2007 daher tratamiento no quirurgico en un adulto con clase iii

CASE REPORT

Nonsurgical treatment of an adult with aClass III malocclusionWissam Daher,a Julie Caron,b and Morris H. Wechslerc

Montréal, Québec, Canada

This case report describes the orthodontic treatment of a 43-year-old man with Class III malocclusion andcrossbite of the maxillary anterior teeth. Treatment options included orthognathic surgery, nonextractiontreatment, premolar extractions, and mandibular incisor extraction. The patient opted for nonsurgicaltreatment that included the extraction of a mandibular central incisor. (Am J Orthod Dentofacial Orthop 2007;
132:243-51)
The frequency of Class III malocclusions varies indifferent racial groups. The incidence amongwhite people is 1% to 4%; among black people, it

is 5% to 8%; in Asians, it ranges from 4% to 14%.1-3 Theetiology of this condition varies from 1 person to the next;implicated factors include (1) heredity—eg, the Haps-burg chin; (2) environmental influences—eg, anteriorfunctional shifts of the mandible or mouth breathing,which can become a positive stimulus for mandibulargrowth; and (3) pathologies—eg, pituitary tumors re-sponsible for acromegaly.

Patients with a Class III malocclusion can havevarious combinations of skeletal and dental discrepan-cies. It is important to diagnose these to adequatelytreat the underlying cause or causes of the problem.Critical factors to be evaluated include the sagittalpositions of the maxilla, the mandible, the maxillaryand mandibular alveolar processes, and vertical devel-opment. Guyer et al,4 for example, found that 57% ofpatients with a normal or prognathic mandible also hada deficient maxilla.

Several clinical findings are regularly seen in ClassIII patients: anterior or posterior crossbites, minimal ornegative overjet, retroclined mandibular incisors, pro-clined maxillary incisors, and functional slides fromcentric relation to centric occlusion.

DIAGNOSIS AND ETIOLOGY

A 43-year-old black man presented for an orthodon-tic consultation (Figs 1-5). His chief complaint was theaPrivate practice, Vancouver, British Columbia, Canada.bPrivate practice, Montréal Québec, Canada.cProfessor, Department of Orthodontics, Université de Montréal, Montréal,Québec, Canada.Reprint request to: Morris H. Wechsler, 5445 Rosedale Ave, Montreal, Quebec,Canada, H4V 2H7; e-mail, [email protected], March 2005; revised and accepted, February 2006.0889-5406/$32.00Copyright © 2007 by the American Association of Orthodontists.
doi:10.1016/j.ajodo.2006.02.034
unesthetic appearance of his maxillary anterior teeth,which were behind the mandibular incisors. There wereno significant findings in his medical and dental histo-ries. Clinical examination also confirmed the apparentfacial asymmetry caused by mandibular deviation to theleft as well as mandibular protrusion, a concave profile,and deviation of the nose to the right. When he smiled,only half of the maxillary incisor showed, and therewas no gingival display.

The patient had complete dentition including thirdmolars. He had a Class III dental relationship on the rightside and a Class I relationship on the left side. Themaxillary teeth from the left central incisor to the secondpremolar were in crossbite, and, although the maxillarydental midline was coincident with the facial midline, themandibular dental midline was deviated 5 mm to theleft. Both overjet and overbite were negative, and therewas minor bimaxillary anterior crowding.

The periapical radiographs showed generalized hor-izontal bone loss, and the mandibular incisors appearedto have some shortening of root length. The panoramicradiograph demonstrated condylar asymmetry (longercondylar neck on the right side) and pneumatization ofthe maxillary sinus. There was no evidence of bone ordental pathology and no defective restorations.

The cephalometric tracing and analysis (Table) indi-cated a skeletal Class III relationship with relative maxil-lary retrusion (SNA angle, 83°), mandibular protrusion(SNB angle, 85°), concave profile (N-A-Pog�–3°), andnegative overjet (–2 mm).

