initial presentation of a male patient. The skeletal Class III relationship in this patient was camouflaged by proclined upper incisors as well as slightly

Fig. 9. Initial Records.

individual's lifetime, attempts to minimize and mask the skeletal deformity by maintaining contact between the teeth. This often results in proclination of upper incisors and

Figure 9 illustrates the initial presentation of a male patient. The skeletal Class III relationship in this patient was camouflaged by proclined upper incisors as well as slightly

retroclination of lower incisors in an attempt to minimize the negative overjet.

Fig. 9. Initial Records.

retroclined lower incisors. Anterior open bite was present and the chin was deviated to the right side. Such compensation had given him the best possible soft tissue profile and occlusion biologically possible with such skeletal disharmony. If this case was to be treated with the conventional protocol for orthognathic surgery, the upper incisors would need to be retroclined and the lower incisors would need to be proclined in order to de-compensate the upper and lower arches, achieve sufficient negative overjet, and finally perform the orthognathic surgical procedure. This decompensation would place the teeth in a position which is not "natural" for the current skeletal relationship and is against the compensatory mechanisms which have been at work for many years. The price would have been paid by a relatively long pre-surgical treatment time.

Figure 10 shows the model surgery and fabrication of the intermediate splint to position the maxilla which is then followed by prediction of the final occlusion and preparation of the final splint. The final occlusion is predicted on the models.

Fig. 10. Progress Records.

The surgery first approach was instead utilized in treating this patient. Brackets were bonded three days prior to surgery and passive arch wires were placed. A two-jaw surgical procedure was performed and orthodontic treatment was started in six weeks. Figure 11 shows the bonding of brackets before surgery followed by progress records of the patient. The bite settled as the teeth were aligned and decompensated. Patient was debonded after finishing and detailing. The total treatment time was eighteen months. Figure 12 shows the final records of the patient at the time the appliances were removed.

Fig. 11. Progress Records A) Bracket position before placement of passive arch wires, B) 4 months after surgery, C) 9 months after surgery, D) 11 months after surgery.

The surgery first approach was instead utilized in treating this patient. Brackets were bonded three days prior to surgery and passive arch wires were placed. A two-jaw surgical procedure was performed and orthodontic treatment was started in six weeks. Figure 11 shows the bonding of brackets before surgery followed by progress records of the patient. The bite settled as the teeth were aligned and decompensated. Patient was debonded after finishing and detailing. The total treatment time was eighteen months. Figure 12 shows the

Fig. 11. Progress Records A) Bracket position before placement of passive arch wires, B) 4

months after surgery, C) 9 months after surgery, D) 11 months after surgery.

final records of the patient at the time the appliances were removed.

Fig. 12. Final Records

#### **3.2 Regional Acceleratory Phenomenon (RAP)**

The regional acceleratory phenomenon (RAP) was well described by Frost in 1993. After an osteotomy, bone remodeling around the healing tissue facilitates the healing process. This regional acceleratory phenomenon can be utilized by the orthodontist following orthognathic surgery to accelerate tooth movement. By performing surgery first, this period of rapid metabolic activity within the tissues can be harvested for efficient orthodontic treatment.

The extent and duration of this window of opportunity becomes an important issue in these cases. In order to answer this question, the by-products of bone metabolism have been measured in patients' blood samples following orthognathic surgery. Alkaline phosphatase and C-terminal telopeptide of type I collagen are two bone markers which have been studied. The former is associated with osteoblastic activity while the latter is a by-product of osteoclastic breakdown of bone. The results of one such study show that orthognathic surgery triggers three to four months of higher osteoclastic activities and metabolic changes in the dentoalveolus (Liou et al., 2011a, 2011b). This short period of regional acceleratory phenomenon is a possible explanation for shortened treatment time in surgery first orthodontics.

The regional acceleratory phenomenon is not exclusive to surgery first approach. In the conventional approach, this phenomenon is seen after decompensation has been accomplished and patient has had the surgical procedure completed. The surgery first approach however, utilizes this golden opportunity to speed up the decompensation process which occurs after the surgery unlike the traditional approach. Since the decompensation of the arches is the most time consuming step of the way, the regional acceleratory phenomenon is used when it is needed the most.

Despite the findings demonstrated as case reports on shortened treatment time, the actual duration of the window of time during which the regional acceleratory phenomenon can be utilized for orthodontic tooth movement is still unknown. Various studies have shown different lengths of accelerated tooth movement. Hence, more studies are required at the time being to give sufficient evidence on the actual molecular basis for the accelerated tooth movement as well as the duration of this phenomenon after surgical procedures.

#### **4. Treatment planning considerations**

Careful planning is the key to the success of any orthognathic surgery case especially when the surgical procedure is to be performed prior to orthodontic treatment. As with any orthodontic treatment, obtaining high quality records including intraoral and extra-oral pictures, models, and radiographs is the first step.

Multiple treatment planning considerations must be taken into account when orthognathic surgery is being performed without prior orthodontic treatment. The orthodontist plans the surgery on the pre-operative models in such a way that a relatively stable occlusion can be achieved during surgery. The teeth will be decompensated to normal positions and angulations following surgery; therefore, the transitional occlusion must allow for post surgical movement of teeth. Since the incisors cannot be used as a guide to predict the final occlusion in surgery first cases, the molar relationship can be utilized as a starting point to come up with a temporary occlusion.

The regional acceleratory phenomenon (RAP) was well described by Frost in 1993. After an osteotomy, bone remodeling around the healing tissue facilitates the healing process. This regional acceleratory phenomenon can be utilized by the orthodontist following orthognathic surgery to accelerate tooth movement. By performing surgery first, this period of rapid metabolic activity within the tissues can be harvested for efficient orthodontic

The extent and duration of this window of opportunity becomes an important issue in these cases. In order to answer this question, the by-products of bone metabolism have been measured in patients' blood samples following orthognathic surgery. Alkaline phosphatase and C-terminal telopeptide of type I collagen are two bone markers which have been studied. The former is associated with osteoblastic activity while the latter is a by-product of osteoclastic breakdown of bone. The results of one such study show that orthognathic surgery triggers three to four months of higher osteoclastic activities and metabolic changes in the dentoalveolus (Liou et al., 2011a, 2011b). This short period of regional acceleratory phenomenon is a possible explanation for shortened treatment time in surgery first

The regional acceleratory phenomenon is not exclusive to surgery first approach. In the conventional approach, this phenomenon is seen after decompensation has been accomplished and patient has had the surgical procedure completed. The surgery first approach however, utilizes this golden opportunity to speed up the decompensation process which occurs after the surgery unlike the traditional approach. Since the decompensation of the arches is the most time consuming step of the way, the regional

Despite the findings demonstrated as case reports on shortened treatment time, the actual duration of the window of time during which the regional acceleratory phenomenon can be utilized for orthodontic tooth movement is still unknown. Various studies have shown different lengths of accelerated tooth movement. Hence, more studies are required at the time being to give sufficient evidence on the actual molecular basis for the accelerated tooth

Careful planning is the key to the success of any orthognathic surgery case especially when the surgical procedure is to be performed prior to orthodontic treatment. As with any orthodontic treatment, obtaining high quality records including intraoral and extra-oral

Multiple treatment planning considerations must be taken into account when orthognathic surgery is being performed without prior orthodontic treatment. The orthodontist plans the surgery on the pre-operative models in such a way that a relatively stable occlusion can be achieved during surgery. The teeth will be decompensated to normal positions and angulations following surgery; therefore, the transitional occlusion must allow for post surgical movement of teeth. Since the incisors cannot be used as a guide to predict the final occlusion in surgery first cases, the molar relationship can be utilized as a starting point to

movement as well as the duration of this phenomenon after surgical procedures.

acceleratory phenomenon is used when it is needed the most.

**4. Treatment planning considerations** 

come up with a temporary occlusion.

pictures, models, and radiographs is the first step.

**3.2 Regional Acceleratory Phenomenon (RAP)** 

treatment.

orthodontics.

The inclination of upper incisors is important in determining the need for possible extractions. If the upper incisor is excessively proclined, extractions may be considered to allow retraction of upper incisors post-operatively. As a rule of thumb, if the upper incisor to occlusal plane angulation is less than 53 to 55 degrees (Liao et al., 2010), extraction must be considered. Another possibility involves changing the position of the whole maxilla so that the occlusal plane is steeper and producing more upright maxillary incisors. Also, one might distalize the maxillary posterior segments using zygomatic plates as shown by Nagasaka et al. (2009) and Villegas et al. (2010) thus opening space to retrocline the maxillary incisors.

When placing upper and lower models into occlusion, the transverse dimension of the arches in many cases does not allow perfect interdigitation. Hence, the transverse dimension often poses a special challenge when performing model surgery in surgery first cases. The midlines must be coincident or close to it after surgery and proper buccal overjet must be established bilaterally. Depending on the degree of discrepancy between the two arches, the orthodontist can resolve this issue by planning for segmental osteotomies in more severe cases or possibly plan on resolving the issue post-surgically by arch coordination and elastics.

The most challenging and time consuming step in preparing for surgery first orthodontics is the prediction of the final occlusion based on the current position of teeth. The experience of the orthodontist plays a very important role in the process. The term intended transitional malocclusion (ITM) is used to describe the occlusion which will be used to fabricate the surgical splint and is the surgeon's guide during surgery (Park et al., 2011). The ITM must be stable enough to allow predictable splint fabrication and skeletal movement. Therefore, at least a three-point contact must be established between the upper and lower models when deciding on the ITM. In cases where such temporary occlusion cannot be established, it is advisable to initiate some orthodontic movement in order to relieve some of the interferences and allow for a more stable transitional malocclusion to be established. In a Class III skeletal malocclusion after surgery, a Class I or II malocclusion with the characteristic dental compensations of a Class III malocclusion is established. The decompensation of the teeth is performed following surgery. The following cases demonstrate the importance of meticulous treatment planning in surgery first orthodontics.

Figure 13 demonstrates the initial records of a 24 year old female patient who presented with chief complaints of a long face, strong chin, and difficulty in pronunciation (lisping sound).

Upon initial examination, the patient had a Class III malocclusion with anterior open bite. The upper second premolars were displaced palatally and the upper right first premolar was restored with an ill-fitting full coverage crown due to lack of sufficient space which compromised the tooth esthetically and periodontally. It was determined that extractions in the maxillary arch will be needed to allow for decompensation of teeth after surgery. Model surgery was performed allowing upper second premolar extraction during surgery. The concept behind extraction of upper second premolars can be explained in terms of conventional decompensation procedure as well. If the case was being treated with orthodontic decompensation of teeth prior to surgery, one way to achieve sufficient negative overjet would have been to extract the upper premolars to allow retraction and retroclination of upper incisors. In surgery first approach, extracting the premolars during surgery provides for the space needed to decrease the overjet and retract the incisors after surgery. Careful planning and precise surgical delivery is of utmost importance in such cases due to the added complexity of simultaneous extractions. Figure 14 shows the model surgery and set-up of the case during surgical planning.

Fig. 13. Initial Records.

Fig. 14. Model Surgery.

The indirect bonding technique was used in this case which allowed the bending of stainless steel passive arch-wires on the models. The bonding of brackets, placement of the wire, and splint try-in were done at the same visit a few days prior to surgery. Orthodontic movement was initiated 7 weeks after the surgical procedure was completed (Figure 15).

surgery provides for the space needed to decrease the overjet and retract the incisors after surgery. Careful planning and precise surgical delivery is of utmost importance in such cases due to the added complexity of simultaneous extractions. Figure 14 shows the model

The indirect bonding technique was used in this case which allowed the bending of stainless steel passive arch-wires on the models. The bonding of brackets, placement of the wire, and splint try-in were done at the same visit a few days prior to surgery. Orthodontic movement

was initiated 7 weeks after the surgical procedure was completed (Figure 15).

surgery and set-up of the case during surgical planning.

Fig. 13. Initial Records.

Fig. 14. Model Surgery.

Fig. 15. Initiation of orthodontic movement.

Fig. 16. Orthodontic Treatment in Progress A) 5 months B) 13 months into treatment.

Case was debonded after 16 months of active orthodontics. Figure 17 shows the final records with good occlusion and esthetics.

Fig. 17. Final Records.

The results of this particular case were stable over a two year retention period. Figure 18 shows the intraoral images at two years after removal of the orthodontic appliances.

Case was debonded after 16 months of active orthodontics. Figure 17 shows the final records

The results of this particular case were stable over a two year retention period. Figure 18

shows the intraoral images at two years after removal of the orthodontic appliances.

with good occlusion and esthetics.

Fig. 17. Final Records.

Fig. 18. Retention after two years.

#### **4.1 Protocol variations**

While the sequence of treatment is similar, different protocols are being used to prepare the patient for surgery, perform the surgical procedure, and initiate orthodontic treatment. Orthodontists often have their own customized preferences which have developed in their years of practice.

In most cases, the brackets and the wires are placed right before surgery. While some clinicians prefer to bond the wire directly to the surface of teeth, others choose to utilize the conventional orthodontic attachments. Although bonding the wire directly to the teeth is very fast, it makes post-surgical orthodontics a problem since teeth need to be bonded at that point. Given the healing period after surgery, it is very difficult to place brackets on teeth while minimizing patient discomfort.

Different types of wires are being used by orthodontists across the globe prior to surgery. Contrary to conventional orthognathic surgery cases, in surgery first treatments leveling and aligning have not yet been performed which makes it very difficult to place the wire. Some orthodontists prefer to place a passive stainless steel wire which has been bent and adapted to each tooth to prevent any tooth movement. The first author's preference is to use 0.022 slot brackets as well as passive stainless steel wires of 0.017 inch x 0.025 inch dimensions. Other orthodontists who use the surgery first approach have opted to use nickel-titanium wires at time of surgery. Finally, a few orthodontists prefer not to place any wires at the time of surgery.

The use of nickel-titanium wires translates into immediate tooth movement after surgery which can be an advantage. However, in doing so, the orthodontist loses the opportunity to observe the stability of the surgical correction prior to starting the tooth movement. The rapid acceleratory phenomenon not only affects the tooth movement but also can affect the alveolar bone. Hence, it is the first author's preference not to use these wires or elastics immediately after surgery to prevent unwanted movement of the alveolar process and rather wait for about 4 to 6 weeks after surgery.

The use of surgical splint during and after surgery also varies between different orthodontists. While some advocate the use of the splint only during surgery, other groups have advocated its use anywhere between one to four weeks after surgery. Nagasaka et al. have used removable Gelb–type splints post operatively (Nagasaka et al., 2009). The first author's preference is to leave the splint in for about 4 to 6 weeks after surgery and if an open bite is observed, to use elastic between the splint and the mini-screws or to leave the splint for a longer period of time. The use of mini-screws will further be discussed in the following section. Also, during the post-surgical period, the first author tries to avoid vertical elastics and allows the bite to settle as the dental compensations resolve. Table 1 summarizes the first author's protocol in comparison to other existing protocols.


Table 1. Comparison of first author's protocol with other protocol variations.

#### **4.2 Use of skeletal anchorage in conjunction with surgery first approach**

In recent years, temporary anchorage devices have become very popular in orthodontics. The use of skeletal anchorage has provided for more predictable orthodontic movements while minimizing the undesirable side effects. Some authors have placed great emphasis on the use of mini plates and mini screws to control the inclination of the upper incisors and to prevent the relapse of an anterior crossbite in Class III cases (Liao et al., 2010).

The surgery first approach requires meticulous treatment planning and collaboration between the orthodontist and the orthognathic surgeon. The model surgery is based on the

Some orthodontists prefer to place a passive stainless steel wire which has been bent and adapted to each tooth to prevent any tooth movement. The first author's preference is to use 0.022 slot brackets as well as passive stainless steel wires of 0.017 inch x 0.025 inch dimensions. Other orthodontists who use the surgery first approach have opted to use nickel-titanium wires at time of surgery. Finally, a few orthodontists prefer not to place any

The use of nickel-titanium wires translates into immediate tooth movement after surgery which can be an advantage. However, in doing so, the orthodontist loses the opportunity to observe the stability of the surgical correction prior to starting the tooth movement. The rapid acceleratory phenomenon not only affects the tooth movement but also can affect the alveolar bone. Hence, it is the first author's preference not to use these wires or elastics immediately after surgery to prevent unwanted movement of the alveolar process and

The use of surgical splint during and after surgery also varies between different orthodontists. While some advocate the use of the splint only during surgery, other groups have advocated its use anywhere between one to four weeks after surgery. Nagasaka et al. have used removable Gelb–type splints post operatively (Nagasaka et al., 2009). The first author's preference is to leave the splint in for about 4 to 6 weeks after surgery and if an open bite is observed, to use elastic between the splint and the mini-screws or to leave the splint for a longer period of time. The use of mini-screws will further be discussed in the following section. Also, during the post-surgical period, the first author tries to avoid vertical elastics and allows the bite to settle as the dental compensations resolve. Table 1

**First Author's Protocol Other Protocol Variations** 

No wires

No brackets ( wires bonded directly to teeth)

Nickel titanium wires

( less than 1 month)

No use of splints after surgery (splints only used during surgery) Use of splint 4 weeks after surgery

Start moving teeth soon after surgery

summarizes the first author's protocol in comparison to other existing protocols.

Table 1. Comparison of first author's protocol with other protocol variations.

**4.2 Use of skeletal anchorage in conjunction with surgery first approach** 

prevent the relapse of an anterior crossbite in Class III cases (Liao et al., 2010).

In recent years, temporary anchorage devices have become very popular in orthodontics. The use of skeletal anchorage has provided for more predictable orthodontic movements while minimizing the undesirable side effects. Some authors have placed great emphasis on the use of mini plates and mini screws to control the inclination of the upper incisors and to

The surgery first approach requires meticulous treatment planning and collaboration between the orthodontist and the orthognathic surgeon. The model surgery is based on the

.022 bracket slots 0.018 brackets

0.017 x 0.025 stainless steel passive wires

Release splint from maxilla but patient continues to use splint and simple elastics

If mandible is stable, at 5-7 weeks start moving teeth with NiTi or copper NiTi

Heavy intermaxillary elastics full time for 2- 3 weeks, then check if teeth go into splint

prior to surgery

smoothly without elastics

wires at the time of surgery.

rather wait for about 4 to 6 weeks after surgery.

orthodontist's vision on what is achievable post orthodontically based on previous experience. Hence, many uncertainties remain at the time the patient is sent to surgery. By utilizing the temporary anchorage devices, many orthodontists try to have a "back-up" system which can be used to help in post-surgical orthodontic phase. These devices are anywhere from single mini-implants to titanium plates which can be placed at the time of surgery.

Nagasaka et al. have advocated the use of zygomatic plates as temporary anchorage devices to aid in post-operative orthodontic movement (Nagasaka et al., 2009). In one case report, a Class III surgery first case was corrected surgically to a Class I skeletal relationship with a Class II dental tendency. Since the teeth were not decompensated prior to surgery, after the surgery the occlusion was expected to exhibit excessive overjet. During orthognathic surgery zygomatic plates were placed. The plates were then used to distalize the upper arch post-operatively to achieve Class I canines and ideal overjet (Nagasaka et al., 2009).

Figure 19 shows the initial presentation of a female patient. The skeletal Class III pattern was accompanied by open bite and mild crowding in both arches. the upper incisors had previously been restored with full coverage crowns.

Fig. 19. Initial Records.

After careful treatment planning, model surgery was performed to predict the final position of teeth and fabricate the splint. Prior to surgery, teeth were bonded and stainless steel arch wires were passively engaged (Figure 20). Patient underwent a two-jaw surgical procedure and at the time of surgery four mini-implants were placed mesial to upper and lower canines. The mini-implants were used after surgery to settle the bite with elastics. Figure 21 shows the progress of the case and the use of temporary anchorage devices in settling the bite.

Fig. 20. Placement of passive stainless steel wires prior to surgery.

After careful treatment planning, model surgery was performed to predict the final position of teeth and fabricate the splint. Prior to surgery, teeth were bonded and stainless steel arch wires were passively engaged (Figure 20). Patient underwent a two-jaw surgical procedure and at the time of surgery four mini-implants were placed mesial to upper and lower canines. The mini-implants were used after surgery to settle the bite with elastics. Figure 21 shows the

progress of the case and the use of temporary anchorage devices in settling the bite.

Fig. 20. Placement of passive stainless steel wires prior to surgery.

Fig. 21. Progress Records.

Case was finished in nineteen months with acceptable occlusion and facial aesthetics achieved. Figure 22 shows the final records.

Fig. 22. Final Records.

Fig. 22. Final Records.

The use of temporary anchorage devices becomes more crucial in more complicated cases that are attempted with the surgery first approach. When extractions or segmented osteotomies are planned, prediction of the final occlusion is far more challenging and placement of miniimplants during the surgery allows for efficient mechanics post- surgically. Figure 23 shows the initial presentation of a female patient who was treatment planned for three-piece maxillary osteotomy and mandibular set-back procedures due to a severe transverse discrepancy between the upper and lower jaws and excessive proclination of upper incisors.

Fig. 23. Initial Records.

Upper first premolars were extracted during the surgical procedure and at the same time eight mini-implants were placed. Figure 24 shows the progress of the case immediately after surgery and in weeks that followed.

#### Fig. 24. Progress Records.

The case was finished in nineteen months and the patient was very pleased with the results. Figure 25 illustrates the final records of the patient at the time of appliance removal. Considering the complexity of the case, the treatment time was significantly reduced. However, the upper left canine showed discoloration as treatment continued possibly indicating necrosis as a result of the segmental osteotomy procedure.

Upper first premolars were extracted during the surgical procedure and at the same time eight mini-implants were placed. Figure 24 shows the progress of the case immediately after

The case was finished in nineteen months and the patient was very pleased with the results. Figure 25 illustrates the final records of the patient at the time of appliance removal. Considering the complexity of the case, the treatment time was significantly reduced. However, the upper left canine showed discoloration as treatment continued possibly

indicating necrosis as a result of the segmental osteotomy procedure.

surgery and in weeks that followed.

Fig. 24. Progress Records.

Fig. 25. Final Records.

#### **5. Disadvantages and potential problems**

Performing the surgical procedure prior to orthodontic treatment has multiple advantages, particularly the shortened treatment time. However, there are many drawbacks to this approach which should be taken into consideration.

Predicting the final occlusion is the hardest challenge with surgery first approach. In many cases, the upper and lower models cannot be placed in an ideal occlusion due to multiple dental interferences. If the predicted final occlusion is not achievable or is not planned accurately, the result will be far from ideal. Cases requiring extractions are especially very difficult to plan when performing surgery first. Thus, case selection is of utmost importance.

Even when the final occlusion has been determined carefully by the orthodontist, the surgical procedure must be performed meticulously since any minor surgical error can compromise the result. Hence, the treating orthodontist and orthognathic surgeon must be experienced enough to be able to know the limitations and possibilities.

The planning process is very time consuming in contrast to the total treatment time which is usually shortened. This becomes a financial issue for the treating orthodontist in many cases. Increasing the treatment fee is one solution but it should be reasonable to the patient.

When passive stainless steel wires are placed prior to surgery each wire must be bent to rest passively on the surface of each tooth. This is also another challenging and time consuming procedure for the orthodontist especially when teeth are severely rotated and misaligned. To simplify the pre-surgical bonding procedure, some orthodontists bond the wires directly to the surface of teeth without using any brackets. Even though this can simplify the presurgical appointment, the authors note that there is a higher failure rate during surgery and the need for another bonding appointment at the initiation of orthodontic treatment. Indirect bonding technique can be utilized to allow for accurate bracket positioning as well as bending the passive arch wires beforehand.

To utilize the maximum potential of the regional acceleratory phenomenon, two jaw surgeries are preferred. Also, severe transverse discrepancies sometimes lead to two-piece or three-piece Le Fort I osteotomies. The increase in the number and complexity of osteotomy procedures poses a greater risk to the patient.

#### **6. A look into the future of "Surgery First" approach**

Despite the many challenges associated with performing the orthognathic surgery prior to decompensation of the arches, the basics of this approach can be incorporated into treatment planning other surgical cases to reduce the pre-surgical treatment time. Careful treatment planning and prioritizing the steps that are absolutely necessary prior to the surgical procedure while leaving other steps until the surgery is performed can speed up the process. In doing so, the patient will be able to have the surgery sooner than the traditional approach and the orthodontist will be able to use the rapid acceleratory phenomenon when it is needed the most.

Figure 26 shows the initial presentation of a patient who presented with severe skeletal Class III malocclusion and anterior open bite. The upper incisors were proclined and the lower incisors were severely retroclined. The lower right lateral incisor was lingually blocked out and the lower arch was constricted with lingually tipped teeth.

The complexity of the case called for starting the orthodontic treatment before performing surgery. However, during the treatment planning process the emphasis was placed on doing minimal orthodontic preparation for surgery to reduce the time spent in pre-surgical orthodontics. The decompensation process in this case would have otherwise taken a very long time if the conventional approach was utilized.

One month after placement of brackets on the upper arch, a lower Schwartz expansion appliance was used to expand the lower arch and upright the lower posterior segments. The

accurately, the result will be far from ideal. Cases requiring extractions are especially very difficult to plan when performing surgery first. Thus, case selection is of utmost importance. Even when the final occlusion has been determined carefully by the orthodontist, the surgical procedure must be performed meticulously since any minor surgical error can compromise the result. Hence, the treating orthodontist and orthognathic surgeon must be

The planning process is very time consuming in contrast to the total treatment time which is usually shortened. This becomes a financial issue for the treating orthodontist in many cases. Increasing the treatment fee is one solution but it should be reasonable to the patient. When passive stainless steel wires are placed prior to surgery each wire must be bent to rest passively on the surface of each tooth. This is also another challenging and time consuming procedure for the orthodontist especially when teeth are severely rotated and misaligned. To simplify the pre-surgical bonding procedure, some orthodontists bond the wires directly to the surface of teeth without using any brackets. Even though this can simplify the presurgical appointment, the authors note that there is a higher failure rate during surgery and the need for another bonding appointment at the initiation of orthodontic treatment. Indirect bonding technique can be utilized to allow for accurate bracket positioning as well

To utilize the maximum potential of the regional acceleratory phenomenon, two jaw surgeries are preferred. Also, severe transverse discrepancies sometimes lead to two-piece or three-piece Le Fort I osteotomies. The increase in the number and complexity of

Despite the many challenges associated with performing the orthognathic surgery prior to decompensation of the arches, the basics of this approach can be incorporated into treatment planning other surgical cases to reduce the pre-surgical treatment time. Careful treatment planning and prioritizing the steps that are absolutely necessary prior to the surgical procedure while leaving other steps until the surgery is performed can speed up the process. In doing so, the patient will be able to have the surgery sooner than the traditional approach and the orthodontist will be able to use the rapid acceleratory phenomenon when

Figure 26 shows the initial presentation of a patient who presented with severe skeletal Class III malocclusion and anterior open bite. The upper incisors were proclined and the lower incisors were severely retroclined. The lower right lateral incisor was lingually

The complexity of the case called for starting the orthodontic treatment before performing surgery. However, during the treatment planning process the emphasis was placed on doing minimal orthodontic preparation for surgery to reduce the time spent in pre-surgical orthodontics. The decompensation process in this case would have otherwise taken a very

One month after placement of brackets on the upper arch, a lower Schwartz expansion appliance was used to expand the lower arch and upright the lower posterior segments. The

blocked out and the lower arch was constricted with lingually tipped teeth.

experienced enough to be able to know the limitations and possibilities.

as bending the passive arch wires beforehand.

it is needed the most.

osteotomy procedures poses a greater risk to the patient.

long time if the conventional approach was utilized.

**6. A look into the future of "Surgery First" approach** 

expansion screw was activated two times per week. Figure 27 shows the progress of the case at 1 month, 2 months, and 6 months after the initiation of orthodontic treatment.

Fig. 26. Initial Records.

Fig. 27. Progress Records.

The upper right second molar required a significant amount of buccal root torque in preparation of surgery. A temporary anchorage device was placed palatally between the upper right first and second molars and a power chain was used from the screw to achieve ideal torque. After eight months of orthodontic preparation, the case was ready for orthognathic surgery. Note that the alignment of the arches was not complete but the model surgery performed at this point indicated that the surgical procedure could be performed and the remainder of orthodontic tooth movements could be finished after surgery utilizing the regional acceleratory phenomenon. Figure 28 shows the model surgery and the intraoral pictures at the time of placement of passive archwires for surgery.

Fig. 28. Model surgery and records right before surgery.

After the operation was performed, the leveling, alignment, and the decompensation were completed in one year. Figure 29 shows the progress of the case immediately after, one month, four months, and twelve months after surgery. Note the use of temporary anchorage devices post-surgically.

The upper right second molar required a significant amount of buccal root torque in preparation of surgery. A temporary anchorage device was placed palatally between the upper right first and second molars and a power chain was used from the screw to achieve ideal torque. After eight months of orthodontic preparation, the case was ready for orthognathic surgery. Note that the alignment of the arches was not complete but the model surgery performed at this point indicated that the surgical procedure could be performed and the remainder of orthodontic tooth movements could be finished after surgery utilizing the regional acceleratory phenomenon. Figure 28 shows the model surgery and the intraoral

pictures at the time of placement of passive archwires for surgery.

Fig. 28. Model surgery and records right before surgery.

devices post-surgically.

After the operation was performed, the leveling, alignment, and the decompensation were completed in one year. Figure 29 shows the progress of the case immediately after, one month, four months, and twelve months after surgery. Note the use of temporary anchorage

Fig. 29. Progress records A) immediately after, B) one month C) four months D) twelve months after surgery.

The case was debonded after a total treatment time of 22 months which included 8 months of presurgical orthodontics. Figure 30 shows the final records of the patient at the time of appliance removal.

Fig. 30. Final Records.

This case illustrates that the surgery first approach concepts can be modified to fit the specific needs of the patient. The main principle to keep in mind is not to spend countless months to achieve the absolute ideal presurgical decompensation and leveling. The surgical procedure should be performed as soon as the occlusion allows for a stable post-surgical transitional occlusion. Once again, the experience of the orthodontist and the surgeon are extremely important in treating these cases.

#### **7. Conclusion**

Performing orthognathic surgery before orthodontic treatment has multiple advantages including but not limited to shortened treatment time, increased patient acceptance, and the utilization of the regional acceleratory phenomenon. If the cases are selected carefully, the orthodontist and the surgeon are experienced enough to predict the final occlusion beforehand, and the level of cooperation between the clinicians is high, the results are very promising. However, even the slightest error during the treatment planning, surgical, and post-surgical orthodontic steps can be very difficult to correct. By utilizing the principles of surgery first technique, the pre-surgical orthodontics period can be shortened even if it is not eliminated. As with any other surgical procedure, the patient's well-being and chief complaint should always be the first priority. The future of orthognathic surgery is geared toward minimizing the overall treatment time without compromising the final results.

#### **8. Acknowledgments**

Jeong Kim thanks Dr. Sang H. Park for his collaboration and Dr. Barry Grayson for guidance.

#### **9. References**

298 Orthodontics – Basic Aspects and Clinical Considerations

This case illustrates that the surgery first approach concepts can be modified to fit the specific needs of the patient. The main principle to keep in mind is not to spend countless months to achieve the absolute ideal presurgical decompensation and leveling. The surgical procedure should be performed as soon as the occlusion allows for a stable post-surgical transitional occlusion. Once again, the experience of the orthodontist and the surgeon are

Performing orthognathic surgery before orthodontic treatment has multiple advantages including but not limited to shortened treatment time, increased patient acceptance, and the utilization of the regional acceleratory phenomenon. If the cases are selected carefully, the orthodontist and the surgeon are experienced enough to predict the final occlusion beforehand, and the level of cooperation between the clinicians is high, the results are very promising. However, even the slightest error during the treatment planning, surgical, and post-surgical orthodontic steps can be very difficult to correct. By utilizing the principles of surgery first technique, the pre-surgical orthodontics period can be shortened even if it is not eliminated. As with any other surgical procedure, the patient's well-being and chief complaint should always be the first priority. The future of orthognathic surgery is geared toward minimizing the overall treatment time without compromising the final results.

Fig. 30. Final Records.

**7. Conclusion** 

extremely important in treating these cases.


## 

 

#### 

300 Orthodontics – Basic Aspects and Clinical Considerations

Liou, E.J.; Chen, P.H.; Wang, Y.C.; Yu, C.C.; Huang, C.S. & Chen, Y.R. (2011). Surgery-First

Luther, F.; Morris, D.O. & Hart, C. (2003). Orthodontic Preparation for Orthognathic

Nagasaka, H.; Sugawara, J.; Kawamura, H. & Nanda, R. (2009). "Surgery First" Skeletal

*Orthodontics*, Vol.43, No.2, (February, 2009), pp. 97-105, ISSN 0022-3875 O'Brien, K.; Wright, J.; Conboy, F.; Appelbe, P.; Bearn, D.; Caldwell, S.; Harrison, J.; Hussain,

Orthodontic Efficiency," March 18-20, 2011, Houston, Texas

No.2, (February, 2003), pp. 79-86, ISSN 0288-2027

781-785, ISSN 0278-2391

0266-4356

0022-3875

0198-7569

ISSN 2072-0939

Accelerated Orthognathic Surgery: Postoperative Rapid Orthodontic Tooth Movement, *Journal of Oral and Maxillofacial Surgery*, Vol.69, No.3, (March, 2011), pp.

Surgery: How Long Does It Take and Why? A Retrospective Study. *British Journal of Oral and Maxillofacial Surgery*, Vol.41, No.6, (December, 2003), pp. 401-406, ISSN

Class III Correction Using the Skeletal Anchorage System. *Journal of Clinical* 

J.; Lewis, D.; Littlewood, S.; Mandall, N.; Morris, T.; Murray, A.; Oskouei, M.; Rudge, S.; Sandler, J.; Thiruvenkatachari, B.; Walsh, T. & Turbill, E. (2009). Prospective, Multi-Center Study of the Effectiveness of Orthodontic/Orthognathic Surgery Care in the United Kingdom, *American Journal of Orthodontics and Dentofacial Orthopedics*, Vol.135, No.6, (June, 2009), pp. 709-714, ISSN 0889-5406 Park, S.; Hyon, W.L.; Lee, J.G.; Lee, S.; Lee, Y. & Shin, S. (2011). Increasing Efficiency and

Improving Patient Compliance/Affordability/Orthognathic Surgery With Surgery First Orthognathic Approach (SFOA) . Abstract from *Proceedings of the 3rd William H. Bell Lectureship Symposium*, "Accelerated Orthognathic Surgery and Increased

First" Orthognathics to Correct a Skeletal Class II Malocclusion with an Impinging Bite. *Journal of Clinical Orthodontics*, Vol.44, No.7, (July, 2010), pp. 429-438, ISSN

Treatment for Orthognathic Surgery in Answer to Patient's Request of Immediate Facial Aspect Change. *Journal of Japan Society of Aesthetic Plastic Surgery*, Vol.25,

Dentofacial Asymmetry Using a "Surgery First" Approach. *Journal of Clinical* 

Alveolar Reshaping: Two Case Reports of Decrowding. *International Journal of Periodontics & Restorative Dentistry*, Vol.21, No.1, (February, 2001), pp. 9-19, ISSN

Osteogenic Orthodontics Technique: a 1-Stage Surgically Facilitated Rapid Orthodontic Technique With Alveolar Augmentation. *Journal of Oral Maxillofacial* 

in Surgical-Orthodontic Treatment of Mandibular Prognathism – A Case Report, *Chang Gung Medical Journal*, Vol.33, No.6, (November-December, 2010), pp. 699-705,

Sugawara, J.; Aymach, Z.; Nagasaka, D.H.; Kawamura, H. & Nanda, R. (2010). "Surgery

Tsuroda, H. & Miyamoto, Y. (2003). None or Minimum Pre-operative Orthodontic

Villegas, C.; Uribe, F.; Sugawara, J. & Nanda, R. (2010). Expedited Correction of Significant

Wilcko, M.T.; Wilcko, W.M.; Pulver, J.J.; Bissada, N.F. & Bouquot, J.E. (2009) Accelerated

*Surgery*, Vol.67, No.10, (October, 2009), pp.2149-2159, ISSN 0278-2391 Yu, C.C.; Chen, P.H.; Liou, E.J.; Huang, C.S. & Chen, Y.R. (2010). A Surgery-First Approach

*Orthodontics*, Vol.44, No.2, (February, 2010), pp. 97-103, ISSN 0022-3875 Wilcko, W.M.; Wilcko, T.; Bouquot, J.E. & Ferguson, D.J. (2001) Rapid Orthodontics With  

 














## **Part 4**

## **Temporomandibular Disorder and Orthodontic**

## **Occlusion, Orthodontic Treatment and Temporomandibular Disorders: Myths and Scientific Evidences**

Ephraim Winocur and Alona Emodi-Perlman *Department of Oral Rehabilitation, the Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel* 

#### **1. Introduction**

Temporomandibular joint (TMJ) disorders and related masticatory muscle pain represent the most common chronic orofacial pain condition, and are the main cause of pain of non dental origin in the oro-facial region including head ,neck and face (de Leeuw 2008). The etiology of temporomandibular disorders (TMD) is multifactorial. One of historical proposed factors was improper occlusion (Egermark-Eriksson et al 1990, Kirverskari et al 1992, Pullinger 1993).

In the late 1980s the attention of the orthodontic community regarding TMD was awakened following litigation involving orthodontic treatment as the cause of TMD in an orthodontic patient in the US court. The orthodontist at cause lost the case only because at that time there was a lack in evidence based medicine literature (Pollack 1988).

In 1987 the Board of Trustees of the American Association of Orthodontists (AAO) passed a motion "that the AAO immediately initiate a program to conduct documented studies for the purpose of determining the relationship, or lack thereof, between orthodontic treatment and temporomandibular joint disorders." They also moved to form a new task-oriented committee, the Scientific Studies Committee, to conduct the program. Early in 1988, the committee was formed, consisting of persons with recognized knowledge in this area but with differing backgrounds: a prosthodontist, an oral pathologist, a general practitioner, and two orthodontists. Their conclusion was that orthodontic treatment generally is not a primary factor in TMD (Behrents and White 1992).

Since then many important investigations have been conducted, but still the possible association between orthodontic therapy and TMD signs and symptoms is a matter of debate among orthodontists, orthognatic surgeons, dentists and dental patients.

With the development of new aesthetic orthodontic techniques (lingual orthodontics, invisaline etc.) more adults seek orthodontic treatments, and therefore there appears to be an increased likelihood of orthodontic patients having TMD. Orthodontist should be capable to recognize the signs and symptoms of TMD already during the anamnestic appointment, to inform the patient of the finding, to point it out in the patient file, and if necessary to refer the patient to an Orofacial/TMD specialist.

The objective of this chapter is to discuss the effectiveness of orthodontic intervention in reducing symptoms in people with temporomandibular disorders and to establish if there is any evidence based data that proves that active orthodontic intervention leads to TMD.

In order to fulfill these objectives the following questions should be asked:


#### **2. Temporomandibular disorders**

Temporomandibular disorder (TMD) is a collective term that embraces a number of clinical problems that involve the masticatory muscles, the TMJs and its associated structures, or both. TMD is considered a musculo-skeletal disorder. It is the most prevalent clinical entity affecting the masticatory apparatus, and is the main cause of pain of non dental origin in the oro-facial region (de Leeuw 2008). The main TMD symptom is pain in the masticatory muscles, preauricular area and/or TMJ. As usual in all the musculo-skeletal disorders, pain increases during masticatory function. Other common signs or symptoms are limited or altered jaw movements, joint noises (eg. clicks, crepitus, etc), earache, headache, non specific dental tooth pain etc (Carlsson and de Boever 1994; Dworkin and LeResche 1992). For details regarding the guidelines for classification, assessment and management of TMD please refer to de Leeuw 2008.

The prevalence of TMD signs (e.g. abnormal jaw movements, joint noises, and tenderness on palpation) in the general population, as demonstrated by epidemiologic studies ranges up to 75% of the population. Approximately 33% of the population has at least one symptom (e.g. facial pain, joint pain) (Rugh 1985;Schiffman 1988; Friction and Schiffman 1995).

It is important to state that symptoms and signs are not real muscular or articular compound temporomandibular disorders. A single symptom or sign from the masticatory system is not synonymous with TMD, or automatically leads to a TMD diagnosis. In order to diagnose TMD formal diagnostic criteria should be fulfilled. For more details regarding the diagnosis of TMD, please refer to the AAOP guidelines (de Leeuw 2008), or to the Research Diagnostic Criteria for TMD (Dworkin and Le Resche 1992).

The aetiology and the pathophysiology of TMD are poorly understood. It is generally accepted that it is a multifactorial phenomenon. Contributing factors (central, peripheral, behavioral psychological, physical, etc) may predispose, initiate, or perpetuate temporomandibular disorders. Normally great physiologic and external forces are absorbed in the masticatory system with no consequence. But, if the forces exceed the individual genetic- physiologic tolerance the system may undergo detrimental changes. When the structural tolerance is exceeded breakdown will occur in the weakest structure of the system (teeth, muscles or joints) (Okeson, 2003). In the past occlusion was considered to be the most important contributing factor in TMD, but more recent studies concluded that occlusal factors play no role in the developing of TMD (see below) .

### **3. Occlusion and occlusal adjustment**

328 Orthodontics – Basic Aspects and Clinical Considerations

appointment, to inform the patient of the finding, to point it out in the patient file, and if

The objective of this chapter is to discuss the effectiveness of orthodontic intervention in reducing symptoms in people with temporomandibular disorders and to establish if there is any evidence based data that proves that active orthodontic intervention leads to TMD.

Temporomandibular disorder (TMD) is a collective term that embraces a number of clinical problems that involve the masticatory muscles, the TMJs and its associated structures, or both. TMD is considered a musculo-skeletal disorder. It is the most prevalent clinical entity affecting the masticatory apparatus, and is the main cause of pain of non dental origin in the oro-facial region (de Leeuw 2008). The main TMD symptom is pain in the masticatory muscles, preauricular area and/or TMJ. As usual in all the musculo-skeletal disorders, pain increases during masticatory function. Other common signs or symptoms are limited or altered jaw movements, joint noises (eg. clicks, crepitus, etc), earache, headache, non specific dental tooth pain etc (Carlsson and de Boever 1994; Dworkin and LeResche 1992). For details regarding the guidelines for classification, assessment and management of TMD

The prevalence of TMD signs (e.g. abnormal jaw movements, joint noises, and tenderness on palpation) in the general population, as demonstrated by epidemiologic studies ranges up to 75% of the population. Approximately 33% of the population has at least one symptom (e.g.

