Orthodontics for Orthognathic Surgery

CHAPTER 55

Orthodontics for Orthognathic Surgery Larry M. Wolf Larry olfor ord, d, DMD Eber Eb er L. L. St Stev evao ao,, DD DDS, S, Ph PhD D C. Mo Moody ody Al Alexa exande nderr, DDS, MS Joao Jo ao Robert Robertoo Goncalve Goncalves, s, DDS, PhD

Moderate to severe occlusal discrepancies thetic listening from the first appointment and dentofacial deformities in late adoles- and throughout the treatment will build cents and adults usually require combined trust, impr improve ove comm communica unication tion,, and help orthodontic treatment and orthognathic provide a quality end result for all parties surgery sur gery to to obtain obtain optima optimal, l, sta stable ble,, fun funcc- inv involv olved. ed. Comp Comprehe rehensiv nsivee anal analysis ysis of the tional, and esthetic esthetic results. results. The basic goals goals patient and the complete orthodontic of orthodontics and orthognathic surgery recor records ds (cephalo (cephalograms, grams, pantomo pantomograms, grams, are to (1) satisfy the patients’ patients’ concerns, (2) phot photograp ographs, hs, dent dental al models) models) are imporestablish optimal functional outcomes, tant for diagnosis and development of the and (3) provide provide good esthetic esthetic results. To pres presurgica urgicall orthodontic orthodontic goals. goals. Alth Although ough accomplish this the orthodontist and the detailed analysis analysis of the patient’s patient’s facial and oral and maxillofacial (OMF) surgeon jaw structures from a clinical and radimust be able to correctly diagnose existing ographic perspective are vitally important, dental and skeletal deformities, establish the focus of this chapter chapter will be the the teeth an appropriate appropriate treatment treatment plan, and prop- and orthodontic considerations in prepaerly execute the recommended treatment. ration for orthogna orthognathic thic surgery surgery.. Other The orthodo orthodontis ntistt is limited, limited, to a great great important factors in in diagnosis, diagnosis, treatment extent, exten t, by growth, growth, and although although the orthoortho- plan planning, ning, and outc outcomes omes,, such as patie patient nt dontist dont ist can move teet teeth h and, to some some conc concerns, erns, psyc psychoso hosocial cial facto factors, rs, masti masticato cato-degree, degr ee, the alveo alveolar lar bone, bone, he or she she does ry dysf dysfuncti unction, on, airwa airwayy prob problems, lems, speec speech h not have any appreciable effect on the basal dif difficu ficulti lties, es, te tempo mporom romand andibu ibular lar joint bone of the jaws. The orthodontist’ orthodontist’ss role is (TMJ) pathol pathologies, ogies, and compre comprehensiv hensivee to align the teeth relative to the maxillary orthognathic surgery work-up are disand mandibular jaws. jaws. The OMF surgeon is cussed elsewhere in this book. responsible for surgically repositioning the The normal values provided in this jaw(s) and associated structures. chapter are not absolutes for every patient It is very important to listen to and bec becaus ausee of ind indivi ividua duall size, size, mor morpho pholog logic ic understand the patients patients concerns. concerns. Empa- varia variances nces,, and racial racial and ethnic ethnic differdiffer-

ences. They are provided as a guide to to help the clinician evaluate his or her patient. Establishing an all-inclusive diagnosis is paramount to developing a comprehen comprehen-sive treatm treatment ent plan. plan. The orthodo orthodontist ntist must determine the orthodontic goals based on the pretreatmen pretreatmentt findings and on the projecte projected d treatment treatment outco outcome. me. This chapter will first present orthodontic diagnostic information, followed by orthodonorthodontic treatment considerations.

Clinical and Dental Model Diagnosis From an orthodontic standpoint, in evaluating the occlusion and dental factors, the clinical and dental model analyses correlated with the cephalometric analysis provide the most information for diagnosis and and treatment treatment plannin planning. g. There are 12 basic evaluations that are helpful for these determinations. 1. Arch Arch len lengt gth: h: Th This is asse assessm ssmen entt corr correelates the mesiod mesiodistal istal widths of the teeth relative relative to the amount of alveolar bone available and aids in identifying the the prese presence nce of of cro crowdi wding ng or

1112

Part 8: Orthognathic Surgery

55-1 Arch length assessment correlates the mesiodistal widths widths of the teeth relative to the amount of alveolar bone bone available and aids in identifying the presence presence of crowding or spacing. The curved wire illustrates ideal cuspid and incisor tip position relative to the basal bone. FIGURE

spacing. This helps determ spacing. determine ine if teeth need to be extracted extracted or or if spaces need need to be either created or closed (Figure 55-1). Clinical and dental model assessment correlated to cephalometric analysis will aid in determining arch length requirements. Generally Class II patients will tend to have more crowding in the mandibular arch and less in the maxillary arch, arch, where whereas as Class III patients patients may have spacing in the mandibular

arch but a tendency for crowding in the maxillary arch. 2. Too ooth th-s -siz izee an anal alys ysis is:: Th This is an anal alys ysis is relates rela tes the the mesiodist mesiodistal al width width of the maxillary teeth compared with the mandibular mandi bular teeth teeth.. A tooth-si tooth-size ze discrepancy (TSD) causes incompatibility of the dental dental align alignment ment and and can occur in the anterior anterior teeth, premolars, and molars. molars. Appr Approxi oximate mately ly 40% of patients with dentofacial deformities will have an anterior TSD affecting the anterior six six teeth of the maxillary maxillary and mandibular arches (the mandibular arch is commonly too large compared with the maxillary arch), arch), usually due to small small maxillary maxillary lateral incisors. In such cases proper tooth alignment with all spaces closed often precludes the establi establishme shment nt of a good Class Class I cuspid-molar relationship with treatment me nt.. In Inst stea ead, d, a Cla Class ss II en end-o d-on n cuspid-molar occlusal relationship may result. result. Occasionally the maxillary anterior six teeth may be too large for the mandibular mandibular anterior anterior teeth, creating an excessive anterior overjet when in a Class I cuspid relationship. relationship. Determination of a TSD pretreatmen pretreatmentt will provide the opportunity to correct the TSD during the presurgical orthodon-

tic phase of trea treatmen tment. t. Expla Explainin iningg to to the pat patien ient, t, bef befor oree trea treatme tment, nt, tha thatt small maxillary lateral incisors may need restorative bonding to maximize the quality esthetic and functional outcom out comee is importan important, t, so that that the patient is aware aware from the onset of the time and financial commitment necessary essa ry for treatme treatment. nt. The norma normall mesiodista mesio distall widths widths of each of the perpermanent teeth are recorded in Tables 55-1 and 55-2. Variations from the norm may create difficulties in the teeth fitting properly. Bolto Bo lton n’s analy analysis sis is a meth method od to to correlat corr elatee the widths of the maxillary maxillary and mandibular anterior six teeth. Needle-point calipers can be used to measure measu re each indivi individual dual tooth, tooth, and successive holes punched into a tablet for each of the anterior anterior six teeth teeth for each arch. Then a measurement measurement from from the first to last holes will give the summation mat ion of mes mesiod iodist istal al width widthss of the anterior six teeth for each arch (Figures 55-2 and 55-3). The summation of the mesio mesiodista distall widths widths of the maxmaxillary anterior six teeth measured at the contac contactt level, level, divid divided ed into into the combined combi ned width width of of the mandi mandibular bular anterior six teeth, yields a value called

Table 55-1 55-1 Maxi Maxillary llary Mesiodi Mesiodistal stal Teeth Teeth Diamet Diameters ers

Males Females

Central Incisor*

Lateral Incisor*

Cuspids*

First Bicuspids*

Second Bicuspids*

8.9 (0.59) 8.7 (0.57)

6.9 (0.64) 6.8 (0.64)

8.0 (0.42) 7.5 (0.36)

6.8 (0.47) 6.6 (0.46)

6.7 (0.37) 6.5 (0.46)

First Molars*

Second Molars*

10.6 (0.56) 10.2 (0.58)

9.5 (0.71) 8.8 (0.73)

Adapted from Moyers RE et al. 2 *Measurements in mm (SD).

Table 55-2 55-2

Males Females

Mandibular Mandi bular Mesiod Mesiodistal istal Teeth Teeth Diamet Diameters ers

Central Incisor*

Lateral Incisor*

Cuspids*

First Bicuspids*

Second Bicuspids*

First Molars*

Second Molars*

5.5 (0.32) 5.5 (0.34)

6.0 (0.37) 5.9 (0.34)

7.0 (0.40) 6.6 (0.34)

6.9 (0.63) 6.8 (0.70)

7.2 (0.47) 7.1 (0.46)

10.7 (0.60) 10.3 (0.74)

10.0 (0.67) 9.5 (0.59)

Adapted from Moyers RE et al. 2 *Measurements in mm (SD).

Orthodontics for Orthognathic Surgery

Bolton’s ’s analysis analysis.. Need Needle-poin le-point t 55-2 Bolton calipers are used to measure each tooth at a contact-point level to aid in tooth-size analysis. FIGURE

the intermaxillary (Bolton’s) index. The average index (percentage) is 77.5 ± 3. 3.5. 5.1 A simple conversion conversion of this factor would be to measure the width of the mandibular anterior six teeth and then multipl multiplyy that sum by 1.3. 1.3. This results in a calculated ideal maxillary arch width. width. The differe difference nce between between the calculated and the actual maxillary arch width values determines the TSD (see Figure 55-3). This evaluation is very helpful in determining presurgical orthodontic and surgical goals. TSDs can also occur in the premolar and molar areas (normally the same maxillary and mandibular teeth are similar in size) where the mandibular teeth may be significantly larger than the maxillary teeth. The Bolton’s analysis is not perfect and functions only as a guide in assessing the tooth-size compatibility of the anterior anterior teeth teeth because because it does does not take into consideration the labiolingual olin gual thickn thickness ess of the inciso incisors, rs, the axial incli inclinati nation on of the teet teeth, h, or the thickness and prominence of the marginall ridges gina ridges.. A thin thin labio labiolin lingua guall dimension dimen sion of of the maxill maxillary ary incisors incisors may compensate compensate for small TSDs, but thicker than normal dimensions or prominent marginal ridges may preclude a Class I cuspid relationship

3. Incis Incisor or angu angulat lation ion:: Th This is ref refers ers to the the angula ang ulatio tion n of the max maxill illary ary and and mandibular incisors relative to their respectiv respe ctivee basal basal bones. bones. The dental dental models are correlated to the cephalometric analysis and the ideal axial inclination inclinati on of the incisors incisors determined determined (Figure 55-4). The incisor angulation analysis contributes to the determination of whether extractions extractions are are necessary, spaces need to be created created or eliminated ina ted,, an and d what what mechan mechanics ics are are required to align and level the arches or segments segments of the arches. arches. The key is to get the incisors in proper position and angulation over basal bone.

55-3 Bolton’ Bolton’ss analysis. Successive holes holes are punched into a tablet for each of the anterior six teeth for each arch. Then measuring from the first hole to the last hole will give the summation of the mesiodistal mesiodistal widths widths of the anterior anterior six teeth in each arch. arch. Mul Multiplyin tiplyingg the summation summation of the mandibular anterior six teeth (LA) by 1.3 y ields the calculated arch width for the maxillary anterior six teeth (UA). Subtracting the actual maxmaxillary anterior arch width from the calculated width yields the tooth-size discrepancy. discrepancy. FIGURE

4. Arch Arch wid width th ana analys lysis: is: Thi Thiss refe refers rs to the evaluation of the intra-arch intra-arch transverse widths between the maxillary and mandibular arches. arches. The average average maxillary and mandibular arch widths for adults are listed in Tables 55-3 and 55-4 (data from Uni Universi versity ty of Michi Michigan gan 2 Caucasian study). These averages are only guides and do not account for

even though the Bolton’s index is normal. An accurate dental dental model orthoorthodontic wax set-up may achieve a more accurate assessment.

55-4 Cephalometric analysis. Norm analysis. Normal al maxillary maxillary depth angle is 90˚ ± 3˚ and mandibul mandibular ar depth is 88˚ 88˚ ± 3˚. Norm Normal al occlus occlusal al plane angulation angulation is 8˚ ± 4˚. Normal maxillary incisor angulation to the nasion point A (NA) (NA) line is 22˚ ± 2˚ with the labial labial surface of the incisor being 4 mm ± 2 mm anterior to the NA NA line line.. No Norma rmall mandi mandibul bular ar incisor angulation to the nasion pointt B (NB) line poin line is 20˚ ± 2˚ with the labia labiall surface surface of of the incisor incisor being 4 mm ± 2 mm anterior to the NB line. FIGURE

90 88 22

8

4

4

20

1113

1114


patient size, size, or racial or or ethnic differences. Howev However, er, from a practical standpoint a good way to analyze the arch width is to relate the models to the occlusal position that is to be achieved with the surgical correction and then assess the transverse relationshi relationship. p. For examp ex ample, le, if a patie patient nt has a Clas Classs II II occlusion, occlus ion, positio position n the the models models in a Class I cuspid-molar relation and evaluate the transverse width relationship. Likewise, Like wise, a patient patient with with a Class Class III III occlusion is evaluated by positioning the models into a Class I cuspid-molar relationship. relationsh ip. When a Class Class II relationrelationship is shifted to a Class I relationship, the maxilla may be narrow and require expansion.In expansion. In some cases it may be indicated to evaluate the transverse relationship by placing the models into a Class II molar position position to determine determine if a Class I cuspid and Class II molar relationship (this would require maxillary bicuspid extractions) would be best for that particular patient; this may be benbeneficial when there is significant crowding in the maxillary arch and no crowding in the mandibular arch. arch. Transverse discrepancies will influence the presurgical orthodontics and dictate the surgical procedures required.