TREATMENT OBJECTIVES

The treatment objectives for this patient were tocorrect the crossbite, establish normal overbite andoverjet, align the dental midlines, align and correctrotations of the anterior teeth, obtain a stable occlusalrelationship, and improve the patient’s facial and dental
esthetics by establishing a symmetrical smile.
243

nt fac

t intra

American Journal of Orthodontics and Dentofacial OrthopedicsAugust 2007

244 Daher, Caron, and Wechsler

TREATMENT ALTERNATIVES

This adult patient had no clinically significantmaxillomandibular growth potential to assist in estab-lishing our treatment goals with orthodontics alone.Orthognathic surgery to protract the maxilla with thepossibility of mandibular setback, combined with fixedorthodontic treatment, was discussed with him. Maxi-mum esthetics, ideal occlusion, and skeletal discrep-ancy correction would be possible with this approach.Orthodontics alone would help camouflage some skel-etal and dental aspects of the malocclusion, improvingesthetics and function. The orthodontic options in-

Fig 1. Pretreatme

Fig 2. Pretreatmen

cluded (1) maxillary expansion to correct the crossbite

and create arch space to derotate and align the teethand, if necessary, mandibular incisor extraction tocorrect the overjet and the anterior crossbite; (2) 2mandibular premolar extractions to upright the mandib-ular incisors and correct the mild crowding and thecrossbite; (3) a single mandibular right premolar ex-traction to upright the incisors, correct the crossbite,and establish Class I canine occlusion; and (4) extrac-tion of both mandibular second molars to establish aClass I buccal and canine occlusion and upright themandibular incisors. The latter option would mostlikely require the longest treatment time to retract the

ial photographs.

oral photographs.

premolars and the anterior segment.

American Journal of Orthodontics and Dentofacial OrthopedicsVolume 132, Number 2

Daher, Caron, and Wechsler 245

TREATMENT PROGRESS

The patient refused surgical procedures and opted fororthodontic treatment and camouflage, accepting maxil-lary dental expansion as the first stage of treatment.

Fig 3. Pretreat

Fig 4. Pretreatment panoramic and periapical radiographs.

Treatment began with the placement of a removable

expansion appliance (Fig 6) in the maxillary arch, andthe patient was instructed to activate it twice a week.Subsequently, edgewise brackets were placed on all

dental models.

Fig 5. Pretreatment cephalometric tracing.

ment

maxillary and mandibular teeth, with coil springs be-



tween the maxillary first molars and canines to advancethe anterior teeth.

Because there was little progress in correcting theanterior crossbite, it was decided to extract the man-dibular right central incisor. The patient wore Class IIIelastics full time and a protraction facemask (Fig 7) atnight to aid in the advancement of the maxillary arch.Treatment time was approximately 2 years. Retentionconsisted of a bonded lingual wire on the maxillaryanterior teeth, including the canines. A spring alignerwas used on the mandibular teeth.

TREATMENT RESULTS

At the end of treatment, the crossbites were cor-rected, and acceptable overjet and overbite were estab-lished (Figs 8-12). The posttreatment intraoral photo-graphs show a good Class I occlusion on the left side,with a slight Class III canine relationship on the right.Normal overbite and overjet were achieved, and gingi-val heights on the maxillary anterior teeth were lev-elled. The occlusal views show good forms in botharches. The extraoral frontal view shows a mesofacialappearance, but the profile appears more orthognathic.Posttreatment periapical radiographs show that thelevel of interradicular bone remained relatively stable.The roots of the mandibular anterior teeth remainedparallel despite the extraction of the mandibular centralincisor. The posttreatment panoramic radiograph showsthat bone levels were maintained. The maxillary teethwere advanced slightly, and the mandibular incisorswere retracted. The maxillary skeletal base remainedrelatively stable (SNA angle, 83°), whereas the man-dibular base was reduced (SNB angle, 82°), giving apositive ANB angle (1°). The maxilla advancedslightly. Comparison of the soft-tissue profile in the

Table. Cephalometric measurements

Measurement Standard Initial Final

SNA angle (°) 82 83 83SNB angle (°) 80 85 82ANB angle (°) 2 –2 1Wits (mm) 1 –8 –3SN-Go Gn (°) 32 22 26MP to FH (°) 25 23 23U1 to NA (°) 22 30 25U1 to NA (mm) 4 6 6U1 to FH (°) 111 112 111L1 to NB (°) 25 24 13L1 to NB (mm) 4 6 1.5L1 to MP (°) 90 97 85U1 to L1 (°) 123 128 141Pog to NB (mm) 1 1 0.3

before and after cephalometric tracings (Fig 13) shows

improvement in the profile; the position of the upper lipis closer to the esthetic plane. Separate superimposi-tions of the maxilla and the mandible show that themaxillary teeth appear to have been advanced, whereasthe mandibular anteriors were retroclined. Because nocephalometric radiograph was taken immediately afterfacemask wear, the orthodontic and orthopedic effect ofthe facemask could not be determined precisely. Theforward position of the maxillary base at the end oftreatment was most likely due to the combined effect ofthe facemask and the Class III elastics.