It is important to state that symptoms and signs are not real muscular or articular compound temporomandibular disorders. A single symptom or sign from the masticatory system is not synonymous with TMD, or automatically leads to a TMD diagnosis. In order to diagnose TMD formal diagnostic criteria should be fulfilled. For more details regarding the diagnosis of TMD, please refer to the AAOP guidelines (de Leeuw 2008), or to the

The aetiology and the pathophysiology of TMD are poorly understood. It is generally accepted that it is a multifactorial phenomenon. Contributing factors (central, peripheral, behavioral psychological, physical, etc) may predispose, initiate, or perpetuate temporomandibular disorders. Normally great physiologic and external forces are absorbed in the masticatory system with no consequence. But, if the forces exceed the individual genetic- physiologic tolerance the system may undergo detrimental changes. When the structural tolerance is exceeded breakdown will occur in the weakest structure of the system (teeth, muscles or joints) (Okeson, 2003). In the past occlusion was considered to be the most important contributing factor in TMD, but more recent studies concluded that occlusal

facial pain, joint pain) (Rugh 1985;Schiffman 1988; Friction and Schiffman 1995).

Research Diagnostic Criteria for TMD (Dworkin and Le Resche 1992).

factors play no role in the developing of TMD (see below) .

necessary to refer the patient to an Orofacial/TMD specialist.

1. Does occlusal interferences cause TMD?

3. Does orthodontic treatment cause TMD?

4. Does orthodontic treatment cure or prevent TMD?

2. Does malocclusion cause TMD?

**2. Temporomandibular disorders** 

please refer to de Leeuw 2008.

In order to fulfill these objectives the following questions should be asked:

Occlusion is defined as "the static relationship between the incising or occlusal surfaces of the maxillary or mandibular teeth or tooth analogues. The occlusion should be balanced and as stress free as possible" (The glossary of prosthodontics terms, 2005)

When occlusion was recognized as the main etiologic factors of bruxism and TMD, one of the main therapies used was occlusal adjustment that tried to eliminate all "tooth contacts that inhibit the remaining occluding surfaces from achieving stable and harmonious contacts (occlusal interferences) and may produce pathologic changes in the stomatognathic system (Bakke et al 1992). With time more and more evidenced based data accumulated against this invasive, irreversible technique. We should keep in mind that the prevalence of malocclusion is high: 42 % of the population exhibit Angle class 1, 23 % is class 2 malocclusion and 4% have class 3 malocclusion (Gremillion 1995). In other words, only 31% of the population has a normo-occlusion ("ideal occlusion") according to Angle's classification. Does 69% of the population suffer from TMD, and need to be treated? The answer is definitively NO!

### **4. Temporomandibular disorders & occlusion**

The possible relationship between malocclusion and TMD was first reported in1934 by the otorhinolaryngologist Costen (Costen 1934). After analyzing 11 patients Costen hypothesized that dental changes (e.g. loss of vertical dimension and deep bite) led to anatomical changes in the temporomandibular joints, creating a syndrome composed of impaired hearing, tinnitus, dizziness, burning sensation in the throat and pain of unknown origin on side of face. The treatment proposed by Costen was "correction of the overbite, renewal of molar support to take pressure off the condyle….". The Costen's syndrome converted the temporomandibular disorders into another dental discipline. Dentists started treating patients suffering from "Costen syndrome" with bite raising appliances that augmented the vertical occlusal dimension of the face.

Old myths regarding the relationship between orthodontics treatment and TMD were twofold: In one hand, the myths that orthodontic treatment when done according to specific functional occlusion guidelines (gnathologic principles) reduces the likelihood of subsequently developing temporomandibular disorders, was rebutted. On the other hand the fact that the use of certain traditional orthodontic procedures and/or appliances may increase the likelihood of subsequently developing temporomandibular disorders could not be evidence proved (Rinchuse and Kandasamy , 2009). Many common myths among orthodontists were discussed and declined (Rinchuse and Kandasamy, 2009).The myths were that people with certain types of untreated malocclusion (eg. class II Division 2, deep overbite, and crossbite), excessive incisal guidance or people with gross maxilla – mandibular disharmonies are more likely to develop TMD. Other myths discussed were that pre-treatment radiographs of both TMJs should be taken before starting orthodontic treatment since the position of each condyle in its fossa should be assessed and corrected. They myth rebutted was that adult patients who have some type of occlusal disharmony along with the presence of temporomandibular disorder symptoms will probably require some form of occlusal correction. Finally, they could not found any evidence that retrusion

of the mandible (because of natural causes or after treatment procedures) may cause the articular disc to slip off the front of the condyle and become a major factor in the aetiology of temporomandibular disorders. The assumption that premolar extractions in the upper arch can cause a posterior displacement of the condyle which in turn could be associated with increased risk of joint dysfunction was also refuted (Bonilla et al 1999; Keshvad and Winstanley 2001; Gallo et al 2005). It can be concluded that since none of the above was ever proven, and accordingly cannot stand as evidence based medicine, clinicians should refrain from adopting therapeutic procedures based on it.

Micheloti et al (2005) investigated the effect of an acute occlusal interference on habitual muscle activity. Each individual was monitored for 6 weeks in 4 different conditions: 1.interference free at the beginning, 2.active interference, 3.dummy interference, 4. interference free at the end .The activity of the masseter muscle ipsilateral to the interference side was recorded by a portable EMG recorder. The response of the masticatory system to active occlusal interferences was a reduction in daytime habitual activity of the masseter muscle. None of the subjects reported signs and/or symptoms of TMD. It should be kept in mind that this study was performed on healthy subjects (without present or passed history of TMD). It may be possible that patients suffering already from TMD react differently to an experimentally introduced occlusal interference due to a deficiency in their adaptation capacity (Le Bell et al 2002). This hypothesis is also based in the observation that TMD patients do keep their teeth in contact more often during daytime (Chen, 2005) and therefore are more likely to feel the interference as a disturbing factor (Le Bell et al, 2006; Cao et al 2009). To test this assumption Le Bell et al (2002) performed a randomized double-blind clinical set-up that included healthy women without TMD as well as women with an earlier TMD history. Both groups were randomly divided into true and placebo interference groups. The subjects without a TMD history showed fairly good adaptation to the interferences, but the subjects with a TMD history and true interferences showed a significant increase in clinical signs compared to the other groups. The authors suggest that the etiological role of occlusal interferences in TMD may not have been correctly addressed in previous studies with artificial interferences and allow no conclusions as regards TMD etiology. Bell's group further analyzed the subjective reactions of these individuals. They found that the most prominent symptoms were occlusal discomfort and chewing difficulties. The group reached the conclusion that difference in outcome between the groups with and without a TMD history suggests that there are individual differences in vulnerability to occlusal interferences (LeBell 2006). In a third study (Niemi et al, 2006) the group tested the psychological factors and responses to artificial interferences in subjects with and without a history of TMD. They concluded that psychological factors appear significant for the symptom responses to artificial interferences, and they seem to play a different role in responses in subjects with an earlier TMD history compared to those without.

An occlusal interference animal model was conducted on rats (Cao 2009) by directly bonding crowns of different heights on their molars. The rats showed bilateral mechanical hyperalgesia in the masticatory muscles. The induced hyperalgesia remained 6 days after removal of the crowns and was reduced by injecting N-meyhyl-D-aspartate antagonist, suggesting a central sensitization mechanism. The animal model described mimics clinical masticatory muscle pain and provided a method to further investigate mechanisms of occlusion – related muscle hyperalgesia, and to explore possible pain management strategies.

of the mandible (because of natural causes or after treatment procedures) may cause the articular disc to slip off the front of the condyle and become a major factor in the aetiology of temporomandibular disorders. The assumption that premolar extractions in the upper arch can cause a posterior displacement of the condyle which in turn could be associated with increased risk of joint dysfunction was also refuted (Bonilla et al 1999; Keshvad and Winstanley 2001; Gallo et al 2005). It can be concluded that since none of the above was ever proven, and accordingly cannot stand as evidence based medicine, clinicians should refrain

Micheloti et al (2005) investigated the effect of an acute occlusal interference on habitual muscle activity. Each individual was monitored for 6 weeks in 4 different conditions: 1.interference free at the beginning, 2.active interference, 3.dummy interference, 4. interference free at the end .The activity of the masseter muscle ipsilateral to the interference side was recorded by a portable EMG recorder. The response of the masticatory system to active occlusal interferences was a reduction in daytime habitual activity of the masseter muscle. None of the subjects reported signs and/or symptoms of TMD. It should be kept in mind that this study was performed on healthy subjects (without present or passed history of TMD). It may be possible that patients suffering already from TMD react differently to an experimentally introduced occlusal interference due to a deficiency in their adaptation capacity (Le Bell et al 2002). This hypothesis is also based in the observation that TMD patients do keep their teeth in contact more often during daytime (Chen, 2005) and therefore are more likely to feel the interference as a disturbing factor (Le Bell et al, 2006; Cao et al 2009). To test this assumption Le Bell et al (2002) performed a randomized double-blind clinical set-up that included healthy women without TMD as well as women with an earlier TMD history. Both groups were randomly divided into true and placebo interference groups. The subjects without a TMD history showed fairly good adaptation to the interferences, but the subjects with a TMD history and true interferences showed a significant increase in clinical signs compared to the other groups. The authors suggest that the etiological role of occlusal interferences in TMD may not have been correctly addressed in previous studies with artificial interferences and allow no conclusions as regards TMD etiology. Bell's group further analyzed the subjective reactions of these individuals. They found that the most prominent symptoms were occlusal discomfort and chewing difficulties. The group reached the conclusion that difference in outcome between the groups with and without a TMD history suggests that there are individual differences in vulnerability to occlusal interferences (LeBell 2006). In a third study (Niemi et al, 2006) the group tested the psychological factors and responses to artificial interferences in subjects with and without a history of TMD. They concluded that psychological factors appear significant for the symptom responses to artificial interferences, and they seem to play a different role in

responses in subjects with an earlier TMD history compared to those without.

An occlusal interference animal model was conducted on rats (Cao 2009) by directly bonding crowns of different heights on their molars. The rats showed bilateral mechanical hyperalgesia in the masticatory muscles. The induced hyperalgesia remained 6 days after removal of the crowns and was reduced by injecting N-meyhyl-D-aspartate antagonist, suggesting a central sensitization mechanism. The animal model described mimics clinical masticatory muscle pain and provided a method to further investigate mechanisms of occlusion – related muscle hyperalgesia, and to explore possible pain management strategies.

from adopting therapeutic procedures based on it.

Christensen and Rassouli (1995) placed a rigid unilateral intercuspal interference in 12 subjects, and obtained bipolar surface electromyograms from the right and left masseter muscles during brisk and forceful clenching on the interference. On the side opposite the interference, myoelectric clenching activity was significantly reduced. Correlation analyses showed that the interference elicited a non-linear (complex) co-ordination of the amplitude, but not the duration, of bilateral masseteric clenching activity, i.e. frequently there was significant motor facilitation on the side of the interference, and significant motor inhibition on the side opposite the interference. The author further performed theoretical considerations that predicted that the observed contraction patterns would easily lead to frontal plane rotations of the mandible.

This was further supported by Clark et al (1999). The conclusion of their literature review was that experimental occlusal interferences may induce transient local tooth pain, loosening of the tooth, a slight change in postural muscle tension levels, chewing stroke patterns, and sometimes a clicking joint. They were of the opinion that since such findings are present in relatively asymptomatic patients, these data do not prove that occlusal interferences are causally related to a chronic jaw muscle pain or TMD.

Finally it could be hypothesized that subjects who are occlusally hypervigilant and or predisposed to suffer from TMD may be disturbed by occlusal interferences and increase the activity of the masticatory muscles which leads to pain and dysfunction as demonstrated by McDermid et al (1996); Raphael et al (2000);Hollins et al (2009).In some cases a very serious intractable disorder may be induced by occlusal changes. This disorder was term by Clark (2003) occlusal dysesthesia and is defined as "a persistent uncomfortable sense of maximum intercuspation after all pulpal, periodontal, muscle and TMJ pathologies have been ruled out and a physically obvious bite discrepancy cannot be observed". This serious disorder is was previously termed by Marbach et al (1983) "phantom bite syndrome".

#### **5. Temporomandibular disorders & orthodontics**

An article by McNamara et al (1995) represents the evolution of a solicited manuscript first presented at the International Workshop on the TMDs and Related Pain Conditions, sponsored by the National Institute of Health (Hunt Valley, Md., April 17 to 20, 1994).

Its conclusions were:"(1) signs and symptoms of TMD may occur in healthy persons; (2) signs and symptoms of TMD increase with age, particularly during adolescence, until menopause, and therefore TMDs that originate during orthodontic treatment may not be related to the treatment; (3) in general, orthodontic treatment performed during adolescence does not increase or decrease the chances of development of TMD later in life; (4) the extraction of teeth as part of an orthodontic treatment plan does not increase the risk of TMD; (5) there is no increased risk of TMD associated with any particular type of orthodontic mechanics; (6) although a stable occlusion is a reasonable orthodontic treatment goal, not achieving a specific gnathologic ideal occlusion does not result in signs and symptoms of TMD; and (7) there is little evidence that orthodontic treatment prevents TMD, although the role of unilateral posterior crossbite correction in children may warrant further investigation." (McNamara et al,1995;McNamara and Turp 1997).

Pullinger et al (1993) used a multiple logistic regression analysis to compute the odds ratios for 11 common occlusal features for asymptomatic controls vs. five temporomandibular disorder groups. They found that the following features did not increase the odds to develop TMD: retruded contact position (RCP) to intercuspal position (ICP) occlusal slides < 2 mm, slide asymmetry, unilateral RCP contacts, deep overbite, minimal overjet, dental midline discrepancies, < 4 missing teeth, and maxillo-mandibular first molar relationship or cross-arch asymmetry. They found that groupings of a minimum of two to at most five occlusal variables contributed to the TMD patient groups. On the other hand, significant increases in risk occurred selectively with anterior open bite, unilateral maxillary lingual crossbite overjets> 6-7 mm > 5-6 missing posterior, and RCP-ICP slides > 2 mm. The authors were of the opinion that certain features such as anterior open bite in osteoarthrosis patients were considered to be a consequence of rather than etiological factors for the disorder. They concluded "that occlusion cannot be considered the unique or dominant factor in defining TMD populations".

The hypothesis that different orthodontic techniques such as functional appliances class I/II elastics , chin-cup , headgear , fixed or removable appliances as aetiological factors for TMD has been tested in many studies. Dibbets and Van der Weele (1992) compared children treated with different procedures. Patients were monitored for a 20 year period after the start of orthodontic treatment. Although signs and symptoms of TMD increased with age, after 20 years neither orthodontic treatment showed a causal relationship with signs and symptoms of TMD. Henrikson and Nilner (2000) compared class II division 1 treated and untreated females with normal occlusion (11-15 years old) monitored for 2 years. They reported individual fluctuations of TMD symptoms in all 3 groups. Orthodontic treatment did not increase the risk for aggravating pre-treatment signs of TMD. On the contrary subjects with class II and TMD of muscular origin seemed to improve. Rey et al (2008) compared a sample of class III patients treated with mandibular cervical headgear and class I patients treated orthodonticaly and no treated subjects. No difference in TMD prevalence was found between the 3 groups after 2-3 years. Regarding orthognatic surgery, Farella et al (2007), reported that bi-maxillary osteotomy did not initiate or aggravate signs and symptoms of TMD. A 20 year cohort longitudinal study by MacFariane et al (2009) investigated the relationship between orthodontic treatment and TMD concluded that orthodontic treatment neither causes nor prevents TMD and that participants with a history of orthodontic treatment did not have higher risk of new or persistent TMD .

Henrikson and Nilnerl (2000), prospectively and longitudinally studied signs of TMD and occlusal changes in girls with Class II malocclusion receiving treatment, compared to subjects with untreated Class II malocclusion and with normal occlusion subjects. They concluded that orthodontic treatment does not increase the risk for TMD or for worsen pretreatment signs. On the contrary, they found that subjects with Class II malocclusion and signs of muscular TMD seem to benefit from the orthodontics treatment.

#### **6. Conclusions & clinical aspects**

A recent Cochrane systematic review was published (Luther et al 2010). Its objective was to establish the effectiveness of orthodontic intervention in reducing symptoms in patients with TMD (compared with any control group receiving no treatment, placebo treatment or reassurance) and to establish if active orthodontic intervention leads to TMD. The authors identified 284 records from all databases, but only four demonstrated any data that might be of value with respect to TMD and orthodontics. After further analysis of the full texts of the four studies identified, none of the retrieved studies met the inclusion criteria and all were excluded from this review. The authors' conclusions were: "1.There is insufficient research data on which to base our clinical practice on the relationship of active orthodontic intervention and TMD; 2. There is an urgent need for high quality randomized controlled trials in this area of orthodontic practice; 3. When considering consent for patients it is essential to reflect the seemingly random development/alleviation of TMD signs and symptoms.

#### **7. Summary and conclusions**

332 Orthodontics – Basic Aspects and Clinical Considerations

Pullinger et al (1993) used a multiple logistic regression analysis to compute the odds ratios for 11 common occlusal features for asymptomatic controls vs. five temporomandibular disorder groups. They found that the following features did not increase the odds to develop TMD: retruded contact position (RCP) to intercuspal position (ICP) occlusal slides < 2 mm, slide asymmetry, unilateral RCP contacts, deep overbite, minimal overjet, dental midline discrepancies, < 4 missing teeth, and maxillo-mandibular first molar relationship or cross-arch asymmetry. They found that groupings of a minimum of two to at most five occlusal variables contributed to the TMD patient groups. On the other hand, significant increases in risk occurred selectively with anterior open bite, unilateral maxillary lingual crossbite overjets> 6-7 mm > 5-6 missing posterior, and RCP-ICP slides > 2 mm. The authors were of the opinion that certain features such as anterior open bite in osteoarthrosis patients were considered to be a consequence of rather than etiological factors for the disorder. They concluded "that occlusion cannot be considered the unique or dominant factor in defining

The hypothesis that different orthodontic techniques such as functional appliances class I/II elastics , chin-cup , headgear , fixed or removable appliances as aetiological factors for TMD has been tested in many studies. Dibbets and Van der Weele (1992) compared children treated with different procedures. Patients were monitored for a 20 year period after the start of orthodontic treatment. Although signs and symptoms of TMD increased with age, after 20 years neither orthodontic treatment showed a causal relationship with signs and symptoms of TMD. Henrikson and Nilner (2000) compared class II division 1 treated and untreated females with normal occlusion (11-15 years old) monitored for 2 years. They reported individual fluctuations of TMD symptoms in all 3 groups. Orthodontic treatment did not increase the risk for aggravating pre-treatment signs of TMD. On the contrary subjects with class II and TMD of muscular origin seemed to improve. Rey et al (2008) compared a sample of class III patients treated with mandibular cervical headgear and class I patients treated orthodonticaly and no treated subjects. No difference in TMD prevalence was found between the 3 groups after 2-3 years. Regarding orthognatic surgery, Farella et al (2007), reported that bi-maxillary osteotomy did not initiate or aggravate signs and symptoms of TMD. A 20 year cohort longitudinal study by MacFariane et al (2009) investigated the relationship between orthodontic treatment and TMD concluded that orthodontic treatment neither causes nor prevents TMD and that participants with a history of orthodontic treatment did not have higher risk of new or

Henrikson and Nilnerl (2000), prospectively and longitudinally studied signs of TMD and occlusal changes in girls with Class II malocclusion receiving treatment, compared to subjects with untreated Class II malocclusion and with normal occlusion subjects. They concluded that orthodontic treatment does not increase the risk for TMD or for worsen pretreatment signs. On the contrary, they found that subjects with Class II malocclusion and

A recent Cochrane systematic review was published (Luther et al 2010). Its objective was to establish the effectiveness of orthodontic intervention in reducing symptoms in patients

signs of muscular TMD seem to benefit from the orthodontics treatment.

TMD populations".

persistent TMD .

**6. Conclusions & clinical aspects** 


The main articles reviewed in this chapter are summarized in table 1.


No differences in prevalences of occlusal interferences, or in signs or symptoms of TMD

were found between subjects that had corrective orthodontic treatment and those without such treatment. The associations between TMD and different morphological malocclusions were low. Nevertheless, in a long-term perspective cross-bite, both uni- and

bilateral, anterior open bite, post-, and prenormal occlusion had some association

Pressure pain thresholds of the masseter and

significantly from baseline values throughout the whole study period. The occurrence of signs and symptoms of TMD fluctuates with an unpredictable pattern after orthognathic

with the development of CMD.

temporalis muscles did not change

surgery for class III malocclusions.

treatment.

Scientific literature has not convincingly demonstrated a definitive relationship between static occlusal factors and TMD.

Orthodontic treatment do not increase the risk for TMD or for worsen pre-treatment signs. On the contrary, they found that subjects with Class II malocclusion and signs of muscular TMD seem to benefit from the orthodontics

Since subjects with a TMD history and true interferences showed a significant increase in clinical signs compared to the other groups. The authors suggest that the etiological role of occlusal interferences in TMD may not have been correctly addressed in previous studies with artificial interferences and allow no conclusions as regards TMD etiology

The most prominent symptoms following the introduction of artificial occlusal interferences

difficulties. The difference in outcome between the groups with and without a TMD history suggests that there are individual differences in vulnerability to occlusal interferences.

were occlusal discomfort and chewing

Study Reference\* Study design Conclusions & Comments

Longitudinal

Egermark-Eriksson et al 1990

Farella et al

Gremillion

Henrikson et al 2000

> Le Bell et al 2002

> Le Bell et al 2006

<sup>2007</sup>Longitudinal

<sup>2006</sup>Review article

Prospectivelongitudinal

Randomized double-blind clinical set-up

Randomized double-blind clinical set-up



\* References has been arranged alphabetically according to the first author

Table 1. Summary of main articles reviewed.

The main conclusions are the following:


Psychological factors appeared significant for

interferences, and they seem to play a different role in responses in subjects with an earlier TMD history compared to those without.

Occlusion cannot be considered the unique or dominant factor in defining TMD populations.

Subjects with Class III malocclusions treated with mandibular cervical headgear and fixed appliances do not have greater prevalence of TMD symptoms than do Class I subjects treated with fixed appliances or untreated subjects.

(1) Orthodontic gnathologists have proved no health benefit to justify the many perfunctory exercises of the philosophy. (2) The view that occlusion and condyle position are the primary causes of TMD, and that diagnoses and treatments should be based on these notions, has been discredited. (3) There is little to no evidence that treating subjects with TMJ ID will prevent or mitigate future TMD.

the symptom responses to artificial

Study Reference\* Study design Conclusions & Comments

Randomized double-blind clinical set-up

A multiple logistic regression analysis to compute the odds ratios for 11 common occlusal features for asymptomatic controls (n = 147) vs. five temporomandibula r disorder groups (n=413).

> Retrospective Comparative

Special Review Article

\* References has been arranged alphabetically according to the first author

1. TMD is a collective term embracing a number of clinical problems that involve the

2. The pathogenesis of TMD is not dental – related but rather is a part of a wider family of orofacial pain disorders which account for the need to consider neurologic, endocrine and psychosocial factors during the diagnostic process. Occlusion, condyle position, and lack of canine guidance are not the primary causes of TMD (Manfrendini and Nardini 2010). 3. TMD treatments are no longer dental, but are based on biopsychosocial approach (Rinchuse and Kandasamy 2009). Treatment options are: patient education , cognitive behavior therapy (CBT) (Turk et al 1996; Turk 1997), bio feedback, physiotherapy(Stholer 1999) , acupuncture( List et al 1993), transcutaneous nerve stimulation (TENS), low intensity laser , splint therapy (Greco et al 1997; List and Axelsson 2010), drug therapy,

surgical intervention (Al-Riyami et al 2009), but not occlusal definitive;

Table 1. Summary of main articles reviewed.

masticatory muscles and the TMJs.

The main conclusions are the following:

Niemi et al 2006

Pullinger et al 1993

> Rey et al 2008

Rinchuse & Kandasamy 2009


The authors' clinical recommendations are the following:

	- a. Insignificant symptoms such as painless clicking or movement limitation due to prolonged periods of gum chewing or deviations in opening closing pattern should not delay the beginning of orthodontic treatment.
	- b. If pain and severe dysfunction are present the patient should be referred to a TMD specialist before orthodontic therapy is initiated .
	- a. Temporarily stop active orthodontics treatment.
	- b. Perform basic pain management and supportive therapy in order to reduce the symptoms, after which orthodontic treatment may continue.
	- c. If the symptoms persist, the treatment plan should be reconsidered because the patient might become hypervigilant and of poor adaptation capability. An alternative treatment plan should be considered.
	- a. If the patient was informed before treatment about a possible development of TMD, there should not be a problem explaining that TMD was probably not a result of the orthodontics.
	- b. As TMD sign and symptoms tend to be observed between 20 to 30 years old (De Kanter et al 1993;Mohlin et al 2004) there is a possibility of an orthodontic patient developing symptoms after treatment based only on his/her age.

#### **8. References**


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Cao Y , Xie QF, Li K, Light AR , Fu KY. Experimental occlusal interferences induce longterm masticatory muscle hyperalgesia in rats. Pain. 2009;144:287-293. Carlsson GE , DeBoever JA. Epidemiology. In : Zarb GA ,Carlsson GE ,Sesle BJ , Mohl ND

Chen YJ, Gallo LM, Meler D, Palla S. Individualized oblique-axial magnetic resonance

Chen YJ. Frequency of non-functional tooth contacts in normal subjects and patients with a

Christensen LV , Rassouli NM . Experimental occlusal interferences . Part II . Masseteric EMG responses to an intercuspal interference. J Oral Rehabil . 1995;22:521-531. Christensen LV, Rassouli NM. Experimental occlusal interferences. Part I. A review. J Oral

Clark G, Simmons M. Occlusal Dysesthesia and temporomandibular disorders. Is there a

Clark G, Tsukiyama Y, Baba K, Watanabe T. Sixty-eight years of experimental occlusal interference studies . What have we learned? J Prosthet Dent . 1999;82:704-713. Costen JB. A syndrome of ear and sinus symptoms dependent upon disturbed function of the temporomandibular joint. Ann Ortol Rhinol Laryngol. 1934;43:1-15. De Kanter RJ, Truin GJ, Burgersdijk RC, Van't Hop MA,Battistuzzi PG, Kalsbeek H et al.

symptoms of temporomandibular disorder. J Dent Res 1993;72:1509-1518. De Leeuw R (ed) Orofacial pain; guidelines for assessment, diagnosis, and management. 4th

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Friction JR , Schiffman EL. Epidemiology of temporomandibular disorders . in : Fricton JR ,

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## **Orthodontic Treatment and Temporomandibular Disorders**

Ticiana Sidorenko de Oliveira Capote, Silvana Regina Perez Orrico, Juliana Álvares Duarte Bonini Campos, Fernanda Oliveira Bello Correa and Carolina Letícia Zilli Vieira *Araraquara School of Dentistry, São Paulo State University, UNESP Brazil* 

#### **1. Introduction**

340 Orthodontics – Basic Aspects and Clinical Considerations

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Okeson JP (editor): Management of Temporomandibular Disorders and Occlusion .5th

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Raphael KG, Marbach JJ, Gallagher RM. Somatosensory Amplification and Affective Inhibition are elevated in Myofascial face Pain. Pain Med.2000;1:247-253. Rey D, Oberti G, Bacceti T. Evaluation of temporomandibular disorders in class III patients

Richuse DJ, Kandasamy S. Myths of orthodontic gnathology. Am J Orthod Dentofacial

Rudy TE, Turk DC, Kubinski JA, Zaki HS. Differential treatment response of TMD patients

Rugh JD, Solberg WK. Oral health status in the United States. Temporomandibular

Schiffman E, Fricton J, Haley D, Tylka D, A pressure algometer for myofascial pain syndrome;

Stholer CS, Zarb GA. On the management of temporomandibular disorders : a plea for a low-tech , high-prudence therapeutic approach. J Orofac Pain 1999;13:255-61.

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Rehabilitation;vol 37:411-429 june 2010.

2004;74:319-327.

Temporomandibular disorders (TMD) are characterized by dysfunctions involving the muscles related to chewing, the temporomandibular joint (TMJ) and associated structures.

The most frequent symptom is pain, generally located in the chewing muscles, preauricular area and/or TMJ. In addition to pain, patients often experience limited or asymmetric mandibular movements and TMJ sounds most frequently described as snapping, cracking, gnashing or crepitating and headaches may also occur (Okeson, 1998).

Some studies have demonstrated that morphological malocclusions and occlusal interferences alone may not be considered as etiological factors for the development of TMJ dysfunctions (Vanderas, 1993; Perry, 1995). They may be considered as predisposing factors of TMD because currently psychological aspects are more associated with the appearance of the dysfunction.

However according to Mongini (1977), the occurrence of dysfunctional problems of the stomatognathic system may be related to the termination of orthodontic treatment. Other authors have demonstrated the need for occlusal therapy after termination of orthodontic treatment in order to eliminate the risk of bone reabsorption, muscular pain and TMJ disorders resulting from occlusal trauma (Salzman, 1974; Runge et al., 1989; Gianelly, 1989, Kundinger et al., 1991).

Abd Al-Hadi (1993) showed a high dependence between the frequency of TMD and malocclusion class II division I of Angle, function in group, high values of horizontal overlap and a larger number of contacts on the balancing-side. However Kahn et al. (1999), studying the relationship between occlusion and TMD, suggested the lack of any specific difference in the type of occlusal contacts that distinguish symptomatic from asymptomatic patients.

Winocur et al. (2001), assessing the contribution of some parafunctional activities in the appearance of TMD symptoms, concluded that jaw play was the characteristic most associated to deleterious habits and that the chronic use of chewing gum was an important contributor to noises and pain in the joints.

Considering the multifactorial etiology of TMD, its understanding, treatment and possible prevention becomes one of the greatest challenges for practitioners and their patients. So in view of the need for more studies that correlate TMD and predisposing factors, the objective of this study was to analyze the interaction among TMD, orthodontic treatment and some occlusal characteristics.

### **2. Materials and methods**

The study was submitted and approved by the Human Research Ethics Committee of the Araraquara School of Dentistry, UNESP (no. 112/2000) and all patients signed an informed consent for participating in the study.

Seventy three patients were selected, 40 women and 33 men, ranging from 15 to 25 years of age and with no race distinction. Thirty six individuals had been submitted to orthodontic treatment with a fixed apparatus during periods ending from 6 months to 2 years prior to the study (experimental group). Thirty seven patients who never received orthodontic treatment had normal occlusion (control group). The selected patients had 24 to 32 completely erupted teeth with few dental restorations, no prostheses, no occlusal adjustments and no TMD treatment was conducted prior to the study.

The presence of signs and symptoms of TMD was evaluated by means of a questionnaire providing an anamnestic index (Fonseca, 1994), with a variation ranging from the absence of TMD (0 to 19), to mild TMD (20 to 44), moderate TMD (45 to 69), and severe TMD (70 to 100).

For occlusal evaluation, contacts were analyzed in maximum habitual intercuspal position, with the odontological chair positioned at 180° (lying down position) and at 90° (sitting position). The contacts were marked with the aid of a film for occlusal recording.

The mandible was guided to perform lateral movements to the right and left, mapping contacts and interferences on the balancing and working-sides. The lateral disocclusion was classified as canine guidance (contact between canines on the working side, disoccluding the teeth on the balancing side), partial (contact between canines and premolars on the working side, disoccluding the teeth on the balancing side), in group (contact between canines, premolars and molars on the working side, disoccluding the teeth on the balancing side), or atypical (lateral guidance differing from those mentioned above, such as eccentric movement with disocclusion caused by the incisors and the presence of contacts on the balancing side).

All data were collected by a single previously trained and calibrated examiner and noted on an odontogram designed for this study.

#### **2.1 Statistical analysis**

The interaction among the variables temporomandibular disorder (TMD) (absent, present) and orthodontic treatment (Yes, No) with the variables right lateral type of disocclusion, left lateral type of disocclusion and gender (male, female), being assessed separately, was estimated with a log-linear analysis with a Poisson probability model.

In order to compare the average of occlusal contacts and the number of interferences, according to the absence or presence of TMD and orthodontic treatment, the two-factor Analysis of Variance was applied. The hypothesis of normality and homoscedasticity of the dependent variables were assessed by using Shapiro-Wilk's and Levene's test, respectively.

#### **3. Results**

342 Orthodontics – Basic Aspects and Clinical Considerations

associated to deleterious habits and that the chronic use of chewing gum was an important

Considering the multifactorial etiology of TMD, its understanding, treatment and possible prevention becomes one of the greatest challenges for practitioners and their patients. So in view of the need for more studies that correlate TMD and predisposing factors, the objective of this study was to analyze the interaction among TMD, orthodontic treatment and some

The study was submitted and approved by the Human Research Ethics Committee of the Araraquara School of Dentistry, UNESP (no. 112/2000) and all patients signed an informed

Seventy three patients were selected, 40 women and 33 men, ranging from 15 to 25 years of age and with no race distinction. Thirty six individuals had been submitted to orthodontic treatment with a fixed apparatus during periods ending from 6 months to 2 years prior to the study (experimental group). Thirty seven patients who never received orthodontic treatment had normal occlusion (control group). The selected patients had 24 to 32 completely erupted teeth with few dental restorations, no prostheses, no occlusal

The presence of signs and symptoms of TMD was evaluated by means of a questionnaire providing an anamnestic index (Fonseca, 1994), with a variation ranging from the absence of TMD (0 to 19), to mild TMD (20 to 44), moderate TMD (45 to 69), and severe TMD (70 to

For occlusal evaluation, contacts were analyzed in maximum habitual intercuspal position, with the odontological chair positioned at 180° (lying down position) and at 90° (sitting

The mandible was guided to perform lateral movements to the right and left, mapping contacts and interferences on the balancing and working-sides. The lateral disocclusion was classified as canine guidance (contact between canines on the working side, disoccluding the teeth on the balancing side), partial (contact between canines and premolars on the working side, disoccluding the teeth on the balancing side), in group (contact between canines, premolars and molars on the working side, disoccluding the teeth on the balancing side), or atypical (lateral guidance differing from those mentioned above, such as eccentric movement with disocclusion caused by the incisors and the presence of contacts on the

All data were collected by a single previously trained and calibrated examiner and noted on

The interaction among the variables temporomandibular disorder (TMD) (absent, present) and orthodontic treatment (Yes, No) with the variables right lateral type of disocclusion, left

position). The contacts were marked with the aid of a film for occlusal recording.

adjustments and no TMD treatment was conducted prior to the study.

contributor to noises and pain in the joints.

occlusal characteristics.

100).

balancing side).

**2.1 Statistical analysis** 

an odontogram designed for this study.

**2. Materials and methods** 

consent for participating in the study.

Seventy-three individuals participated, from whom 54.8% were female, 50.7% had not been submitted to orthodontic treatment, and 89% presented some degree of temporomandibular disorder. The average age was 20.03+3.38 years old.

The distribution of the participants according to gender, temporomandibular disorder and orthodontic treatment can be found in Table 1.


Table 1. Distribution of individuals according to gender, temporomandibular disorder and orthodontic treatment.

The interaction among the variables temporomandibular disorder (TMD) (absent TMD=0, present TMD=1) and orthodontic treatment (Yes, No) with the variable right lateral type of disocclusion is shown in Table 2.


Table 2. Distribution of individuals according to orthodontic treatment, presence (TMD=1) or absence (TMD=0) of temporomandibular disorder and right lateral disocclusion.

The pattern of total independence between the variables reproduces, appropriately, the scores observed (G2=18.153; p=0.078). There is evidence that the variables are independent (2=16.852; p=0.112).


The interaction among the variables temporomandibular disorder (TMD) (absent TMD=0, present TMD=1) and orthodontic treatment (Yes, No) with the variable left lateral type of disocclusion is shown in Table 3.

Table 3. Distribution of individuals according to orthodontic treatment, presence (TMD=1) or absence (TMD=0) of temporomandibular disorder and left lateral disocclusion.

In the same way as previously, the variables left lateral type of disocclusion, orthodontic treatment and temporomandibular disorder reproduce, appropriately, the scores observed (G2=7.534; p=0.674). There is evidence that the variables are independent (2=8.083; p=0.621).

The interaction among the variables temporomandibular disorder (TMD) (absent TMD=0, present TMD=1) and orthodontic treatment (Yes, No) with the variable gender is shown in Table 4.


Table 4. Distribution of individuals according to orthodontic treatment, presence (TMD=1) or absence (TMD=0) of temporomandibular disorder and gender.

The variables gender, orthodontic treatment and temporomandibular disorder reproduce appropriately, either, the scores observed (G2=2.825; p=0.588). There is evidence that the variables are independent (2=2.778; p=0.596).

The interaction among the variables temporomandibular disorder (TMD) (absent TMD=0, present TMD=1), orthodontic treatment (Yes, No) with the variables number of contacts in sitting position, number of contacts in lying down position, age, number of occlusal interferences on the right side, number of occlusal interferences on the left side is shown in Table 5.

The individuals who were not submitted to orthodontic treatment were significantly older and showed a higher number of sitting contacts and a higher number of left lateral interferences. The individuals without TMD showed a number of sitting and lying down contacts, significantly higher than those individuals with TMD.


Table 5. Distribution of individuals according to orthodontic treatment, presence (TMD=1) or absence (TMD=0) of temporomandibular disorder, number of contacts in sitting position, number of contacts in lying down position, age, number of occlusal interferences on the right side and number of occlusal interferences on the left side.

### **4. Discussion**

344 Orthodontics – Basic Aspects and Clinical Considerations

The interaction among the variables temporomandibular disorder (TMD) (absent TMD=0, present TMD=1) and orthodontic treatment (Yes, No) with the variable left lateral type of

**Left lateral disocclusion TMD=0 TMD=1 TMD=0 TMD=1 Total**  Canine 8 9 12 9 38 Partial 3 2 5 1 11 In group 2 5 2 1 10 Atypical 5 3 3 3 14 **Total** 18 19 22 14 73 Table 3. Distribution of individuals according to orthodontic treatment, presence (TMD=1)

In the same way as previously, the variables left lateral type of disocclusion, orthodontic treatment and temporomandibular disorder reproduce, appropriately, the scores observed (G2=7.534; p=0.674). There is evidence that the variables are independent (2=8.083;

The interaction among the variables temporomandibular disorder (TMD) (absent TMD=0, present TMD=1) and orthodontic treatment (Yes, No) with the variable gender is shown in

**No orthodontic treatment Orthodontic treatment Gender TMD=0 TMD=1 TMD=0 TMD=1 Total**  Male 9 7 9 8 33 Female 9 12 13 6 40 **Total** 18 19 22 14 73 Table 4. Distribution of individuals according to orthodontic treatment, presence (TMD=1)

The variables gender, orthodontic treatment and temporomandibular disorder reproduce appropriately, either, the scores observed (G2=2.825; p=0.588). There is evidence that the

The interaction among the variables temporomandibular disorder (TMD) (absent TMD=0, present TMD=1), orthodontic treatment (Yes, No) with the variables number of contacts in sitting position, number of contacts in lying down position, age, number of occlusal interferences on the right side, number of occlusal interferences on the left side is shown in

The individuals who were not submitted to orthodontic treatment were significantly older and showed a higher number of sitting contacts and a higher number of left lateral interferences. The individuals without TMD showed a number of sitting and lying down

or absence (TMD=0) of temporomandibular disorder and left lateral disocclusion.

or absence (TMD=0) of temporomandibular disorder and gender.

contacts, significantly higher than those individuals with TMD.

variables are independent (2=2.778; p=0.596).

**No orthodontic treatment Orthodontic Treatment** 

disocclusion is shown in Table 3.

p=0.621).

Table 4.

Table 5.

Many etiological factors had been related to TMD among which may be cited arthritis, tumors, congenital malformation, traumatic injuries, degenerative and neurological alterations, muscular diseases, cerebrovascular diseases, occlusal interferences and psychological aspects. According to Okeson (1998) a specific and unique etiologic factor has not been detected.

Over the years, much was discussed about the role of occlusal factors in the etiology of TMD.

Although Schwartz & Chayes (1968) believe that dental occlusion is a secondary factor in the development of TMD, other studies (Stuart, 1964; Guichet & Niles, 1970) have indicated occlusal interference as the primary etiological factor.

On the other hand, Mohlin & Kopp (1978) and Seligman et al. (1988), evaluating patients regarding the presence of dysfunction and pain in the masticatory muscles, concluded that there was no significant correlation between occlusal interferences and these alterations.

To evaluate the distribution of occlusal contacts in individuals with TMD, Ciancaglini et al. (2002) developed a study with 25 students, of both genders aged 19 to 30, that presented signs and symptoms of TMD and 25 subjects in the control group. No difference was found regarding the total number, distribution and intensity of the contacts between the groups. However, intraindividual analysis demonstrated that there was a significant bilateral asymmetry in the number of contacts in both groups. Ciancaglini et al. (2003) verified the existence of a weak correlation between unilateral TMD and the number of occlusal contacts.

According to our results, the individuals without TMD showed a number of sitting and lying down contacts significantly higher than those individuals with TMD.

The importance of occlusal factors in the complex and controversial concept of TMD etiology cannot be totally neglected. Weak, but still significant associations were found between long-term development of TMD, and some malocclusions like a lateral forced bite between retruded contact position and intercuspal position, as well as unilateral crossbite, may be a potential risk factor in this respect (Egermark et al., 2003).

The possible relationship of orthodontic treatment with signs and symptoms of TMD has also been studied lately.

He et al. (2010) verified centric relation-maximum intercuspation discrepancy in 107 pretreated orthodontic patients with signs and symptoms of TMD and concluded that this discrepancy may be a contributory factor to the development of TMD in these patients.

Karjalainen et al. (1997) evaluated 123 healthy adolescents who had undergone orthodontic treatment regarding the presence of TMD signs and symptoms. The experimental group (patients that presented signs and symptoms of TMD) received occlusal adjustment at base line and repeated every 6 months thereafter, as needed. After 3 years, 96% of the patients returned for revaluation and the number of individuals with muscular pain and signs of TMD diminished significantly in the experimental group but not in the control group. The authors concluded that a therapy of occlusal adjustment may prevent the occurrence of signs of TMD in healthy adolescents that have had orthodontic treatment.

Conti et al. (2003) evaluated the prevalence of temporomandibular disorders in 200 individuals with 9 to 20 years of age, before and after orthodontic treatment. When the TMD anamnestic index for the whole sample was considered, 34% of the subjects had mild TMD, 3.5% had moderate TMD, and 62.5% were considered TMD free. The presence and severity of TMD have not shown any relationship with type of orthodontic mechanics, so the authors concluded that orthodontic treatment was not associated with presence of signs and symptoms of TMD.

In our study, it was found 61.1% of the orthodontic treated individuals had TMD free, 30.6% had mild TMD and 8.3% had moderate TMD. As well as in the study of Conti et al. (2003), no subjects presented severe TMD. Comparing the orthodontically treated and not treated groups according to the presence of TMD, it was observed that in both groups a higher percentage of the sample was associated with absence of TMD and with mild TMD, and no significant interaction between TMD and orthodontic treatment was verified in the different scores.

As such, recommendations concerning the need for occlusal adjustments after orthodontic therapy as a measure to prevent the appearance or aggravation of signs and symptoms of TMD are not conclusive.

In agreement with other studies (Sadowsky & Begole, 1980; Rendell et al., 1992) no significant correlation between TMD and orthodontic treatment was verified in the different scores.

