**4. Selection of the method for eruption of impacted tooth (Closed versus Open)**

Method of exposure is very important to be practical for the surgeon, to be useful for appli‐ cation of biomechanical forces for the orthodontist, and to be beneficial for the patient. Benefits for the patient consist of several immediate and future outcomes; including periodontal health, esthetics, and stability of treatment. Facio-lingual and vertical position of the impacted teeth are very important in determining an appropriate approach for exposure. Buccally/Labially impacted teeth can be accessed after apically positioned flap or closed eruption technique. Excisional uncovering or gingivectomy necessitates special conditions including superficial position of tooth (vertically and facio-lingually), and adequate width of keratinized gingiva. An example of inappropriate surgical approach for uncovering the impacted central is conducting the procedure apical to the mucogingival junction and removing the keratinized gingiva (Figure 6).

Apically positioned flap (Open) or closed eruption technique is an aid for maintenance of the biologic width. The biological width is comprised of epithelial attachment and connective tissue attachment (both dimensions added) coronal to the crest of the alveolar bone. It should be planned to preserve an adequate apico-coronal height of keratinized gingiva (2-3 mm), especially in the presence of thin gingival biotype (transparency of the periodontal probe through gingival margin). In some cases impacted teeth are superficial and coronal or near mucogingival junction, in these circumstances, an apically positioned flap or open approach

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

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

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)

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

3‐ Selection of the method for eruption of impacted tooth (Closed

Method of exposure is very important to be practical for the surgeon, to be useful for application of biomechanical forces for the orthodontist, and to be beneficial for the patient. Benefits for the patient consists several immediate and future outcomes; including periodontal health, esthetics, and stability of treatment. Facio-lingual and vertical position of the impacted teeth are very important in determining an appropriate approach for exposure. Buccally/Labially impacted teeth can be accessed after apically positioned flap or closed eruption technique. Excisional uncovering or gingivectomy necessitates special conditions including superficial position of tooth (vertically and facio-lingually), and adequate width of keratinized gingiva. An example of inappropriate surgical approach for uncovering the impacted central is conducting the procedure apical to mucogingival junction

expander, and banded+palatal acrylic (Haas type) expander can be used for both dental and skeletal expansions.

arch perimeter that can be used for crowding resolution.

versus Open)

and removing the keratinized gingiva. (Figure 6)

shape and size from its lingually collapsed cases to the consequent expanded arch.

gingiva can prevent regular tooth eruption and they can be treated surgically or by laser beam.

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

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

**4. Selection of the method for eruption of impacted tooth (Closed versus**

Method of exposure is very important to be practical for the surgeon, to be useful for appli‐ cation of biomechanical forces for the orthodontist, and to be beneficial for the patient. Benefits for the patient consist of several immediate and future outcomes; including periodontal health, esthetics, and stability of treatment. Facio-lingual and vertical position of the impacted teeth are very important in determining an appropriate approach for exposure. Buccally/Labially impacted teeth can be accessed after apically positioned flap or closed eruption technique. Excisional uncovering or gingivectomy necessitates special conditions including superficial position of tooth (vertically and facio-lingually), and adequate width of keratinized gingiva. An example of inappropriate surgical approach for uncovering the impacted central is conducting the procedure apical to the mucogingival junction and removing the keratinized

Apically positioned flap (Open) or closed eruption technique is an aid for maintenance of the biologic width. The biological width is comprised of epithelial attachment and connective tissue attachment (both dimensions added) coronal to the crest of the alveolar bone. It should be planned to preserve an adequate apico-coronal height of keratinized gingiva (2-3 mm), especially in the presence of thin gingival biotype (transparency of the periodontal probe through gingival margin). In some cases impacted teeth are superficial and coronal or near mucogingival junction, in these circumstances, an apically positioned flap or open approach

regular tooth eruption and they can be treated surgically or by laser beam.

**Open)**

gingiva (Figure 6).

increase in arch perimeter that can be used for crowding resolution.