5. Curve Curve of Sp Spee ee:: Th This is eval evalua uate tess the the vert vertiical position position of the anterior anterior teeth comcompared with the poster posterior ior teeth. teeth. This assessment can be determined by placing the occlusion occlusion of the maxillary maxillary dental model on on a flat plane; plane; the incisors incisors should be about 1 mm above the flat plane (Figure 55-5A). 55-5A). Pl Plac acin ingg the the occlusio occl usion n of the mandib mandibular ular denta dentall model on a flat plane should see the mandibular incisors elevated 1 mm abovee the midbuccal abov midbuccal teeth. teeth. A signifisignificant accentua accentuated ted curve of of Spee in the the maxilla is usually associated with an anterior open bite and a reverse curve associated with an anterior deep bite. An accentu accentuated ated curve curve of Spee in the mandible (Figure 55-5B) is commonly associated with an anterior deep bite and a reverse curve associated with an open bite. bite. Ac Accen centuat tuated ed or reverse reverse curves of Spee will will influence influence whether whether the curve in each arch requires correction, tio n, and ifif so, whe whethe therr the corr correct ection ion will be achieved achieved by orthodontics, orthodontics, with or without extractions, opening spaces, or by surgical intervention. 6. Cuspi Cuspid-m d-mola olarr pos positi ition on:: Th This is ide identi nti-fies the angle classification and dental interre interrelatio lationships nships.. It is usuall usually y

A

B 55-5 A , This maxilla maxillary ry arch demondemonstrates an an increased curve of Spee. B , An accen accen-tuated tuat ed (increas (increased) ed) curve curve of Spee is seen in the mandibular arch. FIGURE

preferable to have a Class I cuspidmolar relationship as an outcome result; howeve however, r, a Class II molar relationship tion ship is accep acceptable table.. A Class Class III molar relationship is less desirable because the mandibular first molar functions against the maxillary second bicuspid, but it may be indicated indicated in some cases.

Tabl ablee 55-3 Ma Maxil xillary lary Arch Arch Wi Width dth*

Males Females

Cuspids†

First Bicuspids†

Second Bicuspids†

First Molars†

Second Molars†

32.3 (1.7) 31.2 (2.45)

36.7 (2.0) 34.6 (3.2)

41.5 (2.5) 39.3 (2.2)

47.1 (2.8) 44.3 (2.3)

52.3 (3.4) 49.3 (2.8)

Cuspids†

First Bicuspids†

Second Bicuspids†

First Molars†

Second Molars†

24.8 (1.3) 23.1 (2.0)

32.8 (1.5) 31.8 (1.4)

37.6 (2.3) 36.8 (1.3)

43.0 (2.7) 41.7 (2.3)

49.0 (2.3) 47.2 (2.1)

Adapted from Moyers RE et al. 2 *All measurements at centroid. †Measurements in mm (SD).

Tabl ablee 55-4 Ma Mandi ndibul bular ar Arch Arch Widt Width* h*

Males Females

Adapted from Moyers RE et al. 2 *All measurements at centroid. † Measurements in mm (SD).


7. Too ooth th arc arch h symme symmetry try:: Th This is com compar pares es the left to right side symmetry within each arch. arch. There may may be a significant significant asymmetry asymmet ry within the the arch, such as a cuspid on one side being more anteriorly positioned in the arch than the cuspid on the opposite side (Figure 55-6). This problem often occurs with a unilateral unilat eral missin missingg tooth. tooth. Also Also,, vertica verticall asymmetries can occur with individual teeth, tee th, sect section ionss of the dentoa dentoalv lveol eolus, us, or the entire dental dental arches, creating a cant in the transverse transverse occlusal occlusal plane. plane. Correctingg these types of rectin of condi conditions tions may may require special orthodontic mechanics, unilateral extraction or opening-up space, spac e, asym asymmetr metric ic ext extract raction ions, s, and and/or /or surgical procedures. 8. Curve Curve of of Wi Wilso lson n (bucca (buccall tooth tooth tippi tipping) ng):: This evaluates the mediolateral position of the occlusa occlusall surfaces surfaces of the maxilla maxillary ry (Figure 55-7) and mandibular posterior teeth.If teeth. If the occlusal surfaces of the maxillary or mandibular posterior teeth are tipped too far buccally, buccally, it may be difficult to achieve a proper occlusal interdigitation relations relationship. hip. In the presence presence of a transverse maxillary maxillary deficiency deficiency with preexisting preexist ing increased increased curve of Wils Wilson on and posterior posterior crossbites, crossbites, it is very difficult, cul t, if no nott imp imposs ossibl ible, e, to co corre rrect ct th thee problem orthodontically orthodontically,, orthopedi orthopedicalcally,, or even with surgically assisted ly assisted rapid

Tooth arch symmetry. This model demonstrates that the cuspid on one side of the arch is significantly more anteriorly positioned in the arch compared with the cuspid on the opposite side. FIGURE 55-6

palatal expansio expansion n (SARPE). (SARPE). The curve of Wilso Wilson n will usually get much worse worse with these mechanics. mechanics. In these types of cases surgical expansion by multiple maxillary osteotomies may be indicated to decrease decrease the curve of Wils Wilson. on. When the mandibular posterior teeth are are tipped tipped buccally, buccally, it is often often related to macroglossia or habitual tongue tong ue posturi posturing. ng. Orthodo Orthodontic ntic lingual tippingg of the posterior tippin posterior teeth teeth is very very difficult when macroglossia is present and will likely be unstable. A reduction glossectomy may be indicated before orthodontics in order to permit a more stable orthodontic result. 9. Mis issi sing ng,, br bro oken do down wn,, or rest restor ored ed teeth:: These must teeth must be identified identified since since they may influence treatment design. If a tooth is nonrestorable and requires extraction, extract ion, it must be determ determined ined if the extraction space requires orthodontic closure or the space maintained for later dental reco reconstructi nstruction. on. In some some cases it may be helpful to maintain the condemned tooth to improve stability during surgical surgical alignmen alignmentt of the jaws jaws or segments segments thereo thereof, f, with remov removal al postsurg post surgery ery.. Cr Crown ownss on previ previousl ously y restored teeth may need to be redone post-orthodontics and -orthognathic surgery, since the crown crown anatomy may need to be changed for proper occlusion with the new dental relationships. Determination of salvageable teeth and restorative requirements are integral components in the planning and treatment of patien patients. ts.

1115

Curvee of Wi Wilson. lson. This evalu evaluates ates 55-7 Curv the mediolateral mediolateral position of the occlusal surfaces surfaces of the maxillary and mandibular mandibular posterior teeth. teeth. FIGURE

tic forces (Figure 55-8), fa fail ilur uree of a tooth to erupt, submerged or incomincomplete tooth eruption (Figure 55-9), or lack of erupt eruption ion of of a tooth tooth comp compare ared d with adjacent teeth and alveolar bone growth. The most sensitive sensitive diagnostic diagnostic test is percussion, percussion, where the ankylosed ankylosed tooth too th has a high, high, clea clear, r, soli solid d metallic metallic sound.. A normal sound normal tooth tooth has a dull sound, being protected protected by the the PDL. PDL. However Howe ver,, an erupted erupted tooth tooth with an an impacted tooth directly against it will also have a solid sound to percussion. Normal multirooted teeth present a more solid sound than single-rooted teet te eth. h. Th Ther erefo efore re,, per percus cussi sion on te testi sting ng should be compared with similar teeth (ie, test bicuspi bicuspids ds against against bicuspids, bicuspids, molars against molars, molars, using both sides of the arch). arch). An ankylose ankylosed d tooth tooth lacks lacks

10.. Anky 10 Ankylo lose sed d te teet eth: h: If un undi diag agno nose sed, d, ankylosed teeth can have devastating effects on the presurgical orthodontics. tic s. Toot ooth h ankyl ankylosi osis, s, the fusi fusion on of of alveolar bone and cementum, cementum, results from damage to the periodontal ligament (PDL). FIGURE 55-8 This dental model shows a An ankylosed tooth may be identi- palatally displaced displaced tooth, unrespons unresponsive ive to orthofied by failure to move with orthodon- dontic mechanics, indicating probable ankylosis. ankylosis.

1116


55-9 This pantomogram demonstrates incomplete eruption of a primary tooth without a permanent successor, successor, indicating ankylosis. ankylosis. FIGURE

mobility. Over 90% of mobility. of ankylo ankylosed sed teeth teeth are deciduous; deciduous; most often often the second second molar followed by the first molar. 3 Ankylosed primary teeth are not susceptible to resorption by the follicle of the underlying permanent tooth and may result in its impaction.3 Ankylosed teeth can cause significant problems with jaw growth and development. Early ankylosis ankylosis results in noneruption or partial eruption, resulting in incomplete development of the alveolar process.4 Permanent teeth may be displaced from normal eruption pathways with resulting loss of alveolar alve olar bone bone height. height. The failure failure of an ankylosed tooth to erupt may allow adjacent teeth to drift and permit super-erupt super -eruption ion of of the tooth tooth in the the opposing arch. Ankylosed teeth do not respond to orthodontic forces and can create significant orthodontic problems when malaligned and tied into the orthodontic arch wire (Figure 55-10).5 The ankylosed tooth functions as an anchor and in active uncontrolled orthodontics, orthod ontics, will move adjacent adjacent teeth to align with with its position, position, with subsesubsequent developm development ent of an occlusal occlusal and possibly facial deformity.

11. Perio Periodon dontal tal evalu evaluati ation: on: Th This is is very importa imp ortant, nt, sin since ce preexis preexistin tingg peri peri-odontal pathologies could be exacerbated during orthodontic and orthognathic surgical treatments.6 Factors that can adversely affect the health and outcome of the periodontal periodontal tissues as well as the orthodontics and orthognathic surgery include smoking, excessi exc essive ve consumptio consumption n of alco alcohol hol or caffeine, caffe ine, habit habitual ual pattern patternss such as as bruxism brux ism and clenching, clenching, pre preexi existin stingg connective tissue/autoimmune disease ea ses, s, di diab abeete tes, s, ma maln lnut utri riti tion on,, an and d other diseases that could affect the local tissue blood supply perfusion, and healin healing. g. Any pretr pretreatmen eatmentt of acute or chronic periodontal disease should be addressed prior to the orthodontics and and surgery. surgery. The lack of of attached gingiva around the teeth (most commonly seen in the mandibular anterior arch) can cause gingiv gin gival al ret retrac ractio tion, n, los losss of of bon bone, e, and loosen loo sening ing of of tee teeth th if ort orthod hodon ontic ticss is initiated and the mandibular incisors are tipped forward (Figure 55-11). Gingival grafting may be indicated prior to orthodontics to provide

attached gingiva so as to prevent these prob pr oble lems ms.. Go Good od comm commun unica icati tion on between betwe en the perio periodont dontist, ist, ortho orthodondontist, tis t, and OM OMF F surgeo surgeon n is of of utm utmost ost importance. Orthodontics can help prepare interdental osteotomy sites by tipping the roots roots of the adjacent adjacent teeth teeth away away from each other to increase the interosseous space between the roots. There have have been been a number number of studies demonstrating that interdental osteotomies have a minimal effect on the periodontium when they are properly performed.7–11 Having healthy stable dental tissues to work with during the orthodontics and surgery will maximize the periodontal outcome as well as the the overall outcome. The failure to recognize preexisting periodontal patholo pathology, gy, identify risk factors, poor perfo performanc rmancee of surge surgery, ry, and/ and/or or lack of attention to detail could result result in significant periodontal problems as well as other problems that could compromise the final result. 12. Tongu onguee assessment: assessment:An An enlarged enlarged tongue tongue (macroglossia) can cause dentoskeletal

A

B

This illustration depicts a partially submerged ankylosed maxillary cuspid (A) (A).. Iftie Iftied d into an active straight arch wire (B) , the adjacent teeth will be orthodontically moved toward toward the ankylosed tooth, tooth, resulting in the development of a significant malocclusion. malocclusion. FIGURE 55-10


• • • •

• FIGURE 55-11 Pe Perio riodon donta tall concern concerns. s. Th This is patient had lack lack of attach attached ed gingiva prior to initiation of orthodon orthodontics tics and was left untreated,causing severe gingival retraction retraction and loss of support support-ing bone. bone. Gingiva Gingivall grafting grafting should should have been been performed performe d prior to initiation of orthodon orthodontics. tics.

deformities, deformitie s, insta instability bility of ortho orthodont dontic ic and orthognathic surgical treatments, and create create masticatory masticatory,, speech, and airway management problems. problems. There are a number numb er of con congeni genital tal and and acquired acquired causess of true macr cause macroglos oglossia, sia, incl including uding muscu mu scula larr hype hypertr rtrop ophy hy,, gla gland ndul ular ar hyper hy perpla plasia sia,, hem hemang angiom ioma, a, lym lympha phanngioma, Down syndrome, syndrome,and and BeckwithWiedemann Wiedeman n syndrome. Acquired factors include acrome acromegaly galy,, myxe myxedema, dema, amylo am yloido idosis sis,, te terti rtiary ary syphilis syphilis,, cys cysts ts or 12 tumors, and neurologic neurologic injury. There are specific clinical and cephalometric features that may help the clinician identify the presence or absence of macroglossi macro glossia, a, altho although ugh not not all of these features are alway alwayss present. present. Specific clinical features include the following (Figure 55-12):

55-12 Ma Macrogl croglossi ossia. a. Some of of the cliniclinical features associated with macroglossia include anterior open bite, diastemata between the teeth, teeth, accentuate accen tuated d curve of of Spee maxill maxillary ary arch, arch, and reverse curve of Spee mandibular mandibular arch. FIGURE

•

• • • • • •

Reverse cur ve ve of of Wilson of of mandibular posterior teeth Acc ccen entu tuat ated ed cu curv rvee of of Sp Spee ee in th thee maxillary arch Reverse cu curv rvee of Spee in the mandibular arch Incr In crea ease sed d trans transve vers rsee widt width h of maxillary and mandibular arches Dias Di aste tema mata ta wit with h incr increa ease sed d inci inciso sorr angulation in the mandibular and/or maxillary arches

