**2. Cost-Benefit Analysis (CBA)/ Cost-Effectiveness Analysis (CEA)**

Cost-benefit analysis (CBA) or Cost-effectiveness analysis (CEA) requires quantifiable input data; both methods are accounting techniques that have been applied to medical decisionmaking. Using Standard CEA, benefits are expressed either directly or indirectly in terms of "quality of life" improvement, and costs are expressed in monetary values and in morbidity and mortality. Using CBA, benefits and costs are all converted into monetary equivalents.[4] The CBA is also defined as a systematic process for calculating and comparing benefits and costs of a project or decision i.e. exposure of impacted tooth and ALTA correction versus alternative treatment modalities. Results must be treated with caution, making it difficult to make robust claims about the comparative cost-effectiveness of either treatment plan.

Systemic conditions or metabolic disturbances may be related to multiple impacted teeth. To achieve optimum results, an interdisciplinary teamwork is needed between the orthodontist, oral surgeon, prosthodontist and possibly some other specialties. The patient shown in Figure 1 an active social person, had several impactions in both jaws but was seeking a swift procedure to get his anterior teeth. The facial profile, esthetic smile, and time spent for each appointment in a nonprofit dental center were also among his concerns. It seems that the selected option for the patient had more benefit gain in comparison to cost (time, pain, inconveniences, and risks and...etc.).

In the first step clinicians should make a decision from the CBA/CEA perspective to select the best option appropriate for the individual looking for treatment of the impacted tooth/teeth.

#### **2.1. Early intervention for impaction prevention**

Space deficiency has been mentioned as the first etiologic factor for a palatal impaction. Many other contributing factors are associated with a palatal impaction such as over-retention of the primary canines, abnormal position of the tooth bud, disturbances in tooth eruption, localized pathologic lesions, abnormal sequence of eruption, missing lateral incisors or abnormal form of the lateral incisor roots (e.g. dilacerations), presence of an alveolar cleft, supernumerary tooth, and idiopathic factors.[5]

Crowding, thick soft tissue, supernumerary tooth/teeth, and tipped tooth/teeth situations are considered as barriers to eruption. During the regular orthodontic examination of a patient (Figure 2) an impaction was discovered on panoramic radiography suspected to be an abnormal position of the tooth bud but proximity of developing root of tooth 14 and crown of #13 (FDI Two-Digit Notation- ISO 3950) in addition to their abnormal route are the major In first step clinicians should make a decision from CBA/CEA perspective to select the best option appropriate for the individual looking for treatment of the impacted tooth/teeth. As mentioned earlier, cost is not only money and other aspects of the cost including the time, disturbances, risks, and… should be taken into account. Orthodontic Considerations in Surgical Interventions for Impacted Teeth http://dx.doi.org/10.5772/59143 71

Figure 1. Cost versus benefit appraisal for the above patient were considered according to the duration of the treatment versus time needed to receive anterior implants and reliability of this option. Multiple impacted teeth were extracted and after placement of allografts-based bone graft substitute, four dental implant were inserted. Patient continued his treatment and implant were used as anchorage for extruding mandibular impacted teeth. **Figure 1.** Cost versus benefit appraisal for the above patient was considered according to the duration of the treatment versus time needed to receive anterior implants and reliability of this option. Multiple impacted teeth were extracted and after placement of allograft-based bone graft substitute, four dental implants were inserted. The patient continued his treatment and the implants were used as anchorage for extruding mandibular impacted teeth.