76 A Textbook of Advanced Oral and Maxillofacial Surgery Volume 2

Figure 6. An inappropriate order to expose the impacted left central incisor. Incorrect technique is independent of tools i.e. laser beam or scalpel; a required width of attached gingiva (necessary for periodontal health) has been removed to create a buttonhole window (Left-clinical) as an unaccepted procedure with a bonded attachment. On the first right slice of CBCT, an odontoma-like malformations is obvious but has been neglected during the surgical intervention (red arrow). **Figure 6.** An inappropriate way to expose the impacted left central incisor. Incorrect technique is independent of tools i.e. laser beam or scalpel; a required width of attached gingiva (necessary for periodontal health) has been removed to create a buttonhole window (Left) as an unaccepted procedure with a bonded attachment. On the first right slice of CBCT, an odontoma-like malformation is obvious but has been neglected during the surgical intervention (red arrow).

is indicated but the author suggests minimum apical repositioning of the flap equal to the amount needed for bonding of an orthodontic bracket in proper position for avoiding future apical migration of the gingival margin. Uneven gingival contours can be corrected by cosmetic periodontal plastic surgery (laser, scalpel, or radiosurgery) if adequate soft tissue exist. Uncontrolled tipping toward labial/buccal can produce gingival/bone recession plus a long clinical crown that should be avoided. Apically positioned flap (Open) or closed eruption technique is an aid for maintenance of the biologic width. The biological width is comprised of epithelial attachment and connective tissue attachment (both dimensions added) coronal to the crest of the

When impacted teeth need a facial (labial or buccal) approach, and the position of tooth is deep, closed eruption is an option. In the aforementioned situation, an apically positioned flap will not be stable and rebound of soft tissue may occur in addition to unwanted exposed parts of the bone that should be covered by a flap (Figure 7).

During tooth exposure, care should be given to protect root surface, for example; by avoiding the usage of sharp or rotary instrument if possible because bone and the unerupted tooth are color matched and any damage to the root leads to periodontal ligament breakdown, increased risk of ankylosis, and increased risk for future bone and gingival recession (deleterious effects to periodontal health and esthetics). Thin layers of bone can be removed by periosteal elevator or similar instruments e.g. curette to reach the coronal part of the tooth (Figure 7).

Soft tissue covering the hard palate is called masticatory mucosa and it consists of keratinized stratified squamous epithelium. Since the palate is covered with keratinized mucosa or attached gingiva, problems with alveolar mucosa are not part of this operational area. If the bulge of an impacted canine is obvious from the palatal aspect, the cuspid tooth should be located superficially and accessible after soft tissue removal plus removal of covering bone. The patient shown in Figure 8, had no canine bulge on the left side on facial aspect (top rowleft and center slides) but it was seen on the palatal aspect clinically (top row-right slide) and also in CBCT (bottom- left and center). Uncovering the tooth and bonding through a small window can be hectic using a scalpel a palatal flap may help in achievement an isolated and dry environment for the bonding and open or close eruption technique. Again sufficient bone removal is recommended without damage to the tooth root because PDL is the interface for tooth movement and the enamel of the crown has no potential for participating in bone remodeling and consequent tooth movement. Absolute anchorage was used for eruption of reach coronal part of tooth (Figure 7).

alveolar bone. It should be planned to preserve an adequate apico-coronal height of keratinized gingiva (2-3 mm), especially in the presence of thin gingival biotype (transparency of the periodontal probe through gingival margin). In some cases impacted teeth are superficial and coronal or near mucogingival junction, in these circumstances, an apically positioned flap or open approach is indicated but author suggest minimum apical repositioning of the flap that equals the amount needed for bonding of orthodontic bracket in proper position for avoiding future apical migration of gingival margin. Uneven gingival contours can be corrected by cosmetic periodontal plastic surgery (laser, scalpel, or radiosurgery) if adequate soft tissue exist. Uncontrolled

When impacted teeth may have facial (labial or buccal) approach, and the position of tooth is deep; best technique is closed eruption. In the afore mentioned situation, an apically positioned flap will not be stable and rebound of soft tissue may happen

During the tooth exposure, care should be given to protect root surface, for example; by avoiding the usage of sharp or rotary instrument if possible because bone and unerupted tooth are color matched and any damage to root leads to periodontal ligament breakdown, increased risk of ankylosis, and increased risk for future bone and gingival recession (deleterious effects to periodontal health and esthetics). Thin layers of bone can be removed by periosteal elevator or similar instruments e.g. curette to

tipping toward labial/buccal can produce gingival/bone recession plus a long clinical crown that should be avoided.

(not reintrusion of tooth) in addition to unwanted exposed parts of the bone that should be covered by flap (Figure 7).