Clinical examination of the mandibular position didnot show that the mandible shifted backwards, andthere was no evidence of a centric relation-centricocclusion shift.

DISCUSSION

In treating patients with Class III malocclusions, itis essential to diagnose the components of the maloc-clusion correctly. In dealing with a dentoalveolar ClassIII, it might be possible to achieve an ideal occlusionwith orthodontic tooth movement alone. However, ifthe etiology of the malocclusion is skeletal, or acombination of skeletal and dental factors, then treat-ment combining orthognathic surgery with conven-tional orthodontics is frequently necessary to obtain aresult closer to the ideal. The timing of treatment is alsoimportant. In a case of early diagnosis of Class IIImalocclusion with maxillary deficiency in the latedeciduous or early mixed dentition—ie, during theperiod of growth—a rapid palatal expansion appliancecombined with a protraction facemask might be auseful treatment option.5 However, if the skeletal dis-crepancy is caused by excessive growth of the mandi-ble, there seems to be little that can be done because“inhibiting mandibular growth has proven to be almostimpossible,”6 and orthognathic surgery to set back themandible at the end of adolescent growth seems to bethe only viable option. For adults, fewer methods oftreatment are available: either a combination of orth-odontics and surgery or camouflage orthodontic treat-ment with various extraction combinations, dependingon the severity of the malocclusion. It is important tolisten to the patient’s main concerns in order to respondadequately to his or her needs.

The most effective and efficient timing for suchtreatment has been suggested to be the early mixeddentition,7 before the patient is 8 years of age,8 beforeage 10,6 until the age of 12,9 or even throughoutpuberty.10 However, to our knowledge, no publisheddata in the literature advocate the use of protractionforce combined with maxillary expansion in nongrow-
ing adults. For this patient, the expansion appliance and

ask w



the facemask therapy provided enough dentoalveolarcompensation to correct the crossbite and camouflagethe underlying Class III malocclusion. Although thistreatment modality is somewhat unorthodox in an adult,the beneficial results were purely dental and were madepossible by a cooperative and motivated patient.

The effects of mandibular incisor extraction onthe occlusion depend on several factors: amount ofcrowding in both arches, tooth mass relationshipbetween the 2 arches (Bolton analysis), type ofmalocclusion, amounts of overbite and overjet, and

Fig 6. Intraoral photographs during treatmentwith posterior occlusal coverage.

Fig 7. Facem

long-term stability.

The extraction of a mandibular incisor might causeincreases in overjet and overbite11; this effect is usuallydesirable in Class III patients and detrimental in ClassI and Class II patients.12,13 The tooth-mass discrepancycreated by the extraction can be evaluated with a Boltonanalysis, but a diagnostic wax setup is probably thebetter alternative for treatment-planning purposes. Aconcomitant maxillary anterior interproximal enamelreduction is sometimes indicated to compensate for thetooth-mass difference created by the extraction.12 Care-ful planning and clear treatment objectives make this

ing maxillary removable expansion appliance

orn at night.

, show

treatment option viable.

ent fa

nt intr



The rationale for using a fixed retainer in themaxillary arch (and a removable retainer in the man-dibular arch) was that it would counter the possibility ofmandibular incisor proclination, which might lead tospacing between the maxillary anterior teeth, thuscompromising esthetics in the most conspicuous area ofthe mouth. Riedel et al14 suggested that, in patients withcrowded mandibular arches, the removal of a mandib-ular incisor can allow for increased stability in themandibular anterior region even with no permanentretention. In our patient, the 3-year posttreatmentrecords (not shown) demonstrated that the mandibular

Fig 8. Posttreatm

Fig 9. Posttreatme

anterior segment remained stable with the removable

retainer. In retrospect, an occlusal splint in the maxil-lary arch to prevent further incisor wear would alsohave been an excellent preventive measure.

Owen15 described 2 patients who had only a fewsigns and symptoms of temporomandibular dysfunc-tion—ie, sore muscles of mastication and limited man-dibular opening. One mandibular incisor was extractedin each patient. After treatment, muscle tenderness waseliminated, and maximum opening improved. In ourcase, the patient had no symptoms of temporomandib-ular dysfunction either before or after orthodontic treat-ment, and we expect him to have normal temporoman-

cial photographs.

aoral photographs.

dibular joint function in the future. The Class III occlusion



on the right side does not appear to have negativelyaffected the functional occlusion of the teeth on that side.