Sadowsky & Polson (1984) reported that orthodontic treatment performed during adolescence does not generally increase or decrease the risk of developing TMD in later life. Similar results were found by Egermark et al. (2003). After a 20-year follow up of the influence of orthodontic treatment on signs and symptoms of TMDs, the authors verified that subjects who have received orthodontic treatment do not run a higher risk of developing signs and symptoms of TMD later in life.

Thus, the present study showed no difference between the orthodontically treated and nontreated groups in terms of the different TMD scores, although the treated group had not been evaluated regarding the presence or absence of TMD before orthodontic therapy.

The possible relationship of orthodontic treatment with signs and symptoms of TMD has

He et al. (2010) verified centric relation-maximum intercuspation discrepancy in 107 pretreated orthodontic patients with signs and symptoms of TMD and concluded that this discrepancy may be a contributory factor to the development of TMD in these patients.

Karjalainen et al. (1997) evaluated 123 healthy adolescents who had undergone orthodontic treatment regarding the presence of TMD signs and symptoms. The experimental group (patients that presented signs and symptoms of TMD) received occlusal adjustment at base line and repeated every 6 months thereafter, as needed. After 3 years, 96% of the patients returned for revaluation and the number of individuals with muscular pain and signs of TMD diminished significantly in the experimental group but not in the control group. The authors concluded that a therapy of occlusal adjustment may prevent the occurrence of

Conti et al. (2003) evaluated the prevalence of temporomandibular disorders in 200 individuals with 9 to 20 years of age, before and after orthodontic treatment. When the TMD anamnestic index for the whole sample was considered, 34% of the subjects had mild TMD, 3.5% had moderate TMD, and 62.5% were considered TMD free. The presence and severity of TMD have not shown any relationship with type of orthodontic mechanics, so the authors concluded that orthodontic treatment was not associated with presence of signs and

In our study, it was found 61.1% of the orthodontic treated individuals had TMD free, 30.6% had mild TMD and 8.3% had moderate TMD. As well as in the study of Conti et al. (2003), no subjects presented severe TMD. Comparing the orthodontically treated and not treated groups according to the presence of TMD, it was observed that in both groups a higher percentage of the sample was associated with absence of TMD and with mild TMD, and no significant interaction between TMD and orthodontic treatment was verified in the different

As such, recommendations concerning the need for occlusal adjustments after orthodontic therapy as a measure to prevent the appearance or aggravation of signs and symptoms of

In agreement with other studies (Sadowsky & Begole, 1980; Rendell et al., 1992) no significant correlation between TMD and orthodontic treatment was verified in the different

Sadowsky & Polson (1984) reported that orthodontic treatment performed during adolescence does not generally increase or decrease the risk of developing TMD in later life. Similar results were found by Egermark et al. (2003). After a 20-year follow up of the influence of orthodontic treatment on signs and symptoms of TMDs, the authors verified that subjects who have received orthodontic treatment do not run a higher risk of

Thus, the present study showed no difference between the orthodontically treated and nontreated groups in terms of the different TMD scores, although the treated group had not been evaluated regarding the presence or absence of TMD before orthodontic therapy.

signs of TMD in healthy adolescents that have had orthodontic treatment.

also been studied lately.

symptoms of TMD.

TMD are not conclusive.

developing signs and symptoms of TMD later in life.

scores.

scores.

Other authors (Ricketts, 1966; Roth, 1973) disagree and have demonstrated that orthodontic treatment is a possible cause of TMD. Roth analyzed patients of both genders submitted to orthodontic treatment and others not submitted, regarding signs and symptoms of TMD and concluded that in the female patients who had orthodontic treatment presented a significant correlation with facial symptoms of dysfunction.

In this study, it was observed no significant interaction between gender and presence or signs and symtoms of TMD. Some authors agree (Wigdorowicz-Makowerowa et al., 1979; Ludeen et al., 1986; Abd Al-Hadi, 1993) while others (Seligman et al., 1988; Mello & Araújo, 1997; Teixeira et al., 1999; Conti et al., 2003) demonstrate a predominance of the female over the male gender in young patients.

Abd Al-Hadi evaluated 600 asymptomatic students, of both genders ranging from 22 to 28 years of age. The authors verified a significant correlation between TMD and chewing side preference. In addition, as the number of contacts on the non-working side increased, the association with TMD also increased. Nevertheless, no association with gender was observed.

According to the results of this study, no significant interactions were found among occlusal characteristics (type of disocclusion and occlusal interferences) and TMD.

Kahn et al. evaluated the association between molar relationship, lateral movement, and nonworking side contacts with intraarticular TMD. The results demonstrated that symptomatic patients presented a higher prevalence of class II, division 1 related to the left side when compared to the control group. There was a higher prevalence of canine guidance on the right side of symptomatic patients with disk displacement. Asymptomatic patients had a higher prevalence of one or more non-working side contacts compared with symptomatic patients with normal joints and symptomatics with disc displacement. As such the authors were unable to demonstrate a relation between the characteristics studied and intraarticular TMD.

Henrikson & Nilner (2003) observed that orthodontic treatment either with or without extractions did not increase the prevalence or worsen pre-treatment symptoms and signs of TMD, however, the authors verified that type of occlusion may play a role as a contributing factor for the development of TMD. Valle-Corotti et al. (2007) also found that some occlusal characteristics (non-working side contacts) can be factors of risk of TMD, and verified that Class III orthodontic treatment was not associated with the presence of TMD signs and symptoms.

No relationship was found between orthodontic treatment and TMD, but a positive association between TMD and parafunctional habits and reported emotional tension was verified in the study of Conti et al., 2003. According to the authors, the emotional tension is a very frequent complaint in our days, can affect general health and can predispose and cause muscle contractions and parafunctional habits, increasing the risk of initiating TMD symptoms.

It was verified no relationship between TMD and orthodontic treatment in the most of cases, but discussions are still relevant. Although the parafunctional habits and emotional factors are closely related to the etiology of TMD, occlusal characteristics can't be neglected since some studies still find occlusal risk factors for TMDs.

### **5. Conclusion**

According to the results of our study, it was observed no relationship between TMD and orthodontic treatment, and there was no interaction among TMD and characteristics such as gender, lateral type of disocclusion and number of occlusal interferences.

#### **6. References**


According to the results of our study, it was observed no relationship between TMD and orthodontic treatment, and there was no interaction among TMD and characteristics such as

Abd Al-Hadi, L. (1993). Prevalence of temporomandibular disorders in relation to some

Ciancaglini, R; Gherlone, EF; Redaelli, S; Radaelli, G. (2002). The distribution of occlusal

Ciancaglini, R; Gherlone, EF; Redaelli, G. (2003). Unilateral temporomandibular disorder

Conti, A; Freita, M; Conti, P; Henriques, J; Janson, G. (2003). Relationship between signs and

Fonseca, DM; Bonfante, G; Valle, AL; Freitas, SFT. (1994). Diagnóstico pela anamnese da

Gianelly, AA. (1989). Orthodontics, condylar position, and TMJ status. *American Journal of Orthodontics and Dentofacial Orthopedics*, Vol. 95, pp.(521-523). ISSN 0889-5406 Guichet, NF; Niles, F. *Principle of occlusion – A collection of monographs*. Denar Corporation.

He, SS; Deng, X; Wamalwa, P; Chen, S. (2010). Correlation between centric relation-

Karjalainen, M; Le Bell, Y; Jamsa, T; Karjalainen, S. (1997). Prevention of temporomandibular

Kundinger, KK; Austin, BP; Christensen, LV; Donegan, SJ; Ferguson, DJ. (1991). An

*Acta Odontologica Scandinavica*, Vol. 68, pp. (368-376), ISSN 0001-6357 Henrikson, T; Nilner, M. (2003). Temporomandibular disorders, occlusion and orthodontic treatment. *Journal of Orthodontics*, Vol. 30, pp. (129-137), ISSN 1465-3125 Kahn, J; Tallents, RH; Katzberg, RW; Ross, EM; Murphy, WC. (1999). Prevalence of dental

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*Odontologica Scandinavica*, Vol. 55, pp. (319-324), ISSN 0001-6357

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occlusal parameters*. The Journal of Prosthetic Dentistry*, Vol. 70, pp.(345-350), ISSN

contacts in the intercuspal position and temporomandibular disorder. *Journal of* 

and asymmetry of occlusion contacts. *Journal of Oral Rehabilitation*, Vol. 89,pp. (180-

symptoms of temporomandibular disorders and orthodontic treatment: a crosssectional study. *The Angle Orthodontist*, Vol. 73, pp. (411-417), ISSN 0003-3219 Egermark, I; Magnusson, T; Carlsson, GE. (2003). A 20-year follow up of signs and symtoms

of temporomandibular disorders and malocclusions in subjects with and without orthodontic treatment in childhood. *The Angle Orthodontist*, Vol. 73, pp. (109-115),

disfunção crânio-mandibular. *Revista Gaúcha de Odontologia*, Vol. 42, pp. (23-28),

maximum intercuspation discrepancy and temporomandibular joint dysfunction.

occlusal variables and intraarticular temporomandibular disorders: molar relationship, lateral guidance, and nonworking side contacts. *The Journal of* 

disorder - related signs and symptoms in orthodontically treated adolescents. *Acta* 

evaluation of temporomandibular joints and jaw muscles after orthodontic treatment involving premolar extractions. *American Journal of Orthodontics and* 

gender, lateral type of disocclusion and number of occlusal interferences.

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**5. Conclusion** 

**6. References** 

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California: Anaheim, 1970.


## **Temporomandibular Disorders and Orthodontic Treatment – A Review with a Reported Clinical Case**

Tomislav Badel1, Miljenko Marotti2 and Ivana Savić Pavičin3 *1Department of Prosthodontics, School of Dental Medicine, University of Zagreb 2Department of Diagnostic and Interventional Radiology, "Sestre Milosrdnice" University Hospital Center, University of Zagreb 3Department of Dental Anthropology, School of Dental Medicine, University of Zagreb Croatia* 

#### **1. Introduction**

350 Orthodontics – Basic Aspects and Clinical Considerations

Valle-Corotti, K; Pinzan, A; Valle, CVM; Nahás, ACR; Corotti, MV. (2007). Assessment of

Vanderas, AP. (1993). Relations between malocclusion and craniomandibular dysfunction in

Wigdorowicz-Makowerowa, N; Grodzki, G; Panek, H; Maslanka, T; Plonka, K; Palacha, A.

Winocur, E; Gavish, A; Finkelstein, T; Halachmi, M; Gazit, E. (2001). Oral habits among

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temporomandibular disorder and occlusion in treated class III malocclusion patients. *Journal of Applied Oral Science*, Vol. 15, No. 2, pp. (110-114), ISSN 1678-7757

children and adolescents: a review. *Pediatric Dentistry,* Vol. 15, pp. (317-322), ISSN

(1979). Epidemiologic studies on prevalence and etiology of functional disturbances of the masticatory system. *The Journal of Prosthetic Dentistry,* Vol. 41, pp.(76-82),

adolescents girls and their association with symptoms of temporomandibular disorders. *Journal of Oral Rehabilitation,* Vol. 28, pp. (624-629), ISSN 0305-182X

> Temporomandibular disorders (TMDs) are musculoskeletal disorders affecting the temporomandibular joint (TMJ), the masticatory muscles (myogenic subgroup), or both, and they are the most common cause of orofacial somatic nonodontogenic pain. Osteoarthritis (OA) and disc displacement (DD) of TMJ belong to the arthrogenic subgroup of TMDs (Okeson & de Leeuw, 2011).

> The aim of the paper is to evaluate the relationship between malocclusion, orthodontic treatment and development of TMD. The article includes a 5-year follow-up of a female patient who underwent orthodontic treatment instead of TMD treatment.

#### **2. Diagnostics of painful TMDs**

The multifactorial etiopathogenic models of TMDs have no practical use at patient level because certain occlusal conditions, exposure to psychological macrotrauma, bruxist behaviour, etc., cannot be associated with TMD symptoms which are exhibited by the patient. Idiopathic (nonspecific) etiology imposes a personalised approach to every single patient during diagnostics, planning and the use of treatment modalities as well as during recall. TMD symptomatology includes the main symptoms such as pain of masticatory muscles and/or TMJ, limited and painful mouth opening as well as pathologic noise in the joints. Pain is the most important symptom in TMDs pathogenesis due to which patients seek treatment and therefore, the main aim of the treatment is pain removal (Jürgens, 2009).

The biopsychosocial component is strongly based on chronification of musculoskeletal pain. The biopsychosocial concept includes a combination of biological and psychological considerations on the etiology of TMDs, particularly those accompanied by chronic pain. Chronic pain has its etiologic basis in somatosensory and psychosocial factors. Patients with chronic pain live with their biological problem (pain activation with or without obvious pathology), which can have a psychological foundation as well as effects on their behaviour. Specific social (interpersonal) relations often have negative effects for patients (Türp, 2000; Giannakopoulos et al., 2010).

The most widespread system of standardised examination of patients and asymptomatic individuals is the use of RDC (Research diagnostic criteria)/TMD, which includes a clinical examination in Axis I, and a psychiatric testing in Axis II (Dworkin & Le Resche, 1992). RDC/TMD system classifies TMDs into three subclasses: muscle disorders, DD, and arthralgia/arthritis/arthropathy. The importance of such a system is that it shows a possibility of defining certain diagnoses of TMDs wherein the diagnosis of one subgroup does not exclude the diagnosis from the other subgroup in the same patient. Nevertheless, there are certain limitations because RDC/TMD does not include a supplementary magnetic resonance imaging (MRI) diagnostics.

#### **2.1 Manual functional analysis**

Bumann in collaboration with Groot Landeweer provided an overall system to diagnose TMDs, and, together with Lotzmann, confirmed it by thorough MRI diagnostics of TMJ (Bumann & Lotzmann, 2002). The use of manual functional analysis (MFA) is particularly stressed in the evaluation of the condition of the stomatognathic system prior to major irreversible procedures in order to avoid delayed detection of more or less pronounced clinical signs and symptoms of TMDs which would not be recognized and treated on time in such a case (Figure 1). MFA is a result of collaboration between the orthodontist and physiotherapist and its first purpose was to perform screenings prior to orthodontic treatment (Bumann & Lotzmann, 2002). By including MRI along with prior use of MFA, the less known diagnoses can be established such as partial DD and DD upon excursive movement of TMJ (Badel et al., 2009a).

Fig. 1. Dynamic compression starts with the therapist cranially pressuring the distal edge of the mandibular corpus (left), and dorsal passive compression (right).

The main purpose of clinical diagnostics is to determine the pathological condition of masticatory muscles and/or the TMJs. A standard dental examination focusing on dental status and occlusion is insufficient for diagnostics as well as just measuring the mouth opening (Kropmans et al., 2000). Manual diagnostic methods of the stomatognathic system are necessary for (von Piekartz, 2005):


chronic pain live with their biological problem (pain activation with or without obvious pathology), which can have a psychological foundation as well as effects on their behaviour. Specific social (interpersonal) relations often have negative effects for patients (Türp, 2000;

The most widespread system of standardised examination of patients and asymptomatic individuals is the use of RDC (Research diagnostic criteria)/TMD, which includes a clinical examination in Axis I, and a psychiatric testing in Axis II (Dworkin & Le Resche, 1992). RDC/TMD system classifies TMDs into three subclasses: muscle disorders, DD, and arthralgia/arthritis/arthropathy. The importance of such a system is that it shows a possibility of defining certain diagnoses of TMDs wherein the diagnosis of one subgroup does not exclude the diagnosis from the other subgroup in the same patient. Nevertheless, there are certain limitations because RDC/TMD does not include a supplementary magnetic

Bumann in collaboration with Groot Landeweer provided an overall system to diagnose TMDs, and, together with Lotzmann, confirmed it by thorough MRI diagnostics of TMJ (Bumann & Lotzmann, 2002). The use of manual functional analysis (MFA) is particularly stressed in the evaluation of the condition of the stomatognathic system prior to major irreversible procedures in order to avoid delayed detection of more or less pronounced clinical signs and symptoms of TMDs which would not be recognized and treated on time in such a case (Figure 1). MFA is a result of collaboration between the orthodontist and physiotherapist and its first purpose was to perform screenings prior to orthodontic treatment (Bumann & Lotzmann, 2002). By including MRI along with prior use of MFA, the less known diagnoses can be established such as partial DD and DD upon excursive

Fig. 1. Dynamic compression starts with the therapist cranially pressuring the distal edge of

The main purpose of clinical diagnostics is to determine the pathological condition of masticatory muscles and/or the TMJs. A standard dental examination focusing on dental status and occlusion is insufficient for diagnostics as well as just measuring the mouth opening (Kropmans et al., 2000). Manual diagnostic methods of the stomatognathic system

the mandibular corpus (left), and dorsal passive compression (right).

Giannakopoulos et al., 2010).

resonance imaging (MRI) diagnostics.

movement of TMJ (Badel et al., 2009a).

are necessary for (von Piekartz, 2005):

**2.1 Manual functional analysis**

#### **2.2 Clinical importance of imaging modalities**

A limiting factor in the study of TMDs is radiologic diagnostics, which is often used in dental treatment of teeth and jaw bones. Traditional x-ray images as well as conventional and computed tomography (CT) cannot show all the functional elements of TMJ. The key component in articular biomechanics is the relationship between the articular plate or disc as a cartilaginous structure and the condylar head as an osseous structure. Another factor is the disc-condyle complex relationship with the posterior plane of the articular eminence, across which the articular complex moves simultaneously on mouth opening.

Ahmad et al. (2009) believe that panoramic x-ray and TMJ radiography should not be included into diagnostic procedure at the specialist level. CT is indicated in individuals who have clinical signs of OA and who cannot be exposed to strong magnetic field due to claustrophobia, metal implants or pacemakers. In individuals with such limitations, CT would not be an adequate diagnostic means if they only have DD without any changes in hard osseous tissues. When the MRI finding of OA needs to be confirmed by CT, which is still the gold standard in diagnostics of osseous tissues of joints (Figure 2), one should bear in mind the exposure to x-ray radiation. MRI is a radiologic technique of layered imaging in the desired plane without moving the body and without exposing the patient to ionised radiation. As in the other fields of diagnostics in medicine, MRI is qualitatively better because it enables imaging of soft tissues without invasive effects on the recorded object as opposed to arthrography. Therefore, MRI has become the gold standard of diagnostics and the dominant radiologic technique in diagnostics of TMDs enabling the imaging of cartilaginous articular surfaces and it can successfully show the position of the articular disc (Badel et al., 2009a; Badel et al., 2010a).

Fig. 2. Computed tomography (left) of temporomandibular joint with degenerative bone changes (1 condyle, 2 articular eminence, 3 external acoustical meatus, 4 osteophyte) and magnetic resonance imaging (right) with anterior displaced disc (arrow).

In orthopedics, the possibilities of manual tests and limitations of traditional radiologic examinations as well as advantages of MRI have already been evaluated. The relationship between pain and diagnostic findings has also been researched, particularly the relationship between the knee and the lumbar region of the spine. Regarding clinical diagnostics, Palla (1998) concluded that certain forms of TMDs do not have specific signs, that is, certain diagnostic tests have low validity and reliability.

### **3. Epidemiology of TMD and the use of MRI**

A high prevalence of symptoms, 25-75%, out of which the major part of the symptoms were pathological noise in the TMJ, was determined in general population by various methods of data gathering (questionnaires, clinical examination, use of radiologic modalities). Although there are some methodological discrepancies which can be hinder the direct comparison of epidemiologic results of TMD, it is certain that temporomandibular pain has a low prevalence, mostly less than 10% of general population, and most often only 5% (Durham, 2008). In an epidemiologic study, Gesch et al. (2004a) determined by a clinical examination of 49.9% of the population that there is at least one clinical sign of TMD, whereas only 2.7% had painful TMJ.

Another issue in the TMD epidemiology is dependence on the age and gender of the patient. Manfredini et al. (2010) differentiated two age peaks (two peaks of greatest incidence) in TMD patients (30-35 and 50-55 years) with female: male ration 5:1, which partly coincides with previous knowledge that the greatest prevalence is in women of reproductive age (that is between 18-45) (Palla, 1998; Badel, 2007a; Durham, 2008). Although osteoarthritis has only partly greater prevalence in elderly people, it is obvious that TMDs do not progress with patients' age. Using MRI, Schmitter et al. (2010) proved that in elderly population, each gender equally, there is a discrepancy of high incidence (70%) of OA signs accompanied by low incidence of clinical signs of TMD (out of 30 subjects only one had painful TMJ). Predominance of females in TMD patients is explained by the effects of female hormones or attribute this to the gender distinction, biological and physiological differences, behavioural characteristics, and genetic factors (Wang et al., 2008).

In order to plan and perform orthodontic treatment, it is important to have all the data regarding TMD symptoms as well as the need to treat them in the population of children and adolescents during the period of growth and the development of jaws and teeth. The issue of orthodontics is related to data gathered within epidemiologic studies of young people. In this way, in a group of adolescents and young adults, Casanova-Rosado et al. (2006) found that 16.55% of them had orthodontic treatment. Some grade of TMD was found by clinical examination in 46.1% of subjects, predominantly females with bruxist behaviour and psychosocial variables (stress and anxiety). However, it is not evident to what extent were the subjects treated orthodontically. Le Resche et al. (2005) pointed to the higher prevalence of pain, including TMD pain (in terms of multiple pain problems) during pubescent development of girls. Pereira et al. (2009) found at least one sign or symptom of TMD in 12.26% of children aged between 4-12 (in 5 boys and 8 girls). Bonjardim et al. (2003) determined a low prevalence of TMD signs and symptoms in children aged between 3 and 5 (primary dentition): 3.03% had TMJ sounds and 4.04% had jaw pain without any gender differences. Köhler et al. (2009) followed the occurrence of signs and symptoms of TMD during 20 years, with the first examination at the age of three. It was determined that TMD symptoms had higher incidence in later examinations (incidence 5-9%) while at the youngest age, there was almost none. However, the need for treatment is particularly low

between pain and diagnostic findings has also been researched, particularly the relationship between the knee and the lumbar region of the spine. Regarding clinical diagnostics, Palla (1998) concluded that certain forms of TMDs do not have specific signs, that is, certain

A high prevalence of symptoms, 25-75%, out of which the major part of the symptoms were pathological noise in the TMJ, was determined in general population by various methods of data gathering (questionnaires, clinical examination, use of radiologic modalities). Although there are some methodological discrepancies which can be hinder the direct comparison of epidemiologic results of TMD, it is certain that temporomandibular pain has a low prevalence, mostly less than 10% of general population, and most often only 5% (Durham, 2008). In an epidemiologic study, Gesch et al. (2004a) determined by a clinical examination of 49.9% of the population that there is at least one clinical sign of TMD, whereas only 2.7%

Another issue in the TMD epidemiology is dependence on the age and gender of the patient. Manfredini et al. (2010) differentiated two age peaks (two peaks of greatest incidence) in TMD patients (30-35 and 50-55 years) with female: male ration 5:1, which partly coincides with previous knowledge that the greatest prevalence is in women of reproductive age (that is between 18-45) (Palla, 1998; Badel, 2007a; Durham, 2008). Although osteoarthritis has only partly greater prevalence in elderly people, it is obvious that TMDs do not progress with patients' age. Using MRI, Schmitter et al. (2010) proved that in elderly population, each gender equally, there is a discrepancy of high incidence (70%) of OA signs accompanied by low incidence of clinical signs of TMD (out of 30 subjects only one had painful TMJ). Predominance of females in TMD patients is explained by the effects of female hormones or attribute this to the gender distinction, biological and physiological differences, behavioural

In order to plan and perform orthodontic treatment, it is important to have all the data regarding TMD symptoms as well as the need to treat them in the population of children and adolescents during the period of growth and the development of jaws and teeth. The issue of orthodontics is related to data gathered within epidemiologic studies of young people. In this way, in a group of adolescents and young adults, Casanova-Rosado et al. (2006) found that 16.55% of them had orthodontic treatment. Some grade of TMD was found by clinical examination in 46.1% of subjects, predominantly females with bruxist behaviour and psychosocial variables (stress and anxiety). However, it is not evident to what extent were the subjects treated orthodontically. Le Resche et al. (2005) pointed to the higher prevalence of pain, including TMD pain (in terms of multiple pain problems) during pubescent development of girls. Pereira et al. (2009) found at least one sign or symptom of TMD in 12.26% of children aged between 4-12 (in 5 boys and 8 girls). Bonjardim et al. (2003) determined a low prevalence of TMD signs and symptoms in children aged between 3 and 5 (primary dentition): 3.03% had TMJ sounds and 4.04% had jaw pain without any gender differences. Köhler et al. (2009) followed the occurrence of signs and symptoms of TMD during 20 years, with the first examination at the age of three. It was determined that TMD symptoms had higher incidence in later examinations (incidence 5-9%) while at the youngest age, there was almost none. However, the need for treatment is particularly low

diagnostic tests have low validity and reliability.

had painful TMJ.

**3. Epidemiology of TMD and the use of MRI** 

characteristics, and genetic factors (Wang et al., 2008).

(1-2%). Huddleston Slater et al. (2007) did a targeted research into prevalence of anterior DD with reduction (accompanied by reciprocal clicking in the TMJ) in children and adolescents which increases with their age, yet there is no statistical difference in prevalence between a subgroup of 18-year-old adolescents and two age groups of adults aged on average 21.9 and 43.5. Prevalence of DD with reduction je rose to 26.6% in adulthood.

MRI diagnostics of a 12-year-old female patient with clinical signs and symptoms of clicking in both jaws was performed as a part of pre-orthodontic treatment. The MRI finding confirmed DD with reduction in the left and without reduction in the right TMJ. The MRI follow-up finding remained unchanged after the treatment of unilateral cross bite. Painless clicking as a compensated condition of TMJ was not sufficient as a symptom which would indicate TMD treatment (Badel et al., 2008a).

In a sample of 40 patients with DD confirmed by MRI, Badel (2007a, 2008b) showed that 25% of them underwent orthodontic treatment (mainly by removable appliances), while in 5 asymptomatic subjects (20%) DD was also determined. Nevertheless, since the asymptomatic group was a population of students of similar age, the share of those with previously performed orthodontic treatments was 40%. Treatment by a fixed appliance was previously performed in an asymptomatic female subject with physiological disc position. Similarly, Katzberg et al. (1996) did not find any correspondence between orthodontic treatment and DD prevalence in patients (77%) and also in asymptomatic subjects (33%).

MRI provides better imaging of soft and hard TMJ structures and since it is not an invasive procedure, it is also used in children of the youngest age. Research has shown that DD is not a congenital disorder and according to Paesani et al. (1999), which has also been confirmed by clinical epidemiologic studies, develops only in older children and adults with the prevalence of as much as 45% (Haiter-Neto et al., 2002). However, studies do not show to what extent is asymptomatic DD related to a possible previous orthodontic treatment (Haiter-Neto et al., 2002).

Numerous studies of TMD patients confirmed the efficiency of MRI use with respect to clinical signs of the disorder (Moen et al., 2010). MRI was very useful in finding or controlling a therapeutic condylar position and its effects on the intraarticular function of TMJ, especially disc position. It has been used in long-term follow-ups of patients without evidence of serious progression of pathological changes in intraarticular structures (de Bont et. al., 1997). Even the subsequent occurrence of osteoarthritic changes in joints of DD patients during the follow-up period did not have clinical manifestations (Kurita et al., 2006). On the other hand, Tominaga et al. (2007) pointed to the changes in disc position with partial displacement occurring in the period of children's growth and development. This stresses the need for thorough analysis of TMJ on three representative layers in an oblique sagittal line in order to avoid doubts about the usefulness of MRI findings (Bumann & Lotzmann, 2002), which still poses a problem of how to interpret the disc image with respect to its physiological position or anterior displacement (Petersson, 2010).

Jensen & Ruf (2007) followed subclinical and clinical symptoms of TMD which were detected and managed by MFA in a group of students. In a period of 2.4 years on average, an increase of those with clinical signs of TMD occurred. Subclinical signs fluctuated a great deal yet one out of three students in the subgroup developed clinically manifested TMD.

#### **4. Occlusion and TMD**

Occlusion was considered a possible etiopathogenic factor of TMD but their relationship is complex and still remains partially unexplained. Occlusal treatment is important not only to patients but also to dentists – nearly half of the interviewed Swedish dentists consider that the replacement of molars is necessary due to development of TMD and compromising of masticatory function (Lyka et al., 2001). The importance of occlusion in etiopathogenesis has been redefined by refuting the mechanistic conception which has been present from the beginning of scientific research of TMD. Loss of teeth and/or disorders of occlusion are certainly illnesses by nature but any type of irreversible occlusal treatment cannot be associated with causal treatment of TMD (Slavicek, 2009; Carlsson, 2010).

In an epidemiologic study, Gesch et al. (2004b) found a low incidence of certain variables of malocclusion (unilateral open bite, negative overjet and unilateral cross-bite in men, and edge-to-edge bite in women) with signs or symptoms of TMD. In both genders, anatomically correct occlusion was not significantly associated with TMD compared with malocclusions. By including static and dynamic factors of occlusion, a significant correlation with TMD incidence has been statistically determined but with a low correlation coefficient. Anterior open bite, deep overjet 6 mm or more, unilateral cross-bite and difference between centric relation and maximal intercuspidation amounting to more than 2 mm with more than six posterior teeth to be replaced can be considered increased risk factors for TMD (Pullinger et al., 1993). Conversely, Rammelsberg (1998) offered a review of etiopathogenic model of DD development wherein high abrasion and insufficient restorative procedure on posterior teeth are risk factors causing occlusal instability. In their research, 34% of patients with DD with reduction previously underwent orthodontic treatment. As opposed to that, only 16% of asymptomatic individuals and 14% of patients with DD without reduction were previously orthodontically treated. In order to further confirm the relationship between orthodontic treatment and development of TMD, a follow-up targeted study should be carried out prior to and after orthodontic treatment.

In a population of children, Pereira et al. (2009) did not find any correlation between malocclusion and TMD but they identified bruxism and posterior cross bite as risk factors for TMD. Tecco et al. (2010a) and Tecco & Festa (2011) found a correlation between TMD with painful symptoms in children (5-15 years of age) and unilateral cross bite, but not with TMJ sounds. Myofascial pain was more prevalent in females. Huddleston Slater et al. (2007) found that age, history of orthodontic treatment, overbite and protrusion were significantly associated with DD with reduction. In their study, Badel et al. (2008b) found a significantly higher prevalence of hyperbalance and interference contacts in asymptomatic patients compared to TMD patients. No difference was found between Angle's classes in patients with DD and asymptomatic individuals. There was a statistically significant difference in teeth contact between the maximal intercuspidation and centric positions patients and asymptomatic subjects. Augthun et al. (1998) did not find any correlations between occlusal variables and forms of DD. However, it has been established that the rate of class II increases consecutively depending on the following subjects: asymptomatic subjects, patients with DD with reduction and patients with DD without reduction (14%/33%/52%), while the share of subjects with class I decreases simultaneously (43%/30%/18%).

Taking into account the great number of static and dynamic occlusal variables, it is difficult to comprehend the overall correlation with the development of TMDs due to the often nonstandardised studies based on occlusal analysis (John, 1996). According to John et al. (1998), 'complex interaction' is the only but scientifically non-defined link between occlusion and TMDs. Occlusion ensures orthopedic stability of TMJ whereas the occlusal stability is ensured by mutually antagonistic contacts in a position of maximal intercuspidation. When the relationship between the two factors is compromised, it could lead to an overload of articular structures and consequently pose a risk of TMD development. The changes in occlusal relations are pronounced in etiopathogenesis, causing co-contraction of antagonist muscles the purpose of which is to protect the agonists and remove pain. The influence of possible adverse chronic effects can be avoided by the adaptation of muscular activity (Okeson, 2003).

The importance of occlusal interferences was perceived differently regarding the etiopathogenesis of TMDs. Le Bell et al. (2002) found that artificial interferences do not stimulate the development of dysfunctional symptoms in healthy subjects, instead they adapt successfully to them. In patients whose medical histories show TMD interferences stimulate the recurrence of stronger symptoms.

There is a dichotomy between scientific and clinical concepts of occlusion, which can be explained by the concept of integrated neurobiological system (Türp & Schindler, 2003). Occlusion is a basic component of dental restorative procedures, which changes or supplements the compromised or lost occlusal relations in each segment of planning the procedure. Pathogenetic and therapeutic effects of myofascial pain can be explained only as a mutual relationship between occlusion and neuromusculature. The results of La Bella et al. (2002) are explained by the neurobiological hypothesis based on the differentiated activity of the part of the muscle in which increased tension and pain can occur. The changes in occlusal relations cause a mild unloading in painful muscles or within the structures of TMJ which means that different condyle positions during treatment can have the same effect. However, the mutual relationship between occlusal interferences and microtrauma has not been completely explained (Türp & Schindler, 2003).

#### **4.1 Hypervigilance**

356 Orthodontics – Basic Aspects and Clinical Considerations

Occlusion was considered a possible etiopathogenic factor of TMD but their relationship is complex and still remains partially unexplained. Occlusal treatment is important not only to patients but also to dentists – nearly half of the interviewed Swedish dentists consider that the replacement of molars is necessary due to development of TMD and compromising of masticatory function (Lyka et al., 2001). The importance of occlusion in etiopathogenesis has been redefined by refuting the mechanistic conception which has been present from the beginning of scientific research of TMD. Loss of teeth and/or disorders of occlusion are certainly illnesses by nature but any type of irreversible occlusal treatment cannot be

In an epidemiologic study, Gesch et al. (2004b) found a low incidence of certain variables of malocclusion (unilateral open bite, negative overjet and unilateral cross-bite in men, and edge-to-edge bite in women) with signs or symptoms of TMD. In both genders, anatomically correct occlusion was not significantly associated with TMD compared with malocclusions. By including static and dynamic factors of occlusion, a significant correlation with TMD incidence has been statistically determined but with a low correlation coefficient. Anterior open bite, deep overjet 6 mm or more, unilateral cross-bite and difference between centric relation and maximal intercuspidation amounting to more than 2 mm with more than six posterior teeth to be replaced can be considered increased risk factors for TMD (Pullinger et al., 1993). Conversely, Rammelsberg (1998) offered a review of etiopathogenic model of DD development wherein high abrasion and insufficient restorative procedure on posterior teeth are risk factors causing occlusal instability. In their research, 34% of patients with DD with reduction previously underwent orthodontic treatment. As opposed to that, only 16% of asymptomatic individuals and 14% of patients with DD without reduction were previously orthodontically treated. In order to further confirm the relationship between orthodontic treatment and development of TMD, a follow-up targeted study should be

In a population of children, Pereira et al. (2009) did not find any correlation between malocclusion and TMD but they identified bruxism and posterior cross bite as risk factors for TMD. Tecco et al. (2010a) and Tecco & Festa (2011) found a correlation between TMD with painful symptoms in children (5-15 years of age) and unilateral cross bite, but not with TMJ sounds. Myofascial pain was more prevalent in females. Huddleston Slater et al. (2007) found that age, history of orthodontic treatment, overbite and protrusion were significantly associated with DD with reduction. In their study, Badel et al. (2008b) found a significantly higher prevalence of hyperbalance and interference contacts in asymptomatic patients compared to TMD patients. No difference was found between Angle's classes in patients with DD and asymptomatic individuals. There was a statistically significant difference in teeth contact between the maximal intercuspidation and centric positions patients and asymptomatic subjects. Augthun et al. (1998) did not find any correlations between occlusal variables and forms of DD. However, it has been established that the rate of class II increases consecutively depending on the following subjects: asymptomatic subjects, patients with DD with reduction and patients with DD without reduction (14%/33%/52%),

while the share of subjects with class I decreases simultaneously (43%/30%/18%).

Taking into account the great number of static and dynamic occlusal variables, it is difficult to comprehend the overall correlation with the development of TMDs due to the often non-

associated with causal treatment of TMD (Slavicek, 2009; Carlsson, 2010).

carried out prior to and after orthodontic treatment.

**4. Occlusion and TMD** 

Reflex response to peripheral stimulus, that is, occlusal interference via periodontal receptors, can be modulated in the central nervous system in such a way that the stimulus causing normal opening in that case causes mouth closing. The hypothalamus and the limbic system mediate in tonus increase in affective conditions and under stress, whereas the reflex response to occlusal stimulus depends on the current state of agitation of those centres. In patients, even the slightest interference can produce the state of high stimulation and muscle hyperactivity, which can cause TMD at a lower level of adaptation. In other individuals with low level of activity of those centres an increase of muscle tonus due to occlusal interference does not occur. Parafunction is initiated only when the occlusal changes turn into a disturbance which leads to an awareness of pathological occlusal relations. A patient does not react to a harmful periodontal stimulus due to disturbed efficiency of behavioural mechanisms by diminishing the parafunction, instead it gains strength. Only in cases of hypervigilance, the occlusal changes will lead to TMD, due to increased awareness of one's own body and intensified activity of emotional motor system such as stress, pain or psychosocially caused parafunction. Hypervigilance is a changed form of observation wherein the harmful nociceptive stimuli are intensified (Hollins et al, 2009; Palla, 1998).

#### **5. Concepts of TMDs treatment**

The concept of TMDs treatment procedures is indirectly connected with the already established symptoms and signs from the medical history and clinical examination. Since the exact pathophysiological mechanism of TMDs development has not been fully explained, the main goal of the treatment is the management, reduction and removal of temporomandibular pain. Treatment procedures are divided into reversible and irreversible procedures. Since the treatment is mostly empirical, that is, performed by evaluating the clinical significance if the established symptoms, the reversible procedures are mostly used. Treatment indications, type of treatment procedures and their practical application are based on the existence of a specific form of myogenic and/or arthrogenic disorder in the stomatognathic system accompanied by certain intensity of temporomandibular pain (Gremillion, 2002; Palla, 1998).

The course of development of neuroplastic processes in the central nervous system is prevented by the treatment of acute temporomandibular pain, and those processes result in development of chronic pain (pain present longer than 6 months). The treatment of temporomandibular pain is based on the following (Green, 2006; Palla, 1998, Palla, 2003):


#### **5.1 Aims and forms of the initial treatment**

The initial treatment comprises different and to a certain extent, specific procedures and means the main feature of which is to be as non-invasive as possible. The diagnosis should be discussed with the patient as well as its possible etiology and pathophysiology and the prognosis and its possible course of treatment. The patient should understand the diagnosis, especially if it is accompanied by chronic pain. Successfully informing the patient creates a placebo effect thus reducing the secondary induced psychological disorder which can compromise the success of the treatment. The patient is additionally motivated by the good prognosis of treatment. Diet consisting of soft food is recommended as well as instructions on how to change oral activity in the sense of self-observation and self-correction of oral habits and parafunctions (Green, 2006).

Physical and manual therapy plays an important role in treatment of all rheumatic disorders and at the same time it actively involves the patient in the course of the treatment. The aim is to remove musculoskeletal restrictions such as pain removal, detoning and stretching of hypertonic muscles. Therapy is conducted by ultrasound, TENS, laser, kinesiotherapy by Schulte, localised massage, etc. (Badel et al., 2010b). Nonsteroidal anti-rheumatics are indicated in acute pain of different etiologies. Due to systemic side-effects in the gastrointestinal tract and due to blood circulation disorders in kidneys, it s recommended to prescribe selective inhibitors of the prostaglandin synthesis which should be taken during a longer period of time (Badel et al., 2007b).

The irreversible treatment mostly implies surgical procedures. Arthrocentesis (removal of inflammatory exudate), surgical reposition of articular disc (arthrotomy), discectomy, placement of articular disc implants and condylectomy can be performed on the TMJ. Arthroscopy is a diagnostic-treatment method used for imaging of intraarticular pathologic changes with the possibility of their simultaneous removal (Machon et al., 2010; Palla, 1998).

#### **5.2 Occlusal splints**

358 Orthodontics – Basic Aspects and Clinical Considerations

The concept of TMDs treatment procedures is indirectly connected with the already established symptoms and signs from the medical history and clinical examination. Since the exact pathophysiological mechanism of TMDs development has not been fully explained, the main goal of the treatment is the management, reduction and removal of temporomandibular pain. Treatment procedures are divided into reversible and irreversible procedures. Since the treatment is mostly empirical, that is, performed by evaluating the clinical significance if the established symptoms, the reversible procedures are mostly used. Treatment indications, type of treatment procedures and their practical application are based on the existence of a specific form of myogenic and/or arthrogenic disorder in the stomatognathic system accompanied by

The course of development of neuroplastic processes in the central nervous system is prevented by the treatment of acute temporomandibular pain, and those processes result in development of chronic pain (pain present longer than 6 months). The treatment of temporomandibular pain is based on the following (Green, 2006; Palla, 1998, Palla, 2003):

the morphofunctional features do not make the TMJ absolutely unique in the human

symptoms and clinical signs have complex features of musculoskeletal disorder;

 patients are successfully treated by simple and non-invasive treatment procedures; the patient's psychological reaction should not be in proportion with the somatic

 the treatment approaches to non-chronic and chronic temporomandibular pain differ; the evaluation of the purposefulness and the optimal efficiency of the initial treatment

The initial treatment comprises different and to a certain extent, specific procedures and means the main feature of which is to be as non-invasive as possible. The diagnosis should be discussed with the patient as well as its possible etiology and pathophysiology and the prognosis and its possible course of treatment. The patient should understand the diagnosis, especially if it is accompanied by chronic pain. Successfully informing the patient creates a placebo effect thus reducing the secondary induced psychological disorder which can compromise the success of the treatment. The patient is additionally motivated by the good prognosis of treatment. Diet consisting of soft food is recommended as well as instructions on how to change oral activity in the sense of self-observation and self-correction of oral

Physical and manual therapy plays an important role in treatment of all rheumatic disorders and at the same time it actively involves the patient in the course of the treatment. The aim is to remove musculoskeletal restrictions such as pain removal, detoning and stretching of hypertonic muscles. Therapy is conducted by ultrasound, TENS, laser, kinesiotherapy by Schulte, localised massage, etc. (Badel et al., 2010b). Nonsteroidal anti-rheumatics are indicated in acute pain of different etiologies. Due to systemic side-effects in the gastrointestinal tract and due to blood circulation disorders in kidneys, it s recommended to

certain intensity of temporomandibular pain (Gremillion, 2002; Palla, 1998).

occlusion is not a crucial etiopathogenic factor;

**5.1 Aims and forms of the initial treatment** 

habits and parafunctions (Green, 2006).

**5. Concepts of TMDs treatment** 

body;

pathology;

is necessary.

The occlusal splint is the most common and efficient treatment procedure of arthrogenic and/or myogenic forms of TMDs and bruxism. The occlusal stability is established by specific morphology of the splint which is placed on the teeth alignment of one jaw thus serving as an orthopedic means of TMJ stabilisation (de Leeuw, 2008; Okeson, 2003). The occlusal splint is used as a temporary means of obtaining therapeutic occlusion and as a preparatory stage for definite prosthetic treatment (Badel, 2003).