Figure 7. Upper right central incisor is positioned horizontally. Apically positioned flap is not indicated in the present situation and ordered closed eruption surgical approach. Thin overlying bone can be removed with periosteal elevator instead of rotary instrument (burs) and bonding performed in isolated dry environment (top row). After wound healing, tooth 11 can be pulled toward dental arch by means of absolute anchorage (Mini-screws) or after bonding upper dental arch (continuous wire). In the present condition, orthodontic attachment was bonded in lingual fossa of tooth 11 and ligature wire was placed out of flap for biomechanical extrusive forces (Bottom row). **Figure 7.** Upper right central incisor is positioned horizontally. An apically positioned flap is not indicated in the present situation and a closed eruption surgical approach may be used. Thin overlying bone can be removed with a periosteal elevator instead of rotary instrument (burs) and bonding performed in an isolated dry environment (top row). After wound healing, tooth 11 can be pulled towards the dental arch by means of absolute anchorage (miniscrews) or after bonding upper dental arch (continuous wire). In this case, an orthodontic attachment was bonded in the lingual fossa of tooth 11 and ligature wire was placed out of the flap for biomechanical extrusive forces (bottom row).

tooth #23 by means of Seifi Twin Screws (STS) for protecting other teeth from early unwanted orthodontic forces (Figure 8). Soft tissue covering hard palate is called masticatory mucosa and it consists of keratinized stratified squamous epithelium. Since

palate is covered with keratinized mucosa or attached gingiva, problems with alveolar mucosa are not applied to this part of operational area. If the bulge of impacted canine is obvious from palatal aspect, cuspid tooth should be located superficial and

has not potential for participating in bone remodeling and consequent tooth movement. Absolute anchorage was used for eruption

Figure 8. Patient G.H. with an impacted tooth #23, underwent a surgical uncovering of palatal left canine (mirror image after surgery-bottom right). An absolute anchorage by combination of two miniscrew and a cantilever helical loop (Seifi Twin screws/STS) was used for forced eruption or extrusion of impacted canine without exerting unwanted orthodontic force to the adjacent teeth. Miniscrews were covered by composites for better performance of spring and sustained stability. **Figure 8.** Patient with an impacted tooth #23 underwent a surgical uncovering of a palatal left canine (mirror image after surgery-bottom right). An absolute anchorage by combination of two miniscrews and a cantilever helical loop (Seifi Twin Screws/STS) was used for forced eruption or extrusion of impacted canine without exerting unwanted or‐ thodontic force to the adjacent teeth. Miniscrews were covered by composites for better performance of springs and sustained stability.

4‐ Selection of the appropriate (efficient) biomechanical approach

After selection of proper approach to reach the impacted tooth, an appropriate biomechanical approach should be selected. A proper biomechanic system is capable of protecting periodontium and avoiding any unwanted tooth movement or root damage of

 In contrast to dental implants, orthodontic miniscrews are loaded immediately, and most authors suggest the use of light forces early on.(12) Only a few studies, mostly on animals, have dealt with the investigation of tissue reaction to immediate loading of miniscrew implants. Miniscrew implants can be immediate loaded (there is no need for a waiting period for osseointegration, in contrast to orthodontic implants), reducing the total treatment time. There is no need for complicated clinical and laboratory procedures (i.e., fabrication of acrylic splints by taking imprints with additional implant copying systems to accurately transfer

Direct anchorage screws are useful when prognosis of the eruption (impacted tooth) is questionable. If the impacted tooth is ankylosed, by applying force from a continuous arch, dental arch could be deflected toward ankylosed tooth (sometimes creating open bites) but an absolute anchorage could be a valuable tool to determine the sensitive stage of tooth eruption without endangering the adjacent anchored teeth (Figure 8). Direct anchorage can be used for anterior retraction in protrusion cases or non-extraction treatment of the Class III malocclusions (retraction of lower anterior sextant) and cases who has midline shift toward previous extraction sites (Figure 9). Protraction of upper dentition is possible by using miniscrews in anterior part of facial portion or palatal part. Better results in protraction of upper dentition can be expected by using miniscrews in combination with miniplates. In some situations transpalatal arch (TPA) is used for eruption of impacted teeth as a direct anchorage unit that its resistance to displacement depends on the number of teeth and the root surface area of them (Figure 10). Following force application, some mobility or movement of teeth will be noticeable and in X-ray examination, disappearance of lamina dura plus widening of PDL will be evident; these are sequel of force dispersion in the dental anchorage units. In maximum anchorage cases (Group A), mesial movement of posterior teeth (protraction) should be less than 25% of extraction site, in moderate anchorage

a‐ Anchorage preparation (Direct Vs Indirect)

the implant position to cast models) to facilitate safe and precise implant insertion.(13)

the adjacent teeth.