• • • •

•

Gro ross ssly ly en enla larg rged ed,, wi wide de,, br broa oad,and d,and flat tongue Open Op en bit bitee (ant (anter erio iorr or po post ster erio ior) r) Man andi dibu bula larr pr prog ogna nath this ism m Class Cl ass II IIII malo maloccl cclusi usion on wit with h or or with with-out anterior and posterior crossbite Chro Ch roni nicc pos postu turi ring ng of th thee ton tongu guee between the teeth at rest (rule out habitual habi tual posturin posturingg of a normalnormalsized tongue) Incr In crea ease sed d cur curve ve of Wil ilso son n of of ma maxxillary posterior teeth

Crenat Cren atio ions ns (s (sca call llop opin ing) g) on th thee tongue Glos Gl ossi siti tiss (due (due to to exc exces essi sive ve mo mout uth h breathing) Spee Sp eech ch art artic icul ulat atio ion n dis disor orde ders rs Asym As ymme metry try in th thee ma maxi xill llary ary or mandibular arches associated with an asymmetric tongue Diff Di ffic icul ulty ty eat eatin ingg and and swa swall llow owin ingg (severe cases) Inst In stab abil ility ity in in ortho orthodo dont ntic ic mech mechan an-ics or orthognathic surgical procedures that in normal circumstances would be stable Air irwa wayy dif diffi ficu cult ltie ies, s, su such ch as sle sleep ep apnea, apn ea, sec second ondary ary to ora orall or or oropharyngeal obstruction Drooling

Cephalometric radiographic features commonly seen with macroglossia (Figure 55-13) include include the following: • •

Ton ongu guee fill fillin ingg the the oral oral cav cavit ityy and and extruding through an anterior open bite Mand Ma ndib ibul ular ar den dento toal alve veol olar ar pro protru tru-sion or bimaxillary dentoalveolar protrusion Macroglossia. Macrogl ossia. Cephalo Cephalo-metric analysis shows mandibular dentoalveolar protrusion and overangulation of the mandibular mandibular anterior anterior teeth. teeth. The tongue fills the oral cavity ( dotted dotted line)) and the oropharyngeal airway is line decreased (normal distance from posterior aspect of tongue to posterior phapharyngeal wall is 11 mm). FIGURE 55-13

90 84

•

•

1117

22 14

3

5

9

35

1118 • • • • • •


Overan Over angu gula lati tion on of of th thee maxi maxill llar aryy and and mandibular anterior teeth Dispr Di sprop opor ortio tiona nate tely ly exce excess ssiv ivee mandibu mandibu-lar growth Decr De crea ease sed d oro oroph phary aryng ngea eall air airwa way y Inc ncre reas ased ed go goni nial al an angl glee Incr In crea ease sed d mand mandib ibul ular ar pla plane ne an angle gle Incre In crease ased d mand mandibu ibular lar oc occlu clusal sal pla plane ne angle

Most open bite cases are not related to macroglos macr oglossia. sia. In fact it has has been estabestablished that closing open bites with orthognathic surgery will allow a normal tongue (which is a very adaptable organ) to readjustt to the altered adjus altered volum volumee of the oral oral cavity cavi ty,, with lit little tle tend tendenc encyy towar toward d 13,14 relapse. However How ever,, if true macro macroglossi glossiaa is present with the open bite, bite, then instability of the orthodontics orthodontics and orthognathic orthognathic surgery will likely likely occur, occur, with a tendency tendency for the the open bite to to return. return. Pseud Pseudoomacroglossia is a condition where the tongue tong ue may be normal normal in size, but it appears large relative to its anatomic interrelationships. relationshi ps. This can be created created by (1) habitu hab itual al pos postur turing ing of the to tongu ngue; e; (2) hypertrophied tonsils and adenoid tissue displacing displ acing the the tongue tongue forward forward;; (3) low low palatal palat al vault, vault, decre decreasin asingg the oral cavity cavity volume; volu me; (4) transver transverse, se, verti vertical, cal, or anteroanteroposter pos terior ior defic deficien iency cy of the maxil maxillary lary and/or mandibular arches decreasing oral cavity volum volume; e; and (5) tumors tumors that that displace the tongu tongue. e. Pseu Pseudomacr domacroglossi oglossiaa must be distinguished from true macroglossia because the methods of management are different.

Diagnostic List Before a treatment plan can be properly developed deve loped,, a diagnostic diagnostic list list of the existing existing problems is established based on patient concerns, conc erns, and clini clinical, cal, radio radiographi graphic, c, dental model, and other indicated indicated evaluations. This will include all findings relative to musculoskeletal and dental imbalances, occlusal occlu sal problems, problems, esth esthetic etic concerns, concerns, TMJ and/or myofascial myofascial pain problems, problems, missing

teeth, teet h, cr cro own wns, s, br brid idge ges, s, en endo dodo dont ntic ical ally ly treated teeth (these teeth are sometimes ankylo ank ylosed sed), ), per period iodont ontal al pro proble blems, ms, ot other her functional disorders, disorders, as well as any any other other medical factors that may affect treatment outcomes. The treatment plan is is formulated from the diagnostic problem list.

The basic presurgical orthodontic goals are as follows:

incisors. Howev However, er, these presurgical presurgical orthodonticc goals donti goals may may be differ different ent if if the occlusal plane angle is to be altered surgically.. Rem cally Removal oval of dent dental al compensatio compensations ns is helpful before surgery so that maximum skeletal ske letal correct correction ion can be achieved. achieved. An exact orthodontic orthodontic treatment treatment plan, including the specific mechanics and anchorage requirements necessary to position the teeth to satisfy the presurgical orthodontic goals, must be developed and and executed. executed.

• •

Initial Surgical Treatment Objective

Presurgical Orthodontic Goals

• • •

•

Align an Align and d posit position ion te teeth eth ov over er basa basall bone bone Avo void id exc excess essiv ivee intru intrusio sion n or or extr extrusi usion on of te teet eth h Dec eco omp mpen ensa satte te teet eth h Avo void id un unst stab able le ex expa pans nsio ion n of of th thee den den-tal arches Avo void id clas classs II II and and cla class ss III III mec mechan hanics ics (unless required for dental decompensation correction in the arches) Perf Pe rfor orm m stab stable le and and pre predi dicta ctabl blee orth orthoodontics

Relative to to the position of the maxillary and mandibular incisors,the incisors, the ideal presurgipresurgical orthodontic goals are as follows: 1. Posit Position ion the lon longg axis axis of the max maxill illary ary central incisors approximately 22˚ to the nasion point A (NA) (NA) line, with the labial surface of the incisors 4 mm anteanterior to the NA line relative to a normally positioned maxilla and normal occlusal plane angle (see Figure 55-4) 2. Po Posit sitio ion n the the long long axis axis of the man mandib dibuular central incisors 20˚ to the nasion point B (NB) line with the labial surface of the incisors 4 mm anterior anterior to that line relative to a normally positioned mandible and normal occlusal plane angle (see Figure 55-4) 3. Sat Satisf isfyy arch arch lengt length h requi requirem rement entss (crowding or spacing) We have found that using the ideal position of the maxillary maxillary and mandibular incisors to the NA and NB lines, lines, respectively (see tively (see Figure 55-4), is the most convenient and practical method to establish the presurgical orthodontic goals for the

The surgical treatment objective (STO), also known known as a predictio prediction n tracing, tracing, is a two-dimensional two-dimensio nal visual projection projection of the changes in osseous, osseous, dental, and soft soft tissues as a result result of ortho orthodont dontics ics and orthogorthognathic surgical surgical correction correction of the dentofadentofacial and occlusal deformity. deformity. The purpose of the ST STO O is is thre threefo efold: ld: (1) est establ ablish ish presurgical orthodontic orthodontic goals, (2) develop an accurate surgical objective that will achieve the best functional and esthetic result, and (3) create a facial profile profile objective which can be used as a visual aid in consultation with the patient and family member mem bers. s. A pre predic dictio tion n trac tracing ing of the anticipated presurgical orthodontic dental movementss is created by placing an acetate movement sheet on the original cephalometric tracing and retracing the teeth into the position they will be placed with the presurgical orthodontics, orthodontics, based on the goals and available mechanics (Figure 55-14A). The initial STO is then constructed with the teeth in their presurgical orthodontic final position. The STO has significant importance in two two phases phases of of trea treatment tment plan planning ning:: (1) the initial STO is prepared before treatment to determine the orthodontic and surgical goals; and (2) the final STO is preprepared after the presurgical orthodontics are completed but prior to surgery to determine the exact vertical and anteroposterior skeletal and soft tissue movements to be achieved (Figure 55-14B). The


1119

3 8 3 4

13

A

B

13

FIGURE 55-14

A , Presurgical orthodontics. The orthodontic movements are are traced on the acetate paper overlying the original lateral cephalometric cephalometric tracing with the the teeth teeth in their their pred predeterm etermined, ined, simul simulated ated position positions. s. The solid lines , are the the original original posi position tion of of the teeth. teeth. The dashed lines are the new position of the teeth following following simulated simulated extraction extraction of four first bicuspids bicuspids and orthodontic orthodontic closure closure of the spaces. B , Sur Surgical gical treatment treatment objective ( STO). STO). This is an example of a completed final STO which shows the predicted outcome of the presurgical presurgical orthodontics and the the anticipated surgical treatment. The arrows and numbers indicate the direction direction and millimeters of movement.

STO is invaluable to the orthodontist and surgeon in establishing treatment objectives and projected projected results, results, acting as as the treatment plan blueprint.

Definitive Interdisciplinary Treatment Plan The definitive treatment plan is formulated based on the patient’s patient’s concerns, clinical evalua eva luatio tion, n, rad radiog iograp raphic hic analysi analysis, s, den denta tall model evalu evaluatio ation, n, init initial ial STO STO,, and other relevant evaluations. evaluations. The general sequencsequencing of the treatment that may may be involved is described below.

Dental and Periodontal Treatment Any indicated periodontal or general dental care related to maintaining teeth or improving dental health should be performed prior to orthodontics and surgicall intervention. The objective is to surgica

maintain as many teeth as possible and stabilize stabil ize the periodonti periodontium. um. Temporary crowns and bridges should be placed where necessary for the orthodontic and surgical phases of the treatment treatment.. Perma Perma-nent crowns crowns,, inl inlays ays,, and bridges bridges should should be constructed and inserted after the surgery and orthodontics have been completed. compl eted. This gives the restorat restorative ive dentist the opportunity to provide escapement grooves grooves,, cuspid protect protection, ion, and incisal guidance for optimum function and esthetics esthetics.. Initia Initiall periodonta periodontall management may include scaling and curettage, curetta ge, eliminat eliminating ing pockets, pockets, as well well as gingival grafting to provide adequate a tt tt ac ac he he d g in in gi giv a. a. O cc cc as as io io na na llll y, y, i n patients with several missing teeth, osseointegrated implant placement prior to orthodontics and orthognathic surgery may provide anchorage for orthodontics and additional dental units

to help in repositioning the jaw structures at surgery.

Presurgical Orthodontics The orthodontist is responsible for positioning the teeth to the most desirable position over basal bone in preparation for surgery surg ery.. The develo development pment of pres prescript cription ion brackets and straight wire orthodontic techniques has helped simplify orthodontics. Most prescription prescription bracket systems are are designed to tip the cuspid roots distally, creating some space between the roots of the lateral lateral incisors and cuspids. cuspids. In cases requiring segmentalization of the maxilla, maxilla, this interdental space may be adequate through which to perform interdental osteot ost eotomi omies, es, but if ina inadeq dequa uate, te, add addit ition ional al room can be created by tipping the lateral incisor roots mesially and the cuspids more distally dist ally.. Bonde Bonded d brackets brackets are clean clean and eliminate interdental spacing problems

1120


created by circumferential bands. Bonded brackets with the currently available resins are quite adequate for orthognathic surgery proce procedures dures.. How However ever,, inaccu inaccurate rate placement of the brackets on the teeth can result in undesired rotations, rotations, vertical discrepancies crepan cies between between teeth, teeth, malali malalignment gnment of margin marginal al ridges and and labial surfaces surfaces of adjacent teeth, and unfavorable root positions. tio ns. Car Carefu efull place placemen mentt of of brac bracke kets ts is is paramount in helping to achieve highquality results. Nickel-titanium or similarly shaped memory arch wires can be advantageous for many orthognathic cases to aid in presurgical orthodontic dental alignment goals. goa ls. Ho Howev wever er,, the there re are are cases cases wher wheree shape memory wires could be detrimental, such as in an anterior anterior open bite bite with an accentuate accentuated d maxillary maxillary curve of of Spee. The use of nickelnickel-titaniu titanium m wires or any any type of straight wire in these cases can can create unstable results such as extrusion of teeth and buccal tipping of the molars as a result result of rec recipro iprocal cal forces. forces. Sta Stainle inless ss steel wires with compensating bends (Figure 55-15A) or sectional wires (Figure 55-15B) may be a better-controlled mechanical mechani cal force force in these these types of cases. The type of arch wire and how long long each is left in place is critical and must be carefully monitored by the orthodontist.