Depending on the indications of use and treatment effects of the occlusal splint, hyperactivity is reduced, that is, the masticatory muscles are relaxed, the condyle is therapeutically positioned, that is, placed into the centric relation position and the behavioural effects increase awareness about the position, function and parafunction of the mandible thus achieving placebo effect (Dylina, 2001).

#### **5.2.1 Classification of occlusal splints**

In occlusal splint treatment the following changes occurred in: biomechanic concepts of their effects, features of their placement and retention on the teeth, morphology of the occlusal plane of the splint and their effect on the position and movements of the mandible.

**Relaxation splints** are used in the treatment of bruxism as well as in management of arthrogenic and myogenic temporomandibular pain. The Michigan splint (occlusal bite plane stabilisation splint with cuspid rise and freedom in centric) by Ramfjord and Ash is a splint covering all the teeth in the jaw, enabling antagonistic contacts on the flat planes according to occlusal concepts of freedom in centric position. Guiding by canines along the modelled planes of the splint is achieved in each extracentric movement (Ash & Schmieseder, 1999).

**Distraction splint** (pivot splint) vertically unloads intraarticular structures by condyle distraction and is indicated in arthroses, perforation of articular disc and anterior DD without reductiong. The splint acts as a hypomochlion in individual bilateral contacts in the molar region, by which distraction (decompression) of TMJs is obtained (Okeson, 2003).

**Repositioning (protrusion/distraction) splint** causes the excentric (anterior) positioning of the mandible and is used for treatment of anterior displacement of the articular disc with repositioning. The aim of the splint treatment is repositioning of the articular disc into the physiological position with respect to the condyle, which is achieved by its occlusal plane. The splint achieves a protrusive (anterior) position of the condyle with a slight distraction effect on the TMJs (Okeson, 2003).

With respect to the variety of design characteristics and the biomechanical effect of occlusal splints, previous concepts of initial treatments have been revised. The effect of anterior displacement/position of the articular disc and subsequent irreversible changes in physiological occlusal relations is questionable. Stabilisation of the mandible in anterior position leads to intraarticular partitioning which can lead to permanent anterior habitual occlusion resulting in malocclusion (back open bite due to extrusion of posterior teeth and orthodontic displacement of anterior teeth) (Brenkert, 2010). In order to avoid irreversible, unwanted changes in the structures of the masticatory system, the Michigan splint is the device of choice due to the proved beneficial effect in alleviation and removal of symptoms TMDs (Badel, 2009b). The occlusal splint, according to the individual case, is combined to a certain extent with other forms of initial treatment of TMDs. In treatment of DD, it is important to consider that repositioning of the articular disc is not satisfactory in as much as 50% of cases and recurrences are possible in 1/3 of the cases (Le Bell & Kirveskari, 1990).

#### **5.3 Implications of orthodontic treatment on TMD**

Orthodontic treatment can be viewed from two different points of view: whether orthodontic treatment has a negative impact on development of signs and symptoms of TMDs and what the role of orthodontic treatment is regarding the modality of TMDs treatment. MRI helped with detection, that is, follow-up of the influence of orthodontic treatment on the intraarticular structures of TMJ. In a group of 15 orthodontic patients (aged between 12 and 17) Pancherz et al. (1999) found clinical signs of TMD in two patients (partial DD in one patient and osteoarthritic changes in the other). All orthodontic patients wore a Herbst appliance during 7 months due to Class II malocclusion. In the follow-up period, DD improved (metric evaluation) and in the other patient, the loss of osteoarthritic changes was considered the result of compensatory joint remodelling. Aidar et al. (2006) performed a metric evaluation of the effects of Herbst treatment in adolescents with Class II Division 1 malocclusion. There was no significant influence of orthodontic treatment on DD development.

Tullberg et al. (2001) conducted a research with a follow-up on the correlation between early (children with primary dentition) and late (children with mixed or permanent dentition treatment of unilateral posterior cross-bite. There was no evidence that early treatment, even the later treatment repeated in 11 out of 44 subjects, was related to significant development of signs and symptoms of TMD. Therefore, even in a case of malocclusion as a risk factor, orthodontic treatment could not be related to the development of TMD. Even the first (early) orthodontic treatment could be repeated in older age (as a late treatment) and the subjects aged 19 would not have more significantly manifested TMD. During a 4-month follow-up, Bourzgui et al. (2010) did not find any correlation between development of TMD symptoms and Angle classes. Although the unilateral posterior cross bite is mentioned as a significant variable in DD of TMJ, in a group of children (average age of 9.3 years) their correlation could not be established by MRI analysis (Pellizoni, 2006).

During a long follow-up, Egermark et al. (2003) investigated the relationship between occlusal variables and development of clinical signs and symptoms of TMDs. From a longterm perspective, subjects were very pleased with the orthodontic treatment, and the treatment received in childhood did not increase the risk for TMDs later in life. In some subjects, lateral forced bite between retruded contact position and intercuspal position, as well as unilateral cross bite might be of importance in this respect. Henrikson & Nilner

With respect to the variety of design characteristics and the biomechanical effect of occlusal splints, previous concepts of initial treatments have been revised. The effect of anterior displacement/position of the articular disc and subsequent irreversible changes in physiological occlusal relations is questionable. Stabilisation of the mandible in anterior position leads to intraarticular partitioning which can lead to permanent anterior habitual occlusion resulting in malocclusion (back open bite due to extrusion of posterior teeth and orthodontic displacement of anterior teeth) (Brenkert, 2010). In order to avoid irreversible, unwanted changes in the structures of the masticatory system, the Michigan splint is the device of choice due to the proved beneficial effect in alleviation and removal of symptoms TMDs (Badel, 2009b). The occlusal splint, according to the individual case, is combined to a certain extent with other forms of initial treatment of TMDs. In treatment of DD, it is important to consider that repositioning of the articular disc is not satisfactory in as much as 50% of cases and recurrences are possible in 1/3 of the cases (Le Bell & Kirveskari, 1990).

Orthodontic treatment can be viewed from two different points of view: whether orthodontic treatment has a negative impact on development of signs and symptoms of TMDs and what the role of orthodontic treatment is regarding the modality of TMDs treatment. MRI helped with detection, that is, follow-up of the influence of orthodontic treatment on the intraarticular structures of TMJ. In a group of 15 orthodontic patients (aged between 12 and 17) Pancherz et al. (1999) found clinical signs of TMD in two patients (partial DD in one patient and osteoarthritic changes in the other). All orthodontic patients wore a Herbst appliance during 7 months due to Class II malocclusion. In the follow-up period, DD improved (metric evaluation) and in the other patient, the loss of osteoarthritic changes was considered the result of compensatory joint remodelling. Aidar et al. (2006) performed a metric evaluation of the effects of Herbst treatment in adolescents with Class II Division 1 malocclusion. There was

Tullberg et al. (2001) conducted a research with a follow-up on the correlation between early (children with primary dentition) and late (children with mixed or permanent dentition treatment of unilateral posterior cross-bite. There was no evidence that early treatment, even the later treatment repeated in 11 out of 44 subjects, was related to significant development of signs and symptoms of TMD. Therefore, even in a case of malocclusion as a risk factor, orthodontic treatment could not be related to the development of TMD. Even the first (early) orthodontic treatment could be repeated in older age (as a late treatment) and the subjects aged 19 would not have more significantly manifested TMD. During a 4-month follow-up, Bourzgui et al. (2010) did not find any correlation between development of TMD symptoms and Angle classes. Although the unilateral posterior cross bite is mentioned as a significant variable in DD of TMJ, in a group of children (average age of 9.3 years) their correlation

During a long follow-up, Egermark et al. (2003) investigated the relationship between occlusal variables and development of clinical signs and symptoms of TMDs. From a longterm perspective, subjects were very pleased with the orthodontic treatment, and the treatment received in childhood did not increase the risk for TMDs later in life. In some subjects, lateral forced bite between retruded contact position and intercuspal position, as well as unilateral cross bite might be of importance in this respect. Henrikson & Nilner

**5.3 Implications of orthodontic treatment on TMD** 

no significant influence of orthodontic treatment on DD development.

could not be established by MRI analysis (Pellizoni, 2006).

(2003) followed the clinical signs and symptoms of TMDs during the fixed orthodontic treatment, especially in girls with Class II malocclusion. They were compared with girls who did not receive treatment and controls with normal occlusion. It was observed that signs and symptoms of TMDs equally develop in all three groups and, over time, they fluctuate considerably and unpredictably. A part of patients with Class II and the myogenic form of TMDs even experienced improvement of their condition due to orthodontic treatment. In any case, fixed orthodontic treatment did not particularly aggravate TMDs compared to the pre-treatment period.

Tecco et al. (2010a) compared the efficiency of TMDs treatment by a fixed orthodontic appliance and the anterior repositioning splint. DD was diagnosed by MRI and the effect of both treatments was beneficial to treatment of myogenic and arthrogenic pain, whereas the repositioning splint proved to be more efficient for removal of pathological noise in the joint. Siegmund & Harzer (2002) showed a detailed orthodontic treatment of a patient with DD. Clinical diagnostics was based on MFA and it was supplemented by axiography. The need for pre-treatment diagnostics and treatment planning was stressed which leads to a successful outcome of fixed orthodontic treatment as well as to the avoidance of complications related to possible exacerbation of TMD symptoms.

Jensen & Ruf (2007) showed that during a long-term orthodontic treatment, significant development of TMD is not to be expected. Likewise, the transformation of subclinical signs into clinical signs of TMD can be expected, which should not be associated with the course of possible orthodontic treatment. Although the results of the above mentioned studies reveal that orthodontic treatment does not have a special effect on the condition of TMDs, it should be taken into account that the studies described the treatment which was indicated for entirely orthodontic reasons. However, each treatment, particularly irreversible ones, runs the risk of adverse effects. Condylar resorption is one of the iatrogenic examples of TMDs development possibly related to orthodontic treatment. Orthodontic forces can often cause undesired reactions of partitioning within the alveolar bone. As in the described case, TMD symptoms were not observed on time thus causing the lack of consistent radiological follow-up (Shen et al., 2005).

Idiopathic condyle resorption is the term for the progressive form of OA of TMJ, which is associated with trauma and orthopedic procedure. Although it is an unwanted complication or an independent pathologic process manifested during orthodontic treatment, it certainly gives an impression of failure and of an even worse condition of the stomatognathic system. In the above mentioned study of patients with DD (Badel, 2007a), in the course of the follow-up of intraarticular condition during the treatment by Michigan splint, a rapid osteoarthritic process in a female bruxist patient with unilateral anterior DD without reduction and also malocclusion of Class II division 1 was found by MRI. Condyle resorption resulting in drastically pronounced open bite was not accompanied by exacerbation of TMD symptoms.

#### **6. Clinical case**

A 26-year-old female patient, previously under orthodontic treatment, was referred to a prosthodontic specialist, complaining of pain in her right TMJ and clicking in the left one with limited mouth opening. The pain was intensified upon chewing.

**Patient's history.** Without any particular reason, the patient experienced clicking in her left TMJ and she contacted her dentist, which happened 7 months prior to her visiting the prosthodontist. Her dentist referred her to an orthodontist. She was treated by a bimaxillary removable appliance (bionator) in order to correct a large horizontal overjet (Angle class II/1).

In the course of the orthodontic treatment, the patient still complained about the clicking and after 4 months pain in the right TMJ appeared. She had difficulties opening her mouth, pain appeared upon each movement of the mandible; she had difficulties adjusting to the new occlusal relations established by the orthodontic appliance and had a swelling in the region of the right TMJ. With respect to the above mentioned symptoms, she felt more comfortable in habitual occlusion than in the anterior therapeutic position achieved by the bionator. However, the patient did not realise at first that the pain in the TMJ was not being treated. The orthodontist did not realise that her intention was not to treat the orthodontic anomaly. Since the treatment by bionator obviously did not affect the TMJ symptomatology in that period, and her condition even worsened, the patient realised that her problems were not resolved by the treatment – instead of the TMJ symptoms she was treated for the orthodontic anomaly. According to the patient, the orthodontist realised this and attempted to stop the treatment by bionator without any particular explanation or further counselling with colleagues.

**Occlusal analysis.** At the first intraoral examination of the patient, two habitual intercuspal positions were detected. Until the lips were spread apart for a detailed dental examination, there was an impression of a physiological relationship between the anterior teeth. However, it was an acquired and forced anterior bite caused by regular wear of the bionator. In this position, the posterior teeth were in non-occlusion (Figure 3).

Fig. 3. Occlusion in anterior forced bite without (left) and with inserted bionator (right) in the mouth.

The real anterior-posterior relations between the dental arches were shown in the habitual intercuspal position: Angle Class II/1, an 11 mm horizontal overjet and a 4 mm overbite of upper teeth over the lower ones. In the transversal plane there was a 1 mm displacement of the medial line between lower central incisors to the right compared with the upper central incisors due to the loss of previously extracted first molars, especially of the extracted tooth 46 (Figure 4). In both teeth alignments, there was a crowding of posterior regions. The upper anterior teeth were provided with ceramic crowns. In both lateral movements there was a canine guidance, without balanced contacts or interferences. The teeth did not show any clinical signs of dental abrasion.

**Patient's history.** Without any particular reason, the patient experienced clicking in her left TMJ and she contacted her dentist, which happened 7 months prior to her visiting the prosthodontist. Her dentist referred her to an orthodontist. She was treated by a bimaxillary removable appliance (bionator) in order to correct a large horizontal overjet (Angle class

In the course of the orthodontic treatment, the patient still complained about the clicking and after 4 months pain in the right TMJ appeared. She had difficulties opening her mouth, pain appeared upon each movement of the mandible; she had difficulties adjusting to the new occlusal relations established by the orthodontic appliance and had a swelling in the region of the right TMJ. With respect to the above mentioned symptoms, she felt more comfortable in habitual occlusion than in the anterior therapeutic position achieved by the bionator. However, the patient did not realise at first that the pain in the TMJ was not being treated. The orthodontist did not realise that her intention was not to treat the orthodontic anomaly. Since the treatment by bionator obviously did not affect the TMJ symptomatology in that period, and her condition even worsened, the patient realised that her problems were not resolved by the treatment – instead of the TMJ symptoms she was treated for the orthodontic anomaly. According to the patient, the orthodontist realised this and attempted to stop the treatment by bionator without any particular explanation or further counselling

**Occlusal analysis.** At the first intraoral examination of the patient, two habitual intercuspal positions were detected. Until the lips were spread apart for a detailed dental examination, there was an impression of a physiological relationship between the anterior teeth. However, it was an acquired and forced anterior bite caused by regular wear of the

Fig. 3. Occlusion in anterior forced bite without (left) and with inserted bionator (right) in

The real anterior-posterior relations between the dental arches were shown in the habitual intercuspal position: Angle Class II/1, an 11 mm horizontal overjet and a 4 mm overbite of upper teeth over the lower ones. In the transversal plane there was a 1 mm displacement of the medial line between lower central incisors to the right compared with the upper central incisors due to the loss of previously extracted first molars, especially of the extracted tooth 46 (Figure 4). In both teeth alignments, there was a crowding of posterior regions. The upper anterior teeth were provided with ceramic crowns. In both lateral movements there was a canine guidance, without balanced contacts or interferences. The teeth did not show any

bionator. In this position, the posterior teeth were in non-occlusion (Figure 3).

II/1).

with colleagues.

the mouth.

clinical signs of dental abrasion.

Fig. 4. Habitual occlusion in maximum intercuspidation (left), and lateral view of the model transferred to the articulator. Note: a pronounced horizontal overjet (right).

**Clinical diagnostics.** Painful right TMJ with limited mouth opening was diagnosed by clinical examination and MFA according to Bumann and Groot Landeweer (Bumann and Lotzmann, 2002). Active mouth opening amounted to 36 mm, whereas passive mouth opening, that is mouth opening by exerting a mild downward passive force on the lower incisors amounted to 41 mm. Protrusive movement amounted to 6 mm, laterotrusion to the right amounted to 8 mm and laterotrusion to the left amounted to 4 mm. The pain intensity on the visual-analogue scale (VAS) (VAS=0-10; 0-10; 0, no pain; 10, the worst pain) was rated 7.4. On mouth opening there was a deviation to the right. On the right and also left laterotrusal movement, the pain appeared only in the right TMJ. Based on clinical findings and according to MFA (painful right TMJ under active and passive compressions) an anterior DD without reduction in the right TMJ was confirmed. Since the clinical signs of the disorder of the left TMJ were not present (the patient stated that she previously experienced reciprocal clicking), a clinical diagnosis of the left TMJ could not be made.

**Radiological diagnostics**. Panoramic x-ray shows a non-symmetrical relationship between the left and the right condyle: the right condylar head is pointed with a deplaned anterior surface. The bilateral anterior DD was confirmed by MRI. Imaging of both TMJs was performed on a 1T magnetic field device in three different positions: closed mouth position (habitual maximal intercuspidation, anterior position of the mandible caused by orthodontic treatment and open mouth position). The imaging sequences (matrix 256 x 192; 160 x 160 field of view) included the T1 weighted image (TR 450/TE 12), and gradient echo T2 weighted image (TR 760/TE 32), and T2 weighted image (TR 3000/TE 72).

Anterior DD without reduction was confirmed, with collections of inflammatory exudates which are most visible on T2 weighted images (Figure 5). In closed mouth position, the condylar head is anteriorly dislocated (Figure 5a), which is more visible in a forced anterior position (Figure 5b). Further dislocation is minimal (open mouth position) while the disc is constantly anteriorly dislocated and is deformed (Figure 5c). The condyle reaches the peak (zenith) of the articular eminence. Mild osteoarthritic changes in cortical bone of the condylar head in slightly pointed forms without subchondral changes are visible.

The anterior DD with reduction was determined in the left TMJ (Figure 6), which explains the previous symptom of clicking, which vanished in the course of orthodontic treatment. In closed mouth position, the condylar head was centrically placed within the glenoid fossa but in a slightly distraction position resulting in an enlarged intra articular fissure (Figure 6a). The disc was placed anteriorly and remained in this position even when the patient's mandible was in a forced anterior position (Figure 6b). In open mouth position, the disc achieved physiological position with respect to the condyle but it did not reach the peak of the articular eminence (Figure 6c). However, the mobility of the left condyle is more pronounced than in the right joint. The condylar head was slightly pointed with a hint of osteoarthritic changes appearing as a thickened tip of the cortical bone. Subchondral structures had an adequate signal and there was no articular effusion.

Fig. 5. Magnetic resonance images of the right temporomandibular joint in the position of maximum habitual intercuspidation (a), forced anterior position (b) and open mouth position (c). Note: non-reduced anterior displaced disc (short arrow), joint effusion (marked with \*), and degenerative changes of cortical condylar head (long arrow).

Fig. 6. Magnetic resonance images of the left temporomandibular joint in the position of maximum intercuspidation (a), forced anterior position (b) and open mouth position (c). Note: anterior displaced disc with reduction (short arrows) and degenerative changes of anterior part of cortical condylar head (long arrow).

**Treatment.** The stabilization splint (according to some authors the Michigan splint) (Badel, 2007a) is indicated for the initial treatment of pain caused by anterior DD (Figure 7). It temporarily provides stable joint position, and in addition, reduces abnormal muscle activity. Both jaw alginate impressions were taken and the splint was fabricated in a new therapeutic position, that is, in a position of centric relation. This was also the best position

but in a slightly distraction position resulting in an enlarged intra articular fissure (Figure 6a). The disc was placed anteriorly and remained in this position even when the patient's mandible was in a forced anterior position (Figure 6b). In open mouth position, the disc achieved physiological position with respect to the condyle but it did not reach the peak of the articular eminence (Figure 6c). However, the mobility of the left condyle is more pronounced than in the right joint. The condylar head was slightly pointed with a hint of osteoarthritic changes appearing as a thickened tip of the cortical bone. Subchondral

Fig. 5. Magnetic resonance images of the right temporomandibular joint in the position of maximum habitual intercuspidation (a), forced anterior position (b) and open mouth position (c). Note: non-reduced anterior displaced disc (short arrow), joint effusion (marked

Fig. 6. Magnetic resonance images of the left temporomandibular joint in the position of maximum intercuspidation (a), forced anterior position (b) and open mouth position (c). Note: anterior displaced disc with reduction (short arrows) and degenerative changes of

**Treatment.** The stabilization splint (according to some authors the Michigan splint) (Badel, 2007a) is indicated for the initial treatment of pain caused by anterior DD (Figure 7). It temporarily provides stable joint position, and in addition, reduces abnormal muscle activity. Both jaw alginate impressions were taken and the splint was fabricated in a new therapeutic position, that is, in a position of centric relation. This was also the best position

anterior part of cortical condylar head (long arrow).

with \*), and degenerative changes of cortical condylar head (long arrow).

structures had an adequate signal and there was no articular effusion.

for stabilization splint fabrication since it ensures a stable position of condyle in the articular fossa. It also enables the removal of the retrodiscal tissue load exerted by the condyle since the articular disc is permanently protruded, that is displaced anteriorly (Badel et al., 2003). The patient was instructed to wear the appliance while sleeping and was asked to come for a check-up in a week.

Fig. 7. Michigan splint on a model (left) and the inserted splint in the patient's mouth (right).

In collaboration with a rheumatologist-physiatrist, the patient was referred to physical therapy, which consisted of a routine protocol: TENS (transcutaneous electroneural stimulation), topical non-steroidal analgesic ketoprofen (*Fastum gel*) three times a day and a kinesiotherapy programme by Schulte (Badel et al., 2010b). She continued performing the exercises by Schulte three times a day at home.

Besides stopping the orthodontic treatment, the patient initially wore the Michigan splint for about 5 months. After 6 months, a more significant ability of mouth opening (45 mm) was measured but pain in both joints was still present, particularly upon yawning (VAS=8). While the left joint was painful on wider mouth opening, pain in the right joint was more expressed and accompanied by slight crepitations. The patient was aware of the chronic nature of her pain because, as she stated, she 'got used to' the pain. She stressed the efficiency of oral exercises and topical application of the ketoprofen gel (*Fastum gel*).

**Long year follow-up.** At a recall 5 years later, the patient did not have pain in the TMJs and only felt discomfort in the right TMJ during wide mouth opening with clinically evidenced minor crepitations. However, she felt discomfort in the right joint on yawning ad sleeping on the right side of her face. When eating an apple and yawning, she sometimes felt pain in the right joint (VAS=4). Also, she mentioned rare occurrences of clicking in the right joint which was also painful. Maximum mouth opening still amounted to 45 mm, which is significant regarding the pre-treatment measurements and equal to the measurements after the initial treatment. Now, she does not have any esthetic or functional needs for orthodontic treatment.

A control MRI taken on the same device showed visible degenerative changes in both TMJs. Significant changes in the sense of OA development occurred in the right joint: the condyle was deplaned and an osteophytic formation on the anterior edge contributed to the unshapely appearance. The disc was deformed with anterior displacement (Figure 8a). Even in the anterior position, the disc still remained in front of the condyle (Figure 8b). In open mouth position, the condyle reached the eminence while the disc remained nonreduced (Figure 8c).

Fig. 8. Follow-up examination of the right temporomandibular joint by magnetic resonance imaging in the position of habitual maximum intercuspidation (a), forced anterior position (b) and open mouth position (c). Note: non-reduced and deformed anterior displaced disc (short arrow) and the osteophyte formation on the anterior edge of the condyle (long arrow).

In closed mouth position (habitual occlusion), a compensatory fibrosation of retrodisc tissue along with the deplaned condylar head of an appropriate size was visible in the left joint (Figure 9a). In the forced anterior position, the greatest part of the disc was placed anteriorly from the condyle (Figure 9b), whereas there was an almost complete reduction of displacement in open mouth position, that is, the disc was almost symmetrically repositioned on the condyle (Figure 9c). The condyle-disc complex almost reached the peak of the eminence when the patient wore the bionator, and also in the position of maximum mouth opening.

Fig. 9. Follow-up examination of the left temporomandibular joint by magnetic resonance imaging in the position of habitual maximum intercuspidation (a), forced anterior position (b) and open mouth position (c). Note: disc displacement with reduction (arrows), and fibrosation of the retrodisc tissue (marked with \*).

#### **7. Discussion and general remarks**

Orthodontic treatment should be planned carefully if there are underlying symptoms of TMDs. Clinical importance of certain dysfunctional symptoms has altered the concept of *normal* functioning of the stomatognathic system. A perfected interpretation of certain diagnostic symptoms enables the correct establishing of clinical diagnostic parameters and other diagnostic modalities of TMDs. The approach to patient in the sense of personalised

Fig. 8. Follow-up examination of the right temporomandibular joint by magnetic resonance imaging in the position of habitual maximum intercuspidation (a), forced anterior position (b) and open mouth position (c). Note: non-reduced and deformed anterior displaced disc (short arrow) and the osteophyte formation on the anterior edge of the condyle (long arrow).

In closed mouth position (habitual occlusion), a compensatory fibrosation of retrodisc tissue along with the deplaned condylar head of an appropriate size was visible in the left joint (Figure 9a). In the forced anterior position, the greatest part of the disc was placed anteriorly from the condyle (Figure 9b), whereas there was an almost complete reduction of displacement in open mouth position, that is, the disc was almost symmetrically repositioned on the condyle (Figure 9c). The condyle-disc complex almost reached the peak of the eminence when the patient wore the bionator, and also in the position of maximum

Fig. 9. Follow-up examination of the left temporomandibular joint by magnetic resonance imaging in the position of habitual maximum intercuspidation (a), forced anterior position (b) and open mouth position (c). Note: disc displacement with reduction (arrows), and

Orthodontic treatment should be planned carefully if there are underlying symptoms of TMDs. Clinical importance of certain dysfunctional symptoms has altered the concept of *normal* functioning of the stomatognathic system. A perfected interpretation of certain diagnostic symptoms enables the correct establishing of clinical diagnostic parameters and other diagnostic modalities of TMDs. The approach to patient in the sense of personalised

fibrosation of the retrodisc tissue (marked with \*).

**7. Discussion and general remarks** 

mouth opening.

dental medicine gains importance when dealing with patients suffering from certain diagnoses of TMDs. Furthermore, the issue of occlusion in dental medicine has reached a dogmatic level, which in case of TMD patients should not apply, particularly the use of irreversible treatment methods as well as planning of possible preventive procedures (Carlsson, 2010).

As with many other musculoskeletal disorders in the human body, according to modern biomedical beliefs, they are of non-specific etiopathology, that is, they are idiopathic on the level of the individual patient (Green, 2006). Correlating TMDs with numerous etiopathogenic factors does not result in efficient determination of their cause-effect relation. Therefore, current opinion is that TMDs are idiopathic in origin and the correlation with certain etiologic factors cannot be entirely confirmed; on the other hand, the question of chronic musculoskeletal (or non-malignant) pain becomes dominant within the field of pain medicine. Consequently, pain and TMDs cannot be observed only on the level of occlusion, individual patients' wishes regarding esthetic dentistry and relying on scientifically unverified but traditional treatment indications.

Clinical examination, particularly manual examination techniques of patients with TMDs are an indispensable part of diagnostics by which the indication for imaging techniques is determined. MRI has become the gold standard in diagnostics and differential diagnostics of TMDs because it enables imaging of hard and soft tissues of TMJ (primarily the disc) and joint effusion. Although MRI is the gold standard in TMJ diagnostics, there is still no gold standard in diagnostics of temporomandibular pain. Indeed, MRI is not an appropriate screening method but a strictly applied diagnostic and differential-diagnostic method (Ahmad et al., 2009).

TMDs treatment planning can be carried out as the initial treatment and upon reaching a satisfactory degree of recovery, the definitive treatment can be planned as well. This may be applied to all TMDs patients, regardless of their having intact teeth with respect to physiological occlusal relations as well as to patients in need of orthodontic or prosthodontic treatment or even an oral surgical procedure. One should bear in mind the fact that definite treatment should have its indications and should be in accordance with the patient's wishes as well as with the actual state of occlusion and the level of TMDs treatment. In managing of TMDs patients there are always doubts about the indications for definite treatment, if there was a possibility of treating the painful TMD only by reversible treatment modalities, that is, by initial treatment. By recognizing the signs and symptoms of TMDs and by choosing initial methods of treatment as the methods of choice, the excessive use of diagnostics (for example, MRI) as well partial or complete overtreatment modalities are avoided (De Boever, et al., 2008; Türp, 2002).

The possibility of incorrect treatment in cases of TMDs patients can happen as it was shown in the clinical case of the female patient described in this paper, which was contrary to her wishes and individual needs of malocclusion treatment. Excessive, unnecessary and incorrect treatment methods of TMDs patients can have legal repercussions (Manfredini et al., 2011).

The patient has a input in the planning of own treatment and the dentist should consider the patient's wishes, and the current trend is to collaborate with other dental and medical specialists which is a multidisciplinary approach (De Boever et al., 2008).

Since clinical TMDs symptoms range from painless clicking up to severe pain causing problems in basic functioning upon eating and speech, the question arises when TMDs symptoms should be treated. In cases of adolescent patients with an occlusal anomaly there are considerations of whether orthodontic treatment can prevent their exacerbation, particularly pain. Since prevention implies the possibility of affecting causal factors of the disease, there is a lack of scientific facts to support that (Luther, 1998).

The absence of temporomandibular pain and mild functional difficulties caused by remaining TMD symptoms represent the group of passive need for TMD treatment. The idiopathic concept of development of TMDs cannot accept the concept by Kutilla et al. (1996) of active and passive TMD prevention. Preventive measures cannot be planned in patients with unknown etiology. Since the topic of this paper is the relationship between orthodontics and TMDs (although numerous studies are not methodologically coordinated and neither is the sample of patients who are primarily orthodontic or primarily with TMDs), the review papers on this subject constantly reach the conclusion that orthodontics neither treats TMDs nor causes them in particular (Macfarlane et al., 2009). As it happens in every definitive treatment in the stomatognathic system, painful forms of TMDs aggravate orthodontic treatment which was previously planned due to malocclusion rather than TMDs. In the course of orthodontic treatment previously latent symptoms of TMDs may appear (that is why MFA is significant as a clinical screening test) or manifested TMDs symptoms may develop although the patient did not experience such symptoms at any level prior to this. Such a condition particularly aggravates further orthodontic treatment so that it is recommended to temporarily discontinue the orthodontic treatment according to the need and the level of the presence of symptoms (Michelotti & Iodice, 2010). The part of the functional treatment termed initial symptomatic treatment, which should provide a satisfactory degree of painful function of stomatognathic system, should be carried out in order to continue the orthodontic treatment (Badel, 2007a).

In a review of methods of clinical TMD evaluation in population of children and adolescents, Toscano & Defabianis (2009) pointed to a great variability of results which causes problems in their direct possibility of comparison. However, it can be concluded that joint sounds and TMJ symptoms are the most common in that subgroup of population. Bionators initially look like a sort of combined upper and lower Hawley retainer, but do not fasten to the teeth and are not used for post-brace removal treatment. Bionators are held in the mouth within the space that the teeth surround when biting. In the described clinical case, a distinction should be made between short-term wear of bionator and the exacerbation of painful clinical signs and symptoms of TMD as well as manifestation of osteoarthritis with prior DD within a 5-year-follow-up, which was confirmed by MRI. Such long-term effects of MRI imaging of TMJs cannot be ascribed to orthodontic treatment because degenerative changes accompanied by various conditions of DD, according to Kurita et al. (2006) develop even without any clinical symptoms. After all, DD of TMJ can be expected even in asymptomatic subjects (Badel et al., 2008c).

According to the American Academy of Pediatric Dentistry (2010) there are reversible and irreversible methods of TMD treatment. Irreversible methods of treatment include occlusal adjustment, mandibular repositioning (by a repositioning appliance) and also orthodontic treatment, without specific instructions on which group of treatment modalities is recommendable. Regarding the use of reversible treatment methods, there are some positive

Since clinical TMDs symptoms range from painless clicking up to severe pain causing problems in basic functioning upon eating and speech, the question arises when TMDs symptoms should be treated. In cases of adolescent patients with an occlusal anomaly there are considerations of whether orthodontic treatment can prevent their exacerbation, particularly pain. Since prevention implies the possibility of affecting causal factors of the

The absence of temporomandibular pain and mild functional difficulties caused by remaining TMD symptoms represent the group of passive need for TMD treatment. The idiopathic concept of development of TMDs cannot accept the concept by Kutilla et al. (1996) of active and passive TMD prevention. Preventive measures cannot be planned in patients with unknown etiology. Since the topic of this paper is the relationship between orthodontics and TMDs (although numerous studies are not methodologically coordinated and neither is the sample of patients who are primarily orthodontic or primarily with TMDs), the review papers on this subject constantly reach the conclusion that orthodontics neither treats TMDs nor causes them in particular (Macfarlane et al., 2009). As it happens in every definitive treatment in the stomatognathic system, painful forms of TMDs aggravate orthodontic treatment which was previously planned due to malocclusion rather than TMDs. In the course of orthodontic treatment previously latent symptoms of TMDs may appear (that is why MFA is significant as a clinical screening test) or manifested TMDs symptoms may develop although the patient did not experience such symptoms at any level prior to this. Such a condition particularly aggravates further orthodontic treatment so that it is recommended to temporarily discontinue the orthodontic treatment according to the need and the level of the presence of symptoms (Michelotti & Iodice, 2010). The part of the functional treatment termed initial symptomatic treatment, which should provide a satisfactory degree of painful function of stomatognathic system, should be carried out in

In a review of methods of clinical TMD evaluation in population of children and adolescents, Toscano & Defabianis (2009) pointed to a great variability of results which causes problems in their direct possibility of comparison. However, it can be concluded that joint sounds and TMJ symptoms are the most common in that subgroup of population. Bionators initially look like a sort of combined upper and lower Hawley retainer, but do not fasten to the teeth and are not used for post-brace removal treatment. Bionators are held in the mouth within the space that the teeth surround when biting. In the described clinical case, a distinction should be made between short-term wear of bionator and the exacerbation of painful clinical signs and symptoms of TMD as well as manifestation of osteoarthritis with prior DD within a 5-year-follow-up, which was confirmed by MRI. Such long-term effects of MRI imaging of TMJs cannot be ascribed to orthodontic treatment because degenerative changes accompanied by various conditions of DD, according to Kurita et al. (2006) develop even without any clinical symptoms. After all, DD of TMJ can be

According to the American Academy of Pediatric Dentistry (2010) there are reversible and irreversible methods of TMD treatment. Irreversible methods of treatment include occlusal adjustment, mandibular repositioning (by a repositioning appliance) and also orthodontic treatment, without specific instructions on which group of treatment modalities is recommendable. Regarding the use of reversible treatment methods, there are some positive

disease, there is a lack of scientific facts to support that (Luther, 1998).

order to continue the orthodontic treatment (Badel, 2007a).

expected even in asymptomatic subjects (Badel et al., 2008c).

results obtained by, for example, Tecco et al. (2010) who found a positive effect of a fixed orthodontic appliance and the anterior repositioning splint on TMDs. Arthrocentesis proved to be efficient in combination with the occlusal splint (Machon et al., 2011). The use of the repositioning splint should be controlled and short-term because it can result in development of posterior open bite as a result of partitioning of intraarticular structures of TMJ on forced anterior bite (Türp, 2002; Brenkert, 2010). In such a case the initial treatment can be a failure because repositioning of this kind does not imply moving the anteriorly displaced disc (displacement reduction) but moving the condyle into a position which reduces the displacement thus causing clicking. Asymptomatic causes in non-patients show that DD does not necessarily mean the appearance of symptoms suggesting that such causative treatment is not in accordance with the principle of symptomatic treatment of TMDs (Badel et al, 2008c; Türp, 2002). When choosing the right initial occlusal treatment, permissive and non-invasive occlusal splints, such as the Michigan splint, are given the advantage (Dylina, 2001).

Optimal cost-effectiveness and health care efficiency are achieved by using palliative treatment procedures which cannot result in potentially incorrect, excessive, insufficient or untimely treatment of TMDs (Figure 10).

Fig. 10. The relationship between diagnostic and treatment procedures in patients with temporomandibular disorders.

#### **8. Acknowledgment**

This paper is a part of the scientific project No. 065-0650445-0441 supported by the Ministry of Science, Education and Sports, Republic of Croatia.

#### **9. References**


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## **Dentofacial Aspects of the Changes in Body Posture, Investigation Procedures**

Emil Segatto and Angyalka Segatto

*University of Szeged, Department of Orthodontics and Pediatric Dentistry Hungary* 

#### **1. Introduction**

376 Orthodontics – Basic Aspects and Clinical Considerations

Türp, J.C. & Schindler, H.J. (2003) Zum Zusammnehang zwischen Okklusion und

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temporomandibular disorders. *Medical Hypotheses*, Vol.71, No.4, pp. 564-567, ISSN

The literature exploring the reasons and the development of the orofacial-orthopaedic anomalies and orthodontic deviations deals measurably with the correlation of these deviations and postural disorders. The development of certain pathological curvatures different from the physiological curvatures of the spine is mainly responsible for the majority of the postural deviations present during the pre-puberty. No spinal curvatures are found in the frontal plane at healthy people. In a normal spine there are four types of spinal curvatures (thoracic and sacral kyphosis, and cervical and lumbar lordosis) in the sagittal plane responsible for the upstanding posture. These curvatures become the characteristic attributes of an individual at the age of six-seven (Bellyei, 1995).

During growth the functional disorders at the spinal and body muscles are manifested in poor postures of different severity and directions. These can result in considerable spinal and therefore trunk inclinations in the frontal, the sagittal or both planes. If observed in time the poor or abnormal posture can be corrected with effective muscle strengthening exercises. The failure of the early discovery and of the early started corrective muscle exercises result in the consolidation of the pathological posture and in the development of the spinal deformities. The development of these skeletal problems is associated in many instances by other primary factors of which entire scale has not been disclosed so far. Without reference to the several different causative factors the general characteristic of all spinal deformities is that the active muscle strengthening exercises are not suitable for the fully management though the progression rate can be positively influenced.

The pathological curvature found on any segment of the spine playing a primary role in establishing the static balance induces the apparition of compensating curvatures that many times due to their positional attributes result in abnormal head posture. This way the spinal curvatures found in the frontal plane result in laterally tilted head posture, while the pathological spinal curvatures in the sagittal plane result in forward, respectively backward tilted head posture. In case of compensating spinal deformities the head posture is normal and compensating spinal malformations evolved in lower position level.

The literature studying the deformation of the facial skeletal structures deals with the cause and effect correlations regarding the head posture disorders in several publications (Solow & Tallgren, 1976; Marcotte, 1981; Solow & Siersbaek-Nielsen, 1986). According to the authors discovering positive relations, the head posture altered in the growth period through the gravitational effects - induces pathological soft tissue load (Solow & Kreiborg, 1977), that on the basis of the functional matrix theory results in an abnormal development of the cartilage and bone structures concerning the direction and size (Proffit & Fields, 2000).

The literature has disclosed the examination of those subjects suffering from spinal deformities who have scoliosis characterized with curvatures in the frontal plane. There are no detailed data on a comprehensive dentofacial screening at patients with Scheuermann's disease with increased thoracic kyphosis inducing forward tilted head posture. The available researches deal with the dentofacial deviations that can be connected with the examined spinal deformities or with the patients with abnormal head postures. No one research has attempted to specifically examine the previously mentioned two subject groups with congenial methods and in the same time as regards the earlier determined dentofacial deviations, having separated the correlation with the functional and/or structural etiological problems.

The literature presenting the dentofacial aspects of the spinal deformities versus the orofacial orthopaedic examinations at patients with postural disorders does not have a long history. The difficulty of the accurate determination of the postural features was the main reason. The modernization of the posture examining radiation free methods has brought a break-through in this matter, rasterstereography being the most outstanding technology. This examination method enables the calibrated determination of such numerical parameters helping to indirectly describe the spinal curvatures responsible for poor body posture and it can be used for comparison at examinations performed on a large sample. The examination of the dentofacial deviation associated to the postural deformities comprised beside routine orthodontic examination methods functional and radiologic procedures as well. The latter mainly includes the evaluation of the lateral cephalogram, P-A cephalogram and Orthopantomograms (OPG). The P-A cephalogram unlikely the lateral cephalogram and the OPG is not a routine radiologic procedure in orthodontics. As a result of our researches made to decrease the radiation load, the self-developed OPG analysing software is suitable for the expansive topographic asymmetry examinations of the mandible. This way the P-A cephalograms becomes unnecessary.

During our research activity we could amend for the first time the results of the dentofacial examinations of the samples screened by the rasterstereographic method with the results of such a comprehensive examination where the evaluations of the lateral cephalograms were unified with the very detailed data of the mandibular asymmetry examinations. The asymmetry examinations have pointed out results showing close correlation with certain elements of the lateral cephalogram analyses that can substitute during the determination of the dentofacial sample. These findings defines further examination directions for the radiation load reduction with determining such measurements elaborated on OPG's that can replace the performance of the lateral cephalograms in cases that were considered positive during an orthopaedic screening.

The purpose of the chapter is to give a comprehensive vision about the correlation between the dentofacial problems and the changes in body posture which play an etiologic role in their development, with detailed presentation of the specific malformations of both fields, completed with the presentation of the up to date methods of investigation.

#### **2. Factors causing changes in body posture**

Among the factors influencing the static body posture - beside the lower limbs structural asymmetries - the structural deviations of the pelvis as well as the malformations of the direction of the spine and the supporting body muscles are present. The structural malformations of the pelvis are relatively rare, and nowadays the disadvantageous effects of the limb asymmetries influencing the body posture are more easily treated with the modern orthopaedic appliances. Due to the earlier mentioned cause and effect correlation among the body posture deviations playing a significant role in the alteration of the head posture, the alterations in the spine and supporting body muscle position deserve more attention because of the frequency indices and the difficult therapeutic treatment. The more severe part of the latter deviation-group is formed by the spinal deformities while the more frequent part by the body muscle morphofunctional deviations.

#### **2.1 Spinal disorders**

378 Orthodontics – Basic Aspects and Clinical Considerations

& Tallgren, 1976; Marcotte, 1981; Solow & Siersbaek-Nielsen, 1986). According to the authors discovering positive relations, the head posture altered in the growth period through the gravitational effects - induces pathological soft tissue load (Solow & Kreiborg, 1977), that on the basis of the functional matrix theory results in an abnormal development of the cartilage and bone structures concerning the direction and size (Proffit & Fields, 2000). The literature has disclosed the examination of those subjects suffering from spinal deformities who have scoliosis characterized with curvatures in the frontal plane. There are no detailed data on a comprehensive dentofacial screening at patients with Scheuermann's disease with increased thoracic kyphosis inducing forward tilted head posture. The available researches deal with the dentofacial deviations that can be connected with the examined spinal deformities or with the patients with abnormal head postures. No one research has attempted to specifically examine the previously mentioned two subject groups with congenial methods and in the same time as regards the earlier determined dentofacial deviations, having separated the correlation with the functional and/or structural

The literature presenting the dentofacial aspects of the spinal deformities versus the orofacial orthopaedic examinations at patients with postural disorders does not have a long history. The difficulty of the accurate determination of the postural features was the main reason. The modernization of the posture examining radiation free methods has brought a break-through in this matter, rasterstereography being the most outstanding technology. This examination method enables the calibrated determination of such numerical parameters helping to indirectly describe the spinal curvatures responsible for poor body posture and it can be used for comparison at examinations performed on a large sample. The examination of the dentofacial deviation associated to the postural deformities comprised beside routine orthodontic examination methods functional and radiologic procedures as well. The latter mainly includes the evaluation of the lateral cephalogram, P-A cephalogram and Orthopantomograms (OPG). The P-A cephalogram unlikely the lateral cephalogram and the OPG is not a routine radiologic procedure in orthodontics. As a result of our researches made to decrease the radiation load, the self-developed OPG analysing software is suitable for the expansive topographic asymmetry examinations of the mandible.

