66267747 Orthodontics for Orthognathic Surgery

C H A P T E R 5 5

Orthodontics for Orthognathic Surgery

Larry M. Wolford, DMDEber L. L. Stevao, DDS, PhDC. Moody Alexander, DDS, MSJoao Roberto Goncalves, DDS, PhD

Moderate to severe occlusal discrepanciesand dentofacial deformities in late adoles-cents and adults usually require combinedorthodontic treatment and orthognathicsurgery to obtain optimal, stable, func-tional, and esthetic results. The basic goalsof orthodontics and orthognathic surgeryare to (1) satisfy the patients’ concerns, (2)establish optimal functional outcomes,and (3) provide good esthetic results. Toaccomplish this the orthodontist and theoral and maxillofacial (OMF) surgeonmust be able to correctly diagnose existingdental and skeletal deformities, establishan appropriate treatment plan, and prop-erly execute the recommended treatment.The orthodontist is limited, to a greatextent, by growth, and although the ortho-dontist can move teeth and, to somedegree, the alveolar bone, he or she doesnot have any appreciable effect on the basalbone of the jaws. The orthodontist’s role isto align the teeth relative to the maxillaryand mandibular jaws. The OMF surgeon isresponsible for surgically repositioning thejaw(s) and associated structures.

It is very important to listen to andunderstand the patients concerns. Empa-

thetic listening from the first appointmentand throughout the treatment will buildtrust, improve communication, and helpprovide a quality end result for all partiesinvolved. Comprehensive analysis of thepatient and the complete orthodonticrecords (cephalograms, pantomograms,photographs, dental models) are impor-tant for diagnosis and development of thepresurgical orthodontic goals. Althoughdetailed analysis of the patient’s facial andjaw structures from a clinical and radi-ographic perspective are vitally important,the focus of this chapter will be the teethand orthodontic considerations in prepa-ration for orthognathic surgery. Otherimportant factors in diagnosis, treatmentplanning, and outcomes, such as patientconcerns, psychosocial factors, masticato-ry dysfunction, airway problems, speechdifficulties, temporomandibular joint(TMJ) pathologies, and comprehensiveorthognathic surgery work-up are dis-cussed elsewhere in this book.

The normal values provided in thischapter are not absolutes for every patientbecause of individual size, morphologicvariances, and racial and ethnic differ-

ences. They are provided as a guide to helpthe clinician evaluate his or her patient.

Establishing an all-inclusive diagnosisis paramount to developing a comprehen-sive treatment plan. The orthodontistmust determine the orthodontic goalsbased on the pretreatment findings and onthe projected treatment outcome. Thischapter will first present orthodontic diag-nostic information, followed by orthodon-tic treatment considerations.

Clinical and Dental Model DiagnosisFrom an orthodontic standpoint, in eval-uating the occlusion and dental factors,the clinical and dental model analyses cor-related with the cephalometric analysisprovide the most information for diagno-sis and treatment planning. There are 12 basic evaluations that are helpful forthese determinations.

1. Arch length: This assessment corre-lates the mesiodistal widths of theteeth relative to the amount of alveo-lar bone available and aids in identify-ing the presence of crowding or

1112 Part 8: Orthognathic Surgery

spacing. This helps determine if teethneed to be extracted or if spaces needto be either created or closed (Figure 55-1). Clinical and dentalmodel assessment correlated tocephalometric analysis will aid indetermining arch length require-ments. Generally Class II patients willtend to have more crowding in themandibular arch and less in the max-illary arch, whereas Class III patientsmay have spacing in the mandibular

arch but a tendency for crowding inthe maxillary arch.

2. Tooth-size analysis: This analysisrelates the mesiodistal width of themaxillary teeth compared with themandibular teeth. A tooth-size dis-crepancy (TSD) causes incompatibili-ty of the dental alignment and canoccur in the anterior teeth, premolars,and molars. Approximately 40% ofpatients with dentofacial deformitieswill have an anterior TSD affecting theanterior six teeth of the maxillary andmandibular arches (the mandibulararch is commonly too large comparedwith the maxillary arch), usually dueto small maxillary lateral incisors. Insuch cases proper tooth alignmentwith all spaces closed often precludesthe establishment of a good Class Icuspid-molar relationship with treat-ment. Instead, a Class II end-on cuspid-molar occlusal relationshipmay result. Occasionally the maxillaryanterior six teeth may be too large forthe mandibular anterior teeth, creat-ing an excessive anterior overjet whenin a Class I cuspid relationship. Deter-mination of a TSD pretreatment willprovide the opportunity to correct theTSD during the presurgical orthodon-

tic phase of treatment. Explaining tothe patient, before treatment, thatsmall maxillary lateral incisors mayneed restorative bonding to maximizethe quality esthetic and functionaloutcome is important, so that thepatient is aware from the onset of thetime and financial commitment nec-essary for treatment. The normalmesiodistal widths of each of the per-manent teeth are recorded in Tables55-1 and 55-2. Variations from thenorm may create difficulties in theteeth fitting properly.

Bolton’s analysis is a method tocorrelate the widths of the maxillaryand mandibular anterior six teeth.Needle-point calipers can be used tomeasure each individual tooth, andsuccessive holes punched into a tabletfor each of the anterior six teeth foreach arch. Then a measurement fromthe first to last holes will give the sum-mation of mesiodistal widths of theanterior six teeth for each arch (Fig-ures 55-2 and 55-3). The summationof the mesiodistal widths of the max-illary anterior six teeth measured atthe contact level, divided into thecombined width of the mandibularanterior six teeth, yields a value called

FIGURE 55-1 Arch length assessment correlatesthe mesiodistal widths of the teeth relative to theamount of alveolar bone available and aids inidentifying the presence of crowding or spacing.The curved wire illustrates ideal cuspid andincisor tip position relative to the basal bone.

Table 55-1 Maxillary Mesiodistal Teeth Diameters

Central Lateral First Second First Second Incisor* Incisor* Cuspids* Bicuspids* Bicuspids* Molars* Molars*

Males 8.9 (0.59) 6.9 (0.64) 8.0 (0.42) 6.8 (0.47) 6.7 (0.37) 10.6 (0.56) 9.5 (0.71)Females 8.7 (0.57) 6.8 (0.64) 7.5 (0.36) 6.6 (0.46) 6.5 (0.46) 10.2 (0.58) 8.8 (0.73)

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

Table 55-2 Mandibular Mesiodistal Teeth Diameters

Central Lateral First Second First Second Incisor* Incisor* Cuspids* Bicuspids* Bicuspids* Molars* Molars*

Males 5.5 (0.32) 6.0 (0.37) 7.0 (0.40) 6.9 (0.63) 7.2 (0.47) 10.7 (0.60) 10.0 (0.67)Females 5.5 (0.34) 5.9 (0.34) 6.6 (0.34) 6.8 (0.70) 7.1 (0.46) 10.3 (0.74) 9.5 (0.59)

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

Orthodontics for Orthognathic Surgery 1113

the intermaxillary (Bolton’s) index.The average index (percentage) is 77.5± 3.5.1 A simple conversion of this fac-tor would be to measure the width ofthe mandibular anterior six teeth andthen multiply that sum by 1.3. Thisresults in a calculated ideal maxillaryarch width. The difference betweenthe calculated and the actual maxillaryarch width values determines the TSD(see Figure 55-3). This evaluation isvery helpful in determining presurgi-cal orthodontic and surgical goals.TSDs can also occur in the premolarand molar areas (normally the samemaxillary and mandibular teeth aresimilar in size) where the mandibularteeth may be significantly larger thanthe maxillary teeth.

The Bolton’s analysis is not perfectand functions only as a guide inassessing the tooth-size compatibilityof the anterior teeth because it doesnot take into consideration the labi-olingual thickness of the incisors, theaxial inclination of the teeth, or thethickness and prominence of the mar-ginal ridges. A thin labiolingualdimension of the maxillary incisorsmay compensate for small TSDs, butthicker than normal dimensions orprominent marginal ridges may pre-clude a Class I cuspid relationship

even though the Bolton’s index is nor-mal. An accurate dental model ortho-dontic wax set-up may achieve a moreaccurate assessment.

3. Incisor angulation: This refers to theangulation of the maxillary andmandibular incisors relative to theirrespective basal bones. The dentalmodels are correlated to the cephalo-metric analysis and the ideal axialinclination of the incisors determined(Figure 55-4). The incisor angulationanalysis contributes to the determina-tion of whether extractions are neces-sary, spaces need to be created or elim-inated, and what mechanics arerequired to align and level the archesor segments of the arches. The key is toget the incisors in proper position andangulation over basal bone.

4. Arch width analysis: This refers to theevaluation of the intra-arch transversewidths between the maxillary andmandibular arches. The average maxil-lary and mandibular arch widths foradults are listed in Tables 55-3 and 55-4(data from University of Michigan Caucasian study).2 These averages areonly guides and do not account for

FIGURE 55-2 Bolton’s analysis. Needle-pointcalipers are used to measure each tooth at acontact-point level to aid in tooth-size analysis.

FIGURE 55-3 Bolton’s analysis. Successive holesare punched into a tablet for each of the anteriorsix teeth for each arch. Then measuring from thefirst hole to the last hole will give the summationof the mesiodistal widths of the anterior six teethin each arch. Multiplying the summation of themandibular anterior six teeth (LA) by 1.3 yieldsthe calculated arch width for the maxillary ante-rior six teeth (UA). Subtracting the actual max-illary anterior arch width from the calculatedwidth yields the tooth-size discrepancy.

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FIGURE 55-4 Cephalometricanalysis. Normal maxillary depthangle is 90˚ ± 3˚ and mandibulardepth is 88˚ ± 3˚. Normal occlusalplane angulation is 8˚ ± 4˚. Normalmaxillary incisor angulation to thenasion point A (NA) line is 22˚ ± 2˚with the labial surface of the incisorbeing 4 mm ± 2 mm anterior to theNA line. Normal mandibularincisor angulation to the nasionpoint B (NB) line is 20˚ ± 2˚ withthe labial surface of the incisorbeing 4 mm ± 2 mm anterior to theNB line.


patient size, or racial or ethnic differ-ences. However, from a practical stand-point a good way to analyze the archwidth is to relate the models to theocclusal position that is to be achievedwith the surgical correction and thenassess the transverse relationship. Forexample, if a patient has a Class IIocclusion, position the models in aClass I cuspid-molar relation and eval-uate the transverse width relationship.Likewise, a patient with a Class IIIocclusion is evaluated by positioningthe models into a Class I cuspid-molarrelationship. When a Class II relation-ship is shifted to a Class I relationship,the maxilla may be narrow and requireexpansion. In some cases it may be indi-cated to evaluate the transverse rela-tionship by placing the models into aClass II molar position to determine if aClass I cuspid and Class II molar rela-tionship (this would require maxillarybicuspid extractions) would be best forthat particular patient; this may be ben-eficial when there is significant crowd-ing in the maxillary arch and no crowd-ing in the mandibular arch. Transversediscrepancies will influence the presur-gical orthodontics and dictate the surgi-cal procedures required.