To follow are basic presurgical orthodontic factors that commonly must be addressed in preparing patients for orthognathic surgery. It is important to avoid interarch class II mechan mechanics ics (ie, (ie, class II elasti elastics, cs, gro growth wth appliances, TMJ “disk recapturing” recapturing”splints, splints, Herbst’ss appliances) unless they are specifHerbst’ ically required during the presurgical orthodontics (ie, (ie, to correct correct arch asymmeasymmetry, decompensate mandibular arch with lingually inclined mandibular incisors). Long-term class II mechanics positions the mandibular condyle downward and forward in the fossa and may allow hypertrophy (thickening) (thickening) of the TMJ bilaminar bilaminar tissues (Figure 55-16). This same situation can occur in patients with a “Sunday” “Sunday” bite. In these these situatio situations, ns, follo following wing surgical surgical mandibular mandi bular advancem advancement, ent, the bilaminar bilaminar tissue will slowly thin out over time causing a slow relapse relapse of the mandible toward toward a Class II relationship. relationship. In addition posturing the mandible forward for an extended time could result result in foreshortening foreshortening of the anterior articular disk attachments, increasin incr easingg the risk of TMJ articular articular disk disk displacement postsurgery postsurgery.. If a patient has has been treated treated with longterm class II mechanics or has a “Sunday” bite, it may be an advantage to use light light class III mechanics for a few months presurgery

55-16 Us Usee of lon long-t g-term erm cla class ss II mechanics, anterior repositioning splints, growth devices, or “Sunday “Sunday”” bite relationships relationships can can cause hypertroph hype rtrophyy of the bilaminar bilaminar tissue, positi positioning oning the condyle downward and forward in the fossa. Postsurg Pos tsurgery ery,, particu particularly larly with mand mandibular ibular advancements,, this tissue will slowly thin out, advancements and the condyles will move posteriorly in the fossa causing a shift of the mandible and and occlusion toward a Class II position. FIGURE

to eliminate the hypertrophied bilaminar tissue and to decompensate for any unstable orthodontics that may may have been created. created. If the TMJ articular disk does become displaced, it would be better to to have that occur occur before surgery because the articular disk can be surgically repositioned and stabilized with high predictability at the same time as the orthognathic surgery.15–18 Attempts to recapture a TMJ displaced disk with splint therapy prior to surgery could be detrimental to the patient relative to outcome stability and and pain. pain. In most most cases cases nonsurgic nonsurgical al “recapturi “re capturing” ng” the disk procedur procedures es have proved clinically unsuccessful.

Treatment Options for Specific Orthodontic Problems

A

B

A , Compensating steps (arrow) have been placed in the orthodontic arch wire so that the anterior teeth are aligned at an elevated level compared with the posterior teeth to eliminate extrusion or intrusion of teeth that may otherwise result result in unstable orthodontic movements. B , Secti Sectioning oning the arch wire (arrow) is another approach to aligning teeth at separate independent levels to avoid extrusion or intrusion of teeth as seen seen in this maxilla. However However,, the use of of sectional wires may decrease decrease positional control of the teeth adjacent adjacent to the ends of the cut wire. FIGURE 55-15

This section presents specific dental malrelationships relationsh ips and the orthodontic and surgical treatment options for consideration. Comprehensive Comprehe nsive assessment assessment of the patient patient and developing treatment objectives will aid in selecting the appropriate treatment.

Adjustment for Tooth-Size Discrepancy Usually TSDs occur Usually occur because of small maxillary lateral incisors, making the combined


mesiodistal width of the maxillary mesiodistal maxillary anterior six teeth too small to fit properly around the mandibular anterior six teeth, so that when the teeth are properly aligned, aligne d, an end-on end-on Class II cuspid cuspid relarelationship will result (Figure 55-17). If the Bolton’s analysis indicates a significant TSD, presurgical orthodontic adjustments can usually correct the discrepancy and aid in providing a solid Class I cuspid relationship at surgery and in the final outcom out come. e. TSD TSDss can also also occur occur in the bicuspids bicuspi ds and molars, molars, with the maxillary maxillary teeth usually being too small compared with the mandibular teeth. The following following are treatment options that can be used to correct TSDs. Slenderizing Teeth (Interproximal Tooth Size Reduction) This technique reduces the mesiodistal dimension dimension of the involved involved teeth. tee th. Sinc Sincee most TSDs involv involvee larger mandibular anterior teeth compared to the maxillary anterior anterior teeth, slenderizing the mandibular anterior teeth can address the issue (Figure 55-18). Approximately 10 to 12% of of the mesiodistal width can be safely removed from each tooth with 50% of the interpro interproximal ximal enamel enamel remainin remaining. g. Up to 3 mm of reduc reduction tion can can usually usually be safely achieved in the mandibular anterior

55-17 This patient has well-aligned and leveled teeth in each arch. Maxillary lateral lateral incisors are small creating a tooth-size discrepancy (TSD). Note that with the best possible possible fit, the patient has an end-on Class II occlusal relationship secondary to the TSD. FIGURE

A

1121

B

55-18 Mandibular anterior teeth can be slenderized using (A) diamond strip or (B) thin cylindrical diamond bur to reduce the width of the teeth at the the contact level. Spacing generated generated can then be closed with orthodontics. FIGURE

six teeth. teeth. Slen Slenderiz derizing ing the mandibul mandibular ar anterior teeth is an advantageous procedure, dur e, whe where re the the maximu maximum m width width of the incisors is toward toward the incisor incisor edge, particularly in the the presence of crowding and/or over ov eran angu gula lati tion on of of th thee mand mandibu ibula larr incis in cisor ors. s. It is is not adva advant ntage ageou ouss if the mandibular anterior teeth are decreased in angulation angula tion (lingu (lingual al inclinat inclination), ion), since closing the resultant spaces will further decrease the incisor angulation and may adversely affect esthetics esthetics and stability. This technique is not indicated when the contact points are positioned toward the gingiva, as this could result in tissue strangulation with loss of papilla and interdental interdental bone, creat creating ing signifi significant cant periodo periodontal ntal issues. In the rare case where where the maxillary maxillary teeth are too large for the mandibular teeth, the maxillary teeth can be slenderized, but this is best used used when the maxilmaxillary teeth are crowded and/or overangulated, and the individua individuall crowns crowns are wider than normal (see Table 55-1). When TSDs occurs in the bicuspid and/or and /or mola molarr area, area, sle slende nderizi rizing ng the the mandibular teeth will usually correct the problem, unless the slenderizing slenderizing will cause excessi exc essive ve retractio retraction n of the mandibu mandibular lar anterio ant eriorr teet teeth. h. If thi thiss appea appears rs to to be be a potential outcome, outcome, then careful closure closure of the spacing by loosing (slipping) posterior anchorage (using mechanics that will

move the posterior teeth forward instead of the anterior anterior teeth backward) backward) may solve the problem. problem. This approach approach may may include class II mechanics to provide forward forces on the posterior teeth or moving one tooth at a time on each side. Dental implants placed adjacent to or posterior to the molars could provide stable anchorage to aid in applying the mechanics necessary to push the posterior teeth forward. Creating Space In the Arch This can enlarge the circumferen circumference ce of the involved involved arch. Since TSDs are are often related related to small maxillary lateral incisors, opening space around the maxillary lateral incisors may be a logical approach. approach. A simple technique technique involves invo lves placement placement of coil springs between the cuspids and lateral incisors incisors and if needed between the lateral incisors and central incisors to open spaces (Figure 55-19). At the end of treatmen treatmentt the lateral incisors incisors can be built up by bonding, veneers veneers,, or crowns. crowns. This technique can also be used in the mandibular arch when the mandibular anterior teeth are too small compared to the maxillary anterior anterior teeth. In either arch arch this technique is most applicable when the teeth are decreased decreased in angulation angulation,, since opening space will increase the axial inclination nati on of the inciso incisors. rs. It may not not be indiindicated when the maxillary or mandibular incisors are overangula overangulated ted or crowded, crowded, as

1122


55-19 Placing coil springs between the maxillary cuspids and lateral incisors as well as the lateral incisors and central incisors can open up spacing around the lateral incisors to correct a toothsize discrepancy. discrepancy. Pos Post-trea t-treatment, tment, the lateral incisors can be built up by bonding, bonding, venee veneers, rs, or crowns. crowns. FIGURE

the resultant increased angulation may be unstable and cause untoward periodontal chang ch anges. es. Ho Howev wever er,, if the there re is sig signi nific fican antt crowding crowd ing or overangulation overangulation of the incisors requirin req uiringg extra extractio ction n of of bicu bicuspids spids,, durin duringg closure of the bicuspid bicuspid spacing by by retraction of of the anteri anterior or teeth, teeth, spac spacee could could be created around the lateral incisors. When maxillary incisors are already overangulated, overangulat ed, it is not feasible feasible to open spaces during the presurgical orthodontics. In this situation performing performing interdental osteotomies between the maxillary cuspids and lateral incisors will permit opening space at surgery and the incisors can also be uprighted to decrease their axial angula angulation tion.. A maximum maximum 3 mm of spacing (1.5 mm on each side) can usually be acquired with this approach. When the TSD occurs in the bicuspid or molar area, space can be opened around the maxillary bicuspids and/or molars to compensate for the tooth mass deficiency. Bonding, Bon ding, vene veneers, ers, or crowns crowns can then then be placed to eliminate the created space. Altering Axial Inclina Altering Inclination tion of Incisor Incisorss This technique can affect the labial circumfe cum fere renc ncee of th thee anter anterio iorr teeth teeth.. Increased axial inclination slightly increases the arch arch length, length, and decrease decreased d axial inclination slightly decreases it. Application of this techn technique ique would would result result in

increasing the maxillary incisors’ incisors’ angulation above normal and decreasing the mandibular mandi bular incisors incisors’’ angul angulation ation below below normal. This technique can accommodate accommodate small TSD differences, but may place place the teeth in a compromised position relative to stability and esthetics. Surgery can alter the axial inclination of the anterior anterior teeth. teeth. In the maxillary arch, arch, interdental osteotomies between the lateral inciso incisors rs and and cuspids, cuspids, and in in the mandibular arch anterior subapical osteotomies, osteotomie s, will provide a means means to alter axial inclination inclination of of the incisors. incisors. Altering Mesiodistal Mesiodistal Angulation of Maxillary Incisors Ti Tippi pping ng the the roots roots of the maxillary central incisors distally away from each other alters alters the position position of the contact cont act points, points, maki making ng the interconta intercontact ct distance on each tooth tooth slightly wider. This can only be used for small differences. However, Howeve r, it then usually usually requires requires recontouring touri ng of the dista distall aspect aspect of the inciso incisorr edges and could cause a soft tissue void between the mesial contact points and gingival tissues (“the black triangle”), triangle”), creating much concern concern for the patient. This technique is rarely r arely recommended. Extraction of Mandi Extraction Mandibular bular Incisor Incisor This technique should only be used for large TSDs (5 mm or more) more) and only if there is significant crowding and/or significant overa ov erang ngula ulati tion on of th thee mandib mandibul ular ar incisors. Removing a mandibular incisor usually creates a significant space (the width widt h of the too tooth) th),, and clo closur suree of tha thatt space may significantly decrease the axial inclination of the mandibular incisors. In addition it may cause a decreased transverse width between the cuspids resulting in relative relative narrowing narrowing of both maxillary and mandibular mandibular arches. arches. Extrac Extraction tion of a mandibular incisor incisor may produce an increa inc reased sed over overjet jet.. If the pat patien ientt has has a good maxillary arch but mandibular crowding and overangulation, overangulation, large TSD, and an end-on or slight Class III anterior

occlusion, the single single mandibular incisor extraction may be the treatment of choice. An alternative alternative in cases with large tooth-size discrepancies would be to slenderize the mandibular anterior teeth and create spacing around the maxillary lateral incisors. A surgical alternative for a large TSD, when the teeth are not crowded and have good axial angulation, angulation, would be to to extract the mandibular incisor and perform a vertical ostectomy through the mandible at the extraction site and rotate the segments together to eliminate the extraction space (Figure 55-20). This would prevent further decreased decr eased angulat angulation ion of the incisors incisors with subsequent orthodontics but may narrow the anterior anterior aspect of the mandible.

Correct Overangulated (Proclined) and/or Crowded Maxillary Anterior Teeth Overangulated and/or crowded maxillary anterior teeth are most commonly seen in patients with maxillary deficiency (hypoplasia) (hypop lasia).. The follo following wing treatmen treatmentt methods can be used to correct this type of sit situat uation ion.. Slenderizing and Retraction This technique involves involves removal removal of tooth structure at the contact points and is applicable when there is a rare reverse TSD with the maxillary anterior teeth too large for the mandibular anterior teeth. Usually up to 3 mm of tooth structur structuree can be be safely safely removed remo ved from from the conta contact ct area area of the maxillary anterior six teeth with a margin of 50% of of ena enamel mel rema remaini ining ng at the the concontact areas. areas. How However ever,, this could could make make the maxillary incisors slightly smaller in size unless they are significantly oversized to begin with. Extraction and Retraction First or second bicuspids can be extracted dependingg on in on the the am amou ount nt of cr crow owdin ding, g, th thee anchorage anchora ge requirements, requirements, and the amount of retr retracti action on of the inci incisor sorss nec necessa essary ry..


related to bite related bite force force influe influences nces.. The amount of of crowdi crowding ng may also also influence influence which teeth to extract.