During our research activity we could amend for the first time the results of the dentofacial examinations of the samples screened by the rasterstereographic method with the results of such a comprehensive examination where the evaluations of the lateral cephalograms were unified with the very detailed data of the mandibular asymmetry examinations. The asymmetry examinations have pointed out results showing close correlation with certain elements of the lateral cephalogram analyses that can substitute during the determination of the dentofacial sample. These findings defines further examination directions for the radiation load reduction with determining such measurements elaborated on OPG's that can replace the performance of the lateral cephalograms in cases that were considered

The purpose of the chapter is to give a comprehensive vision about the correlation between the dentofacial problems and the changes in body posture which play an etiologic role in

etiological problems.

This way the P-A cephalograms becomes unnecessary.

positive during an orthopaedic screening.

The common feature of the spinal deformities is the steady, structural deviation of the spine vertebrae which manifests in the pathological curvatures found on the affected spine segment due to the cumulated effects. Based on the frequency indices the two most prevailing spinal deformities are the scoliosis and the Scheuermann's disease, or Scheuermann's kyphosis. While the scoliotic curvature is a lateral curvature in the frontal plane, at Scheuermann's disease the hyperkyphosis developed due to the increase of the physiological thoracic kyphotic curvature. The appearance time and the progression of these deviations can be very diverse. We have to take into consideration that the quick condition decline most frequently is at the beginning of puberty, which – based on the earlier literature – significantly influences the development of the dentofacial deviations (Huggare et al., 1991).

#### **2.1.1 Scoliosis**

Scoliosis - its first written records are connected to Hippocrates – is a pathological entity with unknown aetiology. Its characteristic feature is the lateral spinal curvature developed as a result of the asymmetric growth of the vertebrae (Lowe et al., 2000). No spinal deviations are found in the frontal plane at healthy people. With the development of the structural deviations the pathological spinal curvatures become steady later, so the spinal deformity developed this way is called scoliosis. The curvatures found in the frontal plane are accompanied by the rotations measurable at horizontal plane as well as the altered curvatures in the sagittal plane. These deformities most often affect the thoracic and the lumbar segment segregated or entirely affecting such compensating curvatures that are entitled to ease the load and to balance the compression areas.

Scoliosis can be divided upon several aspects. Basically we can talk about primary and secondary scoliosis. The asymmetric growth developed on the spinal vertebral level is the reason of the primary deviation. This can be congenital or acquired. The acquired primary scoliosis can be further divided into idiopathic, traumatic, infectious, neuromuscular, tumorous and degenerative. Scoliosis according to the direction of the curvature can be classified as follows: convex to the right or left, or of double direction. Scoliosis can further be classified by the localization of the curvatures. The curvatures can be structural or functional, as well as compensated or non-compensated. The most frequently examined type is the primary idiopathic scoliosis due to its incidence, its particular clinical feature and its progression. According to when onset occurs scoliosis can be: juvenile and adolescent. While at the juvenile scoliosis 90% of the cases show spontaneous improvement, the adolescent scoliosis is a progressive type deviation and till the age of 25 is constantly worsening in different phases (Herman et al., 1985).

During the examination of the affected spinal segment the morphological features detected on both side of the spinal curvature show correlation with the severity of the curvature. The vertebral bodies broaden on the convex side, the rips are deforming and lifting towards the dorsal while the radius of their curvature is decreasing. On the concave side the vertebral bodies are narrower; the ribs are deformed while losing their normal curvatures they are curving straightforward (Bellyei, 1995). When scoliosis is present, the thoracic kyphosis decreases, straightens or could become lordotic. On the convex side at the apex of the curvature the ribs are heightened because of the spinal torsion, while on the concave side the ribs are sinking. The direction of the ribs deformation on the foreside of the thorax is opposed. The childhood clinical symptoms become localized on the spinal deformity, pains and other complaints are missing. Larger curvatures can be seen due to the postural and the caused structural asymmetries.

The basic conclusions of the researches related to the aetiology of the idiopathic structural scoliosis as regards the development of the scoliosis are the following: correlates to the adolescent growth-spurt; in girls the development of the curvature tends to be of a greater severity; presence of different deformities and genetically inherited (Hadley, 2000). Among the several aetiological factors the most often mentioned are the defect on level of CNS, the failure in the control of the melatonin production, the effect of calmodulin, the collagen abnormality, the altered platelets, as well as several hypothetical genetic inheritance – autosomal dominant inheritance, multi gene inheritance, multi-factorial inheritance and the X-linked dominant inheritance (Wise et al., 2000; Inoue et al., 2002; Parent et al., 2005).

Because of the diversity of world-wide applied early screening protocols, different occurrence data are available. The screenings at school showed such visually detectable body asymmetry at 15% of girls and boys at age 10 and 14, which were later proved by radiological examinations. The international literature data reports a ratio of 10 girls for every one boy (Morissy & Weinstein, 2006). On the basis of the earlier mentioned the classic idiopathic structural scoliosis is a right-curved, dorsal, lateral spinal curvature found at girls between age 10 and 12. The rotation evolved among the affected vertebrae and the presence of the torsion - a shift between certain elements within the vertebrae - is also characteristic features of the disease (Bagnall, 2008). The natural process of scoliosis is basically determined by the etiology and the outline of the curvature. The most frequent symptoms of the untreated scoliosis: the progression of the curvature, back pains, cardiopulmonary complaints and psychosocial problems. Though the mentioned symptoms are present in most of the cases, the effects on the entire organism are various. One single constant adjunct element to the untreated scoliosis, which shows a close correlation with the degree of the curvature, is the decrease of the pulmonary function. This is ascribable to the lateral disease curbed their every day activities (Lin et al., 2001).

#### **2.1.2 Scheuermann's disease**

380 Orthodontics – Basic Aspects and Clinical Considerations

tumorous and degenerative. Scoliosis according to the direction of the curvature can be classified as follows: convex to the right or left, or of double direction. Scoliosis can further be classified by the localization of the curvatures. The curvatures can be structural or functional, as well as compensated or non-compensated. The most frequently examined type is the primary idiopathic scoliosis due to its incidence, its particular clinical feature and its progression. According to when onset occurs scoliosis can be: juvenile and adolescent. While at the juvenile scoliosis 90% of the cases show spontaneous improvement, the adolescent scoliosis is a progressive type deviation and till the age of 25 is constantly

During the examination of the affected spinal segment the morphological features detected on both side of the spinal curvature show correlation with the severity of the curvature. The vertebral bodies broaden on the convex side, the rips are deforming and lifting towards the dorsal while the radius of their curvature is decreasing. On the concave side the vertebral bodies are narrower; the ribs are deformed while losing their normal curvatures they are curving straightforward (Bellyei, 1995). When scoliosis is present, the thoracic kyphosis decreases, straightens or could become lordotic. On the convex side at the apex of the curvature the ribs are heightened because of the spinal torsion, while on the concave side the ribs are sinking. The direction of the ribs deformation on the foreside of the thorax is opposed. The childhood clinical symptoms become localized on the spinal deformity, pains and other complaints are missing. Larger curvatures can be seen due to the postural and the

The basic conclusions of the researches related to the aetiology of the idiopathic structural scoliosis as regards the development of the scoliosis are the following: correlates to the adolescent growth-spurt; in girls the development of the curvature tends to be of a greater severity; presence of different deformities and genetically inherited (Hadley, 2000). Among the several aetiological factors the most often mentioned are the defect on level of CNS, the failure in the control of the melatonin production, the effect of calmodulin, the collagen abnormality, the altered platelets, as well as several hypothetical genetic inheritance – autosomal dominant inheritance, multi gene inheritance, multi-factorial inheritance and the X-linked dominant inheritance (Wise et al., 2000; Inoue et al., 2002; Parent et al., 2005).

Because of the diversity of world-wide applied early screening protocols, different occurrence data are available. The screenings at school showed such visually detectable body asymmetry at 15% of girls and boys at age 10 and 14, which were later proved by radiological examinations. The international literature data reports a ratio of 10 girls for every one boy (Morissy & Weinstein, 2006). On the basis of the earlier mentioned the classic idiopathic structural scoliosis is a right-curved, dorsal, lateral spinal curvature found at girls between age 10 and 12. The rotation evolved among the affected vertebrae and the presence of the torsion - a shift between certain elements within the vertebrae - is also characteristic features of the disease (Bagnall, 2008). The natural process of scoliosis is basically determined by the etiology and the outline of the curvature. The most frequent symptoms of the untreated scoliosis: the progression of the curvature, back pains, cardiopulmonary complaints and psychosocial problems. Though the mentioned symptoms are present in most of the cases, the effects on the entire organism are various. One single constant adjunct element to the untreated scoliosis, which shows a close correlation with the degree of the curvature, is the decrease of the pulmonary function. This is ascribable to the lateral

worsening in different phases (Herman et al., 1985).

caused structural asymmetries.

The disease developed with the enlargement of the thoracic kyphosis of the spine and as a result of the structural deviation of the involved spinal segment was named and described as "kyphosis dorsalis juvenilis" by Scheuermann, a Danish radiologist (Ali, 1999). There are several names for the disorder in the literature: M.Scheuermann, osteochondrosis juvenilis dorsi, kyphosis dorsalis juvenilis, Scheuermann's kyphosis, juvenile kyphosis, Calvé's disease (Lowe, 1999). Actually the deformity is considered to be a form of juvenile osteochondrosis of the spine.

The degree of the thoracic kyphosis varies at healthy individuals; the normal curvature of the thoracic spine is between 20 and 40 degrees. The kyphotic curvature of more than 40-45 degrees gives the impression of a humpback, which is sometimes accompanied by the forward tilted head posture. Under the most frequently affected thoracic segment the increased compensatory lordosis of the lumbar part appears. In 25-30 % of the cases a moderate, generally functional dorso-lumbar scoliosis associates the previously mentioned deviations (Lemirre et al., 1996).

According to the localization the Scheuermann's disease can be classified in three main types. The type localized on the thoracic part is the most frequent, it extends on more vertebrae and usually painless. The dorso-lumbar interim type is rare, it covers several vertebrae and pain can be observes. The rarest type is the lumbar localized, it affects only one vertebrae and it is usually accompanied by pain (Bellyei, 1995). The children suffering from Scheurmann's disease are thin, have weak body muscles manifested in poor body posture and in abnormal head posture. In the majority of the cases the increased thoracic kyphosis causes only interim disturbance of growth and lasts till the end of growth with no progression. In a minor number severe progression can be observed, these can hardly be cured with conservative treatments. In these cases the thoracic kyphosis is very increased and the deformity is accompanied by complaints. In general there is no correlation between the onset of the complaints and the severity of the kyphosis - even a severe kyphosis can be painless, and in fact with a mild kyphotic curvature severe pains can be detected.

Similarly as in the case of scoliosis the earlier age the symptoms are present, the more favourable the prognosis is. Progression speeds up at the puberty phase. In this development period the growth of muscles cannot follow the fast grow of the bones. As a result of the endocrine harmonization and the increased stress the severity of deformity develops together with the complaints (Deacon et al., 1985).

The accurate etiology of the disease is still unknown. Some researchers consider the disease as deviations present at the level of the intervertebral discs among the vertebrae; others think that the endochondral ossification disorder of end plates is the causative factor. The notion "insufficientia vertebrae" introduced by Schanz originates the development of the deviation to the balance disorder of the active (muscular) and passive (skeletal) system. Today it is a well-known fact that beside the mechanical factors, weight and height also play an important role. Some researchers proved the presence of the autosomal dominant inheritance – the expected incidence for the repetition of the disorder in the family of the child with Scheuermann's disease is 50 %. Literature sources reports on very diverse incidence values. These vary between 0.4% - 8%, with similar ratio in the two genders (Tribus, 1998).

The most characteristic symptom of the disorder is the increased thoracic kyphosis indicating forward tilted hunchback posture. The compensatory lordosis of the spine segment found caudally from the deformity is less visible similarly to the functional scoliosis present as an accompanying symptom in some of the cases. It is more common the forward tilted head posture as well as the pendulous upper limbs attributable to the myasthenia. The characteristic of the disease is the presence of the "wedging" shape vertebrae developed on the involved spine segment, which makes the kyphotic curvature more increased. The Schmorl's nodes developed as a result of the forces acting through the anterior flattened vertebral discs and the presence of the uneven, attenuated endplate surfaces are very important in the distinctive diagnosis (Bradford, 1981). In case of untreated kyphotic curvature with less than 100 degrees the decrease of the pulmonary function is not common. In case of a kyphotic curvature with more than 100 degrees, with apex of the curve located between 1 and 8 thoracic vertebrae always can be seen restrictive pulmonary disorder (Murray et al., 1993).

#### **2.2 Postural problems**

The harmonic spinal curvature system proper to the individual in case of normal static development appears by the age of 6-7. The abnormal or poor body posture develops most frequently due to the spinal deformities in the sagittal plane. When developing beside the lowered load capacity of the spinal and body muscles the lack of will-powers needed for normal body posture as well as psychic factors play a significant role. Postural problems can be divided into three main groups: dorsum rotundum – thoracic kyphosis larger than the normal; dorsum kypholordoticum – increased thoracic kyphosis accompanied by compensatory increased lumbar lordosis and dorsum planum – thoracic kyphosis smaller than the normal. The common feature of postural problems is that they can be corrected by active muscle power. Accompanying symptoms are: loose joints, pes planovagus and vaulted abdomen, procident shoulders and frequent abdominal breathing (Bellyei, 1995).

#### **2.3 Methods of investigation**

The examination of the presented postural problems is partly done by physical and partly by instrumental diagnostic examination methods. The use of the clinical examination methods besides the orthopedic consulting-hours is standing orders at school and paediatrician consultation hours. The completion of the instrumental examinations and the result evaluations require specialist background and consulting-room environment.

The observation being used as a first step in the physical examination methods trends to body postures and respectively to the possible asymmetries. The higher-degree pathological spinal curvatures become visible by influencing the body posture. The lateral curvatures higher than 5 degree are responsible for the asymmetric appearance. The increased curvature can be observed laterally on the thoracic segment of the vertebrae with palpation.

an important role. Some researchers proved the presence of the autosomal dominant inheritance – the expected incidence for the repetition of the disorder in the family of the child with Scheuermann's disease is 50 %. Literature sources reports on very diverse incidence values. These vary between 0.4% - 8%, with similar ratio in the two genders

The most characteristic symptom of the disorder is the increased thoracic kyphosis indicating forward tilted hunchback posture. The compensatory lordosis of the spine segment found caudally from the deformity is less visible similarly to the functional scoliosis present as an accompanying symptom in some of the cases. It is more common the forward tilted head posture as well as the pendulous upper limbs attributable to the myasthenia. The characteristic of the disease is the presence of the "wedging" shape vertebrae developed on the involved spine segment, which makes the kyphotic curvature more increased. The Schmorl's nodes developed as a result of the forces acting through the anterior flattened vertebral discs and the presence of the uneven, attenuated endplate surfaces are very important in the distinctive diagnosis (Bradford, 1981). In case of untreated kyphotic curvature with less than 100 degrees the decrease of the pulmonary function is not common. In case of a kyphotic curvature with more than 100 degrees, with apex of the curve located between 1 and 8 thoracic vertebrae always can be seen restrictive pulmonary

The harmonic spinal curvature system proper to the individual in case of normal static development appears by the age of 6-7. The abnormal or poor body posture develops most frequently due to the spinal deformities in the sagittal plane. When developing beside the lowered load capacity of the spinal and body muscles the lack of will-powers needed for normal body posture as well as psychic factors play a significant role. Postural problems can be divided into three main groups: dorsum rotundum – thoracic kyphosis larger than the normal; dorsum kypholordoticum – increased thoracic kyphosis accompanied by compensatory increased lumbar lordosis and dorsum planum – thoracic kyphosis smaller than the normal. The common feature of postural problems is that they can be corrected by active muscle power. Accompanying symptoms are: loose joints, pes planovagus and vaulted abdomen, procident shoulders and frequent abdominal breathing (Bellyei, 1995).

The examination of the presented postural problems is partly done by physical and partly by instrumental diagnostic examination methods. The use of the clinical examination methods besides the orthopedic consulting-hours is standing orders at school and paediatrician consultation hours. The completion of the instrumental examinations and the

The observation being used as a first step in the physical examination methods trends to body postures and respectively to the possible asymmetries. The higher-degree pathological spinal curvatures become visible by influencing the body posture. The lateral curvatures higher than 5 degree are responsible for the asymmetric appearance. The increased curvature can be observed laterally on the thoracic segment of the vertebrae with palpation.

result evaluations require specialist background and consulting-room environment.

(Tribus, 1998).

disorder (Murray et al., 1993).

**2.3 Methods of investigation** 

**2.2 Postural problems** 

The examination of the child's back in forward bend position (Adam's test) follows. At children with scoliosis a rib hump can be seen on the convex side of the curvature, which can be measure by the help of a scoliometer. At children with Scheuermann's disease during the test while the apex of the curvature is pushed down the patient is asked to chase by lifting their arms and head. As opposed to healthy as well as children with postural problems the kyphosis in case of Scheuermann's disease hardly decrease or not at all. As a last step during the examination of the locomotion range of the spine the aim of the trunk bending forward and back and laterally is to detect the restrain, which can be cause by the fixation of the involved spine deformity. At the potential pathological cases screened during testing the performation of an instrumental examination is suggested to confirm the diagnosis (Tribus, 1998).

The most frequent instrumental diagnostic examination methods are the radiological procedures. The methods developed to evaluate the radiograms taken from different sides are of high accuracy, due to their widespread use their evaluations are permeable, they are easily understood both in therapy and researches and can be used by all.

Fig. 1. Measurement of the: scoliotic curvature according to Cobb (a) and kyphotic angle (b).

The most prevailing measure for determining the scoliotic curvatures is the determination of the Cobb angle. These are defined by the adjacent angle of the angle between the lines drawn perpendicular along the superior and inferior end plates of the vertebrae bordering the curvature (Fig.1.a.). Since there is not physiological spinal curvature in the frontal plane the measurable Cobb values unequivocally show the presence of scoliosis. The determination of the kyphotic curvature in degrees in case of Scheuermann's disease happens in the same way using the end plates of the superior and inferior vertebrae of the pathological curvature for the measurements (Fig.1.b.). For a Scheuermann's disease diagnosis the presence of the following x-ray symptoms is essential: khypothic curvature greater than 45°; presence of three or more adjacent "wedging" shape vertebrae; presence of Schmorl's nodes (Ali et al., 1999).

Because of the expansion of the spine the amount of the radiation dosage as well as the more frequent x-ray picture taking explained by the disease process have increasingly highlighted the importance of those attempts, which focused on developing diagnostic examination methods with reduced exposure to radiation. These methods deduce the spinal structural deformities from the morphological features of the surface back contour. During their development period in order to increase the accuracy the most important aspect was the comparability with the reliable radiological parameters. At the beginning the radiation free moiré-topography was the greatest break-through, but because of its efficiency indicator did not work out as a routine application (Kim et al., 2001).

The appearance of the rasterstereography providing more accurate values than the moirétopography was a milestone (Frobin & Hierholzer, 1981). In the course of the rasterstereography procedure the testing device (Formetric 2, Diers International GmbH, Schlangenbad, Germany) elaborates a 3-D photographic mapping of the patient's back in upright position. For this purpose the device projects a sensitive gridded picture onto the back of the patient positioned at the suitable distance and way.

Fig. 2. Rasterstereography – reconstruction of the back surface.

The grid transmits accurate data about the back into the video-optical unit. Mapping the entire back takes 0.04 seconds and it is of high accuracy (methodological error < 0.1 mm) (Drerup & Hierholzer, 1987). The associated software units reconstruct the sagittal and frontal intercept of the surface back contour on the basis of certain anatomical structures (vertebra prominens and spinae iliacae)( Drerup & Hierholzer, 1994)(Fig.2.).

With the usage of mathematical algorithms the visualization of the surface back contour is available from both sagittal and frontal side. The shift of the spine from the real perpendicular can be shown with a mathematical modelling. The curvatures in the sagittal plane can be reproduced with a 2.8° accuracy, those in the frontal plane with a 2° accuracy.

The sagittal curvatures can be characterized with the following measurement from lateral aspect: fléche cervicale and fléche lombaire. Both measurements show the distance of the furthest point of a given area calculated from the tangent lined along the hams and blades,

Because of the expansion of the spine the amount of the radiation dosage as well as the more frequent x-ray picture taking explained by the disease process have increasingly highlighted the importance of those attempts, which focused on developing diagnostic examination methods with reduced exposure to radiation. These methods deduce the spinal structural deformities from the morphological features of the surface back contour. During their development period in order to increase the accuracy the most important aspect was the comparability with the reliable radiological parameters. At the beginning the radiation free moiré-topography was the greatest break-through, but because of its efficiency indicator did

The appearance of the rasterstereography providing more accurate values than the moirétopography was a milestone (Frobin & Hierholzer, 1981). In the course of the rasterstereography procedure the testing device (Formetric 2, Diers International GmbH, Schlangenbad, Germany) elaborates a 3-D photographic mapping of the patient's back in upright position. For this purpose the device projects a sensitive gridded picture onto the

The grid transmits accurate data about the back into the video-optical unit. Mapping the entire back takes 0.04 seconds and it is of high accuracy (methodological error < 0.1 mm) (Drerup & Hierholzer, 1987). The associated software units reconstruct the sagittal and frontal intercept of the surface back contour on the basis of certain anatomical structures

With the usage of mathematical algorithms the visualization of the surface back contour is available from both sagittal and frontal side. The shift of the spine from the real perpendicular can be shown with a mathematical modelling. The curvatures in the sagittal plane can be reproduced with a 2.8° accuracy, those in the frontal plane with a 2° accuracy. The sagittal curvatures can be characterized with the following measurement from lateral aspect: fléche cervicale and fléche lombaire. Both measurements show the distance of the furthest point of a given area calculated from the tangent lined along the hams and blades,

not work out as a routine application (Kim et al., 2001).

back of the patient positioned at the suitable distance and way.

Fig. 2. Rasterstereography – reconstruction of the back surface.

(vertebra prominens and spinae iliacae)( Drerup & Hierholzer, 1994)(Fig.2.).

enabling the very accurate approach of the thoracic kyphosis degree (Lippold et al., 2006a)(Fig.3.a.).

Fig. 3. Rasterstereography: fléche cervicale and fléche lombaire (a) and trunk inclination (b).

The most important measurement related to the body posture from lateral aspect is the trunk inclination, which is described by the angle between the vertical based on the vertebra prominens and the straight line between vertebra prominens and the center point of the straight line between the right and left crista iliaca posterior superior (VPDM line) (Fig.3.b.). Three variables are characteristic for the lateral curvatures from frontal aspect (Fig.4.).

Fig. 4. Rasterstereography: maximal lateral deviation (a), surface rotational amplitude (b) and lateral amplitude (c).

The maximal lateral deviation shows the distance of the vertebra found at the apex of the greatest curvature in the spinal frontal plane from the VPDM line (Drerup et al., 1997) (Fig.4.a.). The surface rotational amplitude is the angle between the perpendiculars drawn on the vertebrae showing the greatest rotation on the lateral curvature (Fig.4.b.). The lateral amplitude is the sum of the distances measured from the VPDM line of the opposite side curvatures of the apex vertebra found in the frontal plane (Fig.4.c.).

Beside its outstanding reliability the radiation-free aspect of the method makes it favourable for screening the large patient groups for research purposes. Though when developing several instrumental examination methods the main purpose is the accurate, quick and radiation-free diagnostic, these facts are suitable only for determination of the degree of the body posture disorder without x-ray pictures. The rasterstereography procedure is feasible to define the degree of different spinal disorders (Schulte et al., 2008). When compared to some x-ray measurement we obtain results that are closer to the kyphotic curvature values than in the case of the scoliotic curvatures (Weiss & ElObeidi, 2009). To support the diagnosis of the spinal disorders – structural deformed vertebrae – the evaluation of the spine x-rays are still necessary. In diagnosing the postural problems the rasterstereography is suitable for separating three main types, also for accurate localizing and measuring the curves deviated from the normal but not being steady yet. In order to acknowledge these results taking x-ray pictures of differential diagnosis importance is essential, these being suitable for revealing the lack of "wedging" shape vertebrae and Schmorl's nodes.

#### **3. Dentofacial features associated to changes in body posture**

#### **3.1 Literature review**

In the course of the interdisciplinary researches the investigation of the orthopaedic and orthodontic correlations has an important academic and practical significance concerning the separation of the preventive diagnostic and therapeutic areas within the two specialities. The literature sources reports on several researches that were examining the correlation between certain orthopaedic parameters and certain Angle classes. The results presume possible correlations between the scoliosis and the Angle Class II malocclusion (Huggare et al., 1991) as well as between the poor body posture and Class II malocclusions (Lippold et al., 2003). Similarly the close correlation between the lateral spinal deformity and the unilateral crossbite, as well as the lower midline deviation has been proved in some researches (Huggare, 1998; Ben-Bassat et al., 2006). The cause of the presented malocclusions in majority of the cases is the presence of the skeletal asymmetries. (Sabah, 2002). This is also confirmed by the subgroup of the Angle Class II malocclusion frequently associated with the jaw asymmetry (Ben-Bassat et al., 1993). The registration of the jaw asymmetries related to the scoliosis is due to the tight relation with the adjacent soft tissues and it can be even demonstrated through a simple observation (Korbmacher et al., 2004). The typical deviation of the facial midline and the presence of spinal deformity as a causative agent introduced the naming of facial scoliosis accepted and used in the literature. The findings show a close correlation between the patients with severe scoliosis and the presence of the convergence angle describing the facial scoliosis (U. Hirschfelder & H. Hirschfelder, 1983). The laterally tilted head posture can likely be a cause for the correlation between the facial soft tissue as well as the skeletal asymmetries and the lateral deviation of the spine (Pirttiniemi et al., 1989; Huggare et al., 1991; Huggare, 1998). The pathological symptoms present on the temporomandibular joints level loaded asymmetrical by the abnormal head posture also show a close correlation with the spinal deformities determining the head posture (Kondo & Aoba, 1999). Finally, it is worth mentioning the problems of the dental deformities appearing during the treatment of the scoliosis and as a result of it. This has mainly historic importance since the Milwaukee-brace - which has totally lost ground in the therapeutic practice – played a principal role in the existence of the mentioned dental deformities (Bögi & Nagy, 1970, Paphalmy et al., 1975).

Beside its outstanding reliability the radiation-free aspect of the method makes it favourable for screening the large patient groups for research purposes. Though when developing several instrumental examination methods the main purpose is the accurate, quick and radiation-free diagnostic, these facts are suitable only for determination of the degree of the body posture disorder without x-ray pictures. The rasterstereography procedure is feasible to define the degree of different spinal disorders (Schulte et al., 2008). When compared to some x-ray measurement we obtain results that are closer to the kyphotic curvature values than in the case of the scoliotic curvatures (Weiss & ElObeidi, 2009). To support the diagnosis of the spinal disorders – structural deformed vertebrae – the evaluation of the spine x-rays are still necessary. In diagnosing the postural problems the rasterstereography is suitable for separating three main types, also for accurate localizing and measuring the curves deviated from the normal but not being steady yet. In order to acknowledge these results taking x-ray pictures of differential diagnosis importance is essential, these being

suitable for revealing the lack of "wedging" shape vertebrae and Schmorl's nodes.

In the course of the interdisciplinary researches the investigation of the orthopaedic and orthodontic correlations has an important academic and practical significance concerning the separation of the preventive diagnostic and therapeutic areas within the two specialities. The literature sources reports on several researches that were examining the correlation between certain orthopaedic parameters and certain Angle classes. The results presume possible correlations between the scoliosis and the Angle Class II malocclusion (Huggare et al., 1991) as well as between the poor body posture and Class II malocclusions (Lippold et al., 2003). Similarly the close correlation between the lateral spinal deformity and the unilateral crossbite, as well as the lower midline deviation has been proved in some researches (Huggare, 1998; Ben-Bassat et al., 2006). The cause of the presented malocclusions in majority of the cases is the presence of the skeletal asymmetries. (Sabah, 2002). This is also confirmed by the subgroup of the Angle Class II malocclusion frequently associated with the jaw asymmetry (Ben-Bassat et al., 1993). The registration of the jaw asymmetries related to the scoliosis is due to the tight relation with the adjacent soft tissues and it can be even demonstrated through a simple observation (Korbmacher et al., 2004). The typical deviation of the facial midline and the presence of spinal deformity as a causative agent introduced the naming of facial scoliosis accepted and used in the literature. The findings show a close correlation between the patients with severe scoliosis and the presence of the convergence angle describing the facial scoliosis (U. Hirschfelder & H. Hirschfelder, 1983). The laterally tilted head posture can likely be a cause for the correlation between the facial soft tissue as well as the skeletal asymmetries and the lateral deviation of the spine (Pirttiniemi et al., 1989; Huggare et al., 1991; Huggare, 1998). The pathological symptoms present on the temporomandibular joints level loaded asymmetrical by the abnormal head posture also show a close correlation with the spinal deformities determining the head posture (Kondo & Aoba, 1999). Finally, it is worth mentioning the problems of the dental deformities appearing during the treatment of the scoliosis and as a result of it. This has mainly historic importance since the Milwaukee-brace - which has totally lost ground in the therapeutic practice – played a principal role in the existence of the mentioned dental deformities (Bögi

**3. Dentofacial features associated to changes in body posture** 

**3.1 Literature review** 

& Nagy, 1970, Paphalmy et al., 1975).

The literature examining the orofacial-orthopaedic deviations beside the orthopaedic disorders deals in details with the deviations observed in the sagittal plane and with the analysis of the pathological spinal deformities possibly allocable to them. Among the orthodontic diagnostic radiologic methods the spread of the lateral cephalograms has launched an extensive research activity aiming at investigation the etiology of the dental and skeletal deviation being measurable this way. These researches enlisted the interest to the correlation between the deviations found in the vertical and sagittal plane and the forward, respectively backward tilted head posture (Yamaguchi & Sueishi, 2003). Various researches revealed close relation between the cervical hyperlordosis and the cl. II malocclusions (Solow & Tallgren, 1976; Huggare, 1998). In average a 2 mm lack of space associates the increased craniocervical angle in the upper or lower frontal regions of the dental arch (Solow & Sonnesen, 1998). Different intra-articular distances were recorded on x-ray pictures taken in with the head in various postures, which is probably a manifestation of differences in mandibular loading in the different head postures (Visscher et al., 2000). In order to explain the precise correlations the demand is to take cephalograms in natural head position (Leitao & Nanda, 2000). The basic criteria of taking cephalograms – the head position which is essential for evaluation - contradict the notion of natural head position, therefore this issue is still unsolved (Raju et al., 2001; Halazonetis, 2002). Contradictory to this the investigations searched the cephalograms taken in the positioned posture related to the true vertical and the true horizontal reference, not taking into account the relationship between natural head position and craniofacial morphology. The cephalograms examined this way enabled accurate measurements, hereby appraisable correlations related to maxilla were possible, while the inaccuracy of the mandibular measurement excluded the use of these methods for scientific purposes. Close correlation with the natural head position is shown only by the following measurement: facial axis, lower facial height and the facial ratios (Leitao & Nanda, 2000). The rasterstereographic procedures - used with research purpose recently - have a great importance in the head posture determination, but findings related to the connection between the body posture affected by the spine morphology and the head posture are still humble in number. The examination of the orthodontic deviations at children with Scheuermann's disease cannot be found in the qualified literature apart from the publications presenting some partial findings of our researches (Segatto et al., 2006, 2008).

There is a relatively great number of findings in the literature dealing with the relationship between the characteristics of the body posture determined by rasterstereographic procedures and certain orofacial-orthopaedic parameters. During the examination of the dental features the investigation did not show any close correlation between the characteristics of the spine morphology and the overjet (Lippold et al., 2006b). Similarly no close correlation was revealed between the mandibular position and the variables of the kyphotic and the lordotic angle or the pelvic inclination (Lippold et al., 2005). Among the craniofacial skeletal parameters the facial axis, the mandibular plane and the facial depth showed a significant correlation with the degree of the cervical curvature (Murray et al., 1993). Similarly, the facial axis together with the lordotic angle and the pelvic inclination, the inner gonial angle and the mandibular plane with the lordotic angle and the pelvic inclination, as well as the facial depth with the pelvic inclination showed a significant correlation (Lippold et al., 2006b). Finally the examination of the correlation between the pelvic torsion, the facial axis and the facial depth whereby the vertical and the sagittal mandibular parameters are in close correlation with the body posture needs to be mentioned (Lippold et al., 2007).

#### **3.2 Methods of investigation**

The examination of the dentofacial feature follows the standard orthodontic intra- and extraoral examination protocol. Beside the physical functional and morphological examinations the evaluation of the x-ray pictures are paid great attention. The physical tests focused on the measurement of the TMJ condition and the activity of the adjacent muscles. The applied procedures comprise of the determination of the movement ranges and the detection of the differences between the sides. The extra-oral part of the morphological tests focused on the observation of the abnormal facial ration and the registration of the facial asymmetries. During the intraoral test the dental and occlusion features were examined. Vertical features: the frontal open bite and the deep bite as well as the lateral deep bite; sagittal features: the frontal overjet, crossbite, as well as the molar relationship ranged in Angle classes.

For analysing the skeletal features, for mapping the dentoskeletal conditions and for determining the position of the two jaws to each other and to the base of the skull the evaluation of different radiograms are available. During several researches the evaluation of the lateral cephalogram, the postero-anterior cephalogram as well as the orthopantomogram pictures provided the data. The standardized conditions provide the adaptability of the radiograms for researches. The determination of the skeletal features on the lateral and the postero-anterior cephalograms is done with one of the known evaluation methods. The most frequently measured parameters on the postero-anterior cephalogram by Ricketts are as follows: the inclination of the occlusal plane, postural symmetry, maxillary ratio, mandibular ratio, maxillary-mandibular midline; while on the lateral cephalogram: the maxillary depth, the ramus position, the facial axis, the lower facial height and the mandibular plane angle. Beside the determination of the asymmetry of the cranial structures on the postero-anterior cephalogram we used the parameters obtained during the definition of the mandibular asymmetries for our researches. Contrary to the cephalometric measurement when measuring the mandibular asymmetry no evaluation software was available. To overcome the compilation difficulties of the digital x-ray pictures and to evaluate quickly and accurately a large number of radiograms we developed the first mandibular asymmetry evaluating software. The measurements done by AsymmetrixX were based on previously accepted methods, which were modified taking into account the compilation characteristics. The asymmetry index calculation is used for the comparison of the distances of the two mandibular-halves (d) on the basis of the following formula: d asymmetry-index (AI) = │(dright – dleft)/(dright + dleft) │x 100. The importance of the mandibular asymmetry examination is provided by those findings that confirm that two-third of the asymmetries originates from the lower third of the face, and the size or the positional disorders of the mandible are responsible for their development (Vig & Hewitt, 1975; Farkas & Cheung, 1981).

The application of the Orthopantomogram being part of the orthodontic routine radiograms to the examination of mandibular asymmetries has a long history. In the early period of the application the problem of the reproducibility had to be solved; the solution was the creation of the head position standards (Larheim & Svanaes, 1986). After this, in order to eliminate the distortions emerging as the attribute of taking radiograms those recommendations were created that aimed to exclude certain measurement direction from the calculations (Habets et al., 1987). It proved to be similarly useful the application of the threshold value of 6% in the course of introducing the asymmetry index for substituting the head position deviations (Habets et al., 1988). On the basis of the asymmetry index formula

The examination of the dentofacial feature follows the standard orthodontic intra- and extraoral examination protocol. Beside the physical functional and morphological examinations the evaluation of the x-ray pictures are paid great attention. The physical tests focused on the measurement of the TMJ condition and the activity of the adjacent muscles. The applied procedures comprise of the determination of the movement ranges and the detection of the differences between the sides. The extra-oral part of the morphological tests focused on the observation of the abnormal facial ration and the registration of the facial asymmetries. During the intraoral test the dental and occlusion features were examined. Vertical features: the frontal open bite and the deep bite as well as the lateral deep bite; sagittal features: the

frontal overjet, crossbite, as well as the molar relationship ranged in Angle classes.

for their development (Vig & Hewitt, 1975; Farkas & Cheung, 1981).

The application of the Orthopantomogram being part of the orthodontic routine radiograms to the examination of mandibular asymmetries has a long history. In the early period of the application the problem of the reproducibility had to be solved; the solution was the creation of the head position standards (Larheim & Svanaes, 1986). After this, in order to eliminate the distortions emerging as the attribute of taking radiograms those recommendations were created that aimed to exclude certain measurement direction from the calculations (Habets et al., 1987). It proved to be similarly useful the application of the threshold value of 6% in the course of introducing the asymmetry index for substituting the head position deviations (Habets et al., 1988). On the basis of the asymmetry index formula

For analysing the skeletal features, for mapping the dentoskeletal conditions and for determining the position of the two jaws to each other and to the base of the skull the evaluation of different radiograms are available. During several researches the evaluation of the lateral cephalogram, the postero-anterior cephalogram as well as the orthopantomogram pictures provided the data. The standardized conditions provide the adaptability of the radiograms for researches. The determination of the skeletal features on the lateral and the postero-anterior cephalograms is done with one of the known evaluation methods. The most frequently measured parameters on the postero-anterior cephalogram by Ricketts are as follows: the inclination of the occlusal plane, postural symmetry, maxillary ratio, mandibular ratio, maxillary-mandibular midline; while on the lateral cephalogram: the maxillary depth, the ramus position, the facial axis, the lower facial height and the mandibular plane angle. Beside the determination of the asymmetry of the cranial structures on the postero-anterior cephalogram we used the parameters obtained during the definition of the mandibular asymmetries for our researches. Contrary to the cephalometric measurement when measuring the mandibular asymmetry no evaluation software was available. To overcome the compilation difficulties of the digital x-ray pictures and to evaluate quickly and accurately a large number of radiograms we developed the first mandibular asymmetry evaluating software. The measurements done by AsymmetrixX were based on previously accepted methods, which were modified taking into account the compilation characteristics. The asymmetry index calculation is used for the comparison of the distances of the two mandibular-halves (d) on the basis of the following formula: d asymmetry-index (AI) = │(dright – dleft)/(dright + dleft) │x 100. The importance of the mandibular asymmetry examination is provided by those findings that confirm that two-third of the asymmetries originates from the lower third of the face, and the size or the positional disorders of the mandible are responsible

**3.2 Methods of investigation** 

the difference of 6% between the two sides equals to an asymmetry index of 3%. The results vary between 0% (full symmetry) and 100% (full asymmetry), and results below 3% conventionally counts as symmetric.

Several papers dealt with the control of the genuineness of the early protocols and of the reliability of the method (Schulze et al., 2000; Stramotas et al., 2002; Saglam, 2003). A couple of them provide newer measurement and structural methods, too. There were some attempts to determine the mandibular asymmetries on the basis of the soft tissues contour with the help of graphical applications, however, the variedly implemented analysis of the OPG's remained the gold standard (Edler et al., 2003; Good et al., 2006).

In the period of the spread of the mandibular asymmetry measurements the distances to be compared became measurable by re-tracing the OPG's and by compiling the reference points and lines. With the spread of the digital x-rays the compilation of the distances required the use of graphical design programs, which meant a great difficulty for a medical research expert. The awkward compilation procedure assumed a deep knowledge of the design program and the long evaluation procedure suitable for limited data collection did not enable the examination of large patient group. The modern cephalometric procedure in the case of the digital lateral and PA cephalograms enabled the combination of the latter ones and the graphical applications used at the mandibular asymmetry measurements. As a result of this the number of the measurements increased and more accurate analysis are possible.

The analysing program AsymmetrixX developed to satisfy the provided claims were made in Delphi 7 development environment (Fig.5.). The principal accuracy of the measurements is determined by the size of the reference point and the thickness of the compiled added lines, whose size is: 1 pixel = 0.26 mm. Because of the measurement accuracy and the comparability it is important to unify the size of the OPG's to be analysed, which complies with the calibration requirement as well. After setting the adequate sharpness and contrast rates the selection of the OPG can be done by browsing from any paths. Before this the data required by the program for identifying the examined person (name, date of birth, date of taking the OPG) are recorded.

Fig. 5. Drawings performed with AsymmetrixX.

In the first step of the analysis by superposing the moveable Codr – Tgrr line appearing next to the right mandibular ramus to the Codr (Condylion dorsale right) and the Tgrr (Tangent ramus right) points we receive the right ramus tangent. By confirming the movement we determine the Codr point at the meeting of the tangent and the condylion, then the Tgrr point as a next step. After this the moveable Gnr – Tgcr line appears under the mandibular corpus, which we superpose on the Gnr (Gnathion right) and the Tgcr (Tangent corpus right) points, and we receive the right corpus tangent. After the fixation, next to the mentum we determine the Gnr point at the meeting of the tangent and the corpus, then the Tgcr point before the mandibular corner, at the meeting of the tangent and the corpus. Simultaneously with this, on the ramus tangent a slidable added perpendicular line appears; we fix it by moving it up to the top point of the processus condylaris. The next required point is the Cor (Condylion right) determined at the meeting of the fixed added line and the top point of the processus condylaris. By fixing it, the next slidable added line perpendicular to the ramus tangent appears, which we set to the bottom point of the Incisura mandibulae, and the meeting point determines the point Incr (Incisura mandibulae right).

The determination of the aforementioned reference points and lines should be followed by the left counterparts: left ramus tangent, Codl (Condylion dorsale left), Tgrl (Tangent ramus left), left corpus tangent, Gnl (Gnathion left), Tgcl (Tangent corpus left), Col (Condylion left), then Incl (Incisura mandibulae left). After the compilation of the paired measurement points come the unpaired points, which are requested in the following order by the program: the ANS (Anterior nasal spine), the is (incision superior), the ii (incision inferior), then finally the Sy (Symphysis mandibulae). After the fixation of this latter a line compiled from this point appears automatically, which will be perpendicular to the added line linking the meeting points of the bilateral ramus and corpus tangents (Gor – Gonion right and Gol – Gonion left). The program measures the distance of the other three odd points from this line. This way the ANS distance indicates the mentum deviation from the mid-facial reference structures, and the distance of the two dental midlines indicates the deviation thereof from the mandibular midline.