5. Curve of Spee: This evaluates the verti-cal position of the anterior teeth com-pared with the posterior teeth. Thisassessment can be determined by plac-ing the occlusion of the maxillary den-tal model on a flat plane; the incisorsshould be about 1 mm above the flatplane (Figure 55-5A). Placing theocclusion of the mandibular dentalmodel on a flat plane should see themandibular incisors elevated 1 mmabove the midbuccal teeth. A signifi-cant accentuated curve of Spee in themaxilla is usually associated with ananterior open bite and a reverse curveassociated with an anterior deep bite.An accentuated curve of Spee in themandible (Figure 55-5B) is commonlyassociated with an anterior deep biteand a reverse curve associated with anopen bite. Accentuated or reversecurves of Spee will influence whetherthe curve in each arch requires correc-tion, and if so, whether the correctionwill be achieved by orthodontics, withor without extractions, opening spaces,or by surgical intervention.

6. Cuspid-molar position: This identi-fies the angle classification and den-tal interrelationships. It is usually

preferable to have a Class I cuspid-molar relationship as an outcomeresult; however, a Class II molar rela-tionship is acceptable. A Class IIImolar relationship is less desirablebecause the mandibular first molarfunctions against the maxillary sec-ond bicuspid, but it may be indicatedin some cases.

Table 55-3 Maxillary Arch Width*

Cuspids† First Bicuspids† Second Bicuspids† First Molars† Second Molars†

Males 32.3 (1.7) 36.7 (2.0) 41.5 (2.5) 47.1 (2.8) 52.3 (3.4)Females 31.2 (2.45) 34.6 (3.2) 39.3 (2.2) 44.3 (2.3) 49.3 (2.8)

Adapted from Moyers RE et al.2

*All measurements at centroid.†Measurements in mm (SD).

Table 55-4 Mandibular Arch Width*

Cuspids† First Bicuspids† Second Bicuspids† First Molars† Second Molars†

Males 24.8 (1.3) 32.8 (1.5) 37.6 (2.3) 43.0 (2.7) 49.0 (2.3)Females 23.1 (2.0) 31.8 (1.4) 36.8 (1.3) 41.7 (2.3) 47.2 (2.1)

Adapted from Moyers RE et al.2

*All measurements at centroid.†Measurements in mm (SD).

FIGURE 55-5 A, This maxillary arch demon-strates an increased curve of Spee. B, An accen-tuated (increased) curve of Spee is seen in themandibular arch.

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7. Tooth arch symmetry: This comparesthe left to right side symmetry withineach arch. There may be a significantasymmetry within the arch, such as acuspid on one side being more anteri-orly positioned in the arch than thecuspid on the opposite side (Figure 55-6). This problem often occurs with aunilateral missing tooth. Also, verticalasymmetries can occur with individualteeth, sections of the dentoalveolus, orthe entire dental arches, creating a cantin the transverse occlusal plane. Cor-recting these types of conditions mayrequire special orthodontic mechanics,unilateral extraction or opening-upspace, asymmetric extractions, and/orsurgical procedures.

8. Curve of Wilson (buccal tooth tipping):This evaluates the mediolateral positionof the occlusal surfaces of the maxillary(Figure 55-7) and mandibular posteriorteeth. If the occlusal surfaces of the max-illary or mandibular posterior teeth aretipped too far buccally, it may be diffi-cult to achieve a proper occlusal inter-digitation relationship. In the presenceof a transverse maxillary deficiency withpreexisting increased curve of Wilsonand posterior crossbites, it is very diffi-cult, if not impossible, to correct theproblem orthodontically, orthopedical-ly, or even with surgically assisted rapid

palatal expansion (SARPE). The curveof Wilson will usually get much worsewith these mechanics. In these types ofcases surgical expansion by multiplemaxillary osteotomies may be indicatedto decrease the curve of Wilson.

When the mandibular posteriorteeth are tipped buccally, it is oftenrelated to macroglossia or habitualtongue posturing. Orthodontic lingualtipping of the posterior teeth is verydifficult when macroglossia is presentand will likely be unstable. A reductionglossectomy may be indicated beforeorthodontics in order to permit a morestable orthodontic result.

9. Missing, broken down, or restoredteeth: These must be identified sincethey may influence treatment design. Ifa tooth is nonrestorable and requiresextraction, it must be determined if theextraction space requires orthodonticclosure or the space maintained forlater dental reconstruction. In somecases it may be helpful to maintain thecondemned tooth to improve stabilityduring surgical alignment of the jawsor segments thereof, with removalpostsurgery. Crowns on previouslyrestored teeth may need to be redonepost-orthodontics and -orthognathicsurgery, since the crown anatomy mayneed to be changed for proper occlu-sion with the new dental relationships.Determination of salvageable teeth andrestorative requirements are integralcomponents in the planning and treat-ment of patients.

10. Ankylosed teeth: If undiagnosed,ankylosed teeth can have devastatingeffects on the presurgical orthodon-tics. Tooth ankylosis, the fusion ofalveolar bone and cementum, resultsfrom damage to the periodontal liga-ment (PDL).

An ankylosed tooth may be identi-fied by failure to move with orthodon-

tic forces (Figure 55-8), failure of atooth to erupt, submerged or incom-plete tooth eruption (Figure 55-9), orlack of eruption of a tooth comparedwith adjacent teeth and alveolar bonegrowth. The most sensitive diagnostictest is percussion, where the ankylosedtooth has a high, clear, solid metallicsound. A normal tooth has a dullsound, being protected by the PDL.However, an erupted tooth with animpacted tooth directly against it willalso have a solid sound to percussion.Normal multirooted teeth present amore solid sound than single-rootedteeth. Therefore, percussion testingshould be compared with similar teeth(ie, test bicuspids against bicuspids,molars against molars, using both sidesof the arch). An ankylosed tooth lacks

FIGURE 55-6 Tooth arch symmetry. This modeldemonstrates that the cuspid on one side of thearch is significantly more anteriorly positionedin the arch compared with the cuspid on theopposite side.

FIGURE 55-7 Curve of Wilson. This evaluatesthe mediolateral position of the occlusal surfacesof the maxillary and mandibular posterior teeth.

FIGURE 55-8 This dental model shows apalatally displaced tooth, unresponsive to ortho-dontic mechanics, indicating probable ankylosis.


mobility. Over 90% of ankylosed teethare deciduous; most often the secondmolar followed by the first molar.3

Ankylosed primary teeth are not sus-ceptible to resorption by the follicle ofthe underlying permanent tooth andmay result in its impaction.3

Ankylosed teeth can cause signifi-cant problems with jaw growth anddevelopment. Early ankylosis results innoneruption or partial eruption,resulting in incomplete development ofthe alveolar process.4 Permanent teethmay be displaced from normal erup-tion pathways with resulting loss ofalveolar bone height. The failure of anankylosed tooth to erupt may allowadjacent teeth to drift and permitsuper-eruption of the tooth in theopposing arch. Ankylosed teeth do notrespond to orthodontic forces and cancreate significant orthodontic prob-lems when malaligned and tied into theorthodontic arch wire (Figure 55-10).5

The ankylosed tooth functions as ananchor and in active uncontrolledorthodontics, will move adjacent teethto align with its position, with subse-quent development of an occlusal andpossibly facial deformity.

11. Periodontal evaluation: This is veryimportant, since preexisting peri-odontal pathologies could be exacer-bated during orthodontic and orthog-nathic surgical treatments.6 Factorsthat can adversely affect the health andoutcome of the periodontal tissues aswell as the orthodontics and orthog-nathic surgery include smoking,excessive consumption of alcohol orcaffeine, habitual patterns such asbruxism and clenching, preexistingconnective tissue/autoimmune dis-eases, diabetes, malnutrition, andother diseases that could affect thelocal tissue blood supply perfusion,and healing. Any pretreatment ofacute or chronic periodontal diseaseshould be addressed prior to theorthodontics and surgery. The lack ofattached gingiva around the teeth(most commonly seen in themandibular anterior arch) can causegingival retraction, loss of bone, andloosening of teeth if orthodontics isinitiated and the mandibular incisorsare tipped forward (Figure 55-11).Gingival grafting may be indicatedprior to orthodontics to provide

attached gingiva so as to prevent theseproblems. Good communicationbetween the periodontist, orthodon-tist, and OMF surgeon is of utmostimportance.

Orthodontics can help prepareinterdental osteotomy sites by tippingthe roots of the adjacent teeth awayfrom each other to increase theinterosseous space between the roots.There have been a number of studiesdemonstrating that interdentalosteotomies have a minimal effect onthe periodontium when they are prop-erly performed.7–11 Having healthystable dental tissues to work with dur-ing the orthodontics and surgery willmaximize the periodontal outcome aswell as the overall outcome. The fail-ure to recognize preexisting periodon-tal pathology, identify risk factors,poor performance of surgery, and/orlack of attention to detail could resultin significant periodontal problems aswell as other problems that couldcompromise the final result.

12. Tongue assessment: An enlarged tongue(macroglossia) can cause dentoskeletal

FIGURE 55-9 This pantomogram demonstratesincomplete eruption of a primary tooth withouta permanent successor, indicating ankylosis.

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

A B


deformities, instability of orthodonticand orthognathic surgical treatments,and create masticatory, speech, and air-way management problems. There are anumber of congenital and acquiredcauses of true macroglossia, includingmuscular hypertrophy, glandularhyperplasia, hemangioma, lymphan-gioma, Down syndrome, and Beckwith-Wiedemann syndrome. Acquired fac-tors include acromegaly, myxedema,amyloidosis, tertiary syphilis, cysts ortumors, and neurologic injury.12 Thereare specific clinical and cephalometricfeatures that may help the clinicianidentify the presence or absence ofmacroglossia, although not all of thesefeatures are always present. Specificclinical features include the following(Figure 55-12):

• Grossly enlarged, wide, broad, andflat tongue

• Open bite (anterior or posterior)• Mandibular prognathism• Class III malocclusion with or with-

out anterior and posterior crossbite• Chronic posturing of the tongue

between the teeth at rest (rule outhabitual posturing of a normal-sized tongue)

• Increased curve of Wilson of max-illary posterior teeth

• Reverse curve of Wilson ofmandibular posterior teeth

• Accentuated curve of Spee in themaxillary arch

• Reverse curve of Spee in themandibular arch

• Increased transverse width ofmaxillary and mandibular arches

• Diastemata with increased incisorangulation in the mandibularand/or maxillary arches

• Crenations (scalloping) on thetongue

• Glossitis (due to excessive mouthbreathing)

• Speech articulation disorders• Asymmetry in the maxillary or

mandibular arches associatedwith an asymmetric tongue

• Difficulty eating and swallowing(severe cases)

• Instability in orthodontic mechan-ics or orthognathic surgical proce-dures that in normal circumstanceswould be stable

• Airway difficulties, such as sleepapnea, secondary to oral ororopharyngeal obstruction

• Drooling

Cephalometric radiographic featurescommonly seen with macroglossia (Figure55-13) include the following:

• Tongue filling the oral cavity andextruding through an anterior open bite

• Mandibular dentoalveolar protru-sion or bimaxillary dentoalveolarprotrusion

FIGURE 55-11 Periodontal concerns. Thispatient had lack of attached gingiva prior to initi-ation of orthodontics and was left untreated, caus-ing severe gingival retraction and loss of support-ing bone. Gingival grafting should have beenperformed prior to initiation of orthodontics.