concerns. It was postulated that rapid developing root with differentiating cells of the dental papilla plus vascular pressure toward malposed erupting crown of tooth 13 had caused both teeth to deviate from their normal route. After extraction of the upper right first primary molar, the pressure was relieved. By using a banded expander and extraction it seems that more space was provided for erupting teeth and the impacted canine is getting more vertical relative to the initial radiograph. Early intervention for impaction prevention Space deficiency has been mentioned as the first etiologic factor for palatal impaction. Many other contributing factors are associated with palatal impaction such as over-retention of the primary canines, abnormal position of the tooth bud, disturbances in tooth eruption, localized pathologic lesions, abnormal sequence of eruption, missing lateral incisors or abnormal form of the lateral incisor roots (e.g. dilacerations), presence of an alveolar cleft, supernumerary tooth, and idiopathic factors.(5) Crowding, Thick soft tissue, Supernumerary tooth/teeth, and tipped tooth/teeth situations are considered as barriers to eruption. During the regular orthodontic examination (patient K.E.-Figure 2) an impaction condition was discovered in panoramic

radiograph suspected to abnormal position of the tooth bud but proximity of developing root of tooth 14 and crown of #13 (FDI

#### **2.2. Difficulty index as a tool for expression of the "Cost"** Two-Digit Notation- ISO 3950) in addition to their abnormal route are the major concerns. It was postulated that rapid developing root with differentiating cells of dental papilla plus vascular pressure toward malposed erupting crown of tooth 13 had

**4.** Selection of the appropriate (effective) biomechanical approach

**5.** Alignment/ Leveling Torque/Angulation (ALTA) corrections

**2. Cost-Benefit Analysis (CBA)/ Cost-Effectiveness Analysis (CEA)**

make robust claims about the comparative cost-effectiveness of either treatment plan.

Systemic conditions or metabolic disturbances may be related to multiple impacted teeth. To achieve optimum results, an interdisciplinary teamwork is needed between the orthodontist, oral surgeon, prosthodontist and possibly some other specialties. The patient shown in Figure 1 an active social person, had several impactions in both jaws but was seeking a swift procedure to get his anterior teeth. The facial profile, esthetic smile, and time spent for each appointment in a nonprofit dental center were also among his concerns. It seems that the selected option for the patient had more benefit gain in comparison to cost (time, pain, inconveniences, and risks

In the first step clinicians should make a decision from the CBA/CEA perspective to select the best option appropriate for the individual looking for treatment of the impacted tooth/teeth.

Space deficiency has been mentioned as the first etiologic factor for a palatal impaction. Many other contributing factors are associated with a palatal impaction such as over-retention of the primary canines, abnormal position of the tooth bud, disturbances in tooth eruption, localized pathologic lesions, abnormal sequence of eruption, missing lateral incisors or abnormal form of the lateral incisor roots (e.g. dilacerations), presence of an alveolar cleft, supernumerary

Crowding, thick soft tissue, supernumerary tooth/teeth, and tipped tooth/teeth situations are considered as barriers to eruption. During the regular orthodontic examination of a patient (Figure 2) an impaction was discovered on panoramic radiography suspected to be an abnormal position of the tooth bud but proximity of developing root of tooth 14 and crown of #13 (FDI Two-Digit Notation- ISO 3950) in addition to their abnormal route are the major

Cost-benefit analysis (CBA) or Cost-effectiveness analysis (CEA) requires quantifiable input data; both methods are accounting techniques that have been applied to medical decisionmaking. Using Standard CEA, benefits are expressed either directly or indirectly in terms of "quality of life" improvement, and costs are expressed in monetary values and in morbidity and mortality. Using CBA, benefits and costs are all converted into monetary equivalents.[4] The CBA is also defined as a systematic process for calculating and comparing benefits and costs of a project or decision i.e. exposure of impacted tooth and ALTA correction versus alternative treatment modalities. Results must be treated with caution, making it difficult to

**a.** Anchorage preparation (Direct vs. Indirect)

70 A Textbook of Advanced Oral and Maxillofacial Surgery Volume 2

**b.** Force application

and...etc.).

**2.1. Early intervention for impaction prevention**

tooth, and idiopathic factors.[5]

The canine is the second most commonly impacted tooth (after the third molar), with the rate of maxillary canine impaction ranging from approximately 1% to 3% [6] and incidence of approximately 20% in orthodontic clinics. Should you ALTA correction of tooth at the expense of extra time and money or extract the impacted tooth, saving time and orthodontic payments for the patient but perhaps at the expense of esthetics and long-term function.