A

B 55-20 In the case case of a tooth-size tooth-size disdiscrepancy (TSD) ≥ 5 mm, in the presen presence ce of well well-aligned teeth in proper angulation, angulation, the TSD can be managed by removing a mandibular central incisor and performing a vertical midline ostectomy (A) with closure closure of that space (B) and and stabilization with a bone plate. FIGURE

Every 1 mm of inci Every incisor sor retract retraction ion will will requiree 1 mm requir mm of space on on each side of the arch. arc h. The Theref refore ore,, if the orthodo orthodonti nticc goal is to retract the maxillary incisors by 3 mm, then 6 mm of maxillary arch arch space will be required requir ed to accompli accomplish sh this. this. Extracting first bicuspids will result in greater incisor retraction, retraction, wherea whereass six multirooted posterior dental units (compared to six single-rooted anterior dental units) provide greater posterior anchorage. Extracting second bicuspids will result in less incisor retraction, retraction, wherea whereass four posterior dental units (compared to eight anterior units) provide less posterior anchorage so that the posterior teeth will move forward a greater amount compared with first first bicuspid extractions. extractions. The occlusal plane angle will also affect the posteriorr anchorage. posterio anchorage. Low occlusal occlusal plane angle cases will have greater posterior anchorage anchora ge stability stability,, even with second second bicusp bic uspid id extrac extractio tion, n, tha than n will high high occlusal plane plane angle cases. cases. High occlusal occlusal plane angle cases will have less posterior anchorage anchora ge stability, stability, even with first bicuspid extraction, extraction, than low low occlusal occlusal plane plane angle cases. These factors are probably probably

Distalizing Posterior Teeth This objective can be accomplished using pendulum-type appliances, applian ces, headge headgear ar,, class II mechan mechanics, ics, or osseointegrated implants (ie, implants posterior teri or to molars molars,, zygo zygomati maticc implants, implants, palat pal atal al impl implan ants, ts, or bucc buccal al cort cortex ex implants). implan ts). Dista Distalizing lizing maxillary maxillary posterior posterior teeth can be augmented with class II mechanics but should only be used shortterm and discontinued several months prior to surgery to minimize postsurgical skeletal relapse potential that can occur with the use of long-t long-term erm class II mechanmechanics and the subsequent adverse effects on the TMJs. Another option is to distalize one one tooth at at a time on each each side of the arch, arch, beginning with the second molars (2 teeth moved move d against 12 anchor teeth). teeth). Anot Another her feasible approach is to use osseointegrated anchors to distalize the maxillary arch, with implants placed in either the zygoma buttress tr ess,, pos poste terio riorr to to sec secon ond d mol molars ars,, or attached to the buccal cortex. The implants can be left submerged after orthodontic treatment treatm ent is completed, completed, or could require require additio addi tional nal surgery surgery for for remov removal al if not removed during the orthognathic surgery.

1123

Maxillary Expansion by Orthodontics, Orthopedics (Rapid Palatal Expansion), and Surgically Assisted Rapid Palatal Expansion These techniques will increase arch length and may allow retraction retraction of the anterio ant eriorr teeth teeth.. Ho Howev wever er,, the theyy will will also also increase the the curve of Wilson as the transverse width of the maxillary arch increases increases because the teeth will expand three times as much as the palate expands (Figure 55-22). In addition addition,, with SARPE, SARPE, the palate palate moves moves inferiorly.. The expanded arches inferiorly arches may not be as orthodontic orthodontically ally stable, stable, requi requiring ring longterm or permanent retention.

Correct Overangulated (Proclined) and/or Crowded Mandibular Anterior Teeth Overangulated and/or crowded mandibular teeth occur most often with mandibular deficiency (hypoplasia). The following following

Anterior Maxillary Segmental Osteotomies This technique permits uprighting of the anterior anterior teeth teeth but will cause the apical base of the segment to shift forward relative to the incisor edges unless teeth are extracted to reposition the incisal edges of the anterio anteriorr teeth teeth posterio posteriorly rly.. Carefu Carefull assessment assessm ent of the profile profile esthetics is necessary to determine determine if the patient patient can esthetically benefit benefit from this this change. The interinter- FIGURE 55-21 An anterior maxillary segmental dental osteotomies should be done between osteotomy can be used to upright the maxillary incisors. However However,, the dentoalveolus dentoalveolus at the apical the lateral incisors and cuspids as this offers base will rotate anteriorly anteriorly if no teeth are extractthe best control in uprighting the segments ed. Since this this may affect affect the position position of the nose nose and upper lip, careful evaluation of facial esth esthetet(Figure 55-21) and also allows opening of ics is necessary necessary to determine if this approach approach is space between the lateral incisors (up to appropriate. Dashed line represents the original 3 mm with 1.5 mm per side) that can be position position of of the anterio anteriorr maxilla, maxilla, and the the solid line represents the uprighted segment. used for correction of crowding or TSD.

1124


treatment options can be used to correct thesee types of cond thes conditio itions. ns. Slenderizing and Retraction This technique involves involves removal removal of tooth structure at the contact points and is most applicable when there is a TSD with the mandibular anterior teeth being too large for the maxillary anterior anterior teeth. Up to to 3 mm of tooth structure can be safely removed from the contact areas areas of the mandibular mandibular anterior six teeth teeth with a margin of 50% of enamel remaining at the contact areas. Subsequent retraction will decrease the axial inclination inclination of the incisors incisors providing that no major crowding is present. Extraction and Retraction First or second bicuspids can be extracted depending on the degr degree ee of angu angulati lation, on, amou amount nt of crowding, crowd ing, the anchorag anchoragee require requirements, ments, and an d the the amou amount nt of re retr trac acti tion on of th thee incisors inci sors neces necessary sary.. Ev Every ery 1 mm of inci incisor sor

retraction will require require 1 mm of space on each ea ch si side de of th thee ar arch ch.. Th Ther eref efor ore, e, if th thee orthodontic goal is to retract the mandibular inciso incisors rs by 3 mm, mm, the then n 6 mm of mandibular arch space will be required to accomplish accompli sh this. Extracting first first bicuspids bicuspids will result in greater incisor retraction, whereas six multirooted posterior dental units (compared with six single-rooted anterior dental units) provide greater posterior teri or anchorage. anchorage. Extra Extractin ctingg the seco second nd bicuspids will result in less incisor retraction, whereas four posterior posterior dental dental units (compared with eight anterior units) provide less posterior posterior anchorage, anchorage, so that the the posterior teeth will move forward a greater amount compared with first bicuspid extractions. extraction s. The occlusal occlusal plane angle will also affect affect the posterior anchorag anchorage. e. Low occlusal plane angle cases will have greater posterio post eriorr anchorage anchorage stability stability,, eve even n with second bicuspid bicuspid extraction, extraction, than will high high occlusal plane angle cases. cases. High occlusal occlusal

plane angle cases will have less posterior anchorage stability even with first bicuspid extraction extractio n than low angle cases. cases. These factors are probably related to bite force influences. enc es. The amount amount of of cro crowdin wdingg may also also influencee which influenc which teeth teeth to extract. If there is a large TSD (≥ 5 mm), the then n extracti extraction on of a mandibular incisor could be considered. Distalize Posterior Teeth The mechanics to accomplish accomplish this include include intra-arch, intra-arch, interarch,, extra arch extraoral oral,, or impla implant nt mecha mechanics. nics. Clas Classs III mechan mechanics ics (ie, (ie, elast elastics, ics, head headgear) gear) can can be used to distalize the the mandibular teeth, but may increase loading on the TMJs and could initiate TMJ problems. problems. Another option option is to distalize one tooth at a time on each side of the arch, arch, beginning with the second second molars (2 teeth moved against 12 anchor teeth). Howeve Ho wever, r, this techni technique que takes takes a lot of time. The placement of dental implants posterior posterior to the molar teeth or in the posterior buccal cortex could facilitate retraction without appreciably increasing the load to the TMJs. Anterior Mandibular Subapical Osteotomies This techn technique ique permits permits upright uprighting ing of the anterior teeth, teeth, but will cause the apical base of the segment to shift forward relative to the chin (Figure 55-23), unless teeth are extracted at the time of surgery to reposition reposition the incisal edges of the anterior teeth posteriorly posteriorly.. Bilateral Mandibular Body Osteotomies This technique will permit uprighting of the anterior teeth and forward rotation rotation of of the chin (Figure 55-24), unless teeth are extracted. Wit Without hout extraction, extraction, bilat bilateral eral body bone grafting will be required to provide bony continuity between the segments and facilitate healing. healing. This technique technique would only only be indicated indi cated if the chin is anterop anteroposte osteriorl riorly y deficient before surgery.

Maxillary expansion expansion by orthodontics, orthodontics, orthopedics, or surgically assisted assisted rapid palatal palatal expansion (SARPE) (SARPE) will cause cause an increase increase of the curve of Wilson. Even with SARPE, SARPE, the occlusal sur face will expand three times as much as as the palate will expand, thus increasing the curve of Wilson. The palate will also move inferiorly. FIGURE 55-22

Mandibular Symphysis Distraction Osteogenesis Thi Thiss tech techniq nique, ue, usu usuall ally y performed with a midline vertical osteotomy,, will allow my allow expansion expansion of the dentoalvedentoalveolus and widening widening of the mandibular arch, arch,


providing room to retract and/or align the teeth.. This is teeth is an exce excellent llent treatm treatment ent method to gain space for major arch length leng th discrepan discrepancies. cies. How However ever,, it is done as a prerequisite surgery to achieve the orthodontic goals prior to the major orthognathic surgery. Orthodontic preparation may be necessary prior to performing the midline vertical vertical osteotomy osteotomy.. The roots of the central incisors (or the adjacent teeth, wherever the osteotomy osteotomy is to be performed) must be tipped away from FIGURE 55-24 Bilateral body osteotomies can each other to make room for the interden- be used to upright the mandibular anterior chin will rotate rotate forward forward unless tal osteotomy osteotomy.. This can be accomplished accomplished teeth, but the chin teeth are are extracted extracted.. A gap created created in the by placing the the mesial aspect of the bracket mandibular body area will require grafting higher than the distal distal aspect on each of the unless teeth are extracted (first bicuspids) to central incisors. Placing a short short segment allow the mandibular anterior teeth to move decreasing the forward movestraight arch wire will then tip the roots posteriorly, thus decreasing ment of of the chin. chin. distally,, creating space distally space to safely perform perform the vertical interdental osteotomy (Figure 55-25) 5525).. If a tooth-borne tooth-borne distraction device relapse postdistraction with less expansion dental tal ar arch ch than than des desir ired. ed. Bon Boneeis used, used, orthod orthodonti onticc treatment treatment on on any of the den other teeth should not be initiated until borne devices are not affected by predisadequate adeq uate healing healing of the distractio distraction n area traction orthodontics. has occurred (approximately 4 months from fro m initiation initiation of the distractio distraction). n). Othe Otherr- Correct Underangulated (Retroclined) Maxillary Incisors wise it may result in developing dental mobility and orthodontic instability instability,, with Underangulated maxillary incisors are the teeth expanding more than the basal most commonly seen in Class II Division 2 bone. This can result result in transverse transverse dental malocclusions or with missing teeth in the arch.. The followi arch following ng approach approaches es can be used to correct correct this type of condition.

1125

result. The use of coil springs springs usually usually works works well for this this situation. situation. If the problem problem is in the lateral incisor incisor area, openin openingg space can help correct the TSD as well as increase the incisor angulation (Figure 55-26). Interarch Mechanics The use use of class III III mechanics (ie, elastics) can increase maxillary illa ry inci incisor sor ang angulat ulation ion.. Ho Howev wever er,, the class III mechanics can be detrimental by overloading the TMJs.

A

B

Correct Crowding Cr Crow owdi ding ng of th thee maxillary anterior teeth can accompany vertically verti cally incli inclined ned teet teeth. h. Ther Therefor efore, e, correcting the crowding will increase the incisor angulation.

55-23 The anterior mandibular subapical osteotomy can be used to upright the mandibular anterior teeth, teeth, causing the apical apical base of the segment to shift forward forward relative to the chin, chin, if teeth (bicuspids) (bicuspids) are not extracted extracted at the time time of surg surgery ery.. This may may or may not not be a desired outcome. outcome. A chin augmentation augmentation may be required to achieve optimal esthetics. FIGURE

Open Space In Class I and Class II patients underangulated incisors may be present because beca use of of previ previous ous extrac extraction tionss (ie, (ie, bicus bicus-pids), pids ), con congeni genitall tallyy missing missing teet teeth, h, previ previous ous trauma trau ma result resulting ing in in loss loss of tee teeth, th, or small small maxillary anterior anterior teeth (ie, (ie, small maxillary maxillary lateral incisors). incisors). Opening space in the bicuspid areas, areas, if the problem problem exists exists there, there, can correct this problem and provide additional dental units for a more complete occlusal

C Mandibular symphysis distraction osteogenesis. A , Often the the incisor roots roots are are very close together. B , Space must must be created created between the roots of teeth adjacent to the intended vertical osteotomy. C , Placing brackets on only the central incisors with the mesial aspect aspect of the brackets higher than the distal aspect on each tooth and placing a short straight wire segment, will tip the roots distally away from each each other, creating space to per form the vertical interdental osteotomy. FIGURE 55-25

1126


Interdental Osteotomies An anterior maxillary subapical osteotomy or segmentalized Le Fort I osteotomy will permit rotatio rotation n of the anterior anterior teeth to increas incr easee their angulat angulation ion.. Ho Howev wever er,, significant room must be created between the roots roots of of the adjacent adjacent teeth (lateral incisors and cuspids) at the osteotomy areas. Since bone removal removal between the teeth teet h may may be requ required ired,, ther theree is an increased increase d risk of damage to the adjacent adjacent teeth. tee th. If the max maxill illaa req requir uires es sur surgica gicall expa ex pans nsio ion, n, then th en segme se gment ntal aliz izat atio ion n between the lateral incisors and cuspids will allow the anterior segment to rotate posteriorly between the expanded posterior segments with fewer requirements for bone bone removal, removal, if require required d at all.