The mandibular incisor extraction helped to align

Fig 10. Posttre

Fig 11. Posttreatment panoramic and periapicalradiographs.

atment dental casts.

the mandibular anterior segment and provided the space

Fig 12. Posttreatment cephalometric tracing.



necessary to upright the incisors, thus facilitating cross-bite correction. Positive overbite and overjet shouldhelp maintain the results. Light forces were usedthroughout the treatment to prevent or minimize apicalroot resorption on the mandibular incisors. The post-treatment radiographs (Fig 11) show satisfactory rootalignment of the mandibular incisors with no evidentroot resorption.

This was a compromise treatment, with an excellentfinal result that has admirably met the patient’s needs.The occlusion is functional and stable, and he has apleasing smile. His quality of life has been greatlyimproved, and surgery was avoided.

CONCLUSIONS

The choice of treatment for any malocclusion mustbe tailored to each patient. All treatment possibilities,including those that are ideal and those that are acompromise, should be considered and explained to thepatient, so that he or she can choose the most accept-able one. All problems perceived by a clinician mightnot be problems in the patient’s eyes. The treatmentthat this patient received satisfied his needs, despite itslimitations. Both the patient and the orthodontist were

Fig 13. Comparison of pro

satisfied with the results. The patient’s chief concern

was addressed and treated to his satisfaction, an estheticsmile was established, and the malocclusion wastreated to a satisfactory and stable result.

REFERENCES

1. Ngan P. Treatment of Class III malocclusion in the primary andmixed dentitions. In: Bishara SE, editor. Texbook of orthodon-tics. Philadelphia: W. B. Saunders; 2001. p. 375.

2. Altemus LA. Frequency of the incidence of malocclusion inAmerican Negro children aged 12-16. Angle Orthod 1959;29:189-200.

3. Garner LD, Butt MH. Malocclusion in black American and NyeriKenyans. Angle Orthod 1985;55:139-46.

4. Guyer EC, Ellis EE 3rd, McNamara JA Jr, Behrents RG.Components of Class III malocclusion in juveniles and adoles-cents. Angle Orthod 1986;56:7-30.

5. Baccetti T, McGill JS, Franchi L, McNamara JA Jr, Tollaro J.Skeletal effects of early treatment of Class III malocclusion withmaxillary expansion and face-mask therapy. Am J OrthodDentofacial Orthop 1998;113:333-43.

6. Fields HW, Proffit WR. Treatment of skeletal problems inpreadolescent children. In: Proffit WR, Fields HW, eds. Contem-porary orthodontics. 3rd ed. St Louis: Mosby; 2000. p. 511-5.

7. McNamara JA. Mixed dentition treatment. In: Graber TM,Vanarsdall RL, editors. Orthodontics: current principles andtechniques. St Louis: Mosby-Year Book; 1994. p. 508.

8. Hickham JH. Maxillary protraction therapy: diagnosis and treat-

efore and after treatment.
file b
ment. J Clin Orthod 1991;25:102-13.



9. Merwin D, Ngan P, Hagg U, Yiu C, Wei SHY. Timing foreffective application of anteriorly directed orthopedic force tomaxilla. Am J Orthod Dentofacial Orthop 1997;112:292-9.

10. Takada K, Petdachai S, Sakuda M. Changes in dentofacialmorphology in skeletal Class III children treated by a modifiedmaxillary protraction headgear and chincup: a longitudinal study.Eur J Orthod 1993;15:211-21.

11. Dacre JT. The long term effects of one lower incisor extraction.
Eur J Orthod 1985;53:706-13.
12. Kokich VG, Shapiro PA. Lower incisor extraction in orthodontictreatment: four clinical reports. Angle Orthod 1984;54:139-53.

13. Zachrisson BU. Important aspects of long term stability. J ClinOrthod 1997;31:562-83.

14. Riedel RA, Little RM, Bui TD. Mandibular incisor extraction:postretention evaluation of stability and relapse. Angle Orthod1992;62:103-16.

15. Owen AH III. Single lower incisor extractions. J Clin Orthod
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2007 daher tratamiento no quirurgico en un adulto con clase iii

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