FIGURE 55-12 Macroglossia. Some of the clini-cal features associated with macroglossia includeanterior open bite, diastemata between the teeth,accentuated curve of Spee maxillary arch, andreverse curve of Spee mandibular arch.

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FIGURE 55-13 Macroglossia. Cephalo-metric analysis shows mandibular den-toalveolar protrusion and overangula-tion of the mandibular anterior teeth.The tongue fills the oral cavity (dottedline) and the oropharyngeal airway isdecreased (normal distance from poste-rior aspect of tongue to posterior pha-ryngeal wall is 11 mm).


• Overangulation of the maxillary andmandibular anterior teeth

• Disproportionately excessive mandibu-lar growth

• Decreased oropharyngeal airway• Increased gonial angle• Increased mandibular plane angle• Increased mandibular occlusal plane

angle

Most open bite cases are not related tomacroglossia. In fact it has been estab-lished that closing open bites with orthog-nathic surgery will allow a normal tongue(which is a very adaptable organ) to re-adjust to the altered volume of the oralcavity, with little tendency towardrelapse.13,14 However, if true macroglossiais present with the open bite, then instabil-ity of the orthodontics and orthognathicsurgery will likely occur, with a tendencyfor the open bite to return. Pseudo-macroglossia is a condition where thetongue may be normal in size, but itappears large relative to its anatomic inter-relationships. This can be created by (1)habitual posturing of the tongue; (2)hypertrophied tonsils and adenoid tissuedisplacing the tongue forward; (3) lowpalatal vault, decreasing the oral cavityvolume; (4) transverse, vertical, or antero-posterior deficiency of the maxillaryand/or mandibular arches decreasing oralcavity volume; and (5) tumors that dis-place the tongue. Pseudomacroglossiamust be distinguished from truemacroglossia because the methods ofmanagement are different.

Diagnostic ListBefore a treatment plan can be properlydeveloped, a diagnostic list of the existingproblems is established based on patientconcerns, and clinical, radiographic, den-tal model, and other indicated evaluations.This will include all findings relative tomusculoskeletal and dental imbalances,occlusal problems, esthetic concerns, TMJand/or myofascial pain problems, missing

teeth, crowns, bridges, endodonticallytreated teeth (these teeth are sometimesankylosed), periodontal problems, otherfunctional disorders, as well as any othermedical factors that may affect treatmentoutcomes. The treatment plan is formulat-ed from the diagnostic problem list.

Presurgical Orthodontic GoalsThe basic presurgical orthodontic goalsare as follows:

• Align and position teeth over basal bone• Avoid excessive intrusion or extrusion

of teeth• Decompensate teeth• Avoid unstable expansion of the den-

tal arches• Avoid class II and class III mechanics

(unless required for dental decompen-sation correction in the arches)

• Perform stable and predictable ortho-dontics

Relative to the position of the maxillaryand mandibular incisors, the ideal presurgi-cal orthodontic goals are as follows:

1. Position the long axis of the maxillarycentral incisors approximately 22˚ tothe nasion point A (NA) line, with thelabial surface of the incisors 4 mm ante-rior to the NA line relative to a normal-ly positioned maxilla and normalocclusal plane angle (see Figure 55-4)

2. Position the long axis of the mandibu-lar central incisors 20˚ to the nasionpoint B (NB) line with the labial sur-face of the incisors 4 mm anterior tothat line relative to a normally posi-tioned mandible and normal occlusalplane angle (see Figure 55-4)

3. Satisfy arch length requirements(crowding or spacing)

We have found that using the idealposition of the maxillary and mandibularincisors to the NA and NB lines, respec-tively (see Figure 55-4), is the most conve-nient and practical method to establish thepresurgical orthodontic goals for the

incisors. However, these presurgical ortho-dontic goals may be different if theocclusal plane angle is to be altered surgi-cally. Removal of dental compensations ishelpful before surgery so that maximumskeletal correction can be achieved. Anexact orthodontic treatment plan, includ-ing the specific mechanics and anchoragerequirements necessary to position theteeth to satisfy the presurgical orthodonticgoals, must be developed and executed.

Initial Surgical Treatment ObjectiveThe surgical treatment objective (STO),also known as a prediction tracing, is atwo-dimensional visual projection of thechanges in osseous, dental, and soft tissuesas a result of orthodontics and orthog-nathic surgical correction of the dentofa-cial and occlusal deformity. The purposeof the STO is threefold: (1) establishpresurgical orthodontic goals, (2) developan accurate surgical objective that willachieve the best functional and estheticresult, and (3) create a facial profile objec-tive which can be used as a visual aid inconsultation with the patient and familymembers. A prediction tracing of theanticipated presurgical orthodontic dentalmovements is created by placing an acetatesheet on the original cephalometric trac-ing and retracing the teeth into the posi-tion they will be placed with the presurgi-cal orthodontics, based on the goals andavailable mechanics (Figure 55-14A). Theinitial STO is then constructed with theteeth in their presurgical orthodontic finalposition.

The STO has significant importancein two phases of treatment planning: (1)the initial STO is prepared before treat-ment to determine the orthodontic andsurgical goals; and (2) the final STO is pre-pared after the presurgical orthodonticsare completed but prior to surgery todetermine the exact vertical and antero-posterior skeletal and soft tissue move-ments to be achieved (Figure 55-14B). The


STO is invaluable to the orthodontist andsurgeon in establishing treatment objec-tives and projected results, acting as thetreatment plan blueprint.

Definitive InterdisciplinaryTreatment PlanThe definitive treatment plan is formulatedbased on the patient’s concerns, clinicalevaluation, radiographic analysis, dentalmodel evaluation, initial STO, and otherrelevant evaluations. The general sequenc-ing of the treatment that may be involved isdescribed below.

Dental and Periodontal TreatmentAny indicated periodontal or generaldental care related to maintaining teethor improving dental health should beperformed prior to orthodontics andsurgical intervention. The objective is to

maintain as many teeth as possible andstabilize the periodontium. Temporarycrowns and bridges should be placedwhere necessary for the orthodontic andsurgical phases of the treatment. Perma-nent crowns, inlays, and bridges shouldbe constructed and inserted after thesurgery and orthodontics have beencompleted. This gives the restorativedentist the opportunity to provideescapement grooves, cuspid protection,and incisal guidance for optimum func-tion and esthetics. Initial periodontalmanagement may include scaling andcurettage, eliminating pockets, as well asgingival grafting to provide adequateattached gingiva. Occasionally, inpatients with several missing teeth,osseointegrated implant placement priorto orthodontics and orthognathicsurgery may provide anchorage fororthodontics and additional dental units

to help in repositioning the jaw struc-tures at surgery.

Presurgical OrthodonticsThe orthodontist is responsible for posi-tioning the teeth to the most desirableposition over basal bone in preparation forsurgery. The development of prescriptionbrackets and straight wire orthodontictechniques has helped simplify orthodon-tics. Most prescription bracket systems aredesigned to tip the cuspid roots distally,creating some space between the roots ofthe lateral incisors and cuspids. In casesrequiring segmentalization of the maxilla,this interdental space may be adequatethrough which to perform interdentalosteotomies, but if inadequate, additionalroom can be created by tipping the lateralincisor roots mesially and the cuspids moredistally. Bonded brackets are clean andeliminate interdental spacing problems

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FIGURE 55-14 A, Presurgical orthodontics. The orthodontic movements are traced on the acetate paper overlying the original lateral cephalometric trac-ing with the teeth in their predetermined, simulated positions. The solid lines, are the original position of the teeth. The dashed lines are the new posi-tion of the teeth following simulated extraction of four first bicuspids and orthodontic closure of the spaces. B, Surgical treatment objective (STO). This isan example of a completed final STO which shows the predicted outcome of the presurgical orthodontics and the anticipated surgical treatment. Thearrows and numbers indicate the direction and millimeters of movement.

A B


created by circumferential bands. Bondedbrackets with the currently availableresins are quite adequate for orthognathicsurgery procedures. However, inaccurateplacement of the brackets on the teeth canresult in undesired rotations, vertical dis-crepancies between teeth, malalignmentof marginal ridges and labial surfaces ofadjacent teeth, and unfavorable root posi-tions. Careful placement of brackets isparamount in helping to achieve high-quality results.

Nickel-titanium or similarly shapedmemory arch wires can be advantageousfor many orthognathic cases to aid inpresurgical orthodontic dental alignmentgoals. However, there are cases whereshape memory wires could be detrimen-tal, such as in an anterior open bite withan accentuated maxillary curve of Spee.The use of nickel-titanium wires or anytype of straight wire in these cases cancreate unstable results such as extrusionof teeth and buccal tipping of the molarsas a result of reciprocal forces. Stainlesssteel wires with compensating bends(Figure 55-15A) or sectional wires (Fig-ure 55-15B) may be a better-controlledmechanical force in these types of cases.The type of arch wire and how long eachis left in place is critical and must be care-fully monitored by the orthodontist.

To follow are basic presurgical ortho-dontic factors that commonly must beaddressed in preparing patients for orthog-nathic surgery.

It is important to avoid interarch classII mechanics (ie, class II elastics, growthappliances, TMJ “disk recapturing” splints,Herbst’s appliances) unless they are specif-ically required during the presurgicalorthodontics (ie, to correct arch asymme-try, decompensate mandibular arch withlingually inclined mandibular incisors).Long-term class II mechanics positionsthe mandibular condyle downward andforward in the fossa and may allow hyper-trophy (thickening) of the TMJ bilaminartissues (Figure 55-16). This same situationcan occur in patients with a “Sunday” bite.In these situations, following surgicalmandibular advancement, the bilaminartissue will slowly thin out over time caus-ing a slow relapse of the mandible towarda Class II relationship. In addition postur-ing the mandible forward for an extendedtime could result in foreshortening of theanterior articular disk attachments,increasing the risk of TMJ articular diskdisplacement postsurgery.