Correct Underangulated (Retroclined) Mandibular Incisors Underangulated mandibular incisors are more commonly seen in patients with prognathic mandibles or with missing teeth. teet h. The following following treatment treatment methods methods can be used to correct this condition. Correct Crowding Cr Crow owdi ding ng of of th thee mandibular anterior teeth often accompa-

A

nies vertically inclined teeth. Therefore Therefore,, correcting the crowding will increase the incisor angulation. Open Space In Class I and Class II patients underangulated incisors may be present prese nt because because of previo previous us extraction extractions, s, congenitally missing teeth, teeth, previous trauma resu resulti lting ng in in loss loss of of te teeth eth,, or smal smalll mandibular mandi bular teeth. teeth. In Class Class III patients patients underangulated incisors may be present due to an excessi excessive ve amount amount of alve alveolar olar bone compared compared with the size of the teeth. If bicusp bicuspids ids are missin missing, g, open opening ing space space in the bicuspid areas can correct this problem and provide additional dental units for a more more complete occlusal result. result. The use of coil springs usually works works well for for this situation (see Figure 55-26). Occasionally a mandibular incisor may be missing for various reasons. reasons. Viable options include opening appropriate space around the remaining three incisors and building up the crowns by bonding, veneers, vene ers, or crowns. crowns. This techni technique que works works best if there is a TSD that that is less than than the width widt h of the missi missing ng tooth. tooth. Ho Howev wever er,, the maxillary dental midline will be in the center cent er of of a mandi mandibular bular incis incisor or.. Ano Another ther option would be to open space in the area

B

Coil springs springs to open space. space. In some cases, cases, “retr “retroclined oclined”” incisors are are a result of of Division 2 malocclusion, crowdin malocclusion, crowding, g, missing dental units, or small small teeth. If there is no significan significantt crowding, crowding, spacing can be created created by the use of coil springs that that will tip the incisors forward. forward. A , Small maxillary maxillary lateral lateral incisors and missing mandibular bicuspids. B , The use of coiled springs springs is demonstrated demonstrated to open up interdental spaces around the maxillary lateral incisor (to correct for an anterior tooth-size discrepancy) and in the mandibular first bicuspid area (to replace a missing dental unit and increase the angulation of the anterior teeth). teeth). The spaces around around the maxillary maxillary lateral incisor incisor can be eliminated by bonding, bonding, veneer veneer,, or crown. In the mandibular arch, the space can be eliminated by surgical ostectomy versus replacement of the missing dental unit by crown-and-bridge or osseointegrated implant and crown. FIGURE 55-26

of the missing missing tooth and then replace it with a dental implant implant or bridge. This technique may work best when there is no TSD with a full-size dental replacement. Interarch Mechanics The use of class II mechanics (ie, elastics, Herbst’ Herbst’ss appliance) can increase mandibular incisor angulation. Howeve However, r, long-term class II mechanics can be detrimental to outcome stability and results, results, becau because se of the potentia potentiall untoward effects on the TMJs. Interdental Osteotomies An anterior subapical osteotomy or bilateral anterior body osteotomies will permit rotation of the anterior teeth to increase their angulation.. How tion However ever,, signi significan ficantt room room must be created crea ted between between the the roots roots of the teeth teeth adjacent adjace nt to the osteot osteotomy omy areas. areas. Since bone removal between the teeth may be required, there is an increased risk of damage to the adjacent teeth.

Correct Excess Curve Curve of Spee: Maxillary Arch This condition is most often seen with anterior open-bite situations and high occlusal plane plane facial types. Careful assessmentt of the curv men curvee of Spe Speee is impo importa rtant nt because using only orthodontic mechanics to correct this condition may not be very stable. stabl e. An increas increased ed curve of of Spee usually usually makes it difficult to get the occlusion to fit together.. The condition can be addressed together by the following treatment options. Extruding Anterior Teeth Conventional orthodontics with straight w ire techniques will tend to extrude the anterior anterior teeth, and as a byproduct will tip the molars buccally,, inc ly increa reasin singg the curve curve of Wils ilson. on. The These se dental changes may be unstable and fraught with relapse potential. Intruding Midbuccal Teeth This is a very difficult technique, technique, unless high-pull high-pull headgear or osseointegrated implants are used to provide intrusive forces. This would


require significant patient compliance and is not a commonly applied procedure. Extraction and Retraction Extraction of maxillary first or second bicuspids with retraction will usually decrease the curve of Spee, providin providingg the incisors are overanguoverangulated to begin with. Orthodonti Orthodo ntic, c, Ort Orthope hopedic, dic, or Sur Surgica gically lly Assisted Rapid Palatal Expansion with Retraction Expan Expansion sion of the maxil maxillary lary arch by any any of these techn techniques iques will increase the arch length and allow some retra re tracti ction on of the ant anteri erior or teeth teeth.. In late late adolescenc adole scencee or adultho adulthood, od, SARPE may provide better stability than the other two technique tech niques. s. Ho Howeve weverr, not notee that the curve curve of Wilson will increase because the expansion at the occlusal level compared with the palate will be a 3:1 ratio.19 Surgical Correction The maxilla can be orthodontically aligned in segments by aligning the four incisors at a different level, compared with the posterior posterior teeth, to avoid extrusion, intrusion, and buccal tipping of teet teeth. h. Placi Placing ng compensati compensating ng vertical steps between the lateral incisors and cuspids (see Figure 55-15A) will accomplish alignme alignment nt at differen differentt levels. levels. For some cases the vertical positional difference may occur between the cuspids and bicuspids, or could occur asymmetrically on one side of the arch compared compared with the other side. The step in the arch would would then be made between the appropriate teeth. Another technique to use involves cutting the arch wire into two or more segments and aligning groups of teeth in individual units (see Figure 55-15B). Ho Howe weve verr, it may be more difficult to control rotations and root root position, position, particularly of the teeth adjacent to the ends of the segmented ment ed wires, wires, comp compared ared with with using using a continuous continuo us wire with compensating vertical steps. The arch can then be leveled surgically with a three-piece maxilla performing osteotomies between the lateral

incisors and cuspids. The three-piece three-piece Le Le Fort Fo rt I osteotom osteotomyy, with inter interden dental tal osteotomies performed between the lateral inciso incisors rs and cuspids cuspids,, will permit permit repositio repo sitioning ning of the anterio anteriorr segment segment independe inde pendent nt of the posterio posteriorr segments segments (Figure 55-27). The anterior segment can be reoriented vertically and anteropo anteropostesteriorly rio rly,, and the the axial axial incl inclina inatio tion n of the incisors can be changed to correct the curve of Spee and achieve the the best interinterdigitatio digit ation n of the segments. segments.

Correct Accentuated Curve of Spee: Mandibular Arch

1127

where the teeth are are more narrow narrow,, below the norma normall cont contact act leve level. l. Ther Therefor efore, e, for every 1 mm of leve leveling ling of of the mandibu mandibular lar arch,, the mandibul arch mandibular ar incisor incisor edges edges will move forward 0.6 mm to 1 mm as the contact points align. Any crowding of the arch will further further contribut contributee to flaring flaring of the incisors. Intruding teeth teeth will decrease the anterior mandibular vertical height and must also be taken into consideration so that the anterior mandibular height is not excessively excessiv ely shortened.

Intruding Mandibular Anterior Teeth Intrusion mechanics can predictably inferiorly position mandibular anterior teeth approximately approxima tely 2 mm. Beyond 2 mm the the vertical vert ical relapse relapse approache approachess 60%. Wi With th accentua acce ntuated ted curves curves of Spee the the contact contact area of the teeth will be at a different different level

Extruding Midbuccal Teeth Extrusion of midbuccal teeth may be more more stable than intrusi intrusion on of ant anterio eriorr teeth. Ho Howevwever, this technique technique is difficult difficult to perform perform witho wit hout ut specia speciall consid considera eratio tions ns.. If th thee patient’s malocclusion has the bicuspids and first molars in in occlusion, occlusion, extrusion will be virtually virtually impossible impossible.. How However ever,, constructing a splint that will open the bite and engage only the mandibular anterior teeth and second second molars, molars, with the bicuspids and and first molars molars out of contact with the splint, splint, will permit extrusion extrusion

A

B

An accent accentuated uated curve of of Spee in the the mandibular arch most often occurs in anterior deep-bite relationships.

55-27 Surgery for correcting correcting an excessive excessive curve of Spee. A , Aligning the maxilla in segments with the incisors at an elevated level compared with the posterior teeth will permit interdental osteotomies to be performed. B , Surgical leveling leveling of the occlusal plane from a predictability and stability standpoint is superior to orthodontic means alone, particularly when no extractions are performed. FIGURE

1128


of the midbucca midbuccall teeth. teeth. Ano Anothe therr alternaalternative would be to correct the accentuated curve of of Spe Speee after after the mandib mandible le and occlusion are surgically repositioned, placing the incisors and molars into proper prop er contact, contact, and then then extrude extrude the midbuccal teeth postsurge postsurgery. ry. With this approach the molars may tip distally and the arch may widen somewhat. Interdental Osteotomies An anterior subapical osteotomy (Figure osteotomy (Figure 55-28) or bilateral anterior body osteotomies (Figure 5529) will will permit downward repositioning of the anterior anterior teeth, teeth, with very stable stable results results when the surgery surgery is properly properly performed. performed. If the anterior anterior vertical height height of the mandible mandible is excessive, excessive, then the subapical osteotom osteotomy y would be indicated since it will shorten the anterior mandibular height by the amount that the incisors are lowered. Bilateral anterior body osteotomies would be indicated when the vertical height of the anterior mandible is normal normal or less, so that the anteanterior height remains unaltered while the curve of Spee is correcte corrected. d.

Correct Reverse Curve of Spee: Maxillary Arch Reverse curves of Spee are more commonReverse commonly seen in Division 2 malocclusions and in vertical maxillary deficiencies with an anterior deep bite. bite. The maxillary maxillary incisors are commonly in a decreased axial inclination. Crowding may or may not be present. Correct Crowding or Division 2 Relations Eliminating crowding and Division 2 dental positions will tip the incisors forward, increasing the incisor axial angulation and decreasing decrea sing the rever reverse se curve curve of Spee. These movements will usually fill out the upper lip, but may decrease decrease the maxillary toot to othh-to to-l -lip ip relat relatio ionsh nship ip.. Ma Maxil xillar lary y incisors may become intruded with a straight wire technique. Extruding Midbuccal Teeth This technique is difficult difficult if the midbuccal teeth teeth are

A

55-28 Subapical osteotomy correcting an accentuated accentuated curve of Spee in the mandibular arch. A , This can be accomplished with a subapical osteotomy composed of two interdental interdental osteotomies and a subapical ostectomy to set the anterior teeth inferiorly. B , C , This is indic indicated ated when the anterior mandibular height is greater than normal, as this technique technique will shorten the the anterior ante rior mandibula mandibularr height. This same same basic technique can be used to elevate the segment to correct a reverse curve of Spee.

B

C

in occlusion with mandibular mandibular teeth. However,, the bite can be opened with a splint ever that affords contact on only the maxillary second molars and anterior anterior teeth, with the maxillary maxil lary midbuccal midbuccal teeth out of cont contact act with the the splint. splint. The midbucc midbuccal al teeth teeth (bicuspids and first molars) can then be extruded into position to improve the curvee of Spe curv Spee. e.

the teeth at different vertical levels to facilitate the surgery and minimize orthodontic relapse potential. It is usually easiest easiest and most applicable to make the osteotomies between the lateral incisors and cuspids. This may particularly be indicated when the maxilla must be repositioned anyway and maxillary expansion expansion is also required. Performing a three-piece segmented maxillary osteotomyy will then allow vertical alteration osteotom between the anterior and posterior segments to level the curve of Spee.

FIGURE

Open Spaces If th thee reve reverse rse curv curvee of Spee is related to missing teeth or TSDs, then spaces can be opened to aid in increasi incr easing ng the axial axial inclinat inclination ion of the incisors and decreasing the reverse curve of Spe Spee. e. The These se spaces spaces can can then be elimi elimi-nated nat ed by bondin bonding, g, cro crown wn and bridge bridge,, or dental implants and crowns. Interdental Osteotomies Multiple maxillary osteotomies can be performed so that the maxilla can be repositioned in segments, enabli ena bling ng leveli leveling ng of the arch. arch. Pr Presu esurgi rgical cal orthodontics should be designed to align

Correct Reverse Curve of Spee: Mandibular Arch This condition is most commonly seen in patien pat ients ts with with macrog macroglos lossia sia,, hab habitu itual al tongue ton gue postur posturing, ing, or tongu tonguee thrust, thrust, with an associated associated anterior open bite. The following techniques can be used to correct this type of cond conditio ition. n. Extruing Anterior Teeth Extrusion of anterior teeth may not be very stable long


1129

there is significant decreased angulation of the incisors, and/or the midline is signifisignificantly deviated to one side.

A

B

A , B , Bilateral mandibular mandibular body osteotomies osteotomies will permit leveling of the excessive curve of Spee without shortening shortening the vertical height of the mandible and are indicated when when the mandibular anterior dental height is normal or even slightly short vertically. vertically. This basic technique can also be used to correct a reverse reverse curve of Spee by elevating the anterior segment. FIGURE 55-29

term, and without permanent retentio retention, n, could result in re-intrusion and redevelopment of an anterior anterior open bite. bite. Intrusion of Midbuc Intrusion Midbuccal cal Teeth Teeth This is a difficult technique but may be accomplished with osseointegrated implants as anchors. anch ors. How However ever,, it is not kno known wn if this would be stable long term. Extract and Retract If the man mandib dibula ularr incisors are significantly overangulated, with wit h or withou withoutt crowdi crowding, ng, bicu bicuspid spid extractions can be performed and the incisors retracted, retracted, which will decrease the reverse rev erse curve curve of Spee Spee.. Bonding the Mandibular Anteriors This technique can be used to level the arch by building build ing up the incisors incisors,, incr increasi easing ng the crown cro wn heig height. ht. Ho Howev wever er,, car caree must must be taken not to exceed a safe crown-root ratio and/or create an esthetic compromise. Interdental Osteotomies Anterior subapical (see Figure 55-28) or anterior bilateral mandibular body osteotomies (see Figure 55-29) can be used to elevate the anterior ant erior teeth teeth.. If the anterio anteriorr mandibular mandibular height is short, then the subapical osteotoosteotomy can also be used to increase the anterior heigh heightt of the man mandib dible. le. If the ant anteri erior or

mandibularr height mandibula height is normal, normal, then the the bilateral anterior body osteotomies will permit perm it elevation elevation of of the anteri anterior or teeth teeth while maintaining the anterior height of the mandible.