When treating impacted teeth, duration of treatment or chairtime, success rate or risks, and complcations (root resorption of impacted or adjacent teeth, ankylosis,..) can be converted to to initial radiograph.

 

caused both teeth deviated from their normal route. After extraction of upper right first primary molar, the pressure would be relieved presumably. By using a banded expander and extraction of tooth #54, it seems that more space is provided for erupting teeth and 54 has less pressure on 13, tooth 54 started to erupt faster and impacted canine is getting more vertical position relative

Figure 2. Impacted canine has angulated towards the horizontal (Top-right) and made the management more challenging and difficult. Impacted tooth 13 has tipped toward a better vertical position (Bottom left to bottom right) in other words Alpha (α) angle is decreased after banded expander installed and tooth 54 (D) was extracted (α1>α2). (Bottom right is the only picture 9 month after intervention) **Figure 2.** Impacted canine has angulated towards the horizontal (Top-right) and made the management more challeng‐ ing and difficult. Impacted tooth 13 has tipped toward a better vertical position (bottom left to bottom right) in other words Alpha (α) angle is decreased after banded expander installed and tooth 54 (D) was extracted (α1>α2).

a single score that would be compared to the benefits. However, sensitivity and specificity of these scores or methods are uncertain and questionable. Many variables have role in determi‐ nation of difficulty for impaction cases including age (over 25 requires longer time), distance of impacted tooth from occlusal plane, mesiodistal location of the crown, angulation of the tooth, transverse relationship of the crown to the midline, location of the impacted tooth cusp/ incisal tip and its relationship to the adjacent teeth (lateral incisor in canine impaction cases), apex position, and transposition with adjacent teeth (lateral incisor and first premolar in canine impaction cases).[7] Angular measurements on lateral cephalometry are Omega (ω) angle and Delta (δ) angle and linear measurement is d2 (Distance to Occlisal Plane) (Figure 3). Angular measurements in panoramic views are the canine inclination (C.I.) to midline or Alpha (α) angle and its inclination to the lateral incisor (or first premolar) or Beta (β) angle (Figure 4 second row). Mesiodistal position of the canine cusp tip in relation to adjacent lateral and central incisors on panoramic radiographs is called "Zone" and numbers 1 to 5 are assigned to its position as it gets closer to the midline (Figure 4-third row).[6] Inclination of the canine Difficulty index as a tool for expression of the "Cost" The canine is the second most commonly impacted tooth (after the third molar), with the rate of maxillary canine impaction ranging from approximately 1% to 3% (6) and incidence of approximately 20% in orthodontic clinics. Should you ALTA correction of tooth at the expense of extra time and money or extract the impacted tooth, saving time and orthodontic payments for the patient but perhaps at the expense of esthetics and long-term function. When treating impacted teeth, duration of treatment or chairtime, success rate or risks, and complcations (root resorption of impacted or adjacent teeth, ankylosis,..) can be converted to a single score that would be compared to the benefits. However,

in the horizontal plane or the degree of mesial orientation of the canine is analyzed by measuring the Gamma (γ) angle between projection of long axis of the canine and the midline of the maxilla in axial CBCT slice of maxilla (Figure 4-bottom left) mesiodistal location of the crown, angulation of the tooth, transverse relationship of the crown to the midline, location of the impacted tooth cusp/incisal tip and its relationship to the adjacent teeth (lateral incisor in canine impaction cases), apex position, and transposition with adjacent teeth (lateral incisor and first premolar in canine impaction cases).(7) Angular measurements on lateral cephalometry are Omega (ω) angle and Delta (δ) angle and linear measurement is d2 (Distance to Occlisal Plane) (Figure 3). Angular measurements in panoramic views are the canine inclination (C.I.) to midline or Alpha (α) angle and its inclination to

of difficulty for impaction cases including age (over 25 requires longer time), distance of impacted tooth from occlusal plane,