If a patient has been treated with long-term class II mechanics or has a “Sunday”bite, it may be an advantage to use light classIII mechanics for a few months presurgery

to eliminate the hypertrophied bilaminartissue and to decompensate for any unstableorthodontics that may have been created. Ifthe TMJ articular disk does become dis-placed, it would be better to have that occurbefore surgery because the articular disk canbe surgically repositioned and stabilizedwith high predictability at the same time asthe orthognathic surgery.15–18 Attempts torecapture a TMJ displaced disk with splinttherapy prior to surgery could be detrimen-tal to the patient relative to outcome stabili-ty and pain. In most cases nonsurgical“recapturing” the disk procedures haveproved clinically unsuccessful.

Treatment Options for Specific Orthodontic Problems This section presents specific dental mal-relationships and the orthodontic and sur-gical treatment options for consideration.Comprehensive assessment of the patientand developing treatment objectives willaid in selecting the appropriate treatment.

Adjustment for Tooth-Size DiscrepancyUsually TSDs occur because of small max-illary lateral incisors, making the combined

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

A B

FIGURE 55-16 Use of long-term class IImechanics, anterior repositioning splints, growthdevices, or “Sunday” bite relationships can causehypertrophy of the bilaminar tissue, positioningthe condyle downward and forward in the fossa.Postsurgery, particularly with mandibularadvancements, this tissue will slowly thin out,and the condyles will move posteriorly in thefossa causing a shift of the mandible and occlu-sion toward a Class II position.


mesiodistal width of the maxillary anteri-or six teeth too small to fit properlyaround the mandibular anterior six teeth,so that when the teeth are properlyaligned, an end-on Class II cuspid rela-tionship will result (Figure 55-17). If theBolton’s analysis indicates a significantTSD, presurgical orthodontic adjustmentscan usually correct the discrepancy andaid in providing a solid Class I cuspidrelationship at surgery and in the finaloutcome. TSDs can also occur in thebicuspids and molars, with the maxillaryteeth usually being too small comparedwith the mandibular teeth. The followingare treatment options that can be used tocorrect TSDs.

Slenderizing Teeth (Interproximal ToothSize Reduction) This technique reducesthe mesiodistal dimension of the involvedteeth. Since most TSDs involve largermandibular anterior teeth compared tothe maxillary anterior teeth, slenderizingthe mandibular anterior teeth can addressthe issue (Figure 55-18). Approximately 10 to 12% of the mesiodistal width can besafely removed from each tooth with 50%of the interproximal enamel remaining.Up to 3 mm of reduction can usually besafely achieved in the mandibular anterior

six teeth. Slenderizing the mandibularanterior teeth is an advantageous proce-dure, where the maximum width of theincisors is toward the incisor edge, partic-ularly in the presence of crowding and/oroverangulation of the mandibularincisors. It is not advantageous if themandibular anterior teeth are decreased inangulation (lingual inclination), sinceclosing the resultant spaces will furtherdecrease the incisor angulation and mayadversely affect esthetics and stability. Thistechnique is not indicated when the con-tact points are positioned toward the gin-giva, as this could result in tissue strangu-lation with loss of papilla and interdentalbone, creating significant periodontalissues. In the rare case where the maxillaryteeth are too large for the mandibularteeth, the maxillary teeth can be slender-ized, but this is best used when the maxil-lary teeth are crowded and/or overangulat-ed, and the individual crowns are widerthan normal (see Table 55-1).

When TSDs occurs in the bicuspidand/or molar area, slenderizing themandibular teeth will usually correct theproblem, unless the slenderizing will causeexcessive retraction of the mandibularanterior teeth. If this appears to be apotential outcome, then careful closure ofthe spacing by loosing (slipping) posterioranchorage (using mechanics that will

move the posterior teeth forward insteadof the anterior teeth backward) may solvethe problem. This approach may includeclass II mechanics to provide forwardforces on the posterior teeth or movingone tooth at a time on each side. Dentalimplants placed adjacent to or posterior tothe molars could provide stable anchorageto aid in applying the mechanics necessaryto push the posterior teeth forward.

Creating Space In the Arch This canenlarge the circumference of the involvedarch. Since TSDs are often related to smallmaxillary lateral incisors, opening spacearound the maxillary lateral incisors maybe a logical approach. A simple techniqueinvolves placement of coil springs betweenthe cuspids and lateral incisors and if need-ed between the lateral incisors and centralincisors to open spaces (Figure 55-19). Atthe end of treatment the lateral incisors canbe built up by bonding, veneers, or crowns.This technique can also be used in themandibular arch when the mandibularanterior teeth are too small compared tothe maxillary anterior teeth. In either archthis technique is most applicable when theteeth are decreased in angulation, sinceopening space will increase the axial incli-nation of the incisors. It may not be indi-cated when the maxillary or mandibularincisors are overangulated or crowded, as

FIGURE 55-17 This patient has well-alignedand leveled teeth in each arch. Maxillary lateralincisors are small creating a tooth-size discrep-ancy (TSD). Note that with the best possible fit,the patient has an end-on Class II occlusal rela-tionship secondary to the TSD.

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

A B


the resultant increased angulation may beunstable and cause untoward periodontalchanges. However, if there is significantcrowding or overangulation of the incisorsrequiring extraction of bicuspids, duringclosure of the bicuspid spacing by retrac-tion of the anterior teeth, space could becreated around the lateral incisors.

When maxillary incisors are alreadyoverangulated, it is not feasible to openspaces during the presurgical orthodon-tics. In this situation performing interden-tal osteotomies between the maxillary cus-pids and lateral incisors will permitopening space at surgery and the incisorscan also be uprighted to decrease theiraxial angulation. A maximum 3 mm ofspacing (1.5 mm on each side) can usuallybe acquired with this approach.

When the TSD occurs in the bicuspidor molar area, space can be opened aroundthe maxillary bicuspids and/or molars tocompensate for the tooth mass deficiency.Bonding, veneers, or crowns can then beplaced to eliminate the created space.

Altering Axial Inclination of IncisorsThis technique can affect the labial cir-cumference of the anterior teeth.Increased axial inclination slightly increas-es the arch length, and decreased axialinclination slightly decreases it. Applica-tion of this technique would result in

increasing the maxillary incisors’ angula-tion above normal and decreasing themandibular incisors’ angulation belownormal. This technique can accommodatesmall TSD differences, but may place theteeth in a compromised position relativeto stability and esthetics.

Surgery can alter the axial inclinationof the anterior teeth. In the maxillary arch,interdental osteotomies between the later-al incisors and cuspids, and in themandibular arch anterior subapicalosteotomies, will provide a means to alteraxial inclination of the incisors.

Altering Mesiodistal Angulation of Maxil-lary Incisors Tipping the roots of themaxillary central incisors distally awayfrom each other alters the position of thecontact points, making the intercontactdistance on each tooth slightly wider. Thiscan only be used for small differences.However, it then usually requires recon-touring of the distal aspect of the incisoredges and could cause a soft tissue voidbetween the mesial contact points and gin-gival tissues (“the black triangle”), creatingmuch concern for the patient. This tech-nique is rarely recommended.

Extraction of Mandibular Incisor Thistechnique should only be used for largeTSDs (5 mm or more) and only if there issignificant crowding and/or significantoverangulation of the mandibularincisors. Removing a mandibular incisorusually creates a significant space (thewidth of the tooth), and closure of thatspace may significantly decrease the axialinclination of the mandibular incisors. Inaddition it may cause a decreased trans-verse width between the cuspids result-ing in relative narrowing of both maxil-lary and mandibular arches. Extractionof a mandibular incisor may produce anincreased overjet. If the patient has agood maxillary arch but mandibularcrowding and overangulation, large TSD,and an end-on or slight Class III anterior

occlusion, the single mandibular incisorextraction may be the treatment ofchoice. An alternative in cases with largetooth-size discrepancies would be toslenderize the mandibular anterior teethand create spacing around the maxillarylateral incisors.

A surgical alternative for a large TSD,when the teeth are not crowded and havegood axial angulation, would be to extractthe mandibular incisor and perform a verti-cal ostectomy through the mandible at theextraction site and rotate the segmentstogether to eliminate the extraction space(Figure 55-20). This would prevent furtherdecreased angulation of the incisors withsubsequent orthodontics but may narrowthe anterior aspect of the mandible.

Correct Overangulated (Proclined) and/or CrowdedMaxillary Anterior TeethOverangulated and/or crowded maxillaryanterior teeth are most commonly seen inpatients with maxillary deficiency(hypoplasia). The following treatmentmethods can be used to correct this typeof situation.

Slenderizing and Retraction This tech-nique involves removal of tooth structureat the contact points and is applicablewhen there is a rare reverse TSD with themaxillary anterior teeth too large for themandibular anterior teeth. Usually up to 3 mm of tooth structure can be safelyremoved from the contact area of themaxillary anterior six teeth with a marginof 50% of enamel remaining at the con-tact areas. However, this could make themaxillary incisors slightly smaller in sizeunless they are significantly oversized tobegin with.

Extraction and Retraction First or sec-ond bicuspids can be extracted depend-ing on the amount of crowding, theanchorage requirements, and the amountof retraction of the incisors necessary.

FIGURE 55-19 Placing coil springs between themaxillary cuspids and lateral incisors as well as thelateral incisors and central incisors can open upspacing around the lateral incisors to correct a tooth-size discrepancy. Post-treatment, the lateral incisorscan be built up by bonding, veneers, or crowns.


Every 1 mm of incisor retraction willrequire 1 mm of space on each side of thearch. Therefore, if the orthodontic goal isto retract the maxillary incisors by 3 mm,then 6 mm of maxillary arch space will berequired to accomplish this. Extractingfirst bicuspids will result in greaterincisor retraction, whereas six multiroot-ed posterior dental units (compared tosix single-rooted anterior dental units)provide greater posterior anchorage.Extracting second bicuspids will result inless incisor retraction, whereas four pos-terior dental units (compared to eightanterior units) provide less posterioranchorage so that the posterior teeth willmove forward a greater amount com-pared with first bicuspid extractions. Theocclusal plane angle will also affect theposterior anchorage. Low occlusal planeangle cases will have greater posterioranchorage stability, even with secondbicuspid extraction, than will highocclusal plane angle cases. High occlusalplane angle cases will have less posterioranchorage stability, even with first bicus-pid extraction, than low occlusal planeangle cases. These factors are probably

related to bite force influences. Theamount of crowding may also influencewhich teeth to extract.

Distalizing Posterior Teeth This objectivecan be accomplished using pendulum-typeappliances, headgear, class II mechanics, orosseointegrated implants (ie, implants pos-terior to molars, zygomatic implants,palatal implants, or buccal corteximplants). Distalizing maxillary posteriorteeth can be augmented with class IImechanics but should only be used short-term and discontinued several monthsprior to surgery to minimize postsurgicalskeletal relapse potential that can occurwith the use of long-term class II mechan-ics and the subsequent adverse effects onthe TMJs. Another option is to distalize onetooth at a time on each side of the arch,beginning with the second molars (2 teethmoved against 12 anchor teeth). Anotherfeasible approach is to use osseointegratedanchors to distalize the maxillary arch, withimplants placed in either the zygoma but-tress, posterior to second molars, orattached to the buccal cortex. The implantscan be left submerged after orthodontictreatment is completed, or could requireadditional surgery for removal if notremoved during the orthognathic surgery.