Anteroposterior Arch Asymmetry Anteroposterior Asymmetr y (Maxilla or Mandible) Anteroposterior Anteropost erior arch arch asymmetry asymmetry,, when the cuspid on one one side of the arch is anterior to the cuspid on the opposite side of the arch, is fairly common in patients with dentofacial deformities. deformities. Arch asymmetries can be related to developmental abnormalities, missing teeth, or ankylosed ankylosed teeth. Dental midlines may not align with the facial midline. Extract Unilater Unilaterally ally In some cases unilateral extraction and retraction will correct the problem. problem. The decision decision must be made as to which tooth tooth to extract. Extraction of a first bicuspid bicuspid will allow allow greater greater anterior retraction compared with extracting a second second bicuspid. This extraction would only only be indicated if there were were significantt overangulation significan overangulation of the incisors, crowdin cro wding, g, and/o and/orr significa significant nt midline midline dental shift. Open Space Unilaterally This technique would be indicated if a tooth is missing,

Interarch Mechanics This technique can be effectively used by incorporating class II mechanics on one side and class III mechanics on the opposite side. Anterior cross-arch elastics can also be helpful. If only one arch arch is involved, involved, then maximizing anchorage in the other arch is very important so that an asymmetry does not develop devel op in the normal normal arch. Osse Osseoint ointeegrated implants can be used as anchors to correct asymmetry in an arch without having to use interarch mechanics. Osteotomies Osteotomie Osteotomiess can be used in the maxillary arch by segmentalization of the maxilla and advancing one side more than the other side. side. Osteotomi Osteotomies es in the mandibular arch to correct arch asymmetry can become somewhat somewhat complex. Anterior subapical osteotomies with removal of a unilateral tooth can correct some large discrepan discr epancies cies (6 to to 9 mm). Ho Howeve wever, r, the subapical osteotomy may need to be combined with ramus sagittal split osteotomies and a unilateral or bilateral body osteotomy,, with or without my without extraction, to shift the occlusion into a symmetric position. These types of of movements require a high degree deg ree of of sur surgica gicall skill, skill, but can can provide provide high-quality outcomes.

Divergence of Ro Divergence Roots ots Adjacent Adjacent to Interdental Surgical Sites When interdental osteotomies are planned it may be necessary for the orthodontist to tip the adjacent tooth roots away away from the the area of the planned planned osteotomy to prevent damage to the teeth (Figure 55-30). If the roots roots are are too too close close together, togethe r, postsurgica postsurgicall periodontal periodontal probproblems may develop with possible loss of interden inte rdental tal bone and and teeth. teeth. Cre Creatin atingg interdental space between the roots significantly nificant ly improves improves the margin of safety safety.. This can be easily achieved by selective

1130


bracket placement. placement. For the tooth tooth mesial to the osteotomy osteotomy,, the bracket is slightly slightly rotated rotate d so that that the mesial aspect aspect of the bracket is positioned slightly more gingivally compared with the distal aspect of the bracket (Figure 55-31). Conversely the distal tooth bracket is positioned so that the distal distal aspect aspect of the bracket bracket is placed slightly more gingivally compared with the the mesial mesial aspect aspect of the brack bracket. et. With a straight wire technique the roots will diverge. Postsurgically, Postsurgicall y, periapical radiography may be necessary for the orthodontist to check for rebonding the adjacent teeth brackets to ensure proper root angulation at completion completion of treatment.

Extraction Versus Nonextraction The decision to extract or not to extract can sometimes sometimes be difficul difficult. t. Ther Theree are a number of factors that that may contribute to to this determination determination.. Overangulated Anterior Teeth Excessive over-angulated anterior teeth may require extraction to set the teeth over basal bone. Howeve Ho wever, r, if the arch arch is to be expanded expanded or teeth slenderized for TSD, TSD, for example, example, then extraction may not be necessary. Crowding This is a common indicator, particularly with major crowding or

A

overangulate overangu lated d teet teeth. h. Ho Howeve wever, r, if cro crowdin wdingg is mild to to moderate, moderate, widen widening ing of the arch arch or teeth slenderizing for TSD may eliminate the need for extraction. Tooth-Size Discrepancy TSD TSDss of sign signifi ifi-cant magnitude may indicate the need for extra ex tract ctio ion, n, pa parti rticul cular arly ly if th thee TSD TSD of th thee anterior mandibular teeth is 5 mm or greater and the mandibular incisors are overangulat overa ngulated ed and/or crowde crowded, d, in which case a mandibular incisor extraction could be considered. Curve of Spee Accent Curve Accentuated uated curves of Spee in the maxillary arch usually have overangulated maxillary maxillary incisors, and reverse reverse curves of Spee in the mandibular mandibular arch usually have overangulated overangulat ed mandibular mandibular incisors. incisors. Extraction of bilat bilateral eral first first or second bicuspids bicuspids and retraction will result in leveling leveling of the arch ar ches es.. Ho Howe weve verr, ar arch ch exp expan ansi sion on,, wh when en indicated, may create create enough room room so that extractions are not necessary necessary.. Arch Asymmetries With significant anteroposterio antero posteriorr arch asymmetries, unilateral or bilateral asymmetric extractions (ie, first bicuspid on on one side and and a second bicuspid on the opposite side) may be indicated when there is coexisting crowding crowdi ng overangulated overangulated incisors, or midline shift.

B

55-30 Interdenta Interdentall osteotomies. A , Pantomogr Pantomogram am demonstrating inadequate inadequate room between the roots of the lateral lateral incisors and cuspids. Performing osteotomies osteotomies with roots in this position position could result in severe periodontal compromise compromise and possible loss of teeth. B, Adequate spaces for interdental interdental osteotomies can be created by selective bracket placement on the adjacent teeth. FIGURE

55-31 Selective bracket placement can create adequate interdental space for osteotomies. On the tooth mesial to the the osteotomy, osteotomy, slightly rotate the mesial aspect of the bracket gingivally, gingivally, and on the distal tooth, tooth, slightly rotate rotate the distal aspect of the bracket bracket gingivally gingivally.. A straight straight wire will then diverge the roots. FIGURE

Coordination Coordinat ion of Maxi Maxillary llary and Mandibular Arch Widths In some cases transverse arch width discrepancies can be corrected with stable and predictable orthodontic movements, but in other cases orthodontic correction may be very unstable and fraught with relapse. It must must be determined whether to correct width problems by orthodontics ti cs,, or orth thop oped edic ics, s, SA SARP RPE, E, or surgi surgica call expansion. expan sion. Eve Even n with SARPE using a fixed fixe d device, device, the palate palate only expand expandss approximately one-third the amount of the expansion that occurs at the occlusal level, leve l, thus incr increasin easingg the the curve curve of of Wi Will19 son. Fo Forr exa examp mple le,, if th thee max maxil illa la is expanded with SARPE and the expansion at the occlusa occlusall level is 6 mm, then the the expansion at the palatal level will only be 2 mm (see Figure 55-22). Patients with reverse curves curves of Wilson in the maxillary maxillary arch may benefit more from these techniques, niqu es, but those those with a pretre pretreatmen atmentt accentuat acce ntuated ed curve of Wil Wilson son may have have unfavorablee results, with subsequent difunfavorabl ficulty getting the buccal cuspids to interdigi inte rdigitate tate.. The following following pred predictab ictable le changes will occur with maxillary arch expansio expa nsion n by orthodontic, orthodontic, ortho orthopedic pedic,, or SARPE procedures.


1. The bit bitee may may open open anter anterior iorly ly,, par partic ticuularly if the maxillary incisors incisors have have significant initial vertical inclination. If the maxillary incisors are overangulated, then the bite may may deepen anterioranteriorly as the spacing is closed. 2. Buc Buccal cal tip tippin pingg of the max maxill illary ary pos poste te-rior teeth will increase the curve of Wilson, because the lingual lingual cusps will move downward relative to the buccal cusps. This may make it very difficult to properly interdigitate the buccal cuspss orthod cusp orthodont ontical ically ly.. The Theref refore ore,, these techniques are not recommended, especially when there there is a preexistpreexisting accentuated accentuated curve of Wilson Wilson.. 3. Lon Long-t g-term erm or perh perhaps aps perm permane anent nt retention may be necessary to counterbalance the orthodontic relapse potential seen in a high percentage of these patients. 4. In late late adole adolesce scent nt and and adult adult patient patients, s, SARPE will likely be necessary to expand the maxilla orthopedically since the midpalatal suture is usually closed. Surgical expansio Surgical expansion n of the maxilla maxilla at the time of the Le Fort Fort I procedure procedure using multiple mult iple segmenta segmentation tion of the maxilla, maxilla, stabilization with bone plates and palatal or occlusal splints, and hydrox hydroxyapatite yapatite synthetic bone grafting in the palate palate and lateral maxillary walls can provide a good outcome. This technique when properly performed is very stable and eliminates the orthodontic relapse potential inherent with the other techniques.

Missing Teeth Teeth can be missing from the arches for a number of reason reasonss such as congenit congenital al absence,, uneruptio absence uneruption, n, previous orthodon orthodon-tic extractions, extractions, extraction extractionss for periodonperiodontal or or dental dental patho pathology logy,, and traum trauma. a. In some cases cases (ie, (ie, cong congenita enitall absence absence of maxillary lateral lateral incisors, incisors, previous inapinappropriate bicuspid extraction) opening space to accommodate replacement teeth may be indicated. indicated. This is most applicable applicable

when the incisors are decreased in angulation without appreciabl appreciablee crowding. crowding. If the incisors are already overangulated and/or crowding crowding is present, then opening space orthodontically may be detrimental to stability and periodontal periodontal health. In this situation with missing maxillary lateral incisors,, the cuspids can be used incisors used as lateral incisors, but may require require considerable considerable recontouring to esthetically and functionally conform to lateral incisor morphology.. Althou phology Although gh this cuspid cuspid substitusubstitution can work well for missing lateral incisors,, it is done incisors done less frequen frequently tly now now that dental implants are so predictable and succes successful, sful, ther thereby eby allo allowing wing the the canine to be placed in its normal and more functional position. When Wh en condi condition tionss permit, permit, open opening ing space for replacement teeth can be accomplished by appropriate mechanics to achieve the required required space. Surgery can also be used to create spacing in some areas. are as. In the mandibul mandibular ar arch, dist distracti raction on osteogenesis can be used to create space. The missing teeth can then be replaced with dent dental al impl implants ants,, bridg bridges, es, or parti partial al dentures for example.

Correction of Rotated Teeth Bracket placement and arch wire adaptation are the primary keys to correcting rotated teeth and it is usually best to achieve these corrections presurgery. However, Howev er, if the malrotations malrotations do not interinterfere with the establishment establishment of the desired desired dentoskeletal dentoske letal relationship, relationship, then the rotations can be corrected corrected postsurgery. postsurgery. Severe rotations may require supracrestal fiberotomy to prevent relapse and improve permanent retention. retention. This can often be done done at the time time of orthognathic surgery. surgery.

Management of Ankylosed Teeth Teeth Treatment of ankylosed teeth teeth depends on (1) whether the tooth is primary or permanent, (2) the surrounding dentition, (3) the eruption status, (4) tooth position position and orient ori entati ation, on, (5) the tim timee of of ons onset et and and

1131

diagnosis, (6) the diagnosis, the age age of the patie patient nt and, and, (7) the treatment goals. Ankylosed Primary Tooth This can impede the development and eruption of thee perma th permane nent nt succ succes esso sorr. If a prima primary ry tooth has a permanent successor successor,, treatment is immediate extraction followed by space maintenance until the permanent tooth toot h erupts. If no permanent permanent successo successorr is present and the primary tooth ankylosis occurs at an early stage in jaw growth and develop deve lopmen mentt with submerg submergenc encee of the tooth eminent, eminent, treatment includes includes extraction and space maintenance. 20 If the anky anky-losis occurs late with no permanent successor,, the occlusal and proximal cessor proximal contacts can be reestablished with restorative dentistry to provide esthetics and function with perhaps many years of service.21 It is important to diagnose and treat the ankylosed tooth before the adolescent growth growt h phase. phase. Ret Retainin ainingg an ankylosed ankylosed tooth during jaw growth leads to arrested develo dev elopme pment nt of of the al alveo veolar lar ridg ridge. e. The severity of alveolar growth growth loss depends on the amount of facial growth left at the time that the the ankylosis ankylosis occurs. occurs. Timi Timing ng the removal of of an ankylosed ankylosed tooth just at the start of the pubert pubertal al phase of adol adolescen escentt growth may achieve the treatment objective of maintaining alveolar ridge height while allowing the tooth to remain long enough to act as a space maintainer and esthetic temporary temporary..22 Ankylosed Permanent Tooth An unrecognized ankylosed permanent tooth tied into the arch wire can result in a significant malocclusion (Figure 55-32). There are several ways ways of treating the permanent permanent ankyankylosed los ed toot tooth. h. If ank ankyl ylosi osiss of th thee perman permanen entt tooth has an early onset during eruption, eruption, the tooth should be luxated, allowing for further eruption.2 If repeat repeated ed luxation luxation proves proves ineffective, the tooth should should be extracted to preventt submerg ven submergenc ence. e. If the ons onset et of of ank ankylo ylosis sis occurs late in the normal eruption pattern, the tooth tooth should be luxated. luxated. If the attempt attempt is