In quantitative terms, the larger the relative risk, the more likely the association is causal. When studying causative factors, it is very important to analyze the strength of the association in addition to the significance. More advanvce canine development, a more medial position of the canice cusp, considering the zones [1-5], and mesial inclination of the canine to midline exceeding 25° (α angle) are powerful factors.[8] the lateral incisor (or first premolar) or Beta (β) angle (Figure 4- second row). Mesiodistal position of the canine cusp tip in relation to adjacent lateral and central incisors on panoramic radiographs is called "Zone" and numbers 1 to 5 are assigned to its position as it gets closer to the midline (Figure 4-third row).(6) Inclination of the canine in the horizontal plane or the degree of mesial orientation of the canine is analyzed by measuring the Gamma (γ) angle between projection of long axis of the canine and the midline of the maxilla in axial CBCT slice of maxilla (Figure 4-bottom left) In quantitative terms, the larger the relative risk, the more likely the association is causal. When studying causative factors, it is very important to analyze the strength of the association in addition to the significance. More advanvce canine development, a more medial position of the canice cusp, considering the zones (1-5), and mesial inclination of the canine to midline exceeding

25° (α angle) are powerful factors.(8)

Figure 3. Angular measurements or inclinations of the canine in the sagittal plane are Omega (ω) angle and Delta (δ) angle (path of eruption) and linear measurement is d2 (Distance to Occlisal Plane). **Figure 3.** Angular measurements or inclinations of the canine in the sagittal plane are Omega (ω) angle and Delta (δ) angle (path of eruption) and linear measurement is d2 (Distance to Occlisal Plane).

a single score that would be compared to the benefits. However, sensitivity and specificity of these scores or methods are uncertain and questionable. Many variables have role in determi‐ nation of difficulty for impaction cases including age (over 25 requires longer time), distance of impacted tooth from occlusal plane, mesiodistal location of the crown, angulation of the tooth, transverse relationship of the crown to the midline, location of the impacted tooth cusp/ incisal tip and its relationship to the adjacent teeth (lateral incisor in canine impaction cases), apex position, and transposition with adjacent teeth (lateral incisor and first premolar in canine impaction cases).[7] Angular measurements on lateral cephalometry are Omega (ω) angle and Delta (δ) angle and linear measurement is d2 (Distance to Occlisal Plane) (Figure 3). Angular measurements in panoramic views are the canine inclination (C.I.) to midline or Alpha (α) angle and its inclination to the lateral incisor (or first premolar) or Beta (β) angle (Figure 4 second row). Mesiodistal position of the canine cusp tip in relation to adjacent lateral and central incisors on panoramic radiographs is called "Zone" and numbers 1 to 5 are assigned to its position as it gets closer to the midline (Figure 4-third row).[6] Inclination of the canine

The canine is the second most commonly impacted tooth (after the third molar), with the rate of maxillary canine impaction ranging from approximately 1% to 3% (6) and incidence of approximately 20% in orthodontic clinics. Should you ALTA correction of tooth at the expense of extra time and money or extract the impacted tooth, saving time and orthodontic payments

When treating impacted teeth, duration of treatment or chairtime, success rate or risks, and complcations (root resorption of impacted or adjacent teeth, ankylosis,..) can be converted to a single score that would be compared to the benefits. However,

Figure 2. Impacted canine has angulated towards the horizontal (Top-right) and made the management more challenging and difficult. Impacted tooth 13 has tipped toward a better vertical position (Bottom left to bottom right) in other words Alpha (α) angle is decreased after banded expander installed and tooth 54 (D) was extracted (α1>α2). (Bottom right is the only picture 9

words Alpha (α) angle is decreased after banded expander installed and tooth 54 (D) was extracted (α1>α2).