Anterior Maxillary Segmental Osteoto-mies This technique permits uprightingof the anterior teeth but will cause the api-cal base of the segment to shift forward rel-ative to the incisor edges unless teeth areextracted to reposition the incisal edges ofthe anterior teeth posteriorly. Carefulassessment of the profile esthetics is neces-sary to determine if the patient can estheti-cally benefit from this change. The inter-dental osteotomies should be done betweenthe lateral incisors and cuspids as this offersthe best control in uprighting the segments(Figure 55-21) and also allows opening ofspace between the lateral incisors (up to 3 mm with 1.5 mm per side) that can beused for correction of crowding or TSD.

Maxillary Expansion by Orthodontics,Orthopedics (Rapid Palatal Expansion),and Surgically Assisted Rapid PalatalExpansion These techniques will increasearch length and may allow retraction of theanterior teeth. However, they will alsoincrease the curve of Wilson as the trans-verse width of the maxillary arch increasesbecause the teeth will expand three times asmuch as the palate expands (Figure 55-22).In addition, with SARPE, the palate movesinferiorly. The expanded arches may not beas orthodontically stable, requiring long-term or permanent retention.

Correct Overangulated (Proclined) and/or CrowdedMandibular Anterior TeethOverangulated and/or crowded mandibu-lar teeth occur most often with mandibu-lar deficiency (hypoplasia). The following

FIGURE 55-20 In the case of a tooth-size dis-crepancy (TSD) ! 5 mm, in the presence of well-aligned teeth in proper angulation, the TSD canbe managed by removing a mandibular centralincisor and performing a vertical midline ostec-tomy (A) with closure of that space (B) and sta-bilization with a bone plate.

A

B

FIGURE 55-21 An anterior maxillary segmentalosteotomy can be used to upright the maxillaryincisors. However, the dentoalveolus at the apicalbase will rotate anteriorly if no teeth are extract-ed. Since this may affect the position of the noseand upper lip, careful evaluation of facial esthet-ics is necessary to determine if this approach isappropriate. Dashed line represents the originalposition of the anterior maxilla, and the solidline represents the uprighted segment.


treatment options can be used to correctthese types of conditions.

Slenderizing and Retraction This tech-nique involves removal of tooth structureat the contact points and is most applica-ble when there is a TSD with the mandibu-lar anterior teeth being too large for themaxillary anterior teeth. Up to 3 mm oftooth structure can be safely removedfrom the contact areas of the mandibularanterior six teeth with a margin of 50% ofenamel remaining at the contact areas.Subsequent retraction will decrease theaxial inclination of the incisors providingthat no major crowding is present.

Extraction and Retraction First or sec-ond bicuspids can be extracted dependingon the degree of angulation, amount ofcrowding, the anchorage requirements,and the amount of retraction of theincisors necessary. Every 1 mm of incisor

retraction will require 1 mm of space oneach side of the arch. Therefore, if theorthodontic goal is to retract the mandibu-lar incisors by 3 mm, then 6 mm ofmandibular arch space will be required toaccomplish this. Extracting first bicuspidswill result in greater incisor retraction,whereas six multirooted posterior dentalunits (compared with six single-rootedanterior dental units) provide greater pos-terior anchorage. Extracting the secondbicuspids will result in less incisor retrac-tion, whereas four posterior dental units(compared with eight anterior units) pro-vide less posterior anchorage, so that theposterior teeth will move forward a greateramount compared with first bicuspidextractions. The occlusal plane angle willalso affect the posterior anchorage. Lowocclusal plane angle cases will have greaterposterior anchorage stability, even withsecond bicuspid extraction, than will highocclusal plane angle cases. High occlusal

plane angle cases will have less posterioranchorage stability even with first bicuspidextraction than low angle cases. These fac-tors are probably related to bite force influ-ences. The amount of crowding may alsoinfluence which teeth to extract. If there isa large TSD (! 5 mm), then extraction of amandibular incisor could be considered.

Distalize Posterior Teeth The mechanicsto accomplish this include intra-arch, inter-arch, extraoral, or implant mechanics. ClassIII mechanics (ie, elastics, headgear) can beused to distalize the mandibular teeth, butmay increase loading on the TMJs and couldinitiate TMJ problems. Another option is todistalize one tooth at a time on each side ofthe arch, beginning with the second molars (2 teeth moved against 12 anchor teeth).However, this technique takes a lot of time.The placement of dental implants posterior tothe molar teeth or in the posterior buccal cor-tex could facilitate retraction without appre-ciably increasing the load to the TMJs.

Anterior Mandibular Subapical OsteotomiesThis technique permits uprighting of theanterior teeth, but will cause the apical base ofthe segment to shift forward relative to thechin (Figure 55-23), unless teeth are extractedat the time of surgery to reposition the incisaledges of the anterior teeth posteriorly.

Bilateral Mandibular Body OsteotomiesThis technique will permit uprighting of theanterior teeth and forward rotation of thechin (Figure 55-24), unless teeth are extract-ed. Without extraction, bilateral body bonegrafting will be required to provide bonycontinuity between the segments and facili-tate healing. This technique would only beindicated if the chin is anteroposteriorlydeficient before surgery.

Mandibular Symphysis DistractionOsteogenesis This technique, usuallyperformed with a midline vertical osteoto-my, will allow expansion of the dentoalve-olus and widening of the mandibular arch,

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


providing room to retract and/or align theteeth. This is an excellent treatmentmethod to gain space for major archlength discrepancies. However, it is doneas a prerequisite surgery to achieve theorthodontic goals prior to the majororthognathic surgery. Orthodontic prepa-ration may be necessary prior to perform-ing the midline vertical osteotomy. Theroots of the central incisors (or the adja-cent teeth, wherever the osteotomy is to beperformed) must be tipped away fromeach other to make room for the interden-tal osteotomy. This can be accomplishedby placing the mesial aspect of the brackethigher than the distal aspect on each of thecentral incisors. Placing a short segmentstraight arch wire will then tip the rootsdistally, creating space to safely performthe vertical interdental osteotomy (Figure55-25). If a tooth-borne distraction deviceis used, orthodontic treatment on anyother teeth should not be initiated untiladequate healing of the distraction areahas occurred (approximately 4 monthsfrom initiation of the distraction). Other-wise it may result in developing dentalmobility and orthodontic instability, withthe teeth expanding more than the basalbone. This can result in transverse dental

relapse postdistraction with less expansionof the dental arch than desired. Bone-borne devices are not affected by predis-traction orthodontics.

Correct Underangulated (Retroclined) Maxillary IncisorsUnderangulated maxillary incisors aremost commonly seen in Class II Division 2malocclusions or with missing teeth in thearch. The following approaches can beused to correct this type of condition.

Correct Crowding Crowding of themaxillary anterior teeth can accompanyvertically inclined teeth. Therefore, cor-recting the crowding will increase theincisor angulation.

Open Space In Class I and Class II patientsunderangulated incisors may be presentbecause of previous extractions (ie, bicus-pids), congenitally missing teeth, previoustrauma resulting in loss of teeth, or smallmaxillary anterior teeth (ie, small maxillarylateral incisors). Opening space in the bicus-pid areas, if the problem exists there, can cor-rect this problem and provide additionaldental units for a more complete occlusal

result. The use of coil springs usually workswell for this situation. If the problem is in thelateral incisor area, opening space can helpcorrect the TSD as well as increase theincisor angulation (Figure 55-26).

Interarch Mechanics The use of class IIImechanics (ie, elastics) can increase max-illary incisor angulation. However, theclass III mechanics can be detrimental byoverloading the TMJs.

FIGURE 55-23 The anterior mandibular sub-apical osteotomy can be used to upright themandibular anterior teeth, causing the apicalbase of the segment to shift forward relative tothe chin, if teeth (bicuspids) are not extracted atthe time of surgery. This may or may not be adesired outcome. A chin augmentation may berequired to achieve optimal esthetics.

FIGURE 55-24 Bilateral body osteotomies canbe used to upright the mandibular anteriorteeth, but the chin will rotate forward unlessteeth are extracted. A gap created in themandibular body area will require graftingunless teeth are extracted (first bicuspids) toallow the mandibular anterior teeth to moveposteriorly, thus decreasing the forward move-ment of the chin.

FIGURE 55-25 Mandibular symphysis distractionosteogenesis. A, Often the incisor roots are veryclose together. B, Space must be created betweenthe roots of teeth adjacent to the intended verticalosteotomy. C, Placing brackets on only the centralincisors with the mesial aspect of the brackets high-er than the distal aspect on each tooth and placinga short straight wire segment, will tip the roots dis-tally away from each other, creating space to per-form the vertical interdental osteotomy.

B

A

C


Interdental Osteotomies An anteriormaxillary subapical osteotomy or seg-mentalized Le Fort I osteotomy will per-mit rotation of the anterior teeth toincrease their angulation. However, sig-nificant room must be created betweenthe roots of the adjacent teeth (lateralincisors and cuspids) at the osteotomyareas. Since bone removal between theteeth may be required, there is anincreased risk of damage to the adjacentteeth. If the maxilla requires surgicalexpansion, then segmentalizationbetween the lateral incisors and cuspidswill allow the anterior segment to rotateposteriorly between the expanded poste-rior segments with fewer requirementsfor bone removal, if required at all.

Correct Underangulated (Retroclined) MandibularIncisorsUnderangulated mandibular incisors aremore commonly seen in patients withprognathic mandibles or with missingteeth. The following treatment methodscan be used to correct this condition.

Correct Crowding Crowding of themandibular anterior teeth often accompa-

nies vertically inclined teeth. Therefore,correcting the crowding will increase theincisor angulation.

Open Space In Class I and Class IIpatients underangulated incisors may bepresent because of previous extractions,congenitally missing teeth, previous trau-ma resulting in loss of teeth, or smallmandibular teeth. In Class III patientsunderangulated incisors may be presentdue to an excessive amount of alveolarbone compared with the size of the teeth.If bicuspids are missing, opening space inthe bicuspid areas can correct this prob-lem and provide additional dental unitsfor a more complete occlusal result. Theuse of coil springs usually works well forthis situation (see Figure 55-26).

Occasionally a mandibular incisormay be missing for various reasons. Viableoptions include opening appropriate spacearound the remaining three incisors andbuilding up the crowns by bonding,veneers, or crowns. This technique worksbest if there is a TSD that is less than thewidth of the missing tooth. However, themaxillary dental midline will be in thecenter of a mandibular incisor. Anotheroption would be to open space in the area

of the missing tooth and then replace itwith a dental implant or bridge. This tech-nique may work best when there is no TSDwith a full-size dental replacement.