In the course of the compilation we received two important reference lines: the GoL (Gonion line) links the two compiled mandibular angles, and the ML (Midline) perpendicular to this indicates the mandibular midline. The two lines develop such a coordinate system, where the coordinates of the determined measurement points indicate the distance thereof from the adequate lines, in absolute values. Besides the distances measured from the two lines the program determines the distance of the projections of the given measurement points (Cor and Incr as well as Col and Incl) falling to the two ramus tangents. The so received RH (ramus height) = Go-Inc section and CH (condylar height) = Inc-Co section are suitable for the formerly applied mandibular asymmetry measurements. Each of the distances measured on the two halves of the mandible are suitable to be applied in the formerly explained asymmetry index formula.

Besides the indication of the length values the program automatically performs the asymmetry index calculations, and it represents the received 67 variables (51 distance measurements, 16 indices) in a csv file suitable for Excel statistical applications, so the possible errors of the manual data recording are eliminated. The graphic presentation of the major results provides useful help for the fellow professions during the quick orientation among the analysis results. At the same time, the storage of all formats of the results is easily solved; they can be used for comparison with further analyses.

Our attempts get deeper connotations by the principles of the human face asymmetry examinations. In case of apparently symmetric, harmonic faces there are often skeletal asymmetries found which seems to confirm the camouflage ability of the soft tissues (Shah & Joshi, 1978). Due to the lack of the criteria system related to the determination of the asymmetry there is no precise threshold value above which the given measurement is asymmetric. At the same time the more visible an asymmetry is, the more attention deserves since the closer it gets to the pathological condition (Rossi et al., 2003). The asymmetries of the craniofacial area are observed as the size disorders of the two face-halves. The amplitude of the real disorders is often decreased by the well functioning adjacent soft tissues through the camouflage effect (Bishara et al., 1994). The most common method to reveal the skeletal asymmetries being present behind the soft tissues is taking frontal cephalograms (P-A). Taking these postero-anterior cephalograms – due to the unnecessary radiation loading – is needed in the case of one-third of those asymmetries where not the mandibular region is responsible for the deformations. At the examination of the mandibular asymmetries, a further disadvantage is the occlusal position that could result in inaccurate measurements in the case of possible functional deviations.

By developing the AsymmetrixX we aimed at working out such analysing software that is suitable for a simple, quick and very accurate asymmetry analysis of the most widespread and suitable for large utilization - panoramic radiograms (OPG). Its usage enables the omission of the indication of the postero-anterior cephalograms related to the asymmetry examination, thus decreasing the patients' radiation load.

#### **4. The use of AsymmetrixX to examine the mandibular asymmetries associated with postural deformities**

#### **4.1 Aim**

390 Orthodontics – Basic Aspects and Clinical Considerations

In the first step of the analysis by superposing the moveable Codr – Tgrr line appearing next to the right mandibular ramus to the Codr (Condylion dorsale right) and the Tgrr (Tangent ramus right) points we receive the right ramus tangent. By confirming the movement we determine the Codr point at the meeting of the tangent and the condylion, then the Tgrr point as a next step. After this the moveable Gnr – Tgcr line appears under the mandibular corpus, which we superpose on the Gnr (Gnathion right) and the Tgcr (Tangent corpus right) points, and we receive the right corpus tangent. After the fixation, next to the mentum we determine the Gnr point at the meeting of the tangent and the corpus, then the Tgcr point before the mandibular corner, at the meeting of the tangent and the corpus. Simultaneously with this, on the ramus tangent a slidable added perpendicular line appears; we fix it by moving it up to the top point of the processus condylaris. The next required point is the Cor (Condylion right) determined at the meeting of the fixed added line and the top point of the processus condylaris. By fixing it, the next slidable added line perpendicular to the ramus tangent appears, which we set to the bottom point of the Incisura mandibulae, and the meeting point determines the point

The determination of the aforementioned reference points and lines should be followed by the left counterparts: left ramus tangent, Codl (Condylion dorsale left), Tgrl (Tangent ramus left), left corpus tangent, Gnl (Gnathion left), Tgcl (Tangent corpus left), Col (Condylion left), then Incl (Incisura mandibulae left). After the compilation of the paired measurement points come the unpaired points, which are requested in the following order by the program: the ANS (Anterior nasal spine), the is (incision superior), the ii (incision inferior), then finally the Sy (Symphysis mandibulae). After the fixation of this latter a line compiled from this point appears automatically, which will be perpendicular to the added line linking the meeting points of the bilateral ramus and corpus tangents (Gor – Gonion right and Gol – Gonion left). The program measures the distance of the other three odd points from this line. This way the ANS distance indicates the mentum deviation from the mid-facial reference structures, and the distance of the two dental midlines indicates the deviation thereof from

In the course of the compilation we received two important reference lines: the GoL (Gonion line) links the two compiled mandibular angles, and the ML (Midline) perpendicular to this indicates the mandibular midline. The two lines develop such a coordinate system, where the coordinates of the determined measurement points indicate the distance thereof from the adequate lines, in absolute values. Besides the distances measured from the two lines the program determines the distance of the projections of the given measurement points (Cor and Incr as well as Col and Incl) falling to the two ramus tangents. The so received RH (ramus height) = Go-Inc section and CH (condylar height) = Inc-Co section are suitable for the formerly applied mandibular asymmetry measurements. Each of the distances measured on the two halves of the mandible are suitable to be applied in the formerly explained

Besides the indication of the length values the program automatically performs the asymmetry index calculations, and it represents the received 67 variables (51 distance measurements, 16 indices) in a csv file suitable for Excel statistical applications, so the possible errors of the manual data recording are eliminated. The graphic presentation of the

Incr (Incisura mandibulae right).

the mandibular midline.

asymmetry index formula.

The aim of the study is the mandibular asymmetry analysis of the children's orthopantomogram participating in the rasterstereographic surface back contour examination with AsymmetrixX in order to detect the correlations between the surface back contour characteristics and the elements of the topographic patterns of an accurate mandibular asymmetry.

#### **4.2 Subjects and methods**

The members of the examination group were selected from 320 children registered at the orthodontic consultations. We used the data of 271 children complied with the selection criteria - spinal deformities neither diagnosed nor treated earlier; dental and orofacialorthopaedic deviations neither diagnosed nor orthodontically treated earlier; had rasterstereographic back contour analysis, and orthopantomogram done during the consultation – for the examinations. Average age of the group: 11Y8M; min.: 7Y2M; max.: 16Y12M; SD: 2Y0M; distribution of the genders: 42.4% boys, 57.6% girls (Fig.6.).

Fig. 6. The distribution of the children participating in the examination by gender.

#### **4.3 Results**

After the descriptive statistical analysis of the orthopaedic and dentofacial instrumental testing data, the detailed comparison of these data served the findings of our researches.

#### **4.3.1 The descriptive statistics of the results obtained by the rasterstereographic surface back contour analysis**

12 variables are determined during the rasterstereographic procedure, some of them related to the characteristics observed on the sagittal, the other on the frontal plane of the surface back contour. With the help of a multidimensional scaling we place the main components of the 12 variables in 2 dimension so that the heavily correlating ones to be close to each other (distance formula: -ln(abs(Pearson r)). This way the variables are separated into 5 groups, which were reduced to three by the importance concerning the view of the examination. The components being in heavy correlation with each other enabled further reduction, finally this decreased the applied indices to three sagittal and three frontal variables. They are the following:


The descriptive statistics of the orthopaedic variables are presented in (Table 1.).

Fig. 6. The distribution of the children participating in the examination by gender.

After the descriptive statistical analysis of the orthopaedic and dentofacial instrumental testing data, the detailed comparison of these data served the findings of our researches.

12 variables are determined during the rasterstereographic procedure, some of them related to the characteristics observed on the sagittal, the other on the frontal plane of the surface back contour. With the help of a multidimensional scaling we place the main components of the 12 variables in 2 dimension so that the heavily correlating ones to be close to each other (distance formula: -ln(abs(Pearson r)). This way the variables are separated into 5 groups, which were reduced to three by the importance concerning the view of the examination. The components being in heavy correlation with each other enabled further reduction, finally this decreased the applied indices to three sagittal and three frontal variables. They are the

**4.3.1 The descriptive statistics of the results obtained by the rasterstereographic** 

The descriptive statistics of the orthopaedic variables are presented in (Table 1.).

**4.3 Results** 

following:

**surface back contour analysis** 





Table 1. The descriptive statistics of the parameters determined by rasterstereography.

#### **4.3.2 The descriptive statistics of the mandibular asymmetry examination results**

The asymmetry examinations of the OPG's of the patient groups were done by the AsymmetrixX analysing software. The program after determining the required tangents and measuring points calculates 67 variables. To reduce these variables we used the 2 dimension projection of the multidimensional scaling of the main components and correlations. This way the variables were classified into three groups, though these groups do not demarcate from each other therefore by further reduction of the heavily correlation variables we did not manage to narrow the number of the measurement suitable for further comparative examination.

Those horizontal linear measurements which due to the inaccuracy of the horizontal lenght measurements characteristics of OPG are omitted from the comparison are not among the applied variables. The remaining 36 variables consist of 6 horizontal and 9 vertical asymmetry indices and 21 vertically oriented distance measurements. The descriptive statistics of the most important vertical mandibular asymmetry variables are presented in (Table 2.).


Table 2. The descriptive statistics of the main vertical parameters determined by AsymmetrixX.

#### **4.3.3 Comparative examination results**

Due to the large number of the comparable variables the examination of correlation between the orthopaedic and dentofacial parameters was done by the stepwise linear regression. In case of the fléche cervicale orthopaedic variable the (CH + RH) mean (*p*<0.0005, coefficient: 1.258), the Tgc–GoL mean (*p*=0.024, coefficient: 0.685), the Gn-GoL mean (*p*=0.016, coefficient: 0.671) and the Tgc-GoL index (*p*=0.002, coefficient: -0.196) seemed to be the significant, absolute linear predictor. The fléche lombaire variable in the linear regression shows correlation only with RH mean (*p*=0.011, coefficient: 0.382). In case of the trunk inclination orthopaedic variable the CH mean (*p*=0.034, coefficient: 0.141) seemed to be the significant, absolute linear predictor.

The maximal lateral deviation, the surface rotational amplitude and the lateral amplitude do not show linear regression correlation with any mandibular asymmetry variables (Table 3.).

Table 3. The rate of the correlation between the orthopaedic and dentofacial parameters.

#### **4.4 Discussion**

394 Orthodontics – Basic Aspects and Clinical Considerations

Table 2. The descriptive statistics of the main vertical parameters determined by

Due to the large number of the comparable variables the examination of correlation between the orthopaedic and dentofacial parameters was done by the stepwise linear regression. In case of the fléche cervicale orthopaedic variable the (CH + RH) mean (*p*<0.0005, coefficient: 1.258), the Tgc–GoL mean (*p*=0.024, coefficient: 0.685), the Gn-GoL mean (*p*=0.016, coefficient: 0.671) and the Tgc-GoL index (*p*=0.002, coefficient: -0.196) seemed to be the significant, absolute linear predictor. The fléche lombaire variable in the linear regression shows correlation only with RH mean (*p*=0.011, coefficient: 0.382). In case of the trunk inclination orthopaedic variable the CH mean (*p*=0.034, coefficient: 0.141) seemed to be the

The maximal lateral deviation, the surface rotational amplitude and the lateral amplitude do not show linear regression correlation with any mandibular asymmetry variables (Table 3.).

AsymmetrixX.

**4.3.3 Comparative examination results** 

significant, absolute linear predictor.

The orthopaedic parameters of the examination group were provided by the rasterstereographic analysis. It means that the back contour morphology was mapped through a simultaneous registration of the deviation of different planes, without taking into account the threshold limit values separating the healthy and unhealthy categories. With the help of the statistical methods, out of the 12 measurements we selected 3 determining the sagittal and 3 determining the frontal curvatures and the positional deviations of the spine in the most precise way. For the comparative examinations 36 asymmetry variables measured on OPG's were used.

The fléche cervicale shows close correlation with the entire ramus height as well as the steepness of the inclination of the mandibular corpus out of the asymmetry variables determined on the mandible so the increased ramus height and mandibular base plane accompany the hyperkyphotic back. The fléche lombaire shows a moderately close correlation with the average of the ramus height, thus accentuation of the lumbar lordosis is associated with an increased ramus height. The trunk inclination shows similar correlation with the degree of the condylar height, therefore the forward inclined body posture presumes increase condylar height.

Based on the result of the comparative examination of the maximal lateral deviation, the surface rotational amplitude and the lateral amplitude the distance between the degree of the lateral deviation of the spine, the degree of vertebral rotation being present at the level of scoliotic curvature and the bilateral spinal curvatures is not associated with any of the mandibular asymmetry variables.

The comparative evaluation of the mandibular asymmetry variables obtained at the large number of patient group screened by the rasterstereographic procedure having used the AsymmetrixX analysing software on examinations brought new results. The asymmetry variables determined with the help of the analysing software show close correlation with the rasterstereographic variables modelling the curvatures on the sagittal plane. The simple, non-invasive examination methods of certain features make possible to explore the given deviations at an early stage and in an interdisciplinary way. The skeletal basis of the postural disorders developing at the same age as well as the early recognition of the mandibular asymmetries showing close correlation therewith should mean the necessity of examining the potentially present joint deviations for the specialists of both fields. The new analysing methods waiting to be introduced are certainly suitable for recognising the features of the asymmetric dentofacial character.

### **5. Conclusions**

The importance of the findings establishing a close correlation between the orthopaedic and orofacial-orthopaedic specialities is described below. The postural problems diagnosed during the pre-puberty as well as the dentofacial problems observed with the spinal deformities adverted to the necessity of the careful and accurate screening in both speciality fields. The prompt orthodontic screening in an early stage of the children diagnosed with spinal deformities can reveal those deviations which can be managed with conservative methods. Similarly to this the joint presence of the dentofacial pattern elements can be a disease-marker from the point of view of revealing a possible orthopaedic background disease.

Our research work focused on the confirmation of the previously listed results and to complement the experienced deficiency accentuating the importance of the identification of such early diseases-markers that can contribute to the formation of already proved associated deformities or to their progression. The early observation methods related to these deformities have to be known by the specialists working in the paediatric field. We have developed the computerized analysing software which significantly simplifies by its accuracy and quickness the early observation of the dentofacial deviations at the mentioned patient groups to help their and the specialists' preventive activity.

The synchronization of the result obtained with the applied examination methods as well as their harmonization with the modern radiologic procedures is a new challenge for the researchers. According to the reviewed detailed information the direction of the researches of this specialty considered to be of high importance has to be determined by the attempts that focus on the elaboration of an automatic classifying system based on the 3D topographic examination of the cranium also contributing to the early orthopaedic diagnosis. On the other hand the work out of those mandibular asymmetry measurements that substitute the disease-marker measurements obtained during the evaluation of the lateral cephalograms and similarly to the rasterstereography further reduce the radiation load of the involved orthopaedic subject is very important.

#### **6. Acknowledgment**

I would like to express my gratitude to my colleague Dr. Carsten Lippold for the patients' database provided and to my friend Éva Szász for her help with the translations.

#### **7. References**

396 Orthodontics – Basic Aspects and Clinical Considerations

AsymmetrixX analysing software on examinations brought new results. The asymmetry variables determined with the help of the analysing software show close correlation with the rasterstereographic variables modelling the curvatures on the sagittal plane. The simple, non-invasive examination methods of certain features make possible to explore the given deviations at an early stage and in an interdisciplinary way. The skeletal basis of the postural disorders developing at the same age as well as the early recognition of the mandibular asymmetries showing close correlation therewith should mean the necessity of examining the potentially present joint deviations for the specialists of both fields. The new analysing methods waiting to be introduced are certainly suitable for recognising the

The importance of the findings establishing a close correlation between the orthopaedic and orofacial-orthopaedic specialities is described below. The postural problems diagnosed during the pre-puberty as well as the dentofacial problems observed with the spinal deformities adverted to the necessity of the careful and accurate screening in both speciality fields. The prompt orthodontic screening in an early stage of the children diagnosed with spinal deformities can reveal those deviations which can be managed with conservative methods. Similarly to this the joint presence of the dentofacial pattern elements can be a disease-marker from the point of view of revealing a possible orthopaedic background

Our research work focused on the confirmation of the previously listed results and to complement the experienced deficiency accentuating the importance of the identification of such early diseases-markers that can contribute to the formation of already proved associated deformities or to their progression. The early observation methods related to these deformities have to be known by the specialists working in the paediatric field. We have developed the computerized analysing software which significantly simplifies by its accuracy and quickness the early observation of the dentofacial deviations at the mentioned

The synchronization of the result obtained with the applied examination methods as well as their harmonization with the modern radiologic procedures is a new challenge for the researchers. According to the reviewed detailed information the direction of the researches of this specialty considered to be of high importance has to be determined by the attempts that focus on the elaboration of an automatic classifying system based on the 3D topographic examination of the cranium also contributing to the early orthopaedic diagnosis. On the other hand the work out of those mandibular asymmetry measurements that substitute the disease-marker measurements obtained during the evaluation of the lateral cephalograms and similarly to the rasterstereography further reduce the radiation

I would like to express my gratitude to my colleague Dr. Carsten Lippold for the patients'

database provided and to my friend Éva Szász for her help with the translations.

patient groups to help their and the specialists' preventive activity.

load of the involved orthopaedic subject is very important.

**6. Acknowledgment** 

features of the asymmetric dentofacial character.

**5. Conclusions** 

disease.


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**Part 5** 

**Orthodontics Risks** 

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## **Risks and Complications Associated with Orthodontic Treatment**

Cristina Teodora Preoteasa, Ecaterina Ionescu and Elena Preoteasa *Faculty of Dental Medicine, "Carol Davila" University of Medicine and Pharmacy, Bucharest Romania* 

#### **1. Introduction**

Orthodontic treatment of malocclusions and craniofacial abnormalities, by ensuring proper alignment of the teeth, harmonious occlusal and jaw relationship, may improve mastication, phonation, facial aesthetics, with beneficial effects on the general and oral health, individual's comfort and self-esteem, having a positive role in improving the quality of life. Therefore, the treatment's objectives are consistent with the aims of medical interventions, namely ensuring health, the "state of complete physical, mental and social well-being", as perceived by the World Health Organization (World Health Organization, 1946).

Like any other medical intervention, orthodontic treatment has, in addition to its benefits, also associated risks and complications. In orthodontics, the risk of "doing harm" is considerably lower compared to other medical interventions, e.g., the surgical ones. However, during the medical act, through usage of various procedures, devices and materials, there might appear unwanted side effects, both local (tooth discolorations, decalcification, root resorption, periodontal complications) and systemic (allergic reactions, chronic fatigue syndrome).

An increased risk of complications may contraindicate the orthodontic therapy or influence its objectives, phases and conduct, aspects directly linked with the quality of the final outcome and prognosis. Generally speaking, the consecutive benefits of the medical intervention must overcome any potential damage. Legal regulations on medical conduct emphases the patient's right, as participant in treatment decision making, to be informed about the benefits and possible risks that might occur. It is recommended to make for each patient a rigorous risk profile analysis, followed by obtaining a signed informed consent. In case side effects appear, the avoidance of informing the patients about possible complications associated with the medical act may lead to malpractice complaints or even lawsuits.

This chapter aims to highlight the main coordinates of risk issues in orthodontics. In this respect, it starts with an analysis of the context in which they occur, followed by a presentation of the main complication linked to orthodontic intervention, and concludes with a general approach of the topic from the perspective of risks management principles The following information represents a literature review, in the context of the current state of knowledge, combined with data from authors' personal observations and research.

### **2. Context of the side effects appearance during orthodontic treatment**

Side effects associated with orthodontic treatment occur within the interaction between factors related to the patient, medical team and orthodontic technique. These can be perceived as elements belonging to the general therapeutic context, present when medical interventions are delivered, and aspects related to a specific therapeutic context, namely linked to the orthodontic intervention (Table 1). Local and systemic side effects may occur to patients (those receiving the intervention), but also to the medical team members (those managing the intervention, handling various materials and instruments).

#### CONTEXT OF RISK OCCURRENCE DURING ORTHODONTIC TREATMENT

General therapeutic context


Specific therapeutic context


Table 1. Main coordinates of risk occurrence during orthodontic interventions.

#### **2.1 General therapeutic context**

During orthodontic therapy complications may be linked to the general context present when medical interventions are delivered, may be appeared in relation to specific patient features, linked to the medical staff responsible for delivering the intervention or associated to a deficient patient-doctor relationship.

There are many variables related to the patient that can influence the risk occurrence during orthodontic therapy. Among these are individual characteristics related to age, gender, environment, physiopathological status, genetic predisposition, psychological type, as well as particularities related to malocclusion (type, etiology, severity) and craniofacial features. In order to reduce the frequency and severity of the complications associated with this type of medical intervention, it is necessary to know the detailed particularities of each case, which need to be integrated within the treatment plan and conduct of the medical care. For example, within various age groups there are specific aspects of the physiopathological status, development and cooperation, which can influence the timing for orthodontic therapy, treatments' objectives, appliances choice, duration of treatment and stability of the outcome. Within young age patients considered appropriate to receive orthodontic intervention, there are mainly those with functional imbalances, anterior or posterior crossbite and those with severe narrow upper dental arch. But there are procedures (like expansion of the lower arch to resolve dental crowding) implemented in the mixed dentition

The following information represents a literature review, in the context of the current state of knowledge, combined with data from authors' personal observations and research.

Side effects associated with orthodontic treatment occur within the interaction between factors related to the patient, medical team and orthodontic technique. These can be perceived as elements belonging to the general therapeutic context, present when medical interventions are delivered, and aspects related to a specific therapeutic context, namely linked to the orthodontic intervention (Table 1). Local and systemic side effects may occur to patients (those receiving the intervention), but also to the medical team members (those

**2. Context of the side effects appearance during orthodontic treatment** 

managing the intervention, handling various materials and instruments).

related to the action mechanism of the orthodontic appliances

General therapeutic context patient's features

 orthodontist related factors doctor-patient relationship Specific therapeutic context

**2.1 General therapeutic context** 

to a deficient patient-doctor relationship.

related to the placement of orthodontic devices

CONTEXT OF RISK OCCURRENCE DURING ORTHODONTIC TREATMENT

related to the relation of the orthodontic appliance with the oral structures

Table 1. Main coordinates of risk occurrence during orthodontic interventions.

related to material properties and technical particularities of the orthodontic appliances

During orthodontic therapy complications may be linked to the general context present when medical interventions are delivered, may be appeared in relation to specific patient features, linked to the medical staff responsible for delivering the intervention or associated

There are many variables related to the patient that can influence the risk occurrence during orthodontic therapy. Among these are individual characteristics related to age, gender, environment, physiopathological status, genetic predisposition, psychological type, as well as particularities related to malocclusion (type, etiology, severity) and craniofacial features. In order to reduce the frequency and severity of the complications associated with this type of medical intervention, it is necessary to know the detailed particularities of each case, which need to be integrated within the treatment plan and conduct of the medical care. For example, within various age groups there are specific aspects of the physiopathological status, development and cooperation, which can influence the timing for orthodontic therapy, treatments' objectives, appliances choice, duration of treatment and stability of the outcome. Within young age patients considered appropriate to receive orthodontic intervention, there are mainly those with functional imbalances, anterior or posterior crossbite and those with severe narrow upper dental arch. But there are procedures (like expansion of the lower arch to resolve dental crowding) implemented in the mixed dentition that are sometimes unstable. Therefore, the orthodontic treatment is often instituted into the late mixed dentition, just before loss of the deciduous mandibular second molar, with the benefits of a better collaboration with the patient, the possibility of using the leeway space and influencing the jaw bone growth, with shortening as much as possible the duration of active treatment (DiBiase, 2002). The treatment of the adult patient often requires particularization of the orthodontic intervention due to oral structures changes and modified physiopathological status. More frequently periodontal alterations are present (reduction of the alveolar bone support with the modification of the tooth's rotation center, favoring a faster tooth movement; increased bone density associated with a slower tooth movement), also a higher intensity and duration of pain and increased prevalence of devital teeth (with an uncertain behavior during tooth movement) (Shah & Sandler, 2006). Modified health status may increase the appearance risk of certain complication or interfere with the orthodontic treatment conduct. For example, in case of bisphosphonates usage, among the side effects, the orthodontist should be concerned about the difficulties of achieving a desired tooth movement (long-lasting aspect after drug discontinuation) and also about the slower bone healing rate with the possibility of osteonecrosis appearance (especially important when tooth extractions, implant placement or phases of orthognathic surgery are planned) (Iglesias-Linares et al., 2010).

A good progress of the orthodontic treatment is related also to the patient's understanding and compliance regarding the physician's indications, which aims mainly the oral hygiene and device maintenance, and rigorousity in attending the periodical appointments. Failure to comply with these conditions may result in damaging the components of the orthodontic appliances, damage of the oral structures (risk factor for demineralizations, caries, discolorations, periodontal damage, bad breath), increased duration of the treatment and not achieving the expected result.

The orthodontist has an important role in preventing the complications associated with this type of treatment, being the manager and implementer of the medical intervention delivered. In order to obtain good results and minimize the complications aspects like an appropriate training, knowledge, clinical skills and experience are needed. Being a distinctive specialty within dentistry, orthodontic training has in many countries a particular education system. Usually a 2 to 3 year period of postgraduate study for qualification in this field is done. Over the last decade, there was also observed in this specialty an increased interest for the concept of evidence-based orthodontics. The orthodontist's challenge in the XXI century is to integrate the best scientific evidence into practice, this representing the "gold" standard of the medical care quality, from the perspective of the current state of knowledge (Ackerman, 2004). Also, in order to achieve a high standard of treatment quality, with minimal complication, it is necessary for the orthodontist to have all the necessary means for implementing the optimal considered treatment. For example, in order to include an orthognathic surgical phase it is necessary for the orthodontist to have a professional collaboration with a maxillofacial surgeon, preferably with his practice as close as possible, for an easy patient's access. Generally we can say that complications that occur due to errors of diagnosis, treatment planning or treatment management related to orthodontist's intervention can be avoided through practitioner's appropriate training, good theoretical knowledge and clinical skills and also possession of all necessary elements for implementation of the treatment plan considered optimal.

The doctor-patient relationship is another important key factor in ensuring a high quality medical act, having either positive or negative impact on treatment conduct. When an orthodontic treatment begins the physician, patient and person with the legal authority for minors become a team with a common goal: insuring the health status for identified problems. Communication is a key element in achieving quality results, but difficulties may arise for various reasons like a child patient, a person with disabilities or lack of interest towards the medical aspects. Generally, the most common difficulties are related to the understanding of the medical aspects by the patient, and complementary, the doctor's ability to make himself understood. When the physician is using a specialized medical language, the patient may feel inferior and may avoid requesting additional data, limiting the possibilities of using the received information. In this regard, it is recommended the clear presentation of the medical information to the patient, in a clear language, avoiding the usage of specialized terminology. Frequently, the orthodontically treated patients are children, the cooperation and communication being in general more difficult in younger ages. In their case, the orthodontic appliance is often accepted consecutive to parents' wishes not as a result of a perceived need, unlike adult patients who are usually more motivated. The parents are generally more aware of the orthodontic treatment's necessity and have a more positive attitude than children, but studies show that the doctor-patient relationship is influenced to a small extent by the parents' attitude (Daniels et al., 2009). In order to ensure an optimal treatment conduct it is recommended to evaluate patient's and family's attitude towards the orthodontic intervention before starting the treatment. When dealing with a negative, reticent patient, sometimes it's wise to postpone the treatment, because difficulties in treatment's progression and negative health or even psychological consequences may appear.

#### **2.2 Specific therapeutic context**

Part of the complications observed during or after orthodontic treatment can be linked to some specific features of this type of medical intervention. These are mainly related to the placement of orthodontic appliances, to their action mechanism, to the relation of the orthodontic device with the oral structures and linked to material properties and technical particularities of the orthodontic appliances.

Orthodontic devices can be fixed, consisting of elements bonded for the entire period of active treatment (brackets, bands) or removable, being present 2 variants (element removal can be done only by orthodontist – e.g., arch-wire, or also by patient – e.g., removable appliance), with different clinical indications, advantages and disadvantages regarding cleaning, microbial loading, patient's compliance etc. Some components are active, others passive, they can detach or break, causing local or general complications. The orthodontic appliances, fixed or removable, are placed in the oral environment, in relation with the anatomical structures and interfering with dento-maxillary apparatus' functions, being usually used for a long period of time. There is a wide range of materials used for orthodontic devices fabrication and usage (e.g., metal - nickel and titanium-based components, acrylics, cements, composites resins, ceramics, latex), which present different biomechanical characteristics and structure than the oral ones. The components of the

possession of all necessary elements for implementation of the treatment plan considered

The doctor-patient relationship is another important key factor in ensuring a high quality medical act, having either positive or negative impact on treatment conduct. When an orthodontic treatment begins the physician, patient and person with the legal authority for minors become a team with a common goal: insuring the health status for identified problems. Communication is a key element in achieving quality results, but difficulties may arise for various reasons like a child patient, a person with disabilities or lack of interest towards the medical aspects. Generally, the most common difficulties are related to the understanding of the medical aspects by the patient, and complementary, the doctor's ability to make himself understood. When the physician is using a specialized medical language, the patient may feel inferior and may avoid requesting additional data, limiting the possibilities of using the received information. In this regard, it is recommended the clear presentation of the medical information to the patient, in a clear language, avoiding the usage of specialized terminology. Frequently, the orthodontically treated patients are children, the cooperation and communication being in general more difficult in younger ages. In their case, the orthodontic appliance is often accepted consecutive to parents' wishes not as a result of a perceived need, unlike adult patients who are usually more motivated. The parents are generally more aware of the orthodontic treatment's necessity and have a more positive attitude than children, but studies show that the doctor-patient relationship is influenced to a small extent by the parents' attitude (Daniels et al., 2009). In order to ensure an optimal treatment conduct it is recommended to evaluate patient's and family's attitude towards the orthodontic intervention before starting the treatment. When dealing with a negative, reticent patient, sometimes it's wise to postpone the treatment, because difficulties in treatment's progression and negative health or even psychological

Part of the complications observed during or after orthodontic treatment can be linked to some specific features of this type of medical intervention. These are mainly related to the placement of orthodontic appliances, to their action mechanism, to the relation of the orthodontic device with the oral structures and linked to material properties and technical

Orthodontic devices can be fixed, consisting of elements bonded for the entire period of active treatment (brackets, bands) or removable, being present 2 variants (element removal can be done only by orthodontist – e.g., arch-wire, or also by patient – e.g., removable appliance), with different clinical indications, advantages and disadvantages regarding cleaning, microbial loading, patient's compliance etc. Some components are active, others passive, they can detach or break, causing local or general complications. The orthodontic appliances, fixed or removable, are placed in the oral environment, in relation with the anatomical structures and interfering with dento-maxillary apparatus' functions, being usually used for a long period of time. There is a wide range of materials used for orthodontic devices fabrication and usage (e.g., metal - nickel and titanium-based components, acrylics, cements, composites resins, ceramics, latex), which present different biomechanical characteristics and structure than the oral ones. The components of the

optimal.

consequences may appear.

**2.2 Specific therapeutic context** 

particularities of the orthodontic appliances.

orthodontic devices come into contact with the oral tissues and fluids, being submitted to some complex conditions: immersion in saliva and ingested fluids, temperature fluctuations, mechanical loading during chewing and activation of the devices, physical or chemical interactions. Therefore the orthodontic appliances must not contain compounds that may cause a toxic response, not cause allergic reaction or have carcinogenic potential, must be resistant to electrochemical corrosion, should not promote the microbial adherence and development, in general - should present an optimal biocompatibility (Atai & Atai, 2007; Bentahar et al., 2005). In this context, it is recommended to use orthodontic devices with lower nickel content, with a good resistance to corrosion and, in order to avoid corrosion of titanium based components, to limit the use of high concentration fluor-based products (Chaturvedi & Upadhayay, 2010). For an optimal treatment conduct the materials must be resistant to forces that are applied during their usage period, should not fracture and should be suitable for processing in any configuration and shape demanded by their clinical application.

In orthodontics treatment outcome is achieved mainly through orthodontic forces action, delivered against teeth muscles and bones, having as result teeth movement, modification of bone morphology or growth. According to patient's particularities treatments must be individualized, for example orthodontic forces should be dosed in relation to aspects like patient's age and oral structure's health status (e.g. increased force magnitude can be a risk factor for root resorption, ankylosis, pulpal and periodontal damage, pain).

The orthodontic appliances, depending on their type, have a direct contact with various structure of oral cavity like teeth, muco-osseus areas of the palate and alveolar bone, tongue, cheeks, gingiva etc. Sometimes an indirect effect of their placement is present, e.g., temporomandibular joint dysfunction and muscles disorders. Various side effects are linked to the orthodontic device presence, due to modifications in oral structure configuration, special measurements of hygiene requirements, attitudes needed for protection of the soft tissues and ensuring good functionality (for example harmless occlusal contacts). Applying the fixed orthodontic devices is associated with possible irreversible enamel changes, difficulties in oral hygiene maintenance due to decreased self-cleaning and multiple new areas for plaque retention, root resorption presence, discomfort and pain.

#### **3. Classification of risks and complications of orthodontic treatment**

During orthodontic treatment management two aspects must be carefully considered, namely the present risks and possible complications. Between these two there is a strong connection, acknowledging them being one of the keys of delivering a safe medical care. A classification, starting from the one presented by Graber (Graber et al., 2004), is the following:

	- local effects, with manifestation on dento-maxillary apparatus structures (enamel demineralizations and discolorations, root resorption, gingivitis);
	- systemic effects (allergic reactions to nickel or latex).
	- mild, reversible (gingivitis);
	- moderate, reversible (fracture of a ceramic crown);
	- standard inherent complications, being included side effects where the orthodontist's role is irrelevant (enamel changes due to acid etching when resins are used as bonding material);
	- complications related to the patient's particularities (individual susceptibility or disease) not disclosed during evaluation, possibly unknown even to the patient (allergic reaction for which history data was inconclusive; severe root resorption and demineralisations present in association with a metabolic disease unidentified at the initial assessment);
	- conditions arising as a result of a passive operator intervention, associated with a lack of proper monitoring (lack of monitoring and proper prevention methods in cases with severe root resorption or decalcifications);
	- medical errors by wrongful medical objectives and deficient treatment conduct (enamel damage due to improper debonding technique; tooth movement into an area with alveolar bone defect causing severe loss of attachment).

#### **4. Presentation of the main complications linked to orthodontic intervention**

Like any other medical intervention, the orthodontic treatment may have, besides the positive effects, also unwanted secondary consequences. In the scientific literature there are numerous conditions to which orthodontic treatment may be associated (Table 2) (Ellis & Benson, 2002; Graber et al., 2004; Lau & Wong, 2006). For most of them a direct cause-efect relation hasn't been proven, but for no reason these aspect should be neglected.

#### **4.1 Dental complications**

Linked to orthodontic intervention, there are described numerous side effects present on tooth level. Among the first etiological hypothesis was the one saying that fixed orthodontic technique may induce enamel changes, both quantitatively (enamel loss during bonding and debonding procedures) and qualitatively (discolorations). On root level the most unwanted side effect taken into consideration in the medical literature is severe root resorption, process associated with root shortening that may lead to an insufficient tooth ability to endure the forces present during oral function performance and in extreme cases early tooth loss. Regarding the pulpal reactions, during action of orthodontic forces may appear a decreased oxygenation of pulpal tissue, varying in the same direction with force magnitude and period of action. Usually the inflammatory reactions that appear are transitory, reversible, but severe modifications, like necrosis, sometimes appear. Greater risk of pulpal reactions is present in teeth with a history of severe periodontal injury during certain orthodontic procedures, e.g., during intrusion and extrusion (Bauss et al., 2008; Bauss et al., 2010).

#### **4.1.1 Enamel damage during bonding and debonding of the orthodontic devices**

Enamel damage that appears as a side effect of the orthodontic therapy is relatively largely related to the bonding and debonding technique. One of the main preoccupations within the current orthodontics is identifying the ways to obtain, at the end of the treatment, a sound, unmodified enamel surface.

#### SIDE EFFECTS AND COMPLICATIONS HYPOTHETICALLY LINKED TO ORTHODONTICS

#### **Dental**

408 Orthodontics – Basic Aspects and Clinical Considerations

severe, irreversible (multiples caries and decalcifications, severe root resorption).

 standard inherent complications, being included side effects where the orthodontist's role is irrelevant (enamel changes due to acid etching when resins

 complications related to the patient's particularities (individual susceptibility or disease) not disclosed during evaluation, possibly unknown even to the patient (allergic reaction for which history data was inconclusive; severe root resorption and demineralisations present in association with a metabolic disease unidentified

 conditions arising as a result of a passive operator intervention, associated with a lack of proper monitoring (lack of monitoring and proper prevention methods in

 medical errors by wrongful medical objectives and deficient treatment conduct (enamel damage due to improper debonding technique; tooth movement into an

moderate, irreversible (enamel fracture during debonding);

cases with severe root resorption or decalcifications);

area with alveolar bone defect causing severe loss of attachment).

relation hasn't been proven, but for no reason these aspect should be neglected.

**4. Presentation of the main complications linked to orthodontic intervention**  Like any other medical intervention, the orthodontic treatment may have, besides the positive effects, also unwanted secondary consequences. In the scientific literature there are numerous conditions to which orthodontic treatment may be associated (Table 2) (Ellis & Benson, 2002; Graber et al., 2004; Lau & Wong, 2006). For most of them a direct cause-efect

Linked to orthodontic intervention, there are described numerous side effects present on tooth level. Among the first etiological hypothesis was the one saying that fixed orthodontic technique may induce enamel changes, both quantitatively (enamel loss during bonding and debonding procedures) and qualitatively (discolorations). On root level the most unwanted side effect taken into consideration in the medical literature is severe root resorption, process associated with root shortening that may lead to an insufficient tooth ability to endure the forces present during oral function performance and in extreme cases early tooth loss. Regarding the pulpal reactions, during action of orthodontic forces may appear a decreased oxygenation of pulpal tissue, varying in the same direction with force magnitude and period of action. Usually the inflammatory reactions that appear are transitory, reversible, but severe modifications, like necrosis, sometimes appear. Greater risk of pulpal reactions is present in teeth with a history of severe periodontal injury during certain orthodontic procedures, e.g., during intrusion and extrusion (Bauss et al., 2008;

**4.1.1 Enamel damage during bonding and debonding of the orthodontic devices** 

Enamel damage that appears as a side effect of the orthodontic therapy is relatively largely related to the bonding and debonding technique. One of the main preoccupations within the

3. based on orthodontist's role in the side effect's occurrence:

are used as bonding material);

at the initial assessment);

**4.1 Dental complications** 

Bauss et al., 2010).

LOCAL EFFECTS

SYSTEMIC EFFECTS


#### **Periodontal**

 gingivitis, periodontitis, gingival recession or hypertrophy, alveolar bone loss, dehiscences, fenestrations, interdental fold, dark triangles;

#### **Temporomandibular joint**


#### **Unsatisfactory treatment outcome**

 inadequate morpho-functional, aesthetic or functional final result, relapse, failure to complete treatment due to treatment dropout.

#### **Psychological**

 teasing, behavioral changes of patients and parents; discomfort associated with pain presence and aesthetic look discontents during orthodontic appliance usage;

#### **Gastro-intestinal**


#### **Cardiac**

#### infective endocarditis;

#### **Chronic fatigue syndrome;**

**Cross infections** 

from doctor to patient, patient to doctor, patient to patient.

Table 2. Main risks and complications associated with the orthodontic treatment.

Before applying brackets, tubes and bands, it is recommended to prepare the surface by pumice prophylaxis in order to increase the bond strength, procedure with great importance especially when self-etched adhesives are used as bonding material (Lill et al., 2008). Cleaning and pumicing procedures are accompanied by enamel loss and fissures on its surface, but these alteration present very low severities, neglectable compared to the ones present after debonding (Øgaard & Fjeld, 2010; Hosein et al., 2004).

By current knowledge, bonding of orthodontic appliances may induce irreversible changes of tooth surface. The most severe modifications appear when resins (especially the conventional ones, with a separate etching phase) are used as bonding materials. The bond strength of these materials is directly related to the resin tags formed, that cannot be removed at orthodontic treatment end. The extent of etching depth depends on numerous factors, among those being the acid type and concentration, time of application, enamel surface characteristics (e.g., in the mandibular molars and premolars usually is present aprismatic enamel that is more resistant to etching, aspect that could contribute to the observed higher debonding failure rate of bracket and tubes). Sometimes, after bracket bonding, demineralised enamel remains uncovered by resin, but usually remineralisation occurs, this not being a risk factor for decay appearance. A more recent bonding technique is the one with self-etched adhesive resin, which produces less enamel damage but has the disadvantages of lower bond strength. Resin-modified glass ionomer cement are preferred as bonding materials due to the reduced enamel involvement, fluor releasing properties and bond strength similar to resins. Fjeld, analyzing enamel alteration after 3 variants of bonding materials (conventional resin with 35% phosphoric etching gel and bonding/resin - Transbond XT, 3M Unitek; self-etching adhesives - Transbond Plus, 3M Unitek; resinmodified glass ionomer cement - Fuji ORTHO LC, GC Corporation used after surface conditioning with 10% polyacrylic acid) observes that the most important changes were associated to the first material usage (thick and relative deep – 10-20µm- resign tags accompanied by an increased surface rugosity). Less severe modifications were observed for the second material (smaller, fewer and less profound – 5-10µm- resin tags). When Fuji ORTHO LC was used no resign tags were observed. Authors conclude that by using the last two variants of bonding material advantages in term of fewer irreversible changes of the enamel surface are present (Fjeld & Øgaard, 2006).

During debonding and removal of the residual material there is a risk of tooth damage (enamel loss, cracks), irreversible complication being seen as hard to avoid. Frequency and gravity of enamel loss is usually smaller when metallic braces and bonding materials based on glass ionomer cements are used. More severe modifications were seen when ceramic brackets and adhesive resins were used as bonding materials. The orthodontist has a big role in preventing this irreversible enamel damage by using an appropriate debonding technique. A safe debonding technique aims to break the link between bracket and adhesive, this being preferred especially when adjacent to the bracket base there is softened, demineralised enamel. The residual bonding material is better to be removed with tungsten carbide burs at low speed, followed by surface polishing with pumice or a paste, in order to decrease rugosity and prevent plaque accumulation (Graber et al., 2004). Horizontal enamel cracks present after debonding are associated directly with the orthodontic technique, the vertical ones being present with a high frequency also in the population without previous orthodontic treatment (Øgaard & Fjeld, 2010).