**Figure 2.** Impacted canine has angulated towards the horizontal (Top-right) and made the management more challeng‐ ing and difficult. Impacted tooth 13 has tipped toward a better vertical position (bottom left to bottom right) in other

<sup>α</sup>1 Angle <sup>α</sup>2 Angle

caused both teeth deviated from their normal route. After extraction of upper right first primary molar, the pressure would be relieved presumably. By using a banded expander and extraction of tooth #54, it seems that more space is provided for erupting teeth and 54 has less pressure on 13, tooth 54 started to erupt faster and impacted canine is getting more vertical position relative

month after intervention)

Difficulty index as a tool for expression of the "Cost"

72 A Textbook of Advanced Oral and Maxillofacial Surgery Volume 2

for the patient but perhaps at the expense of esthetics and long-term function.

to initial radiograph.

 

> Regression analysis indicated that horizontal position, age of patient, vertical height and bucco-palatal position, in descending order of importance, are the factors which determine the difficulty of canine alignment.(9) Sector location and angulation of the unerupted tooth have been analyzed previously as predictors of canine eruption after deciduous extraction. Additionally, sector location has been studied as an indicator of eventual impaction, resulting in good Regression analysis indicated that horizontal position, age of patient, vertical height and bucco-palatal position, in descending order of importance, are the factors which determine the difficulty of canine alignment.[9]

> predictive success (Figure 5).(10) Different indices provide useful treatment planning aid for the management of impacted Sector location and angulation of the unerupted tooth have been analyzed previously as predictors of canine eruption after deciduous extraction. Additionally, sector location has been studied as an indicator of eventual impaction, resulting in good predictive success (Figure 5). [10] Different indices provide useful treatment planning aid for the management of impacted

impactions (the KPG index).(11)

maxillary canines like treatment difficulty index (TDI) [9] and 3D cone beam CT based classification system for canine impactions (the KPG index).[11]

maxillary canines like treatment difficulty index (TDI) (9) and 3D cone beam CT based classification system for canine

Figure 4. Angular measurements in panoramic views are the canine inclination to midline or Alpha (α) angle and its inclination to the lateral incisor or Beta (β) angle (second row). Mesiodistal position of the canine cusp tip in relation to adjacent lateral and central incisors on panoramic radiographs is called "Zone" (third row). Inclination of the canine in the horizontal plane or the **Figure 4.** Angular measurements in panoramic views are the canine inclination to midline or Alpha (α) angle and its inclination to the lateral incisor or Beta (β) angle (second row). Mesiodistal position of the canine cusp tip in relation to adjacent lateral and central incisors on panoramic radiographs is called "Zone" (third row). Inclination of the canine in the horizontal plane or the degree of mesial orientation of the canine is analyzed by measuring the Gamma (γ) angle between projection of long axis of the canine and the midline of the maxilla (bottom left).

degree of mesial orientation of the canine is analyzed by measuring the Gamma (γ) angle between projection of long axis of the Orthodontic Considerations in Surgical Interventions for Impacted Teeth http://dx.doi.org/10.5772/59143 75

Figure 5. Sector I represents area distal to line tangent to distal heights of contour of lateral incisor crown and root. Sector II is mesial to sector I, but distal to bisector of lateral incisor's long axis. Sector III is mesial to sector II, but distal to mesial heights of contour of lateral incisor crown and root. Sector IV includes all areas mesial to sector III (3 red line- Top right). The most superior point of the condyle was selected as a landmark, a bicondylar line was then drawn and used as a constructed horizontal reference line. The measurement was taken of the mesial angle formed by using the constructed horizontal and the long axis of the unerupted tooth (Top right). **Figure 5.** Sector I represents area distal to line tangent to distal heights of contour of lateral incisor crown and root. Sector II is mesial to sector I, but distal to bisector of lateral incisor's long axis. Sector III is mesial to sector II, but distal to mesial heights of contour of lateral incisor crown and root. Sector IV includes all areas mesial to sector III (3 red line-Top right). The most superior point of the condyle was selected as a landmark; a bicondylar line was then drawn and used as a constructed horizontal reference line. The measurement was taken of the mesial angle formed by using the constructed horizontal and the long axis of the unerupted tooth (Top right).