Interarch Mechanics The use of class IImechanics (ie, elastics, Herbst’s appliance)can increase mandibular incisor angula-tion. However, long-term class II mechan-ics can be detrimental to outcome stabilityand results, because of the potential unto-ward effects on the TMJs.

Interdental Osteotomies An anteriorsubapical osteotomy or bilateral anteriorbody osteotomies will permit rotation ofthe anterior teeth to increase their angula-tion. However, significant room must becreated between the roots of the teethadjacent to the osteotomy areas. Sincebone removal between the teeth may berequired, there is an increased risk of dam-age to the adjacent teeth.

Correct Excess Curve of Spee: Maxillary Arch This condition is most often seen withanterior open-bite situations and highocclusal plane facial types. Careful assess-ment of the curve of Spee is importantbecause using only orthodontic mechanicsto correct this condition may not be verystable. An increased curve of Spee usuallymakes it difficult to get the occlusion to fittogether. The condition can be addressedby the following treatment options.

Extruding Anterior Teeth Conventionalorthodontics with straight wire techniqueswill tend to extrude the anterior teeth, andas a byproduct will tip the molars buccal-ly, increasing the curve of Wilson. Thesedental changes may be unstable andfraught with relapse potential.

Intruding Midbuccal Teeth This is a verydifficult technique, unless high-pull head-gear or osseointegrated implants are usedto provide intrusive forces. This would

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

BA


require significant patient compliance andis not a commonly applied procedure.

Extraction and Retraction Extraction ofmaxillary first or second bicuspids withretraction will usually decrease the curve ofSpee, providing the incisors are overangu-lated to begin with.

Orthodontic, Orthopedic, or SurgicallyAssisted Rapid Palatal Expansion withRetraction Expansion of the maxillaryarch by any of these techniques willincrease the arch length and allow someretraction of the anterior teeth. In lateadolescence or adulthood, SARPE mayprovide better stability than the other twotechniques. However, note that the curveof Wilson will increase because the expan-sion at the occlusal level compared withthe palate will be a 3:1 ratio.19

Surgical Correction The maxilla can beorthodontically aligned in segments byaligning the four incisors at a differentlevel, compared with the posterior teeth, toavoid extrusion, intrusion, and buccal tip-ping of teeth. Placing compensating verti-cal steps between the lateral incisors andcuspids (see Figure 55-15A) will accom-plish alignment at different levels. Forsome cases the vertical positional differ-ence may occur between the cuspids andbicuspids, or could occur asymmetricallyon one side of the arch compared with theother side. The step in the arch would thenbe made between the appropriate teeth.Another technique to use involves cuttingthe arch wire into two or more segmentsand aligning groups of teeth in individualunits (see Figure 55-15B). However, itmay be more difficult to control rota-tions and root position, particularly ofthe teeth adjacent to the ends of the seg-mented wires, compared with using acontinuous wire with compensating ver-tical steps. The arch can then be leveledsurgically with a three-piece maxilla per-forming osteotomies between the lateral

incisors and cuspids. The three-piece LeFort I osteotomy, with interdentalosteotomies performed between the lat-eral incisors and cuspids, will permitrepositioning of the anterior segmentindependent of the posterior segments(Figure 55-27). The anterior segment canbe reoriented vertically and anteroposte-riorly, and the axial inclination of theincisors can be changed to correct thecurve of Spee and achieve the best inter-digitation of the segments.

Correct Accentuated Curve ofSpee: Mandibular ArchAn accentuated curve of Spee in themandibular arch most often occurs inanterior deep-bite relationships.

Intruding Mandibular Anterior TeethIntrusion mechanics can predictably infe-riorly position mandibular anterior teethapproximately 2 mm. Beyond 2 mm thevertical relapse approaches 60%. Withaccentuated curves of Spee the contactarea of the teeth will be at a different level

where the teeth are more narrow, belowthe normal contact level. Therefore, forevery 1 mm of leveling of the mandibulararch, the mandibular incisor edges willmove forward 0.6 mm to 1 mm as the con-tact points align. Any crowding of the archwill further contribute to flaring of theincisors. Intruding teeth will decrease theanterior mandibular vertical height andmust also be taken into consideration sothat the anterior mandibular height is notexcessively shortened.

Extruding Midbuccal Teeth Extrusionof midbuccal teeth may be more stablethan intrusion of anterior teeth. Howev-er, this technique is difficult to performwithout special considerations. If thepatient’s malocclusion has the bicuspidsand first molars in occlusion, extrusionwill be virtually impossible. However,constructing a splint that will open thebite and engage only the mandibularanterior teeth and second molars, withthe bicuspids and first molars out of con-tact with the splint, will permit extrusion

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

A B


of the midbuccal teeth. Another alterna-tive would be to correct the accentuatedcurve of Spee after the mandible andocclusion are surgically repositioned,placing the incisors and molars intoproper contact, and then extrude themidbuccal teeth postsurgery. With thisapproach the molars may tip distally andthe arch may widen somewhat.

Interdental Osteotomies An anteriorsubapical osteotomy (Figure 55-28) or bilat-eral anterior body osteotomies (Figure 55-29) will permit downward repositioning ofthe anterior teeth, with very stable resultswhen the surgery is properly performed. Ifthe anterior vertical height of the mandibleis excessive, then the subapical osteotomywould be indicated since it will shorten theanterior mandibular height by the amountthat the incisors are lowered. Bilateral anteri-or body osteotomies would be indicatedwhen the vertical height of the anteriormandible is normal or less, so that the ante-rior height remains unaltered while thecurve of Spee is corrected.

Correct Reverse Curve ofSpee: Maxillary ArchReverse curves of Spee are more common-ly seen in Division 2 malocclusions and invertical maxillary deficiencies with ananterior deep bite. The maxillary incisorsare commonly in a decreased axial inclina-tion. Crowding may or may not be present.

Correct Crowding or Division 2 RelationsEliminating crowding and Division 2 den-tal positions will tip the incisors forward,increasing the incisor axial angulation anddecreasing the reverse curve of Spee.These movements will usually fill out theupper lip, but may decrease the maxillarytooth-to-lip relationship. Maxillaryincisors may become intruded with astraight wire technique.

Extruding Midbuccal Teeth This tech-nique is difficult if the midbuccal teeth are

in occlusion with mandibular teeth. How-ever, the bite can be opened with a splintthat affords contact on only the maxillarysecond molars and anterior teeth, with themaxillary midbuccal teeth out of contactwith the splint. The midbuccal teeth(bicuspids and first molars) can then beextruded into position to improve thecurve of Spee.

Open Spaces If the reverse curve ofSpee is related to missing teeth or TSDs,then spaces can be opened to aid inincreasing the axial inclination of theincisors and decreasing the reverse curveof Spee. These spaces can then be elimi-nated by bonding, crown and bridge, ordental implants and crowns.

Interdental Osteotomies Multiple maxil-lary osteotomies can be performed so thatthe maxilla can be repositioned in segments,enabling leveling of the arch. Presurgicalorthodontics should be designed to align

the teeth at different vertical levels to facili-tate the surgery and minimize orthodonticrelapse potential. It is usually easiest andmost applicable to make the osteotomiesbetween the lateral incisors and cuspids.This may particularly be indicated when themaxilla must be repositioned anyway andmaxillary expansion is also required. Per-forming a three-piece segmented maxillaryosteotomy will then allow vertical alterationbetween the anterior and posterior seg-ments to level the curve of Spee.

Correct Reverse Curve ofSpee: Mandibular ArchThis condition is most commonly seen inpatients with macroglossia, habitualtongue posturing, or tongue thrust, withan associated anterior open bite. The fol-lowing techniques can be used to correctthis type of condition.

Extruing Anterior Teeth Extrusion ofanterior teeth may not be very stable long

FIGURE 55-28 Subapical osteotomy correctingan accentuated curve of Spee in the mandibulararch. A, This can be accomplished with a sub-apical osteotomy composed of two interdentalosteotomies and a subapical ostectomy to set theanterior teeth inferiorly. B, C, This is indicatedwhen the anterior mandibular height is greaterthan normal, as this technique will shorten theanterior mandibular height. This same basictechnique can be used to elevate the segment tocorrect a reverse curve of Spee.A

B C


term, and without permanent retention,could result in re-intrusion and redevelop-ment of an anterior open bite.

Intrusion of Midbuccal Teeth This is adifficult technique but may be accom-plished with osseointegrated implants asanchors. However, it is not known if thiswould be stable long term.

Extract and Retract If the mandibularincisors are significantly overangulated,with or without crowding, bicuspidextractions can be performed and theincisors retracted, which will decrease thereverse curve of Spee.

Bonding the Mandibular Anteriors Thistechnique can be used to level the arch bybuilding up the incisors, increasing thecrown height. However, care must betaken not to exceed a safe crown-root ratioand/or create an esthetic compromise.

Interdental Osteotomies Anterior sub-apical (see Figure 55-28) or anterior bilat-eral mandibular body osteotomies (seeFigure 55-29) can be used to elevate theanterior teeth. If the anterior mandibularheight is short, then the subapical osteoto-my can also be used to increase the anteri-or height of the mandible. If the anterior

mandibular height is normal, then thebilateral anterior body osteotomies willpermit elevation of the anterior teethwhile maintaining the anterior height ofthe mandible.

Anteroposterior Arch Asymmetry (Maxilla or Mandible)Anteroposterior arch asymmetry, whenthe cuspid on one side of the arch is ante-rior to the cuspid on the opposite side ofthe arch, is fairly common in patients withdentofacial deformities. Arch asymmetriescan be related to developmental abnor-malities, missing teeth, or ankylosed teeth.Dental midlines may not align with thefacial midline.

Extract Unilaterally In some cases uni-lateral extraction and retraction will cor-rect the problem. The decision must bemade as to which tooth to extract. Extrac-tion of a first bicuspid will allow greateranterior retraction compared withextracting a second bicuspid. This extrac-tion would only be indicated if there weresignificant overangulation of the incisors,crowding, and/or significant midlinedental shift.

Open Space Unilaterally This techniquewould be indicated if a tooth is missing,

there is significant decreased angulation ofthe incisors, and/or the midline is signifi-cantly deviated to one side.

Interarch Mechanics This technique canbe effectively used by incorporating class IImechanics on one side and class IIImechanics on the opposite side. Anteriorcross-arch elastics can also be helpful. Ifonly one arch is involved, then maximiz-ing anchorage in the other arch is veryimportant so that an asymmetry does notdevelop in the normal arch. Osseointe-grated implants can be used as anchors tocorrect asymmetry in an arch withouthaving to use interarch mechanics.