In order to study enamel changes associated with orthodontic treatment we analyzed 2 pairs of upper premolars with a history of orthodontic treatment (treatment duration of 12 and 23 moths), extracted for orthodontic purposes after treatment plan was reassessed. By microscopic analysis, using magnifications till 5X, on the buccal surface there were identified changes in terms of color and roughness, with clear identification of the area where the bracket was applied. The enamel area corresponding to the bracket's base

By current knowledge, bonding of orthodontic appliances may induce irreversible changes of tooth surface. The most severe modifications appear when resins (especially the conventional ones, with a separate etching phase) are used as bonding materials. The bond strength of these materials is directly related to the resin tags formed, that cannot be removed at orthodontic treatment end. The extent of etching depth depends on numerous factors, among those being the acid type and concentration, time of application, enamel surface characteristics (e.g., in the mandibular molars and premolars usually is present aprismatic enamel that is more resistant to etching, aspect that could contribute to the observed higher debonding failure rate of bracket and tubes). Sometimes, after bracket bonding, demineralised enamel remains uncovered by resin, but usually remineralisation occurs, this not being a risk factor for decay appearance. A more recent bonding technique is the one with self-etched adhesive resin, which produces less enamel damage but has the disadvantages of lower bond strength. Resin-modified glass ionomer cement are preferred as bonding materials due to the reduced enamel involvement, fluor releasing properties and bond strength similar to resins. Fjeld, analyzing enamel alteration after 3 variants of bonding materials (conventional resin with 35% phosphoric etching gel and bonding/resin - Transbond XT, 3M Unitek; self-etching adhesives - Transbond Plus, 3M Unitek; resinmodified glass ionomer cement - Fuji ORTHO LC, GC Corporation used after surface conditioning with 10% polyacrylic acid) observes that the most important changes were associated to the first material usage (thick and relative deep – 10-20µm- resign tags accompanied by an increased surface rugosity). Less severe modifications were observed for the second material (smaller, fewer and less profound – 5-10µm- resin tags). When Fuji ORTHO LC was used no resign tags were observed. Authors conclude that by using the last two variants of bonding material advantages in term of fewer irreversible changes of the

During debonding and removal of the residual material there is a risk of tooth damage (enamel loss, cracks), irreversible complication being seen as hard to avoid. Frequency and gravity of enamel loss is usually smaller when metallic braces and bonding materials based on glass ionomer cements are used. More severe modifications were seen when ceramic brackets and adhesive resins were used as bonding materials. The orthodontist has a big role in preventing this irreversible enamel damage by using an appropriate debonding technique. A safe debonding technique aims to break the link between bracket and adhesive, this being preferred especially when adjacent to the bracket base there is softened, demineralised enamel. The residual bonding material is better to be removed with tungsten carbide burs at low speed, followed by surface polishing with pumice or a paste, in order to decrease rugosity and prevent plaque accumulation (Graber et al., 2004). Horizontal enamel cracks present after debonding are associated directly with the orthodontic technique, the vertical ones being present with a high frequency also in the population without previous

In order to study enamel changes associated with orthodontic treatment we analyzed 2 pairs of upper premolars with a history of orthodontic treatment (treatment duration of 12 and 23 moths), extracted for orthodontic purposes after treatment plan was reassessed. By microscopic analysis, using magnifications till 5X, on the buccal surface there were identified changes in terms of color and roughness, with clear identification of the area where the bracket was applied. The enamel area corresponding to the bracket's base

enamel surface are present (Fjeld & Øgaard, 2006).

orthodontic treatment (Øgaard & Fjeld, 2010).

presented a uniform, white aspect. The enamel area corresponding to the margins of the bracket was assessed as having an irregular aspect, with more severe alteration in the gingival region compared to the occlusal one. The enamel lingual area (considered as control) presented an aspect considered as being uniform (Fig. 1). An increased surface roughness was observed at the area correspondent to the bracket's base, this being probably associated with the resin adhesive material used for bracket bonding (Preoteasa et al., 2011a). Using magnifications of 20X, on the buccal tooth surface were observed multiples unordered fissures, caused probably by the bracket debonding and residual material removal technique. The lingual surface presented also cracks, but fewer, this being probable associated to the occlusal contacts. By analyzing the buccal surface of two newly erupted premolars, without history of orthodontic treatment, a uniform aspect, crack and fissure free surface was observed (Fig. 2).

Fig. 1. Microscopic aspect of the enamel surface of a maxillary first premolar with a history of orthodontic treatment – buccal enamel surface (a); lingual enamel surface (b) magnification 5X.

Fig. 2. Microscopic evaluation of buccal enamel surface for two upper first premolars, one with a history of orthodontic treatment (a); one without previous orthodontic treatment (b) – magnification 20X.

#### **4.1.2 Carious complications associated with the orthodontic intervention**

As the orthodontic technique developed, concerns regarding tooth damage by carious lesions during treatment increased, this being seen today as one of the most frequent unwanted side effect associated with this particular medical intervention. Decay damage associated with orthodontic technique presents some specific particularities. They appear with increased frequency on the tooth's surface where the bracket is bonded, adjacent to its base, they usually have low severity (most of the times are encountered as white spot lesions, more frequently gingival and distal to the bracket's base than mesial or occlusal) (Fig. 3). Evidence shows that the prevalence of this unwanted side effect is nearby 70% for white spot lesions and less than 5% for cavities (Al Maaitah et al., 2011). According to Chapman's study more than 30% of the maxillary incisors, teeth with the greatest esthetic values, present decalcifications after orthodontic intervention (Chapman et al., 2010).

Fig. 3. White spot lesions and cavities related to the presence of orthodontic appliance.

Demineralisations around brackets occur mainly due to improper oral hygiene maintenance. But, in the presence of orthodontic appliance, an increased number of plaque retention areas appear, accompanied by a decrease of the self cleaning. In orthodontic patients plaque coverage is 2 to 3 times higher than the levels present in high plaque forming adults without this type of treatment (Klukowska et al., 2011). It is also observed a decrease of salivary pH and increased level of Streptococcus Mutans and Lactobacillus, elements favoring carioactivity (Vizitiu & Ionescu, 2010). Thus, maintaining a good oral hygiene is mandatory. Also, learning new skills on how to perform oral hygiene and using additional instruments may be needed, e.g., like interdental brush. Consequently, there are higher costs implied, not only financial (the tooth brush wears faster, investments in auxiliary devices like interdental brush or oral shower), but also time-related (more time spent for ensuring a good oral hygiene).

In decay prevention, even if the patient has the main role by maintaining a good oral hygiene, the orthodontist's role isn't neglectable. Before starting the orthodontic therapy it is recommended to evaluate carioactivity and oral hygiene habits, these being sometimes reasons to postpone orthodontic treatment with fixed appliance. Primary prevention methods may be used (e.g., recommendation of how to maintain a good oral hygiene and

As the orthodontic technique developed, concerns regarding tooth damage by carious lesions during treatment increased, this being seen today as one of the most frequent unwanted side effect associated with this particular medical intervention. Decay damage associated with orthodontic technique presents some specific particularities. They appear with increased frequency on the tooth's surface where the bracket is bonded, adjacent to its base, they usually have low severity (most of the times are encountered as white spot lesions, more frequently gingival and distal to the bracket's base than mesial or occlusal) (Fig. 3). Evidence shows that the prevalence of this unwanted side effect is nearby 70% for white spot lesions and less than 5% for cavities (Al Maaitah et al., 2011). According to Chapman's study more than 30% of the maxillary incisors, teeth with the greatest esthetic

values, present decalcifications after orthodontic intervention (Chapman et al., 2010).

Fig. 3. White spot lesions and cavities related to the presence of orthodontic appliance.

good oral hygiene).

Demineralisations around brackets occur mainly due to improper oral hygiene maintenance. But, in the presence of orthodontic appliance, an increased number of plaque retention areas appear, accompanied by a decrease of the self cleaning. In orthodontic patients plaque coverage is 2 to 3 times higher than the levels present in high plaque forming adults without this type of treatment (Klukowska et al., 2011). It is also observed a decrease of salivary pH and increased level of Streptococcus Mutans and Lactobacillus, elements favoring carioactivity (Vizitiu & Ionescu, 2010). Thus, maintaining a good oral hygiene is mandatory. Also, learning new skills on how to perform oral hygiene and using additional instruments may be needed, e.g., like interdental brush. Consequently, there are higher costs implied, not only financial (the tooth brush wears faster, investments in auxiliary devices like interdental brush or oral shower), but also time-related (more time spent for ensuring a

In decay prevention, even if the patient has the main role by maintaining a good oral hygiene, the orthodontist's role isn't neglectable. Before starting the orthodontic therapy it is recommended to evaluate carioactivity and oral hygiene habits, these being sometimes reasons to postpone orthodontic treatment with fixed appliance. Primary prevention methods may be used (e.g., recommendation of how to maintain a good oral hygiene and

**4.1.2 Carious complications associated with the orthodontic intervention** 

regarding diet; usage of fluoride releasing materials for bracket bonding and bands cementation). When necessary, secondary prevention methods must be promptly applied (e.g., increasing patient's compliance through operator's active intervention when white spot lesions are observed). One method for decreasing carioactivity, frequently used by orthodontists and dental practitioners, is fluorisation. A systematic review made in 2004 concludes that there is some evidence that supports the hypothesis that daily fluoride mouthrinse or fluoride-containing cement reduces tooth decay during treatment with fixed braces (Benson et al., 2004). A split-mouth study on this theme is the one made by Shungin reported in 2010, with a 12 years follow-up after active treatment ended. Results show that at the end of the treatment a significant increase of white spot lesion frequency was present, this being followed by a significant progressive decreasing. Also, modifications were significantly less severe in all moments when glass ionomer cement was used as bonding material, compared to the acrylic one (Shungin et al., 2010). Different treatment alternatives may be used when white spot lesions are present at treatment end, among these being: waiting for spontaneous remineralisation, usage of fluor or casein phosphopeptide based products, recommendation to chew sugar-free gums. In frontal teeth, when aesthetic complaints are present, microabrasion may be used.

For a better knowledge of orthodontic biomaterials, needed in order to adequate select them, we made an experiment to comparatively evaluate the surface wettability of some orthodontic bonding materials. 4 commercial products were chosen, different 2 by 2 as type of material and as curing method. Surface wettability was assessed by contact angle measurements using KSV Instruments's CAM 101 device (KSV Instruments, 2008). Results showed that for both glass ionomer cements and composite resins curing mechanism influenced wetting properties, the light curing ones presenting lower contact angle values than the self-curing ones. Also, analyzing the materials with the same curing characteristics, acrylic resins presented higher contact angles than the glass ionomer cements (Table 3). Surface wettability is linked to hidrophylicity and microbial adherence. When choosing between materials with the same clinical use, namely bonding of orthodontic brackets, in order to prevent caries apparition, in high risk patients the practitioner may prefer the chemically-cured composite resin, which is more hydrophobic and theoretically predispose less to plaque accumulation. Regarding glass ionomer cements, that are frequently used for band cementation, in time, due to their hydrophilic character and due to the fact that solubilization can take place, it may appear a space which represents a retention zone for the dental plaque, becoming an etiologic agent for decay and periodontitis. Of course, other properties must be analyzed in order to choose the best suited material for each case, but knowing surface properties may help in this direction and also explain some noticed clinical aspects (Preoteasa et al., 2011b).


Table 3. Contact angle values for some orthodontic materials, with details regarding their characteristics.

#### **4.1.3 Color alterations linked to the orthodontic treatment**

Discoloration present after braces removal may have a negative impact on the aesthetics and patient's satisfaction. Karamouzos et al. in a split-mouth study on 26 orthodontic patients reported that teeth's color parameters changed after orthodontic treatment, 80% of the patients presenting at least one tooth with discolorations appreciated by authors as being unacceptable. Time had an aggravating effect on all color parameters evaluated according to the Commission Internationale de l'Eclairage system (L\*-lightness; a\*-red/green; b\* blue/yellow). There were observed more severe alteration when chemically cured resins were used as bonding material compared to light cured composites (Karamouzos et al., 2010).

Color alterations after orthodontic treatment present a multifactorial etiology, some variables being directly linked to the technique itself. Frequency of these alterations is considerably higher, with increased severity, when fixed appliances are used in comparison with the removable ones. When resins are used for bracket bonding enamel changes are unavoidable (Fig. 4). The resin tags cannot be removed by cleaning procedures without altering considerably the enamel surface. Irreversible changes regarding enamel surface morphology, its rugosity and texture are present, with negative influences on reflection properties, luminosity and optical perception. Evidence shows that adhesives resins used for bracket bonding don't present good color stability in time. Food dyes, ultraviolet light and corrosion products from the orthodontic appliance induce color alterations, with a tendency to modify toward the yellow tones (Faltermeier et al., 2008). In the presence of orthodontic forces that induce variation in pulp vascularization, it is also possible that endogenous discoloration appear, with a premature aging of tooth. Also, if white spots lesions are present, even if remineralisation occurs, most probable the final outcome will be somehow different from the initial enamel structure, the mineral not being identical disposed as in the unaffected enamel, with possible influences on color properties.

Fig. 4. Color changes integrated to usage of composite resins for bracket bonding.

After bracket removal patients frequently wish to increase their appearance by teeth whitening. This procedure presents particularities especially when resins were used as bonding material, due to the remained resins tags. The residual adhesive behaves different compared to adjacent enamel during whitening, being important to accurately evaluate the situation in order to avoid producing a more unpleasant outcome.

Discoloration present after braces removal may have a negative impact on the aesthetics and patient's satisfaction. Karamouzos et al. in a split-mouth study on 26 orthodontic patients reported that teeth's color parameters changed after orthodontic treatment, 80% of the patients presenting at least one tooth with discolorations appreciated by authors as being unacceptable. Time had an aggravating effect on all color parameters evaluated according to the Commission Internationale de l'Eclairage system (L\*-lightness; a\*-red/green; b\* blue/yellow). There were observed more severe alteration when chemically cured resins were used as bonding material compared to light cured composites (Karamouzos et al.,

Color alterations after orthodontic treatment present a multifactorial etiology, some variables being directly linked to the technique itself. Frequency of these alterations is considerably higher, with increased severity, when fixed appliances are used in comparison with the removable ones. When resins are used for bracket bonding enamel changes are unavoidable (Fig. 4). The resin tags cannot be removed by cleaning procedures without altering considerably the enamel surface. Irreversible changes regarding enamel surface morphology, its rugosity and texture are present, with negative influences on reflection properties, luminosity and optical perception. Evidence shows that adhesives resins used for bracket bonding don't present good color stability in time. Food dyes, ultraviolet light and corrosion products from the orthodontic appliance induce color alterations, with a tendency to modify toward the yellow tones (Faltermeier et al., 2008). In the presence of orthodontic forces that induce variation in pulp vascularization, it is also possible that endogenous discoloration appear, with a premature aging of tooth. Also, if white spots lesions are present, even if remineralisation occurs, most probable the final outcome will be somehow different from the initial enamel structure, the mineral not being identical

disposed as in the unaffected enamel, with possible influences on color properties.

Fig. 4. Color changes integrated to usage of composite resins for bracket bonding.

situation in order to avoid producing a more unpleasant outcome.

After bracket removal patients frequently wish to increase their appearance by teeth whitening. This procedure presents particularities especially when resins were used as bonding material, due to the remained resins tags. The residual adhesive behaves different compared to adjacent enamel during whitening, being important to accurately evaluate the

**4.1.3 Color alterations linked to the orthodontic treatment** 

2010).

#### **4.1.4 Dental wear associated to the use of orthodontic appliances**

Another dental alteration present in the orthodontic patient is tooth wear secondary to the contact between teeth and brackets or tubes. A higher gravity of this process was noticed when ceramic brackets are used, Viazis reporting a severity from 9 to 38 times higher compared to the metallic ones (Lau et al., 2006; Viazis et al., 1990).

It is recommended, especially during certain phases of orthodontic treatment, to avoid usage of ceramic brackets in order to minimize the dental wear, as an irreversible treatment complication. For example, when deep bite is present, ceramic brackets on the lower anterior teeth shouldn't be used until sufficient overjet is created in order not to favor wear of the maxillary incisors, side effect with an increase negative impact on the esthetic dimension of the final result. Precautions must be taken when using the ceramic attachment on canine that are in a class II relationship and also during maxillary incisors retraction (Graber et al., 2004).

#### **4.1.5 External apical root resorption in orthodontic therapy**

Apical root resorption is, according to the present knowledge, an unavoidable complication of the orthodontic treatment, microscopic studies showing a prevalence of 100% after the treatment end (Fig. 5 & 6). Segal et al., in a systematic review reported in 2004, using metaanalysis, found a mean value of the root shortening after orthodontic treatment of 1.421 +/- 0.448 mm (Segal et al., 2004). Usually, the process severity is low, root shortening beyond 2mm being present in 5-18% of cases, and beyond 4mm or 1/3 of tooth length in 1-5% of the cases (Lopatiene & Dumbravaite, 2008).

Fig. 5. Aspect of apical third of root of a newly erupted premolar (a), an included molar (b) and a premolar extracted for orthodontic purposes (c) – magnification 4X.

Root resorption's signs and symptoms are usually absent, even mobility been rarely higher than 1st degree on the Miller scale. If in the end of the treatment the root resorption's severity is mild or moderate the tooth prognosis doesn't greatly decrease. Kalkwarf demonstrated that 4 mm root shortening due to this pathological aspect is equivalent to 20% loss of the periodontal attachment, and 3 mm loss equivalent to 1 mm loss of the periodontal attachment (Kalkwarf et al, 1986). The high severity forms of root resorption, corresponding to considerable root shortening with influence on tooth prognosis, are one of the most discussed complications in association with the orthodontic therapy, being perceived as an unpredictable consequence with insufficient knowledge about its treatment alternatives and evolution.

Fig. 6. Resorption lacunae in teeth without (a) and with (b) a history of orthodontic treatment - diameter: (a) 0.72µm; (b) 12.11µm – magnification 20X.

In order to minimize the severity of root resorption a good knowledge of etiopathogenic mechanism is mandatory. Although this aspect presents a series of ambiguities, mainly two categories of factors are incriminated for root resorption appearance, namely related to patient characteristics and to orthodontic technique. Both issues are important to be assessed, the first ones in order to identify high risk patients, and the last ones in order to ensure an orthodontic intervention predisposing at minimum to this unwanted side effect.

By current scientific knowledge, individual susceptibility has the main role in root resorption appearance, aspect difficult to correctly estimate. Indicators of high risk patients may be the signs of root resorption prior to orthodontic therapy, regardless of the presumed cause, and the presence of root resorption in the first degree relatives (Fig. 7). Genetic factors play an important part in root resorption presence, some associations, like the one with the polymorphism of the IL-1beta gene being demonstrated (Bastos Lages et al., 2009). Some study results suggest that this unwanted side effect is different between ethnic groups. Among Asians there is a decreased frequency of root resorption compared to Caucasians or Hispanics (Lopatiene & Dumbravaite, 2008). Modified general health status has been linked to a more severe root resorption process, among the diseases more frequently associated being allergies, asthma, diabetes, arthritis and endocrine disorders (Graber et al., 2004). An

discussed complications in association with the orthodontic therapy, being perceived as an unpredictable consequence with insufficient knowledge about its treatment alternatives and

Fig. 6. Resorption lacunae in teeth without (a) and with (b) a history of orthodontic

In order to minimize the severity of root resorption a good knowledge of etiopathogenic mechanism is mandatory. Although this aspect presents a series of ambiguities, mainly two categories of factors are incriminated for root resorption appearance, namely related to patient characteristics and to orthodontic technique. Both issues are important to be assessed, the first ones in order to identify high risk patients, and the last ones in order to ensure an orthodontic intervention predisposing at minimum to this unwanted side effect.

Fig. 7. Patient with identified susceptibility toward root resorption; mandibular first molar with root resorption signs, having as presumed cause incorrect endodontic treatment (a); progressive resorption at the mandibular second molar and premolar after orthodontic

By current scientific knowledge, individual susceptibility has the main role in root resorption appearance, aspect difficult to correctly estimate. Indicators of high risk patients may be the signs of root resorption prior to orthodontic therapy, regardless of the presumed cause, and the presence of root resorption in the first degree relatives (Fig. 7). Genetic factors play an important part in root resorption presence, some associations, like the one with the polymorphism of the IL-1beta gene being demonstrated (Bastos Lages et al., 2009). Some study results suggest that this unwanted side effect is different between ethnic groups. Among Asians there is a decreased frequency of root resorption compared to Caucasians or Hispanics (Lopatiene & Dumbravaite, 2008). Modified general health status has been linked to a more severe root resorption process, among the diseases more frequently associated being allergies, asthma, diabetes, arthritis and endocrine disorders (Graber et al., 2004). An

treatment - diameter: (a) 0.72µm; (b) 12.11µm – magnification 20X.

evolution.

intervention was applied (b,c).

increased frequency of root resorption was associated to abnormal eruption path, the mechanism considering the pressure of the included tooth on the adjacent tooth roots. It has been mainly observed as being present in the second molars (produced by pressure of the wisdom teeth) and in the lateral incisor or first premolar (pressure exerted by the canine). Open bite is currently seen as a risk factor for root resorption, arguments being linked to the insufficient development of the periodontal tissue of the interested teeth, being incapable to bear orthodontic and occlusal forces, present during oral functions. Other dental anomalies associated with this particular complication are: hypodontia, class II and III Angle, deep bite and increased overjet (Lopatiene & Dumbravaite, 2008; Preoteasa et al, 2009). One aspect confirmed by many study results is that there is a direct relation between root morphology and root resorption process. A greater risk of root resorption present teeth with long and narrow roots, with abnormal root shape in the apical part of the root, especially eroded, pointed, deviated or bottle shape (Artun et al., 2009; Smale et al., 2005). Depending on the tooth's topography root resorption process presents some variability. Maxillary teeth are more prone to develop root resorption compared to the mandibular ones, and frontal teeth more prone than lateral ones (Brezniak & Wasserstein, 2002). Generally it is said that the more resorbed teeth, in a decreasing sequence, are the following: maxillary lateral incisors, maxillary central incisors, lower incisors, maxillary canines, first molars, lower second premolars and maxillary second premolars (Lopatiene & Dumbravaite, 2008). Also teeth with trauma history present a higher risk of root resorption (Artun et al., 2009).

Among risk factors of root resorption related directly to orthodontic technique the most important seem to be: treatment time, the amount of root apex displacement, the type and amount of orthodontic force, and also the type of orthodontic appliance used (Fox, 2005; Segal et al., 2004). Most study results indicate that one of the most important factor in root resorption appearance is treatment duration, an optimal period in order to prevent severe root resorption being less than 1½ years (Apajalahti & Peltola, 2007). A higher frequency of root resorption was linked to intrusion, expecialy when vestibular coronal torque was associated. Heavy and continuous forces are correlated with significantly more root resorption. Type of used orthodontic appliance influences root resorption process, being less severe in treatment delivered by removable orthodontic devices and higher when disjunction and extraoral appliances are used. Current knowledge indicates that bracket prescription and type (e.g., standard edgewise or straight wire technique, conventional or self-ligating) doesn't influence root resorption severity (Weltman et al., 2010.).

Considering the negative impact of severe root resorption it is recommended that the orthodontist take the necessary measures in order to prevent it from happening. During the initial evaluation, the patients with a high risk to develop root resorption should be identified, by considering previous signs of root resorption and local and systemic risk factors. If a patient with a high risk of root resorption is identified, reassessing the treatment objectives is recommended (whenever possible is best to avoid teeth extractions, heavy and continuous forces, disjunction, long treatment duration). In all cases it is recommended, at approximately 6 month after placement of orthodontic appliance, to acknowledge if root resorption signs appeared by analyzing periapical radiographs, at least for the frontal teeth. If, by that moment, there aren't signs of root resorption, the risk of presenting severe risk resorption at the end of the treatment is usually minimal. If, at that moment, sign of root resorption are present most likely during treatment some progressive modification will appear. Evidence shows that 2-3 months pause in orthodontic treatment, with passive wires, decreases the total amount of root resorption (Weltman et al., 2010). If severe signs of root resorption are present the treatment plan must be reassessed. Treatment alternatives may include prosthodontic solution for space closing, striping instead of extractions, sometimes even discontinuing orthodontic therapy. If severe root resorption is present after the active phase ended it is recommended radiological monitoring till process stabilizes. If a progressive evolution is noticed, frequently factors like occlusal trauma or retention devices that continue to develop orthodontic forces are associated, being necessary to address these items.

In order to study some aspects related to the etiology of root resorption, the authors designed and implemented a cross-sectional study who aimed to see if there is a correlation between root resorption's severity and some of the individual particularities that can be assessed before treatment start. A convenience sample of 55 orthodontic patients (74.5% n=41 females and 25.5% - n=14 males) treated in the Department of Orthodontics and dentofacial orthopedics from the Faculty of Dental Medicine, Bucharest, from October 2005- October 2009, was used. Inclusion criteria were: orthodontic patients with fixed metallic appliance, standard edgewise or straight–wire technique, applied bimaxillary for at least 6 months. Patients with previous orthognathic interventions, disjunction, radiological signs of root resorption before treatment start, missing or endodontically treated incisors were excluded. Root resorption was assessed by measurements on panoramic radiographs using the Linge and Linge formula and Adobe Photoshop software, version 6.0 (Linge & Linge, 1991). In order to quantify the extent of root resorption for each patient included in the sample, two indices were used: average root resorption (mean value of root resorption registered for the 8 measured incisors in each patient, registered in mm) and the maximum root resorption (maximum value of root resorption from the 8 measured incisors in each patient, registered in mm). Data collection for the study variables was made using patient's file, photographs, study casts and cephalometric evaluation on teleradiographs. For data analysis STATA statistical software, version 11, was used. The sample presented mostly mild or moderate apical root resorption, with an average value of 1.31mm (standard deviation 0.60). The study evidenced a moderately positive statistically-significant correlation between average root resorption and the value of FMA angle, suggesting that patients with hyperdivergent facial pattern have a more pronounce tendency to develop root resorption after the orthodontic intervention, compared to the hypodivergent ones. Also our results suggest that patients with skeletal open bite tend to be more severely affected by external root resorption (Table 4). By comparing data regarding the root resorption among subgroups (made according to the normal and, respectively abnormal values of the parameters registered from their cephalometric assessment and dental evaluation) some additional information were obtained. Within the subgroups made according to the values of the parameters that evaluate the sagittal skeletal relations, the mean values of root resorption indices evidenced a more severe process in patients with values different from the average. The difference between groups was not statistically significant. Analysis of the subgroups constituted according to the value of the parameters selected for vertical skeletal relations evidenced the tendency of a more severe modification in the cases with higher values than the average (Preoteasa & Ionescu, 2011). Patients with Angle class II or III malocclusion presented more severe modifications than those belonging to class I (Table 5). In conclusion we can say that the pathological process of external root resorption is a reality accompanying frequently the orthodontic intervention, its severity

decreases the total amount of root resorption (Weltman et al., 2010). If severe signs of root resorption are present the treatment plan must be reassessed. Treatment alternatives may include prosthodontic solution for space closing, striping instead of extractions, sometimes even discontinuing orthodontic therapy. If severe root resorption is present after the active phase ended it is recommended radiological monitoring till process stabilizes. If a progressive evolution is noticed, frequently factors like occlusal trauma or retention devices that continue to develop orthodontic forces are associated, being necessary to address these

In order to study some aspects related to the etiology of root resorption, the authors designed and implemented a cross-sectional study who aimed to see if there is a correlation between root resorption's severity and some of the individual particularities that can be assessed before treatment start. A convenience sample of 55 orthodontic patients (74.5% n=41 females and 25.5% - n=14 males) treated in the Department of Orthodontics and dentofacial orthopedics from the Faculty of Dental Medicine, Bucharest, from October 2005- October 2009, was used. Inclusion criteria were: orthodontic patients with fixed metallic appliance, standard edgewise or straight–wire technique, applied bimaxillary for at least 6 months. Patients with previous orthognathic interventions, disjunction, radiological signs of root resorption before treatment start, missing or endodontically treated incisors were excluded. Root resorption was assessed by measurements on panoramic radiographs using the Linge and Linge formula and Adobe Photoshop software, version 6.0 (Linge & Linge, 1991). In order to quantify the extent of root resorption for each patient included in the sample, two indices were used: average root resorption (mean value of root resorption registered for the 8 measured incisors in each patient, registered in mm) and the maximum root resorption (maximum value of root resorption from the 8 measured incisors in each patient, registered in mm). Data collection for the study variables was made using patient's file, photographs, study casts and cephalometric evaluation on teleradiographs. For data analysis STATA statistical software, version 11, was used. The sample presented mostly mild or moderate apical root resorption, with an average value of 1.31mm (standard deviation 0.60). The study evidenced a moderately positive statistically-significant correlation between average root resorption and the value of FMA angle, suggesting that patients with hyperdivergent facial pattern have a more pronounce tendency to develop root resorption after the orthodontic intervention, compared to the hypodivergent ones. Also our results suggest that patients with skeletal open bite tend to be more severely affected by external root resorption (Table 4). By comparing data regarding the root resorption among subgroups (made according to the normal and, respectively abnormal values of the parameters registered from their cephalometric assessment and dental evaluation) some additional information were obtained. Within the subgroups made according to the values of the parameters that evaluate the sagittal skeletal relations, the mean values of root resorption indices evidenced a more severe process in patients with values different from the average. The difference between groups was not statistically significant. Analysis of the subgroups constituted according to the value of the parameters selected for vertical skeletal relations evidenced the tendency of a more severe modification in the cases with higher values than the average (Preoteasa & Ionescu, 2011). Patients with Angle class II or III malocclusion presented more severe modifications than those belonging to class I (Table 5). In conclusion we can say that the pathological process of external root resorption is a reality accompanying frequently the orthodontic intervention, its severity

items.


Table 4. Correlations between root resorption and craniofacial particularities.


Table 5. Root resorption among groups of patients structured according to the normality of investigated parameters.

being associated at some extent with the individual morphological characteristics. A good knowledge on the variables associated to severe root resorption is essential for the identification of the high risk patients, as well as for the selection of the best suited treatment alternative in terms of low probability of root resorption occurrence.

#### **4.2 Periodontal complications**

Periodontal complications are one of the most actual side effects linked to the orthodontics, not rarely being the reason for malpractice complaints. It can be found in various forms, from gingivitis to periodontitis, dehiscence, fenestrations, interdental fold, gingival recession or overgrowth, black triangles (Fig. 8). Severe damage can considerably interfere with the teeth prognosis. Etiopathogeny is complex, involving factors related to the patient (e.g., previous condition present, increased susceptibility, poor oral hygiene) and to orthodontic technique.

Fig. 8. Periodontal alteration present during orthodontic treatment.

Gingivitis usually occurs due to the incorrect maintenance of the oral hygiene, in the presence of the orthodontic appliance, that seems to favor plaque accumulation. Their frequency is increased in some particular situations, like in the presence of orthodontic bands that usually are placed subgingival, accompanied sometime by the solubilisation of luting agent, favoring the gingival overgrowth by mechanical trauma and existence of retention space for plaque accumulation. This is why, in order to ensure a safer medical care, bondable tubes are more indicated than bands. Even so, research has shown that during orthodontic therapy gingival enlargement occurs, but approximately 3 month after the removal of the appliance, in most cases, the gingiva presents a similar aspect as before treatment (Kouraki et al., 2005).

Careful management of orthodontic treatment is recommended when previous periodontal alterations are identified. Orthodontic intervention may aggravate a previous condition, which may lead to severe disease form, sometimes difficult to control. In these cases is best to postpone the treatment till a very good oral hygiene is present and the periodontal disease is stable. During the initial assessment, patients with factors that predispose to worsening the periodontal condition (e.g., presence of diabetes or epilepsy treated with drugs that induce gingival enlargement) need to be identified. During orthodontic therapy it is recommended to insist on the importance of maintaining a good oral hygiene, to monitories the periodontal status (at least every three month to do an examination and dental cleaning) and to take the necessary measures in order to control the risk factors. Also orthodontic therapy should be particularized, e.g., by choosing the treatment alternative

being associated at some extent with the individual morphological characteristics. A good knowledge on the variables associated to severe root resorption is essential for the identification of the high risk patients, as well as for the selection of the best suited

Periodontal complications are one of the most actual side effects linked to the orthodontics, not rarely being the reason for malpractice complaints. It can be found in various forms, from gingivitis to periodontitis, dehiscence, fenestrations, interdental fold, gingival recession or overgrowth, black triangles (Fig. 8). Severe damage can considerably interfere with the teeth prognosis. Etiopathogeny is complex, involving factors related to the patient (e.g., previous condition present, increased susceptibility, poor oral hygiene) and to

Gingivitis usually occurs due to the incorrect maintenance of the oral hygiene, in the presence of the orthodontic appliance, that seems to favor plaque accumulation. Their frequency is increased in some particular situations, like in the presence of orthodontic bands that usually are placed subgingival, accompanied sometime by the solubilisation of luting agent, favoring the gingival overgrowth by mechanical trauma and existence of retention space for plaque accumulation. This is why, in order to ensure a safer medical care, bondable tubes are more indicated than bands. Even so, research has shown that during orthodontic therapy gingival enlargement occurs, but approximately 3 month after the removal of the appliance, in most cases, the gingiva presents a similar aspect as before

Careful management of orthodontic treatment is recommended when previous periodontal alterations are identified. Orthodontic intervention may aggravate a previous condition, which may lead to severe disease form, sometimes difficult to control. In these cases is best to postpone the treatment till a very good oral hygiene is present and the periodontal disease is stable. During the initial assessment, patients with factors that predispose to worsening the periodontal condition (e.g., presence of diabetes or epilepsy treated with drugs that induce gingival enlargement) need to be identified. During orthodontic therapy it is recommended to insist on the importance of maintaining a good oral hygiene, to monitories the periodontal status (at least every three month to do an examination and dental cleaning) and to take the necessary measures in order to control the risk factors. Also orthodontic therapy should be particularized, e.g., by choosing the treatment alternative

treatment alternative in terms of low probability of root resorption occurrence.

Fig. 8. Periodontal alteration present during orthodontic treatment.

**4.2 Periodontal complications** 

orthodontic technique.

treatment (Kouraki et al., 2005).

who favors less accumulation of plaque, devices as simpler as possible and developing small orthodontic forces. In this regard it is recommended to avoid as much as possible hooks, elastic ligatures and chains, bands being preferable to tubes, and metallic ligatures to elastomeric ones.

During some particular orthodontic interventions an increased frequency of periodontal complications was noticed. For example, within extraction treatment after space closure, a higher frequency of periodontal interdental folds, associated sometimes with gingival enlargement, were observed (Fig. 9). Also after moving teeth in the buccal-lingual direction, as in the expansion or intermaxillary disjunction, the risk of fenestrations and dehiscences is higher. In this context it is recommended to choose the treatment alternative that predisposes as little as possible to these impairments.

Fig. 9. Periodontal complications - gingival enlargement, interdental fold - present during orthodontic therapy (a); Gingival recessions associated with crossbite malocclusion, not linked to the orthodontic appliance's presence (b).

#### **4.3 Soft tissue alterations**

During orthodontic treatment intra- and extraoral (face and neck) soft tissue alterations may appear. For the oral lesions, the etiological mechanism involves the direct contact of gingiva and mucosa with brackets, bands, tubes and arches, and it is also related to the incorrect handling of the orthodontic instruments. The outcome usually consists in erosions and ulcerations on the buccal, labial, lingual or gingival mucosa. Pain and discomfort are associated, but by using orthodontic wax it may be possible to ameliorate to some extent the symptoms. Improper hygiene of the removable orthodontic appliances is sometimes associated with stomatitis appearance, which may sometimes be overinfected with Candida albicans (Shah & Sandler, 2006). Headgear appliance was linked to facial and intraoral trauma, appearing accidentally during game, sleep or incorrect handling. Blum-Hareuveni reports a case of a 12 year old boy who presented an ocular trauma by the external headgear arm, during sleep. He developed an intraocular infection (endophthalmitis), the final outcome being severe, decreased visual acuity. The author observes that in 10 out of 11 cases (the ones identified in the medical literature till that point) the consequences were dramatic, visual acuity decreasing to hand movement perception or less (Blum-Hareuveni et al., 2004; Blum-Hareuveni et al., 2006). After several cases of trauma associated with headgear devices were reported, modifications of its design were made in order to prevent this severe possible complication.

#### **4.4 Temporomandibular joint disorders**

Postorthodontically temoporomandibular disorders are usually part of the craniomandibular dysfunction, which includes beside joint modifications also muscle and dental impairments. By the current research knowledge, it isn't clearly elucidated the relation between temporomandibular alterations and orthodontic intervention, usually being found contradictory opinions, explication varying. Some sustain that, by the state of morphofunctional equilibrium present after orthodontic intervention, optimal conditions for this side effects prevention are created. Other believe that, because of the premature occlusal contacts present during therapy, there is a greater risk for this complication to appear (Bourzgui et al., 2010; Gebeile-Chauty et al. 2010).

Before starting orthodontic treatment every patient must be examined in order to detect previous temporomandibular disorders and identify high risk patients. Aspects like inflammatory bone and muscular disorders (reumathoid arthritis), head and neck trauma, chronic head pain or high stress level must be taken into account. If signs and symptoms of temporomandibular disorders are present reaching a diagnosis is mandatory and also establishing its degree of severity. It isn't recommended to start an orthodontic therapy if the patient presents acute or severe signs of pain belonging to the temporomandibular disfunction. If severe modifications are observed during treatment, depending on case's particularities, it might be decided the correction of the abnormal occlusal contacts, referral to an orthopedic surgeon, or even treatment discontinuing. For patient who presented signs of temporomandibular disorder after active orthodontic treatment phase, it is recommended to take the necessary measures in order to prevent the relapse, the maintenance of a good morpho-functional equilibrium being essential. In some cases mouth guards as retention device may help in reducing the symptoms and facilitate healing (Graber et al., 2004).

#### **4.5 Allergic reactions**

One hypothetical reaction linked to the orthodontic treatment is the allergic one. Hypersensitivity reactions can occur associated to the well known allergens like nickel, cobalt, chromium, latex and polymers. The most frequent form is the contact dermatitis of the face and neck, but lesions can appear also on the oral mucosa and gingiva, and rarely even systemic reactions may occur.

Nickel allergies are the most frequent ones in the industrialized countries, manifesting usually as a type IV hypersensitivity reaction. Orthodontic devices contain approximately 8% nickel and the nickel-titanium alloy near 70% nickel (Leite & Bell, 2004). The allergic signs may vary from small rash on skin or mucosa, to generalized dermatitis. In high severity cases the manifestations may lead to discontinuation of the orthodontic treatment.

Another allergen taken into consideration when orthodontic treatment is performed is latex (from medical gloves, elastomeric ligatures, elastic chain, rubber dam etc). Prevalence of latex related allergies is reported as being lower than 1% in the general population, but greater than 5% among dental professionals (Leite, 2004). Associated to it, types I and IV hypersensitivity reactions may appear, the most severe one, type I, being life threatening. In order to ensure a safe medical treatment it is important to identify allergic patients before starting the intervention. Higher risk present people with a history of complex or repeated surgical interventions (prolonged contact with rubber drains and tubes), those with spina bifida, and of course those who reported presence of itching and redness from contact to rubber objects and having allergies or contact dermatitis. A definitive diagnosis is established by combining the anamnestic data with the clinical data and hipersensibility tests. When allergic reaction to latex is identified, alternative latex-free devices should be used, and it is also recommended to avoid nickel-based components (Kolokitha, 2008).

#### **4.6 Infective endocarditis**

422 Orthodontics – Basic Aspects and Clinical Considerations

Postorthodontically temoporomandibular disorders are usually part of the craniomandibular dysfunction, which includes beside joint modifications also muscle and dental impairments. By the current research knowledge, it isn't clearly elucidated the relation between temporomandibular alterations and orthodontic intervention, usually being found contradictory opinions, explication varying. Some sustain that, by the state of morphofunctional equilibrium present after orthodontic intervention, optimal conditions for this side effects prevention are created. Other believe that, because of the premature occlusal contacts present during therapy, there is a greater risk for this complication to appear

Before starting orthodontic treatment every patient must be examined in order to detect previous temporomandibular disorders and identify high risk patients. Aspects like inflammatory bone and muscular disorders (reumathoid arthritis), head and neck trauma, chronic head pain or high stress level must be taken into account. If signs and symptoms of temporomandibular disorders are present reaching a diagnosis is mandatory and also establishing its degree of severity. It isn't recommended to start an orthodontic therapy if the patient presents acute or severe signs of pain belonging to the temporomandibular disfunction. If severe modifications are observed during treatment, depending on case's particularities, it might be decided the correction of the abnormal occlusal contacts, referral to an orthopedic surgeon, or even treatment discontinuing. For patient who presented signs of temporomandibular disorder after active orthodontic treatment phase, it is recommended to take the necessary measures in order to prevent the relapse, the maintenance of a good morpho-functional equilibrium being essential. In some cases mouth guards as retention device may help in reducing the symptoms and facilitate healing (Graber et al., 2004).

One hypothetical reaction linked to the orthodontic treatment is the allergic one. Hypersensitivity reactions can occur associated to the well known allergens like nickel, cobalt, chromium, latex and polymers. The most frequent form is the contact dermatitis of the face and neck, but lesions can appear also on the oral mucosa and gingiva, and rarely

Nickel allergies are the most frequent ones in the industrialized countries, manifesting usually as a type IV hypersensitivity reaction. Orthodontic devices contain approximately 8% nickel and the nickel-titanium alloy near 70% nickel (Leite & Bell, 2004). The allergic signs may vary from small rash on skin or mucosa, to generalized dermatitis. In high severity cases the manifestations may lead to discontinuation of the orthodontic treatment. Another allergen taken into consideration when orthodontic treatment is performed is latex (from medical gloves, elastomeric ligatures, elastic chain, rubber dam etc). Prevalence of latex related allergies is reported as being lower than 1% in the general population, but greater than 5% among dental professionals (Leite, 2004). Associated to it, types I and IV hypersensitivity reactions may appear, the most severe one, type I, being life threatening. In order to ensure a safe medical treatment it is important to identify allergic patients before starting the intervention. Higher risk present people with a history of complex or repeated surgical interventions (prolonged contact with rubber drains and tubes), those with spina

**4.4 Temporomandibular joint disorders** 

(Bourzgui et al., 2010; Gebeile-Chauty et al. 2010).

**4.5 Allergic reactions** 

even systemic reactions may occur.

Infective endocarditis is rarely associated with the orthodontic interventions, but if it does, it can present severe complications that can be life threatening. The American Heart Association recommends prophylactic methods in order to prevent infectious endocarditis appearance if the patient presents prosthetic cardiac valve, previous infective endocarditis, congenital heart disease and cardiac transplantation with cardiac valvulopathy. The prophylaxis is mainly indicated in dental procedures that belong to oral and maxillofacial surgery, endodontics and periodontics, routinely in orthodontics being no need to implement it. Prophylactique therapy may be indicated in some particular orthodontic phases, where bleeding during interventions occur (e.g., teeth extraction, mini-implant placement used for anchorage control, interventions of orthognathic surgery and sometimes during placement and removal of orthodontic bands) (Wilson et al., 2007).