### **3. Space preparation/Barrier removal**

canine and the midline of the maxilla (bottom left).

maxillary canines like treatment difficulty index (TDI) [9] and 3D cone beam CT based

maxillary canines like treatment difficulty index (TDI) (9) and 3D cone beam CT based classification system for canine

classification system for canine impactions (the KPG index).[11]

74 A Textbook of Advanced Oral and Maxillofacial Surgery Volume 2

impactions (the KPG index).(11)

α Angle

γ (Gamma)Angle

β Angle

Zones 5 4 3 2 1

between projection of long axis of the canine and the midline of the maxilla (bottom left).

Figure 4. Angular measurements in panoramic views are the canine inclination to midline or Alpha (α) angle and its inclination to the lateral incisor or Beta (β) angle (second row). Mesiodistal position of the canine cusp tip in relation to adjacent lateral and central incisors on panoramic radiographs is called "Zone" (third row). Inclination of the canine in the horizontal plane or the

**Figure 4.** Angular measurements in panoramic views are the canine inclination to midline or Alpha (α) angle and its inclination to the lateral incisor or Beta (β) angle (second row). Mesiodistal position of the canine cusp tip in relation to adjacent lateral and central incisors on panoramic radiographs is called "Zone" (third row). Inclination of the canine in the horizontal plane or the degree of mesial orientation of the canine is analyzed by measuring the Gamma (γ) angle

2‐ Space preparation/Barrier removal Space is needed (space available) for bringing teeth (teeth materials) into the dental arch. Many mechanisms exist for creating the adequate space including Stripping mesial or distal enamel of the teeth (proximal) with condition of existing Bolton discrepancies between upper and lower dentition, Extraction of premolars, incisors with condition of Bolton ratio considerations, or decayed teeth, Derotation or Uprighting of the posterior teeth after extractions or in the missing teeth conditions, Proclination of anterior teeth, Distalization of the posterior teeth, Orthopedic (Maxilla) or Orthodontic Expansion of dental arches. Space is needed (space available) for bringing teeth (teeth materials) into the dental arch. Many mechanisms exist for creating the adequate space including Stripping mesial or distal enamel of the teeth (proximal) with condition of existing Bolton discrepancies between upper and lower dentition, Extraction of premolars, incisors with condition of Bolton ratio considerations, or decayed teeth, Derotation or Uprighting of the posterior teeth after extractions or in the missing teeth conditions, proclination of anterior teeth, distalization of the posterior teeth, Orthopedic (Maxilla) or Orthodontic Expansion of dental arches.

Constricted arches, dental irregularities, proclinations of teeth relative to jaw bases or patient profile, deep bites and open bites with tight contacts between the teeth should be considered as space deficiency or crowding. Reproximation or proximal stripping produces up to 3.5 mm of space and 1 mm of expansion in the posterior part of maxilla is capable to produce 0.7 mm increase in arch perimeter that can be used for crowding resolution.

Upper dental arch expansion and lower dental arch uprighting (from lingual side to buccal side) produce space for bringing the impacted teeth to the dental arch. After full bonding of the arches, by incremental increase in wire diameter plus changes in cross sections (from round to rectangular) and material (from NiTi to Stainless Steel); dental arches begin to get adapted to final wire shape and size from its lingually collapsed cases to the consequent expanded arch.

Maxillary expansion can be skeletal or orthopedic if it is conducted in appropriate time i.e. before fusion of palatal suture. For maxillary expansion, banded expander (with Hyrax screw and acrylic free palate), banded+bonded (occlusal acrylic coverage) expander, and banded +palatal acrylic (Haas type) expander can be used for both dental and skeletal expansions.

In addition to space regaining in dental arches, physical barriers as supernumerary teeth, odontomas, or other pathologic lesions that inhibits tooth eruption; should be removed. Apart from hard tissue lesions, soft tissue fibrotic hyperplasia or thick fibrotic gingiva can prevent regular tooth eruption and they can be treated surgically or by laser beam.