Osteotomies Osteotomies can be used inthe maxillary arch by segmentalization ofthe maxilla and advancing one side morethan the other side. Osteotomies in themandibular arch to correct arch asymme-try can become somewhat complex. Ante-rior subapical osteotomies with removal ofa unilateral tooth can correct some largediscrepancies (6 to 9 mm). However, thesubapical osteotomy may need to be com-bined with ramus sagittal split osteotomiesand a unilateral or bilateral body osteoto-my, with or without extraction, to shift theocclusion into a symmetric position.These types of movements require a highdegree of surgical skill, but can providehigh-quality outcomes.

Divergence of Roots Adjacent to Interdental Surgical Sites When interdental osteotomies areplanned it may be necessary for theorthodontist to tip the adjacent toothroots away from the area of the plannedosteotomy to prevent damage to the teeth(Figure 55-30). If the roots are too closetogether, postsurgical periodontal prob-lems may develop with possible loss ofinterdental bone and teeth. Creatinginterdental space between the roots sig-nificantly improves the margin of safety.This can be easily achieved by selective

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

A B


bracket placement. For the tooth mesialto the osteotomy, the bracket is slightlyrotated so that the mesial aspect of thebracket is positioned slightly more gingi-vally compared with the distal aspect ofthe bracket (Figure 55-31). Converselythe distal tooth bracket is positioned sothat the distal aspect of the bracket isplaced slightly more gingivally comparedwith the mesial aspect of the bracket.With a straight wire technique the rootswill diverge.

Postsurgically, periapical radiographymay be necessary for the orthodontist tocheck for rebonding the adjacent teethbrackets to ensure proper root angulationat completion of treatment.

Extraction Versus NonextractionThe decision to extract or not to extractcan sometimes be difficult. There are anumber of factors that may contribute tothis determination.

Overangulated Anterior Teeth Excessiveover-angulated anterior teeth may requireextraction to set the teeth over basal bone.However, if the arch is to be expanded orteeth slenderized for TSD, for example,then extraction may not be necessary.

Crowding This is a common indicator,particularly with major crowding or

overangulated teeth. However, if crowdingis mild to moderate, widening of the archor teeth slenderizing for TSD may elimi-nate the need for extraction.

Tooth-Size Discrepancy TSDs of signifi-cant magnitude may indicate the need forextraction, particularly if the TSD of theanterior mandibular teeth is 5 mm orgreater and the mandibular incisors areoverangulated and/or crowded, in whichcase a mandibular incisor extraction couldbe considered.

Curve of Spee Accentuated curves of Speein the maxillary arch usually have overangu-lated maxillary incisors, and reverse curvesof Spee in the mandibular arch usually haveoverangulated mandibular incisors. Extrac-tion of bilateral first or second bicuspidsand retraction will result in leveling of thearches. However, arch expansion, whenindicated, may create enough room so thatextractions are not necessary.

Arch Asymmetries With significantanteroposterior arch asymmetries, unilat-eral or bilateral asymmetric extractions(ie, first bicuspid on one side and a sec-ond bicuspid on the opposite side) maybe indicated when there is coexistingcrowding overangulated incisors, or mid-line shift.

Coordination of Maxillary andMandibular Arch Widths In some cases transverse arch width dis-crepancies can be corrected with stableand predictable orthodontic movements,but in other cases orthodontic correctionmay be very unstable and fraught withrelapse. It must be determined whetherto correct width problems by orthodon-tics, orthopedics, SARPE, or surgicalexpansion. Even with SARPE using afixed device, the palate only expandsapproximately one-third the amount ofthe expansion that occurs at the occlusallevel, thus increasing the curve of Wil-son.19 For example, if the maxilla isexpanded with SARPE and the expansionat the occlusal level is 6 mm, then theexpansion at the palatal level will only be2 mm (see Figure 55-22). Patients withreverse curves of Wilson in the maxillaryarch may benefit more from these tech-niques, but those with a pretreatmentaccentuated curve of Wilson may haveunfavorable results, with subsequent dif-ficulty getting the buccal cuspids tointerdigitate. The following predictablechanges will occur with maxillary archexpansion by orthodontic, orthopedic,or SARPE procedures.

FIGURE 55-30 Interdental osteotomies. A, Pantomogram demonstrating inadequate room betweenthe roots of the lateral incisors and cuspids. Performing osteotomies with roots in this position couldresult in severe periodontal compromise and possible loss of teeth. B, Adequate spaces for interdentalosteotomies can be created by selective bracket placement on the adjacent teeth.

A B

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


1. The bite may open anteriorly, particu-larly if the maxillary incisors have sig-nificant initial vertical inclination. Ifthe maxillary incisors are overangulat-ed, then the bite may deepen anterior-ly as the spacing is closed.

2. Buccal tipping of the maxillary poste-rior teeth will increase the curve ofWilson, because the lingual cusps willmove downward relative to the buccalcusps. This may make it very difficultto properly interdigitate the buccalcusps orthodontically. Therefore,these techniques are not recommend-ed, especially when there is a preexist-ing accentuated curve of Wilson.

3. Long-term or perhaps permanentretention may be necessary to coun-terbalance the orthodontic relapsepotential seen in a high percentage ofthese patients.

4. In late adolescent and adult patients,SARPE will likely be necessary toexpand the maxilla orthopedically sincethe midpalatal suture is usually closed.

Surgical expansion of the maxilla atthe time of the Le Fort I procedure usingmultiple segmentation of the maxilla, sta-bilization with bone plates and palatal orocclusal splints, and hydroxyapatite syn-thetic bone grafting in the palate and lat-eral maxillary walls can provide a goodoutcome. This technique when properlyperformed is very stable and eliminates theorthodontic relapse potential inherentwith the other techniques.

Missing TeethTeeth can be missing from the arches fora number of reasons such as congenitalabsence, uneruption, previous orthodon-tic extractions, extractions for periodon-tal or dental pathology, and trauma. Insome cases (ie, congenital absence ofmaxillary lateral incisors, previous inap-propriate bicuspid extraction) openingspace to accommodate replacement teethmay be indicated. This is most applicable

when the incisors are decreased in angu-lation without appreciable crowding. Ifthe incisors are already overangulatedand/or crowding is present, then openingspace orthodontically may be detrimentalto stability and periodontal health. In thissituation with missing maxillary lateralincisors, the cuspids can be used as later-al incisors, but may require considerablerecontouring to esthetically and func-tionally conform to lateral incisor mor-phology. Although this cuspid substitu-tion can work well for missing lateralincisors, it is done less frequently nowthat dental implants are so predictableand successful, thereby allowing thecanine to be placed in its normal andmore functional position.

When conditions permit, openingspace for replacement teeth can be accom-plished by appropriate mechanics toachieve the required space. Surgery canalso be used to create spacing in someareas. In the mandibular arch, distractionosteogenesis can be used to create space.The missing teeth can then be replacedwith dental implants, bridges, or partialdentures for example.

Correction of Rotated TeethBracket placement and arch wire adapta-tion are the primary keys to correctingrotated teeth and it is usually best toachieve these corrections presurgery.However, if the malrotations do not inter-fere with the establishment of the desireddentoskeletal relationship, then the rota-tions can be corrected postsurgery. Severerotations may require supracrestal fiberot-omy to prevent relapse and improve per-manent retention. This can often be doneat the time of orthognathic surgery.

Management of Ankylosed TeethTreatment of ankylosed teeth depends on(1) whether the tooth is primary or per-manent, (2) the surrounding dentition, (3)the eruption status, (4) tooth position andorientation, (5) the time of onset and

diagnosis, (6) the age of the patient and,(7) the treatment goals.

Ankylosed Primary Tooth This canimpede the development and eruption ofthe permanent successor. If a primarytooth has a permanent successor, treat-ment is immediate extraction followed byspace maintenance until the permanenttooth erupts. If no permanent successor ispresent and the primary tooth ankylosisoccurs at an early stage in jaw growth anddevelopment with submergence of thetooth eminent, treatment includes extrac-tion and space maintenance.20 If the anky-losis occurs late with no permanent suc-cessor, the occlusal and proximal contactscan be reestablished with restorative den-tistry to provide esthetics and functionwith perhaps many years of service.21

It is important to diagnose and treatthe ankylosed tooth before the adolescentgrowth phase. Retaining an ankylosedtooth during jaw growth leads to arresteddevelopment of the alveolar ridge. Theseverity of alveolar growth loss depends onthe amount of facial growth left at the timethat the ankylosis occurs. Timing theremoval of an ankylosed tooth just at thestart of the pubertal phase of adolescentgrowth may achieve the treatment objec-tive of maintaining alveolar ridge heightwhile allowing the tooth to remain longenough to act as a space maintainer andesthetic temporary.22

Ankylosed Permanent Tooth An unrec-ognized ankylosed permanent tooth tiedinto the arch wire can result in a significantmalocclusion (Figure 55-32). There are sev-eral ways of treating the permanent anky-losed tooth. If ankylosis of the permanenttooth has an early onset during eruption, thetooth should be luxated, allowing for furthereruption.2 If repeated luxation proves inef-fective, the tooth should be extracted to pre-vent submergence. If the onset of ankylosisoccurs late in the normal eruption pattern,the tooth should be luxated. If the attempt is


unsuccessful and the tooth does not sub-merge, it may be vertically restored ongrowth maturity. A composite build-up orcrown can be added to a partially eruptedankylosed tooth to level and align the arch.21

A deeply unerupted ankylosed tooth, prima-ry or permanent, may be left undisturbedunless it is infected, alters the alveolar bonegrowth potential, or constitutes an immedi-ate threat to the occlusion or adjacent teeth,or would impede the placement of anosseointegrated implant.3

Other treatment options includeextraction followed by reimplantation,osseointegrated implant, or prostheticreplacement.23 The patient’s developmentalage is very important in considering replac-ing an ankylosed tooth with an osseointe-grated implant. The implant will have thesame effect on growth of the alveolar ridgeas the ankylosed tooth, and therefore shouldbe considered for placement after alveolargrowth is essentially complete.24

Proffit suggests surgical luxation ofthe tooth with extraction forceps disrupt-ing the cementum-bone fusion followedby immediate orthodontic traction tomove the tooth into position.20 Luxationinvolves breaking the bony bridge ofankylosis without damaging the apicalnutrient vessels. This procedure formsfibrous inflammation tissue in the repar-ative process. This tissue forms a falseperiodontal membrane, and tooth erup-

tion may resume. Orthodontic move-ment should begin immediately. Compli-cations include possible crown, root, andalveolar fractures, loss of viability andvitality, as well as re-ankylosis. When anankylosed tooth is impacted, a similartechnique can bring an impacted tooth(usually canines) into the arch. Exposureinvolves surgical uncovering, applicationof orthodontic bonding, and tensionforces applied to direct the tooth intoocclusion. However, if the tooth becomesre-ankylosed, the orthodontic forces willintrude adjacent teeth.