1132


55-32 An ankylosed first molar tied into the arch wire has prevented development of the alveolus and consequently created a significant posterior open bite. FIGURE

unsuccessful and the tooth does not submerge, it may may be vertically vertically resto restored red on growth maturity. maturity. A composite composite build-up or crown can be added to a partially erupted ankylosed tooth to level and align the arch. 21 A deeply unerupted ankylosed ankylosed tooth,primatooth, primary or permanent, permanent, may be left undisturbed undisturbed unless it is infected, alters the alveolar alveolar bone growth potential, potential, or constitutes constitutes an immediate threat to the occlusion or adjacent teeth, or would would impede impede the placem placement ent of of an 3 osseointegrated implant. Other treatment options include extraction followed by reimplantation, osseointegra osseo integrated ted implan implant, t, or prosth prosthetic etic 23 replacement. The patient’s developmental age is very important in considering replacing an ankylosed tooth with an osseointegrated implant. The implant will have the same effect on growth of the alveolar alveolar ridge as the ankylosed tooth,and tooth, and therefore should be considered for placement after alveolar growth is essentially complete.24 Proffit suggests surgical luxation of the tooth with extraction forceps disrupting the cementum-bone fusion followed by immediate orthodontic traction to move the tooth into position. 20 Luxation involves breaking the bony bridge of ankylosis without damaging the apical nutrient vessels. This procedur proceduree forms forms fibrous inflammation tissue in the reparative process. This tissue tissue forms forms a false false periodontal periodon tal membrane, membrane, and tooth tooth erup-

tion may may resume resume.. Ortho Orthodonti donticc movemovement should begin immediately. immediately. Complications include possible crown, root, and alveol alv eolar ar fract fracture ures, s, loss of viabi viability lity and vitality,, as well vitality well as re-anky re-ankylosis. losis. When an ankylosed ankylos ed tooth tooth is is impacted, impacted, a similar similar technique can bring an impacted tooth (usually canines) canines) into the arch. Exposure involves invo lves surgical uncovering, uncovering, applicati application on of ort ortho hodon dontic tic bon bondin ding, g, and te tensi nsion on forces applied to direct the tooth into occlusio occl usion. n. Ho Howev wever er,, if the tooth tooth becomes becomes re-ankylosed, re-anky losed, the orthodontic orthodontic forces will intrude adjacent teeth. Orthodontics for Surgical Management of Ankylosed Teeth Presurgical orthodontics may be indicated to create adequate space (minim (minimum um of 2 to 3 mm) between between the roots roots of the adjacent adjacent teeth teeth to safely safely accommodate interdental osteotomies around arou nd the ankylos ankylosed ed tooth. tooth. Spaci Spacing ng is best assessed with pantomographic or periapical periapic al radiograp radiographs. hs. The ankyl ankylosed osed tooth toot h is left left out of the arch arch wire, wire, and all all other teeth are properly properly aligned. If orthognathic surgery is required to correct a dentofacial dento facial deformi deformity, ty, the orthodont orthodontics ics are performed in the traditional manner, but the ankylosed tooth must remain out of the arch arch wire, wire, unle unless ss it aligns aligns well well with one of the den dental tal segm segment ents. s. Fo Follo llowin wingg surgery,, ortho surgery orthodonti donticc mechanics mechanics can be initiated immediately to help get the mobilized dental segment with the ankylosed tooth into the best possible position. Osteotomy Performing single-tooth osteotomies or sectional-arch osteotomies with mobilization of the segment will permit immediate repositionin repositioningg of the ankylosed tooth (Figure 55-33), or facilitate repositioningg by distraction osteogenesi repositionin osteogenesis. s. In select cases where an ankylosed primary molar is present, without a successor, successor, a treatment option is to remove the ankylosed tooth and eliminate the extraction space by performing a vertical body ostectomy in conjunction with a mandibular

ramus osteotomy and advance the posterior teeth and mandibular body forward (Figure 55-34). This eliminates the need for osseointegrated implants and extensive dental reconstruction.

Final Presurgical Preparation As presurgical orthodontic treatment progresses, gresse s, new diagnosti diagnosticc records records (lateral (lateral ceph ce phal alog ogra rams ms,, pa pant ntom omo ogr gram ams, s, de dent ntal al models) are taken to determine the feasibility and and timing timing of surgical proce procedures. dures. This will also aid the orthodontist in identifying specific areas that may need to be addressed in completing the presurgical orthodontic goals go als (ie (ie,, sec secti tion onal al leve levelin lingg of th thee arch arch

A

B FIGURE 55-33 Single-tooth osteotomies can be performed as isolated cases or they can be per formed in combination with multiple maxillary osteotomies to allow individual movement movement of the dental osseous osseous segments or application of immediate distraction osteogenesis to reposition the tooth properly. properly. The case illustrated had an ankylosed maxillary right cuspid (see Figure 55-8) treated with segmental maxillary osteotomies including a single tooth segment containing the right cuspid cuspid (A, (A, B)


A

B FIGURE 55-34 A , B , An ankylose ankylosed d submerged submerged primary tooth without a permanent successor can be treated treated with extraction extraction of of the primary primary tooth as well as a vertical body ostectomy in con junction with a mandibular ramus sagittal split osteotomy to advance the posterior teeth forward to eliminate the ankylosed tooth and associated space. This eliminates the need need for an osseointe grated implant or crown-and-bridge work.

hooks placed on the brackets ( T pins, K hooks). The least preferred preferred are the hooks on the arch arch wire wire.. The reaso reason n is that that ifif post post-surgery elastics are required for an extended time, the elastics and hooks on the arch wire will activate the the arch wire, possibly creating creating unwanted orthodontic forces and movements (ie, tipping the crowns crowns lingually lingually and the roo roots ts buccal buccally). ly). This undes undesirabl irablee torquing occurs to a much lesser degree when the hooks are directly on the brackets. When the maxilla or mandible are to be segmentalized, it may be better for the the orthodontist to section the arch wire (see Figure 55-15B) and bend the ends inward at the predetermined osteotomy areas immediately prior to surgery, or the surgeon can cut the wire at surgery. The best best type of arch wire to to place place prior to surgery is a rectangular stainless steel wire that fills the bracket bracket slot. For example, exam ple, with an 18 18 slot, slot, a 17 × 25 gauge wire is recom recommend mended, ed, and for for a 22 slot, a 21 × 25 gauge wire is indicated. This will help stabilize the individual dental units together as a whole arch or in segments when segmental segmental surgery surgery is required. required. The final wire should be placed 2 to 3 months prior to surgery.

Postsurgical Orthodontics segments, margin segments, marginal al ridge ridge alignme alignment, nt, vertical dental alignment, alignment, buccal surface surface alignment, additional TSD TSD correction). During surgery the jaws are usually wired together together once or twice, as each jaw is independently mobilized and stabilized with rigid fixation. fixation. To facilitate wiring wiring the jaws together as well as providing a means of usingg postsur usin postsurgical gical ela elastics stics if requ require ired, d, fixtures attached to the brackets or arch wires are usually usually necessary. necessary. Fixtures attached attached to the brackets are dependent on the manufacturer but may include ball hooks built onto the brackets, T pi pins ns,, an and d K hooks, (Figure 55-35). Fixtures attached to the arch wire include crimped-on hooks and soldered pins (Figure 55-36). Hooks built onto the brackets are preferred, preferred, follow followed ed by the other

In preparation for the postsurgery orthodontic phase of treatment, the surgical stastabilizing biliz ing splin splint, t, if used, is usual usually ly remo removed ved 4 to 6 week weekss postsu postsurge rgery ry.. If the pala palatal tal splint design is used and a large maxillary expansion has been performed, the splint can remain for a longer period and the postsurgical orthodontics can be performed forme d around it. The maintena maintenance nce of the splint will enhance the transverse stability and it can be left in for 2 to 3 months or longer long er if nece necessary ssary.. It can be made into a removable appliance. If rigid skelet skeletal al fixation fixation is used, used, acti active ve orthodontics involving changing the arch wires can usually resume 4 to 6 weeks postsurgery,, when patients are usually comfortsurgery able enough to tolerate changing their arch

1133

55-35 Ortho Orthodonti donticc hooks. hooks. Ball hooks hooks built onto the brackets (blue arrows) provide arrows) provide the best stability. stability. Other options include include T pins pins and K hooks (white arrows) or other methods to provide attachments directly on the brackets. FIGURE

wires. The orthod wires. orthodonti ontist st can be be fairly fairly aggressive at finishing the occlusion because the osseous segments can still be moved slightly. The teeth move much more rapidly for the first few months postsurgery because there is an increased bony metaboli meta bolism sm as a result of the surgery surgery.. The orthodontist can therefore accomplish in 1 to 2 weeks what would normally take 4 to 6 weeks weeks to complet complete. e. Appl Applying ying active active mechanics at this early postsurgical orthodontic phase of of treatmen treatmentt and booking booking the patient for a routine orthodontic followup 4 to 6 weeks later could result in uncontrolled excessive orthodontic movements, resulting in an unfavorable outcome.

Soldered pins on the arch wire or crimped hooks (white arrows) onto the arch wire can also be used but are not preferred because the use of postsurgical elastics elastics will activate the arch wire, possibly creating unwanted orthodontic movements. FIGURE 55-36

1134


For most cases the orthodontist should see the patient once a week for the first month, month, then every every 2 weeks for for the next 2 months for adjustments so that orthodontic changes can be closely monitored. tor ed. At the initial initial appointme appointments nts root root positions are are checked, loose brackets brackets and bracket positions are evaluated and corrected, and new arch wires wires are placed placed if indicated. Interarch mechanics (ie, class II or III III elasti elastics, cs, ve verti rtical cal elast elastics ics,, and and/o /orr cross-arch elastics) can be applied as necessary to finalize finalize the occlusion. occlusion. Once the initial healing phase is completed (approximately 3 to 4 months postsurgery) and the occlusio occlusion n is stable, the orthodon orthodontic tic appointment intervals can be extended to the more traditional traditional time frame. The final positioning of of the teeth usually usually takes from from 3 to 12 months months of postsurgical orthodonorthodontic treatment but could be longer depending on the postsurgical orthodontic requirements. requirement s. Although reasonable reasonable stability from surgical healing occurs in approximately 3 to to 4 months, the final postsurgipostsurgical healing phase takes 9 to 12 months.

References 1. Bolton Bolton WA. The clinic clinical al appli applicatio cation n of a toothtoothsize analysis. Am J Orthod 1962;48:504–29. 2. Mo Moyer yerss RE, RE, van der Lind Linden en FPGM FPGM,, Riol Riolo o ML, ML, McN cNam amar araa JA. JA. St Stan anda dard rdss of hu huma man n occlusal occlus al development. development. The University University of Michigan Ann Arbor (MI): The Center for Human Hum an Growth and Development; Development; 1976. p. 53–9 53–94. 4.

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14.. Wi 14 Wick ckwi wire re NA, NA, Wh Whit itee RP Jr, Jr, Pr Prof offi fitt WR. WR. Th Thee effect of mandibular osteotomy osteotomy on on tongue position. J Oral Surg 1972;30:184–90. 1972;30:184–90. 15. Wolf olford ord LM, LM, Kar Karras ras S, Me Mehra hra P. P. Con Concom comita itant nt temporomandibular temporom andibular joint and orthognathic surge surgery: ry: a prelim prelimina inary ry repor report. t. J Oral Maxillofac Surg 2002;60:356–62 2002;60:356–62.. 16. Wolfo olford rd LM, Meh Mehra ra P, Reic Reiche-Fi he-Fische schell O, O, et al. Efficacy of high condylectomy condylectomy for managemanagement of condylar hyperplasia. Am J Orthod Dentofac Orthop 2002;121:136 2002;121:136–51. –51. 17. Meh Mehra ra P, P, Wolfo olford rd LM. LM. The Mitek Mitek mini ancho anchorr for TMJ disc repositioning: repositioning: surgical techtechnique and results. results. Int J Oral Maxillofac Surg 2001;30:497–503. 18. Wolfo olford rd LM, Card Cardenas enas L. Idi Idiopath opathic ic cond condylar ylar resorption reso rption:: diagn diagnosis osis,, treat treatment ment proto protocol, col, and outcomes. outcomes. Am J Orthod Dentofac Dentofac Orthop 1999;116:667–7 1999;116:667–76. 6. 19. Sch Schwar warzz GM, GM, Thr Thrash ash WJ WJ,, Byr Byrd d DL, DL, Jac Jacobs obs JD JD.. Tomogra omographic phic assessmen assessmentt of nasal septal septal changes following surgical-orthodontic rapid maxillary maxillary expansion expansion.. Am J Orthod 1985;87(1):39–45. 20. Pro Proffit ffit WR WR.. Con Contem tempor porary ary ort orthod hodont ontics ics.. St Loui Lo uiss (MO (MO): ): C. C.V V. Mos osby by Co Co.; .; 19 1986 86.. p. 191 191–2, –2, 352 352.. 21.. Wil 21 illi liam amss HS HS,, Zwe weme merr, JD JD,, Ho Hoyt yt DJ DJ.. Tre reat atin ingg ankylosed primary primary teeth in adult adult patients: a case report. Quintessence Int Int 1995;26:161–6. 22. Ste Steine inerr DR. Tim Timing ing of of ext extract raction ion of of ank ankylo ylose sed d teeth to maximize maximize ridge developm development. ent. J Endodont 1997;23:242–5. 23. Gei Geige gerr AM, Bro Bronsk nskyy MJ. Ort Orthod hodont ontic ic manage manage-mentt of anky men ankylose losed d permanent permanent posterior posterior teeth: tee th: a clinica clinicall report report of thre threee cases. cases. Am J Orthod Dentofac Orthop 1994;106:54 1994;106:543–8. 3–8. 24. Oest Oesterle erle LJ. LJ. Impl Implant ant conside consideration ration in the the growgrowing chil child. d. In In:: Hig Higuch uchii KW, KW, edi editor tor.. Ort Orthohodontic dont ic applicati applications ons of of osse osseoint ointegrat egrated ed implants. Chicago (IL): Quintesse Quintessence nce Publishing lish ing Co. Co.;; 2000 2000.. p. 133– 133–59. 59.

Orthodontics for Orthognathic Surgery

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