#### **5. Applications of the risk management principles within orthodontics**

Orthodontic treatment is a complex medical intervention, carried out over a long period of time, during which risks (seen as unplanned events) may materialize as complications. Their presence is linked to several factors like orthodontic technique, medical knowledge in this field, but also to patient's individual particularities (e.g., general and oral health). The outcome can include one or several side effects, generally, but not always, presenting low severity, appeared after initiation of orthodontic therapy or by aggravating some previous conditions. In order to ensure a high quality of the medical care, from the treatment planning phase, the risks must be considered, evaluated and communicated to the patient. This conduct promotes an optimal treatment period with lower risk of disagreements that may lead to malpractice complaint and even lawsuits.

One method for risks assessment may be to follow the methodology described in Risk Management, using the risk matrix (Table 6). This approach includes proactive management items (measures for avoiding and preventing the risk), as well as reactive elements (actions taken for minimizing damage after occurrence of the adverse effect). The use of risk management plan can't guarantee a health care intervention without side effects but, by controlling risks, it may considerably decrease the associated complications, ensuring a better prognosis.

At first it is necessary to identify the risks that are associated with the medical intervention that is going to be applied. By the current medical knowledge there are a great number of complications that are hypothetically linked to the orthodontic treatment. Their occurrence depends on numerous factors, from orthodontic technique (e.g., appliance type) to patient related variables (e.g., oral hygiene habits). These must be considered even from the start because it might influence treatment's objectives, phases and sometimes may even postpone the medical intervention. To identify the risks, it may be helpful for the orthodontist to ask himself the basics question "what may appear? why? how? when?".


Table 6. Risk management phases.

After identifying the risks, the next step is their assessment. The identified risks are analyzed by the probability of appearance (e.g., likelihood; almost certain; likely; possible; unlikely; rare) and impact on the quality of healthcare intervention (e.g., severe; major; moderate; minor; insignificant) in conjunction. An ergonomic method to do this is to give scores to the items investigated and introduce the identified risks in a 2X2 table, this being known as a risk matrix analysis. For example, risk of severe root resorption can be differently assessed depending on case particularities. Generally, it is evaluated as being unlikely to appear, but if it does, it can have a major impact on tooth prognosis. But if, before beginning the orthodontic treatment, there can be detected signs of idiopathic root resorption, the probability of occurrence increases, transforming this risk into a priority issue, needed to be carefully considered when treatment plan is developed.

After that, the risk response is planned for those complications which, corresponding to the previous analysis, present the best chances to negatively influence the treatment outcome. In risk management there are described several techniques that can be applied individual or in conjunction (Piney, 2002). By risk avoidance there are addressed the measurements taken into consideration in order to minimize the situational risk as much as possible. For example in a high risk root resorption case, if it is possible, the treatment objectives should be minimized so treatment duration delivered by the orthodontist will be as short as possible and these means do not favor the side effects appearance. Risk mitigation refers to the actions taken in order to reduce the probability or the impact of the risk event. This type of measure can be integrated to the primary, secondary or tertiary prevention methods described for many pathological medical aspects (Ionescu et al., 2008). For example, in orthodontics there are described various procedures for minimizing enamel demineralization associated with bad oral hygiene habits, from motivating the patient and parents to indicating auxiliary devices (single-tuft brushes, oral irrigators) and fluoridebased products. Risk acceptance suggests the decision to accept the possibility of the event appearance. Acceptance can be passive, when the impact presents a minor impact on the outcome. In orthodontics this can be seen in the acceptance of minor root resorption process, a side effect present with a high frequency after this type of medical interventions, but with insignificant impact on outcome quality. Acceptance can be active; this means that, if the risks occur, the planned methods to minimize its consequences must be implemented. This is the case of infection risk, present in any medical surgical act (e.g., tooth extraction for orthodontic purposes, mini-implants placement, orthognathic surgery phases). Usually, it presents low frequency, but if it occurs, prompt response measurements must be taken. Risk transfer implies a 3rd part that will bear partially or totally the risks if they appear. This type of risk response can be seen in contemporary medical field by the usage of informed consent. Patients are informed about the possible risks and complications of the medical intervention, by signing the informed consent, which certifies the understanding of the aspects mentioned and assume the possibility of side effects occurrence.

#### **6. Conclusions**

424 Orthodontics – Basic Aspects and Clinical Considerations

value for probability (measures the extent to which risk can

value for impact (measures the effect of a particular risk on the

After identifying the risks, the next step is their assessment. The identified risks are analyzed by the probability of appearance (e.g., likelihood; almost certain; likely; possible; unlikely; rare) and impact on the quality of healthcare intervention (e.g., severe; major; moderate; minor; insignificant) in conjunction. An ergonomic method to do this is to give scores to the items investigated and introduce the identified risks in a 2X2 table, this being known as a risk matrix analysis. For example, risk of severe root resorption can be differently assessed depending on case particularities. Generally, it is evaluated as being unlikely to appear, but if it does, it can have a major impact on tooth prognosis. But if, before beginning the orthodontic treatment, there can be detected signs of idiopathic root resorption, the probability of occurrence increases, transforming this risk into a priority

After that, the risk response is planned for those complications which, corresponding to the previous analysis, present the best chances to negatively influence the treatment outcome. In risk management there are described several techniques that can be applied individual or in conjunction (Piney, 2002). By risk avoidance there are addressed the measurements taken into consideration in order to minimize the situational risk as much as possible. For example in a high risk root resorption case, if it is possible, the treatment objectives should be minimized so treatment duration delivered by the orthodontist will be as short as possible and these means do not favor the side effects appearance. Risk mitigation refers to the actions taken in order to reduce the probability or the impact of the risk event. This type of measure can be integrated to the primary, secondary or tertiary prevention methods described for many pathological medical aspects (Ionescu et al., 2008). For example, in orthodontics there are described various procedures for minimizing enamel demineralization associated with bad oral hygiene habits, from motivating the patient and parents to indicating auxiliary devices (single-tuft brushes, oral irrigators) and fluoridebased products. Risk acceptance suggests the decision to accept the possibility of the event appearance. Acceptance can be passive, when the impact presents a minor impact on the outcome. In orthodontics this can be seen in the acceptance of minor root resorption process, a side effect present with a high frequency after this type of medical interventions, but with

issue, needed to be carefully considered when treatment plan is developed.

what may appear? why? how? when?

2. **Risks assessment RISK MATRIX** 

become real)

outcome quality) establishing priorities 3. **Risk response planning**  risk avoidance risk mitigation risk acceptance risk transfer

RISK MANAGEMENT 1. **Risks identification** 

Table 6. Risk management phases.

In conclusion, the risks associated with orthodontic treatment are a reality, complications being a result of a multifactorial process, including aspects related to patient, orthodontist and the technical features of orthodontic appliances and procedures. These can be prevented or limited through identification and implementation of best treatment alternative for each individual case. Patient's compliance is an important factor that can contribute to a high standard outcome, with minimum side effects.

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Leandro Silva Marques1, Paulo Antônio Martins-Júnior1, Maria Letícia Ramos-Jorge1 and Saul Martins Paiva2 *1Federal University of Vales do Jequitinhonha e Mucuri 2Federal University of Minas Gerais Brazil* 

#### **1. Introduction**

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Organization as adopted by the International Health Conference in 1946, In: *Basic* 

Root resorption is a pathological process that causes a shortening of the dental root. Although this condition is generally asymptomatic and missed in diagnosis, it may result in tooth mobility and even tooth loss if not diagnosed and treated early (Ahangari et al., 2010). In orthodontics, induced inflammatory root resorption is a form of pathologic root resorption related to the removal of hyalinized areas of the periodontal ligament following the application of orthodontic forces and is considered an undesirable but unavoidable iatrogenic consequence of orthodontic treatment (Brezniak & Wasserstein, 2002a; Brezniak & Wasserstein, 2002b).

The root resorption may compromise the continued existence and functional capacity of the affected tooth, depending on their magnitude (Brezniak & Wasserstein, 1993a, Brezniak & Wasserstein, 1993b), since the root structure (volume and contour) is changed (Consolaro, 2002). However, as the process of root resorption during orthodontic treatment is usually smooth and ends when the force is removed (Brezniak & Wasserstein, 1993; Levander et al., 1994) some authors have pointed out that the aesthetic and functional improvements justify the risks (Brezniak & Wasserstein, 1993).

#### **1.1 Aims of the chapter**

The aims of this chapter are to give a detailed description of root resorption, how it begins, the mechanisms involved in this condition and how the risk factors described in the literature contribute toward the development of root resorption related to orthodontic treatment. The importance of a thorough patient history and early diagnosis are also discussed. The value of high-quality research, such as longitudinal cohort and prospective studies, randomized clinical trials, systematic reviews and meta-analysis, is stressed in light of the current emphasis on evidence-based dentistry. Care and recommendations, legal implications and a case description of a patient with root resorption following orthodontic treatment are also presented.

### **2. Etiology of root resorption**

Determining the cause of root resorption requires a thorough history, rescuing the previous dental history, addiction, accidentes, previous treatment, associated diseases and other details relevant to pathogenesis, but not always remembered by patients and identified by orthodontists. Several authors have pointed out that the multifactor etiology of root resorption is complex, but the condition appears to result from a combination of individual biologic variability, genetic predisposition and the effect of mechanical factors (Bartley et al., 2011; Weltman et al., 2010; Zahrowski & Jeske, 2011). However, no definitive conclusion has been drawn as to whether sex (Harris et al., 1997; Hendrix et al., 1994; Sameshina & Sinclair, 2001), age (Baumrind et al., 1996; Costopoulos & Nanda, 1996; Harris et al., 1997; Harris & Baker, 1990; Owmann-Moll et al., 1995), tooth extractions (Baumrind et al., 1996; Blake et al., 1995; Hendrix et al., 1994; McNab et al., 2000) and duration of active treatment (Baumrind et al., 1996; Beck & Harris, 1994; Harris et al., 1997; Kaley & Phillips, 1991; Kurol et al., 1996; Mirabella & Artun, 1995; Sameshina & Sinclair, 2001) are risk factors for root resorption. Conflicting data are reported on the relationship between root resorption and hypodontia or partial anodontia (Artun, 2000; Kjaer, 1995, 2000; Lee et al., 1999) and ectopic teeth (Kjaer, 2000; Lee et al., 1999).

#### **2.1 How root resorption begins?**

Orthodontic tooth movement is based on force-induced periodontal ligament and alveolar bone remodeling (Abuabara, 2007). So, orthodontic forces represent a physical agent capable of inducing inflammatory reaction in the periodontium (Giannopoulou et al., 2008). When a tooth moves, a necrosis of periodontal ligament on the pressure side with formation of a cell-free hyaline zone occurs. This event is followed by osteoclast resorption of the neighbouring alveolar bone and bone apposition by osteoblasts on the tension side (Abuabara, 2007). The resorption process of dental hard tissues seems to be triggered by the activity of some cytokines as well as that of bone. Immune cells migrate out of the capillaries in the periodontal ligament and interact with locally residing cells by elaborating a large array of signal molecules (Jäger et al., 2005). According Consolaro et al. (2011), the causes of root resorption should be related to the loss of root surface cementoblasts.

#### **2.2 Orthodontic treatment-related factors**

The ideal force for tooth movement would mimic a physiologic balance between tooth movement and bony adaptation (Paetyangkul et al., 2009). Schwarz (1932) advocated the optimal force level for tooth movement between 7 and 26 g per square centimeter. He also stated that, when force exceeded this threshold, root resorption occurs. When pressure decreases below this limit, root resorption ceases (Owman Moll et al., 1996). This was later conrmed by King and Fischlschweiger (1982), who found that light forces produced insignicant root resorption, whereas intermediate or heavy forces resulted in substantial crater formation.

In this context, several aspects have been related to induce root resorption during orthodontic treatment. This aspects are as follows: treatment duration (Casa et al., 2001; Fox, 2005; Levander & Malmgren, 1988; Otis et al., 2004; Paetyangkul et al., 2011; Sameshima & Sinclair, 2004; Segal et al., 2004), magnitude of the applied forces (Barbagallo et al., 2008; Bartley et al., 2011; Casa et al., 2001; Chan et al., 2005; Harris et al., 2006; Paetyangkul et al.,

Determining the cause of root resorption requires a thorough history, rescuing the previous dental history, addiction, accidentes, previous treatment, associated diseases and other details relevant to pathogenesis, but not always remembered by patients and identified by orthodontists. Several authors have pointed out that the multifactor etiology of root resorption is complex, but the condition appears to result from a combination of individual biologic variability, genetic predisposition and the effect of mechanical factors (Bartley et al., 2011; Weltman et al., 2010; Zahrowski & Jeske, 2011). However, no definitive conclusion has been drawn as to whether sex (Harris et al., 1997; Hendrix et al., 1994; Sameshina & Sinclair, 2001), age (Baumrind et al., 1996; Costopoulos & Nanda, 1996; Harris et al., 1997; Harris & Baker, 1990; Owmann-Moll et al., 1995), tooth extractions (Baumrind et al., 1996; Blake et al., 1995; Hendrix et al., 1994; McNab et al., 2000) and duration of active treatment (Baumrind et al., 1996; Beck & Harris, 1994; Harris et al., 1997; Kaley & Phillips, 1991; Kurol et al., 1996; Mirabella & Artun, 1995; Sameshina & Sinclair, 2001) are risk factors for root resorption. Conflicting data are reported on the relationship between root resorption and hypodontia or partial anodontia (Artun, 2000; Kjaer, 1995, 2000; Lee et al., 1999) and ectopic teeth (Kjaer,

Orthodontic tooth movement is based on force-induced periodontal ligament and alveolar bone remodeling (Abuabara, 2007). So, orthodontic forces represent a physical agent capable of inducing inflammatory reaction in the periodontium (Giannopoulou et al., 2008). When a tooth moves, a necrosis of periodontal ligament on the pressure side with formation of a cell-free hyaline zone occurs. This event is followed by osteoclast resorption of the neighbouring alveolar bone and bone apposition by osteoblasts on the tension side (Abuabara, 2007). The resorption process of dental hard tissues seems to be triggered by the activity of some cytokines as well as that of bone. Immune cells migrate out of the capillaries in the periodontal ligament and interact with locally residing cells by elaborating a large array of signal molecules (Jäger et al., 2005). According Consolaro et al. (2011), the causes of

The ideal force for tooth movement would mimic a physiologic balance between tooth movement and bony adaptation (Paetyangkul et al., 2009). Schwarz (1932) advocated the optimal force level for tooth movement between 7 and 26 g per square centimeter. He also stated that, when force exceeded this threshold, root resorption occurs. When pressure decreases below this limit, root resorption ceases (Owman Moll et al., 1996). This was later conrmed by King and Fischlschweiger (1982), who found that light forces produced insignicant root resorption, whereas intermediate or heavy forces resulted in substantial

In this context, several aspects have been related to induce root resorption during orthodontic treatment. This aspects are as follows: treatment duration (Casa et al., 2001; Fox, 2005; Levander & Malmgren, 1988; Otis et al., 2004; Paetyangkul et al., 2011; Sameshima & Sinclair, 2004; Segal et al., 2004), magnitude of the applied forces (Barbagallo et al., 2008; Bartley et al., 2011; Casa et al., 2001; Chan et al., 2005; Harris et al., 2006; Paetyangkul et al.,

root resorption should be related to the loss of root surface cementoblasts.

**2. Etiology of root resorption** 

2000; Lee et al., 1999).

crater formation.

**2.1 How root resorption begins?** 

**2.2 Orthodontic treatment-related factors** 

2011), direction of tooth movement (Barbagallo et al., 2008; Han et al., 2005) amount of apical displacement (Fox, 2005; Segal et al., 2004), force application method (continuous vs. intermittent) (Brezniak & Wasserstein, 2002; Faltin et al., 2001), type of appliance (Brezniak & Wasserstein, 1993; Pandis et al., 2008) and treatment technique (Bartley et al., 2011; Beck & Harris, 1994; Janson et al., 1999; Marques et al., 2010; Pandis et al., 2008; Parker & Harris, 1998; Scott et al., 2008).

#### **2.2.1 Treatment duration, force application method and magnitude of the applied forces**

In a study, Acar et al. (1999) compared a 100-g force with elastics in either an interrupted (12 hours per day) or a continuous (24 hours per day) application. Group who has teeth experiencing orthodontic movement had signicantly more root resorption than the control group. Besides that, continuous force produced signicantly more root resorption than discontinuous force application.

Later, Ballard et al. (2009) conducted a prospective randomized clinical trial to compare root resorption with two force application patterns (continuous and intermittent) and they concluded that the application of intermittent orthodontic forces of 225 cN for 8 weeks (14 days of force application, 3 days of rest, then 4 days of force application repeated for 6 weeks) caused less root resorption than continuous forces of 225 cN for 8 weeks. The authors stated that, although it might not be clinically practical, compared with continuous forces, intermittent forces might be a safer method to prevent signicant root resorption.

More recently, Paetyangkul et al. (2011) investigated the amounts of root resorption volumetrically after the application of controlled light and heavy forces in the buccal direction for 4, 8, and 12 weeks. They found signicant differences in the extent of root resorption between 4, 8, and 12 weeks of force application (P < 0.001), with substantially more severe resorption in the longer force duration groups. The light force produced signicantly less root resorption than did the heavy force. The authors argued that the duration of force application appears to be an important factor in orthodontic root resorption. Even though the application of light orthodontic forces did not show a signicant difference between 4 and 8 weeks of buccal force application, the amount of root resorption increased signicantly from 8 to 12 weeks of force application. So the duration of orthodontic force application caused more root resorption even when light forces of 25 g were used. This finding agrees with others studies published by Vardimon et al. (1991) and Gonzales et al. (2008). Paetyangkul et al. (2011) affirmed that this might be due to the increased osteoclastic activity around 8 weeks of force application.

In another study, Chan and Darendeliler (2006) found that the mean volume of the resorption craters was 11.59 times greater in the heavy-force group than in the control group. Barbagallo et al. (2008), in a prospective randomized clinical trial compared forces applied with removable thermoplastic appliances (TA) and xed orthodontic appliances. The results showed that teeth experiencing orthodontic movement had signicantly more root resorption than did the control teeth. They also found that heavy force produced signicantly more root resorptions (9 times greater than the control) than light force (5 times greater than the control).

In this context, Harris et al. (2006) conducted a prospective randomized clinical trial to quantify the amount of root resorption when controlled light and heavy intrusive forces were applied to human premolars and to establish the sites where root resorption is more prevalent. They found that the volume of the root resorption craters after intrusion was directly proportional to the magnitude of the intrusive force applied. The findings showed that the control group had fewer and smaller root resorption craters, the light force group had more and larger root resorption craters than the control group, and the heavy force group had the most and the largest root resorption craters of all groups. A trend of linear increase in the volume of the root resorption craters was observed from control to light to heavy groups, and these differences were statistically signicant. The mean volumes of the resorption craters in the light and heavy force groups were 2 and 4 times greater than in the control groups, respectively. The mesial and distal surfaces had the greatest resorption volume, with no statistically signicant difference between the 2 surfaces.

#### **2.2.2 Direction of tooth movement**

Evaluating the direction of tooth movement (intrusive vs. extrusive force), Han et al. (2005) found that root resorption from extrusive force was not signicantly different from the control group. Intrusive force signicantly increased the percentage of resorbed root area (4 fold). The correlation between intrusion or extrusion and root resorption in the same patient was r = 0.774 (P = 0.024).

#### **2.2.3 Amount of apical displacement**

In orthodontics, total apical displacement might represent a better marker for overall treatment activation. A tooth that is moved greater distances through bone is subjected to longer durations of activation. There is no way to move a tooth between two points with xed appliances, without causing hyalinization. Perhaps, this is why maxillary incisors are most likely to exhibit severe levels of root resorption (Segal et al., 2004). Segal et al. (2004) conducted a meta-analysis to elucidate possible treatment-related etiological factors - such as, duration of treatment and apical displacement – for external root resorption and they found that mean apical root resorption was strongly correlated with total apical displacement (r = 0.822) and treatment duration (r = 0.852). In 2005, Fox also found that treatment-related root resorption is correlated with the distance the apex moves and the length of time the treatment took.

#### **2.2.4 Archwire sequence**

Mandall et al. (2006) compared 3 orthodontic archwire sequences in terms of: (1) patient discomfort, (2) root resorption, and (3) time to working archwire. In that study, all patients were treated with maxillary and mandibular preadjusted edgewise appliances (0.022-in slot), and all archwires were manufactured by the same manufacturer. The results showed that there was no statistically signicant difference between archwire sequences, for maxillary left central incisor root resorption (F ratio, P = 0.58). There was also no statistically signicant difference between the proportion of patients with and without root resorption between archwire sequence groups (P = 0.8).

#### **2.2.5 Type of appliance**

Reukers et al. (1998) compared the prevalence and severity of root resorption after treatment with a fully programmed edgewise appliance (FPA) and a partly programmed edgewise appliance (PPA). All FPA patients were treated with 0.022-in slot Roth prescription (''A'' Company, San Diego, Calif), and misplaced brackets were rebonded. All PPA patients were treated with 0.018-in slot Microloc brackets (GAC, Central Islip, NY), and the archwires were adjusted for misplaced brackets. They found no statistically signicant differences in the amount of tooth root loss (FPA, 8.2%; PPA, 7.5%) or prevalence of root resorption (FPA, 75%; PPA, 55%) between the groups.

More recently, Scott et al. (2008) investigated the effect of either Damon3 self-ligating brackets or a conventional orthodontic bracket system on mandibular incisor root resorption. Patients were treated with Damon3 self-ligating or Synthesis (both, Ormco, Glendora, Calif) conventionally ligated brackets with identical archwires and sequencing in all patients. The results showed that mandibular incisor root resorption was not statistically different (Damon3, 2.26 mm, SD 2.63; Syn-thesis, 1.21 mm, SD 3.39) between systems.

#### **2.2.6 Treatment technique**

432 Orthodontics – Basic Aspects and Clinical Considerations

were applied to human premolars and to establish the sites where root resorption is more prevalent. They found that the volume of the root resorption craters after intrusion was directly proportional to the magnitude of the intrusive force applied. The findings showed that the control group had fewer and smaller root resorption craters, the light force group had more and larger root resorption craters than the control group, and the heavy force group had the most and the largest root resorption craters of all groups. A trend of linear increase in the volume of the root resorption craters was observed from control to light to heavy groups, and these differences were statistically signicant. The mean volumes of the resorption craters in the light and heavy force groups were 2 and 4 times greater than in the control groups, respectively. The mesial and distal surfaces had the greatest resorption

Evaluating the direction of tooth movement (intrusive vs. extrusive force), Han et al. (2005) found that root resorption from extrusive force was not signicantly different from the control group. Intrusive force signicantly increased the percentage of resorbed root area (4 fold). The correlation between intrusion or extrusion and root resorption in the same patient

In orthodontics, total apical displacement might represent a better marker for overall treatment activation. A tooth that is moved greater distances through bone is subjected to longer durations of activation. There is no way to move a tooth between two points with xed appliances, without causing hyalinization. Perhaps, this is why maxillary incisors are most likely to exhibit severe levels of root resorption (Segal et al., 2004). Segal et al. (2004) conducted a meta-analysis to elucidate possible treatment-related etiological factors - such as, duration of treatment and apical displacement – for external root resorption and they found that mean apical root resorption was strongly correlated with total apical displacement (r = 0.822) and treatment duration (r = 0.852). In 2005, Fox also found that treatment-related root resorption is correlated with the distance the apex moves and the

Mandall et al. (2006) compared 3 orthodontic archwire sequences in terms of: (1) patient discomfort, (2) root resorption, and (3) time to working archwire. In that study, all patients were treated with maxillary and mandibular preadjusted edgewise appliances (0.022-in slot), and all archwires were manufactured by the same manufacturer. The results showed that there was no statistically signicant difference between archwire sequences, for maxillary left central incisor root resorption (F ratio, P = 0.58). There was also no statistically signicant difference between the proportion of patients with and without root resorption

Reukers et al. (1998) compared the prevalence and severity of root resorption after treatment with a fully programmed edgewise appliance (FPA) and a partly programmed edgewise

volume, with no statistically signicant difference between the 2 surfaces.

**2.2.2 Direction of tooth movement** 

**2.2.3 Amount of apical displacement** 

length of time the treatment took.

between archwire sequence groups (P = 0.8).

**2.2.4 Archwire sequence** 

**2.2.5 Type of appliance** 

was r = 0.774 (P = 0.024).

Brin et al. (2003) examined the effect of 2-phase vs 1-phase Class II treatment on the incidence and severity of root resorption. The results showed that children treated in 2 phases with a bionator followed by xed appliances had the fewest incisors with moderate to severe root resorption, whereas children treated in 1 phase with xed appliances had the most resorption. However, the difference was not statistically signicant. As treatment time increased, the odds of root resorption also increased (P = 0.04). The odds of a tooth experiencing severe root resorption were greater with a large reduction in overjet during phase 2.

#### **2.3 Patient-related risk factors**

Possible patient-related risk factors include a previous history of root resorption (Brezniak & Wasserstein, 1993; Hartseld et al., 2004; Marques et al., 2010), tooth/root morphology, length and roots with developmental abnormalities (Brin et al., 2003; Fox, 2005; ; Marques et al., 2010; Sameshima & Sinclair, 2001, 2004; Smale et al., 2005), genetic influences (Al-Qawasmi et al., 2003; Bollen, 2002; Hartseld et al., 2004; Ngan et al., 2004; Sameshima & Sinclair, 2001), systemic factors (Adachi et al., 1994; Igarashi et al., 1996), including drugs (nabumetone) (Villa et al., 2005), hormone deficiency, hypothyroidism, hypopituitarism (Loberg & Engstrom, 1994; Poumpros et al., 1994), asthma (Brezniak & Wasserstein, 2002; McNab et al., 1999), proximity of root to cortical bone (Horiuchi et al., 1998; Kaley & Phillips, 1991; Otis et al., 2004), alveolar bone density (Midgett et al., 1981; Otis et al., 2004), previous trauma (Brezniak & Wasserstein, 2002; Brin et al., 2003; Hartseld et al., 2004; Mandall et al., 2006), endodontic treatment (Brezniak & Wasserstein, 2002; Hamilton et al., 1999), severity and type of malocclusion (Brin et al., 2003; Sameshima & Sinclair, 2001; Segal et al., 2004), patient age (Bishara et al., 1999; Fox, 2005; Harris et al., 1993; Levander & Malmgren, 1998; Mavragani et al., 2002) and gender (Chan & Darendeliler, 2006; Fox, 2005; Harris et al., 1997; Sameshima & Sinclair, 2001).

#### **2.3.1 Genetic influences**

Although several studies proved that there is a relationship between orthodontic force and root resorption, individual susceptibility also appears to influence the occurrence of root resorption. Since mechanical forces and other environmental factors do not adequately explain the variation seen among individual expressions of root resorption, interest has increased on genetic factors inuencing the susceptibility to root resorptions (Hartseld, 2009). The reaction to orthodontic force, including rate of tooth movement, can differ depending on the individual's genetic background (Abass & Hartsfield, 2007; Iwasaki et al., 2008).

In this context, pro-inflammatory cytokines like interleukin-1 (IL-1) and tumour necrosis factor (TNF) are known to induce synthesis of various proteins that, in turn, elicit acute or chronic inflammation. Al-Qawasmi et al. (2003) identified linkage disequilibrium between the IL-1B gene and root resorption in orthodontically treated individuals. The polymorphism variation was found to account for 15% of the variation in root resorption in that sample. Persons in their sample homozygous for the IL-1B allele 1 had a 5.6 fold (95 % CI 1.9–21.2) increased risk of root resorption greater than 2 mm as compared with those who are not homozygous for the IL-1 beta allele 1. Data indicate that allele 1 at the IL-1B gene, known to decrease the production of IL-1 cytokine in vivo (Pociot et al., 1992), signicantly increases the risk of root resorption (Al-Qawasmi et al., 2003).

#### **2.3.2 Systemic factors**

A study conducted by Nishioka et al. (2006) determined whether there is an association between excessive root resorption and immune system factors. The prevalence of root resorption found was 10.3%. Allergy, abnormalities in root morphology and asthma showed be high risk factors for the development of excessive root resorption during orthodontic tooth movement. The modifying effect of several pharmacological agents on orthodontic root resorption also has been examined. Among them, L-thyroxine has been shown to have an inhibitory effect and clinical application has been attempted (Shirazi et al., 1999). Studies have been published describing anti-inflammatory properties of tetracyclines (and their chemically modified analogues) unrelated to their antimicrobial effect. A significant reduction in the number of mononucleated cells on the root surface was observed. Such cells have been related to root resorption (Mavragani et al., 2005).

Some authors have pointed that bone turnover has an important influence during orthodontic treatment. High bone turnover, found in patients with hyperthyroidism, can increase the amount of tooth movement compared with the normal or low bone turnover state and adult patients. Low bone turnover, found in patients with hypothyroidism, can result more root resorption, suggesting that in subjects where a decreased bone turnover rate is expected, the risk of root resorption could be increased (Verna et al., 2003). Bisphosphonates, potent inhibitors of bone resorption, causes a significant dose-dependent inhibition of root resorption in rats after force application. These results prompt that a thorough case history regarding possible pathophysiological conditions influencing bone metabolism should be performed on an individual patient basis. In subjects where increased bone turnover rates are expected, the reactivation of the appliance could be performed more frequently. However, in patients where decreased bone turnover rates are expected, the reactivation should be carried out less frequently and the risk of root resorption should be carefully evaluated (Verna et al., 2003).

Most studies agree that patients who have extractions during orthodontic treatment have greater chances of severe resorption than those treated without extractions (Beck & Harris, 1994; Harris & Baker, 1990; Hendrix et al., 1994; McNab et al., 2000). One possible explanation for this could be the increased movement and retraction of the apex to close extraction spaces.

Another risk factor for severe root resorption is triangular roots (Marques et al., 2010). The geometric form of dental roots inuences the distribution of forces on the alveolar bone and the dent al structure itself. Blunt roots and pipette-shaped apices (triangular) tend to concentrate the forces in a smaller area than roots with a normal shape (Marques et al., 2010). Most studies agree that pointed roots undergo resorption more frequently than those with normal shape (Hartseld et al., 2004; Nigul & Jagomagi, 2006; Ng'ang'a & Ng'ang'a, 2003; Sameshima & Sinclair, 2001; Smale et al., 2005; Stenvik & Mjor, 1970).

#### **2.4 How root resorption is repaired?**

434 Orthodontics – Basic Aspects and Clinical Considerations

resorption. Since mechanical forces and other environmental factors do not adequately explain the variation seen among individual expressions of root resorption, interest has increased on genetic factors inuencing the susceptibility to root resorptions (Hartseld, 2009). The reaction to orthodontic force, including rate of tooth movement, can differ depending on the

In this context, pro-inflammatory cytokines like interleukin-1 (IL-1) and tumour necrosis factor (TNF) are known to induce synthesis of various proteins that, in turn, elicit acute or chronic inflammation. Al-Qawasmi et al. (2003) identified linkage disequilibrium between the IL-1B gene and root resorption in orthodontically treated individuals. The polymorphism variation was found to account for 15% of the variation in root resorption in that sample. Persons in their sample homozygous for the IL-1B allele 1 had a 5.6 fold (95 % CI 1.9–21.2) increased risk of root resorption greater than 2 mm as compared with those who are not homozygous for the IL-1 beta allele 1. Data indicate that allele 1 at the IL-1B gene, known to decrease the production of IL-1 cytokine in vivo (Pociot et al., 1992), signicantly

A study conducted by Nishioka et al. (2006) determined whether there is an association between excessive root resorption and immune system factors. The prevalence of root resorption found was 10.3%. Allergy, abnormalities in root morphology and asthma showed be high risk factors for the development of excessive root resorption during orthodontic tooth movement. The modifying effect of several pharmacological agents on orthodontic root resorption also has been examined. Among them, L-thyroxine has been shown to have an inhibitory effect and clinical application has been attempted (Shirazi et al., 1999). Studies have been published describing anti-inflammatory properties of tetracyclines (and their chemically modified analogues) unrelated to their antimicrobial effect. A significant reduction in the number of mononucleated cells on the root surface was observed. Such cells

Some authors have pointed that bone turnover has an important influence during orthodontic treatment. High bone turnover, found in patients with hyperthyroidism, can increase the amount of tooth movement compared with the normal or low bone turnover state and adult patients. Low bone turnover, found in patients with hypothyroidism, can result more root resorption, suggesting that in subjects where a decreased bone turnover rate is expected, the risk of root resorption could be increased (Verna et al., 2003). Bisphosphonates, potent inhibitors of bone resorption, causes a significant dose-dependent inhibition of root resorption in rats after force application. These results prompt that a thorough case history regarding possible pathophysiological conditions influencing bone metabolism should be performed on an individual patient basis. In subjects where increased bone turnover rates are expected, the reactivation of the appliance could be performed more frequently. However, in patients where decreased bone turnover rates are expected, the reactivation should be carried out less frequently and the risk of root resorption should be

Most studies agree that patients who have extractions during orthodontic treatment have greater chances of severe resorption than those treated without extractions (Beck & Harris,

individual's genetic background (Abass & Hartsfield, 2007; Iwasaki et al., 2008).

increases the risk of root resorption (Al-Qawasmi et al., 2003).

have been related to root resorption (Mavragani et al., 2005).

carefully evaluated (Verna et al., 2003).

**2.3.2 Systemic factors** 

The transition of active root resorption into a process of repair is associated with the invasion of fibroblast-like cells from the circumference of the resorption crater into the active root resorption site even with a light force. The formation of new tooth-supporting structures is seen in the pheriphery of the resorption lacunae, whereas active resorption by multinucleated odontoclast-like cells took place in the central parts. When orthodontic force is discontinued, the reparative process is similar to early cementogenesis during tooth development (Brudvik & Rygh, 1995a, Brudvik & Rygh, 1995b). It has been suggested that the epithelial cell rests of Malassez might have a significant role in mediating repair cementogenesis (Brice et al., 1991; Hasegawa et al., 2003). The resorptive defects are repaired by the deposition of new cementum and the reestablishment of new periodontal ligament (Andreasen, 1973; Barber & Sims, 1981; Brice et al., 1991; Brudvik & Rygh, 1995b; Langford & Sims, 1982; Reitan, 1974).

#### **3. Quality of research**

Most of the studies cited in this chapter offer a low amount of scientific evidence and therefore do not yet allow the precise prediction of the interaction between orthodontic treatment, genetic/systemic factors and root resorption. Part of this insufficient evidence may be explained by the different methodological criteria employed, different sample sizes and the heterogeneity of the study populations. Thus, the findings have been conflicting, which compromises both the credibility and clinical application of the results. Also, the current state of knowledge does not allow orthodontists to identify which patients are vulnerable. In a recent systematic review, Weltman et al. (2010) stated that ''only 11 trials were considered appropriate for inclusion in this review, and their protocols were too variable to proceed with a quantitative synthesis. This reects the state of the published scientic research on this topic.''

Furthermore, although severe root resorption can have drastic consequences to both treatment and patient health, there is only one study that specifically addresses the risk factors for this condition (Marques et al., 2010**).** The main factors directly involved in severe root resorption are extraction of first premolars, triangle-shaped roots and root resorption before treatment. In cases of extensive root resorption induced by orthodontic movement, there might be flaws in the predictability, prevention, and early diagnosis of this condition. It is therefore important to determine the magnitude and prevalence of root resorption in various populations as well as related risk factors (Marques et al., 2010).

However, some challenging situations may appear to the orthodontist during orthodontic treatments. For example, in the study published by Marques et al. (2010), they found an excessive percentage of patients (6%) that experienced pauses in the mechanical treatment, there was a severe root resorption at the end of the treatment. This finding suggests the influence of genetic factors and further increases the responsibility of orthodontists with regard to this issue. If severe root resorption is identified, the treatment plan should be reassessed with the patient. Alternative options might include prosthetic solutions to close spaces, releasing teeth from active archwires if possible, stripping instead of extracting, and early xation of resorbed teeth (Brezniak & Wasserstein, 2002).

#### **4. Care and recommendations**

Determining the cause of root resorption requires a thorough medical history, including the past history of the tooth involved as well as vices, accidents, types of sports practiced, previous treatment and associated diseases. Relevant details, such as mild trauma (concussion and subluxation) should be analyzed in detail (Consolaro et al., 2011).

As root resorption is often asymptomatic, radiographic images constitute the best way to detect the condition and measure its severity in order to establish an early diagnosis (Eraso et al., 2007), especially control radiographs obtained after six to 12 months of orthodontic treatment (Artun et al., 2009; Weltman et al., 2010). Digital radiography (DR) and digital subtraction radiography (DSR) can be used for the detection of apical root resorption as small as 0.5 mm and lingual resorption of 1 mm or more. In this context, DSR frequently performs better than DR (Ono et al., 2011).

When an orthodontist identifies root resorption in a patient, the severity of the condition is decreased with a pause in active orthodontic movement for two to three months with a use of a passive archwire (Weltman et al., 2010; Zahrowski & Jeske, 2011). However, if the resorption is severe, the orthodontist and patient should reassess the treatment plan (Weltman et al., 2010). Alternative options include prosthetic solutions to close spaces, releasing teeth from active archwires when possible, stripping instead of extracting and early fixation of resorbed teeth (Brezniak & Wasserstein, 2002). If root resorption is diagnosed on the final radiographs after treatment, follow-up radiographic examinations are recommended until the resorption has stabilized (Weltman et al., 2010). However, if it continues, sequential root canal therapy with calcium hydroxide may be considered (Pizzo et al., 2007).

There is little evidence that previous trauma (with no history of root resorption) and unusual tooth morphology play roles in increasing root resorption (Weltman et al., 2010). Caution should be used when retaining the teeth with fixed appliances, as occlusal trauma to the fixed teeth or segments may lead to extreme root resorption (Brezniak & Wasserstein, 2002). As the magnitude of force has been documented to be directly correlated with the severity of root resorption (Casa et al., 2001; Darendeliler et al., 2004; Faltin et al., 2001; Harris et al., 2006), the ideal force for dental movement would mimic a physiologic balance between tooth movement and bone adaptation (Paetyangkul et al., 2011). It is therefore recommended to employ light forces, especially for intrusive movements (Weltman et al., 2010).

### **5. Case report**

436 Orthodontics – Basic Aspects and Clinical Considerations

It is therefore important to determine the magnitude and prevalence of root resorption in

However, some challenging situations may appear to the orthodontist during orthodontic treatments. For example, in the study published by Marques et al. (2010), they found an excessive percentage of patients (6%) that experienced pauses in the mechanical treatment, there was a severe root resorption at the end of the treatment. This finding suggests the influence of genetic factors and further increases the responsibility of orthodontists with regard to this issue. If severe root resorption is identified, the treatment plan should be reassessed with the patient. Alternative options might include prosthetic solutions to close spaces, releasing teeth from active archwires if possible, stripping instead of extracting, and

Determining the cause of root resorption requires a thorough medical history, including the past history of the tooth involved as well as vices, accidents, types of sports practiced, previous treatment and associated diseases. Relevant details, such as mild trauma

As root resorption is often asymptomatic, radiographic images constitute the best way to detect the condition and measure its severity in order to establish an early diagnosis (Eraso et al., 2007), especially control radiographs obtained after six to 12 months of orthodontic treatment (Artun et al., 2009; Weltman et al., 2010). Digital radiography (DR) and digital subtraction radiography (DSR) can be used for the detection of apical root resorption as small as 0.5 mm and lingual resorption of 1 mm or more. In this context, DSR frequently

When an orthodontist identifies root resorption in a patient, the severity of the condition is decreased with a pause in active orthodontic movement for two to three months with a use of a passive archwire (Weltman et al., 2010; Zahrowski & Jeske, 2011). However, if the resorption is severe, the orthodontist and patient should reassess the treatment plan (Weltman et al., 2010). Alternative options include prosthetic solutions to close spaces, releasing teeth from active archwires when possible, stripping instead of extracting and early fixation of resorbed teeth (Brezniak & Wasserstein, 2002). If root resorption is diagnosed on the final radiographs after treatment, follow-up radiographic examinations are recommended until the resorption has stabilized (Weltman et al., 2010). However, if it continues, sequential root canal therapy with calcium hydroxide may be considered (Pizzo

There is little evidence that previous trauma (with no history of root resorption) and unusual tooth morphology play roles in increasing root resorption (Weltman et al., 2010). Caution should be used when retaining the teeth with fixed appliances, as occlusal trauma to the fixed teeth or segments may lead to extreme root resorption (Brezniak & Wasserstein, 2002). As the magnitude of force has been documented to be directly correlated with the severity of root resorption (Casa et al., 2001; Darendeliler et al., 2004; Faltin et al., 2001; Harris et al., 2006), the ideal force for dental movement would mimic a physiologic balance between tooth movement and bone adaptation (Paetyangkul et al.,

(concussion and subluxation) should be analyzed in detail (Consolaro et al., 2011).

various populations as well as related risk factors (Marques et al., 2010).

early xation of resorbed teeth (Brezniak & Wasserstein, 2002).

**4. Care and recommendations** 

performs better than DR (Ono et al., 2011).

et al., 2007).

The case described below illustrates an atypical situation, since with only four months of treatment using alignment and leveling wires (0.14 and 0.16), a severe root resorption was detected. This situation led the orthodontist to stop the orthodontic treatment. Fortunately, the case had low complexity and did not involve extensive tooth movements. In such cases, the orthodontist should be aware of the systematic radiological examinations.

Fig. 1. Initial situation of the patient.

Fig. 2. Panoramic radiograph.

Fig. 3. (a, b). Alignament using wire 0.14.

Fig. 2. Panoramic radiograph.

Fig. 3. (a, b). Alignament using wire 0.14.

Fig. 4. (a, b). Periapical radiographs showing root resorption of superior incisors.

Fig. 5. (a, b). Final aspect of treatment.

Fig. 6. Final panoramic radiograph.

### **6. Conclusions**

While science provides no consistent evidence for the precise identification of the orthodontic patient that will develop root resorption, orthodontists should keep in mind the various indicators known and promote systematic radiographic to monitor their patients. Individualize the diagnosis and treatment plan could mean the difference between the success and failure of orthodontic treatment.

#### **7. Acknowledgments**

The authors thank the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for financial support to carry out this research.

#### **8. References**


While science provides no consistent evidence for the precise identification of the orthodontic patient that will develop root resorption, orthodontists should keep in mind the various indicators known and promote systematic radiographic to monitor their patients. Individualize the diagnosis and treatment plan could mean the difference between the

The authors thank the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

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## *Edited by Farid Bourzgui*

The book reflects the ideas of nineteen academic and research experts from different countries. The different sections of this book deal with epidemiological and preventive concepts, a demystification of cranio-mandibular dysfunction, clinical considerations and risk assessment of orthodontic treatment. It provides an overview of the stateof-the-art, outlines the experts' knowledge and their efforts to provide readers with quality content explaining new directions and emerging trends in Orthodontics. The book should be of great value to both orthodontic practitioners and to students in orthodontics, who will find learning resources in connection with their fields of study. This will help them acquire valid knowledge and excellent clinical skills.

Orthodontics - Basic Aspects and Clinical Considerations

Orthodontics

Basic Aspects and Clinical Considerations

*Edited by Farid Bourzgui*

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