Orthodontics for Surgical Management ofAnkylosed Teeth Presurgical orthodon-tics may be indicated to create adequatespace (minimum of 2 to 3 mm) betweenthe roots of the adjacent teeth to safelyaccommodate interdental osteotomiesaround the ankylosed tooth. Spacing isbest assessed with pantomographic orperiapical radiographs. The ankylosedtooth is left out of the arch wire, and allother teeth are properly aligned. If orthog-nathic surgery is required to correct adentofacial deformity, the orthodonticsare performed in the traditional manner,but the ankylosed tooth must remain outof the arch wire, unless it aligns well withone of the dental segments. Followingsurgery, orthodontic mechanics can beinitiated immediately to help get themobilized dental segment with the anky-losed tooth into the best possible position.

Osteotomy Performing single-tooth os-teotomies or sectional-arch osteotomieswith mobilization of the segment will per-mit immediate repositioning of the anky-losed tooth (Figure 55-33), or facilitaterepositioning by distraction osteogenesis.

In select cases where an ankylosed pri-mary molar is present, without a successor,a treatment option is to remove the anky-losed tooth and eliminate the extractionspace by performing a vertical body ostec-tomy in conjunction with a mandibular

ramus osteotomy and advance the posteri-or teeth and mandibular body forward(Figure 55-34). This eliminates the needfor osseointegrated implants and extensivedental reconstruction.

Final Presurgical PreparationAs presurgical orthodontic treatment pro-gresses, new diagnostic records (lateralcephalograms, pantomograms, dentalmodels) are taken to determine the feasibil-ity and timing of surgical procedures. Thiswill also aid the orthodontist in identifyingspecific areas that may need to be addressedin completing the presurgical orthodonticgoals (ie, sectional leveling of the arch

FIGURE 55-32 An ankylosed first molar tiedinto the arch wire has prevented development ofthe alveolus and consequently created a signifi-cant posterior open bite.

FIGURE 55-33 Single-tooth osteotomies can beperformed as isolated cases or they can be per-formed in combination with multiple maxillaryosteotomies to allow individual movement of thedental osseous segments or application of imme-diate distraction osteogenesis to reposition thetooth properly. The case illustrated had an anky-losed maxillary right cuspid (see Figure 55-8)treated with segmental maxillary osteotomiesincluding a single tooth segment containing theright cuspid (A, B)

A

B


segments, marginal ridge alignment, verti-cal dental alignment, buccal surface align-ment, additional TSD correction).

During surgery the jaws are usuallywired together once or twice, as each jaw isindependently mobilized and stabilized withrigid fixation. To facilitate wiring the jawstogether as well as providing a means ofusing postsurgical elastics if required, fix-tures attached to the brackets or arch wiresare usually necessary. Fixtures attached tothe brackets are dependent on the manufac-turer but may include ball hooks built ontothe brackets, T pins, and K hooks, (Figure55-35). Fixtures attached to the arch wireinclude crimped-on hooks and solderedpins (Figure 55-36). Hooks built onto thebrackets are preferred, followed by the other

hooks placed on the brackets (T pins, Khooks). The least preferred are the hooks onthe arch wire. The reason is that if post-surgery elastics are required for an extendedtime, the elastics and hooks on the arch wirewill activate the arch wire, possibly creatingunwanted orthodontic forces and move-ments (ie, tipping the crowns lingually andthe roots buccally). This undesirabletorquing occurs to a much lesser degreewhen the hooks are directly on the brackets.

When the maxilla or mandible are tobe segmentalized, it may be better for theorthodontist to section the arch wire (seeFigure 55-15B) and bend the ends inwardat the predetermined osteotomy areasimmediately prior to surgery, or the sur-geon can cut the wire at surgery.

The best type of arch wire to placeprior to surgery is a rectangular stainlesssteel wire that fills the bracket slot. Forexample, with an 18 slot, a 17 " 25 gaugewire is recommended, and for a 22 slot, a21 " 25 gauge wire is indicated. This willhelp stabilize the individual dental unitstogether as a whole arch or in segmentswhen segmental surgery is required. Thefinal wire should be placed 2 to 3 monthsprior to surgery.

Postsurgical OrthodonticsIn preparation for the postsurgery ortho-dontic phase of treatment, the surgical sta-bilizing splint, if used, is usually removed 4 to 6 weeks postsurgery. If the palatalsplint design is used and a large maxillaryexpansion has been performed, the splintcan remain for a longer period and thepostsurgical orthodontics can be per-formed around it. The maintenance of thesplint will enhance the transverse stabilityand it can be left in for 2 to 3 months orlonger if necessary. It can be made into aremovable appliance.

If rigid skeletal fixation is used, activeorthodontics involving changing the archwires can usually resume 4 to 6 weeks post-surgery, when patients are usually comfort-able enough to tolerate changing their arch

wires. The orthodontist can be fairlyaggressive at finishing the occlusionbecause the osseous segments can still bemoved slightly. The teeth move much morerapidly for the first few months post-surgery because there is an increased bonymetabolism as a result of the surgery. Theorthodontist can therefore accomplish in 1 to 2 weeks what would normally take 4 to 6 weeks to complete. Applying activemechanics at this early postsurgical ortho-dontic phase of treatment and booking thepatient for a routine orthodontic follow-up 4 to 6 weeks later could result in uncon-trolled excessive orthodontic movements,resulting in an unfavorable outcome.

FIGURE 55-34 A, B, An ankylosed submergedprimary tooth without a permanent successorcan be treated with extraction of the primarytooth as well as a vertical body ostectomy in con-junction with a mandibular ramus sagittal splitosteotomy to advance the posterior teeth forwardto eliminate the ankylosed tooth and associatedspace. This eliminates the need for an osseointe-grated implant or crown-and-bridge work.

A

B

FIGURE 55-35 Orthodontic hooks. Ball hooksbuilt onto the brackets (blue arrows) provide thebest stability. Other options include T pins and Khooks (white arrows) or other methods to pro-vide attachments directly on the brackets.

FIGURE 55-36 Soldered pins on the arch wire orcrimped hooks (white arrows) onto the archwire can also be used but are not preferredbecause the use of postsurgical elastics will acti-vate the arch wire, possibly creating unwantedorthodontic movements.


For most cases the orthodontistshould see the patient once a week for thefirst month, then every 2 weeks for thenext 2 months for adjustments so thatorthodontic changes can be closely moni-tored. At the initial appointments rootpositions are checked, loose brackets andbracket positions are evaluated and cor-rected, and new arch wires are placed ifindicated. Interarch mechanics (ie, class IIor III elastics, vertical elastics, and/orcross-arch elastics) can be applied as nec-essary to finalize the occlusion. Once theinitial healing phase is completed (approx-imately 3 to 4 months postsurgery) andthe occlusion is stable, the orthodonticappointment intervals can be extended tothe more traditional time frame. The finalpositioning of the teeth usually takes from3 to 12 months of postsurgical orthodon-tic treatment but could be longer depend-ing on the postsurgical orthodonticrequirements. Although reasonable stabil-ity from surgical healing occurs in approx-imately 3 to 4 months, the final postsurgi-cal healing phase takes 9 to 12 months.

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size analysis. Am J Orthod 1962;48:504–29.2. Moyers RE, van der Linden FPGM, Riolo ML,

McNamara JA. Standards of humanocclusal development. The University ofMichigan Ann Arbor (MI): The Center forHuman Growth and Development; 1976.p. 53–94.

3. Alling CC III, Helfrick JF, Alling RD. Impactedteeth. Philadelphia (PA): WB Saunders Co.;1993. p. 4.

4. Biederman W. The problem of the ankylosedtooth. In: Spengeman WG, editor. Dentalclinics of North America. Philadelphia(PA): WB Saunders Co.; 1968. p. 409–24.

5. Jacobs SG. Ankylosis of permanent teeth: a casereport and literature review. Aust Orthod J1989;11(1):38–44.

6. Schultes G, Gaggl A, Karcher H. Periodontaldisease associated with interdentalosteotomies after orthognathic surgery. JOral Maxillofac Surg 1998;56:414–7.

7. Wolford LM. Periodontal disease associatedwith interdental osteotomies after orthog-nathic surgery. J Oral Maxillofac Surg.1998;56:417–9.

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10. Kwon H, Philstrom B, Waite DE. Effects on theperiodontium of vertical bone cutting forsegmental osteotomy. J Oral MaxillofacSurg 1985;43:953–5.

11. Fox ME, Stephens WF, Wolford LM, el Deeb M.Effects of interdental osteotomies on theperiodontal and osseous supporting tissues.Int J Adult Orthod Orthogn Surg 1991;6:39–46.

12. Wolford LM, Cottrell DA. Diagnosis ofmacroglossia and indications for reductionglossectomy. Am J Orthod DentofacOrthop 1996;110:170–7.

13. Turvey TA, Journot V, Epker BN. Correction ofanterior open bite deformity: a study oftongue function, speech changes, and sta-bility. J Maxillofac Surg 1976;4:93–101.

14. Wickwire NA, White RP Jr, Proffit WR. Theeffect of mandibular osteotomy on tongueposition. J Oral Surg 1972;30:184–90.

15. Wolford LM, Karras S, Mehra P. Concomitanttemporomandibular joint and orthognath-ic surgery: a preliminary report. J OralMaxillofac Surg 2002;60:356–62.

16. Wolford LM, Mehra P, Reiche-Fischel O, et al.Efficacy of high condylectomy for manage-ment of condylar hyperplasia. Am J OrthodDentofac Orthop 2002;121:136–51.

17. Mehra P, Wolford LM. The Mitek mini anchorfor TMJ disc repositioning: surgical tech-nique and results. Int J Oral Maxillofac Surg2001;30:497–503.

18. Wolford LM, Cardenas L. Idiopathic condylarresorption: diagnosis, treatment protocol,and outcomes. Am J Orthod DentofacOrthop 1999;116:667–76.

19. Schwarz GM, Thrash WJ, Byrd DL, Jacobs JD.Tomographic assessment of nasal septalchanges following surgical-orthodonticrapid maxillary expansion. Am J Orthod1985;87(1):39–45.

20. Proffit WR. Contemporary orthodontics. StLouis (MO): C.V. Mosby Co.; 1986.p. 191–2, 352.

21. Williams HS, Zwemer, JD, Hoyt DJ. Treatingankylosed primary teeth in adult patients: acase report. Quintessence Int 1995;26:161–6.

22. Steiner DR. Timing of extraction of ankylosedteeth to maximize ridge development. JEndodont 1997;23:242–5.

23. Geiger AM, Bronsky MJ. Orthodontic manage-ment of ankylosed permanent posteriorteeth: a clinical report of three cases. Am JOrthod Dentofac Orthop 1994;106:543–8.

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66267747 Orthodontics for Orthognathic Surgery

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