correction of skeletal class iii malocclusion with ... · correction of skeletal class iii...

CASE REPORT

Correction of skeletal Class III malocclusion withclockwise rotation of the maxillomandibularcomplex

I-Ming Tsai,a Chen-Hui Lin,b and Yu-Ching Wangc

Chiayi and Taoyuan, Taiwan

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A 19-year-old woman with skeletal Class III malocclusion, paranasal depression, and a low mandibular planeangle was treated with orthodontics and orthognathic surgery. Dental decompensation and protraction of max-illary right third molar to replace maxillary right second molar were performed before surgery. Clockwise rotationof maxillo-mandibular complex was applied by Le Fort I osteotomy and bilateral sagittal split osteotomies toachieve facial balance. The active treatment period was 12 months. The stable occlusion and skeletal relation-ship were observed after a 10-month follow-up period. (Am J Orthod Dentofacial Orthop 2012;141:219-27)

Treatment for an adult patient with skeletal Class IIImalocclusion requires dentoalveolar compensa-tion or combined orthodontic and surgical proce-

dures, with the aim to achieve normal occlusion andimprove facial esthetics.1-3 In conventional treatmentplanning for orthognathic surgery, the anteroposteriordiscrepancies are corrected by advancement or setbackof the jaws along the existing occlusal plane. Whenvertical change of the maxilla is required, the mandiblewill autorotate; as a consequence of this rotation, theocclusal plane angle will be altered. This principle doesnot always produce optimal esthetic results. Whenchange of the occlusal plane is required for estheticconsiderations, the maxilla and the mandible willrotate together according to the new defined occlusalplane. Reyneke et al4 stated that when a patient needsan occlusal plane change of more than 12�, the situa-tion is significant enough to be considered a deliberateclockwise rotation case. This treatment design, alsoknown as alteration of the occlusal plane or the rotation

ding doctor, Division of Craniofacial Orthodontics, Chang Gung Memorialtal, Chiayi, Taiwan; postgraduate student, Graduate Institute of Dental andfacial Science, College of Medicine, Chang Gung University, Taoyuan,n.ding doctor, Division of Craniofacial Surgery, Chang Gung Memorialtal, Taoyuan, Taiwan.ding doctor, Division of Craniofacial Orthodontics, Chang Gung Memorialtal, Taoyuan, Taiwan.uthors report no commercial, proprietary, or financial interest in thects or companies described in this article.t requests to: Yu-Ching Wang, Division of Craniofacial Orthodontics,Gung Memorial Hospital, No 5 Fu-Sing St, Gueishan, Taoyuan 333,

n; e-mail, [email protected], December 2009; revised and accepted, January 2010.5406/$36.00ight � 2012 by the American Association of Orthodontists..1016/j.ajodo.2010.01.038

of the maxillomandibular complex, is often indicated inpatients who have excessively high or low mandibularplane angles.4,5 The objective of this article was topresent the treatment of a skeletal Class IIImalocclusion in a patient with paranasal depressionand a low mandibular plane angle. The clockwiserotation of maxillo-mandibular complex providedgood maxillary incisor exposure and excellent smilearc, and improved the patient’s facial balance.

DIAGNOSIS AND ETIOLOGY

A Taiwanese woman (age, 19 years 6months) came fortreatment with no history of trauma or serious illness. Shereported her inability to incise food and had esthetic con-cerns with her long and dished-in face (Figs 1-3). She hadreceived orthodontic treatment and interproximal enamelreductionof hermandibular incisors during her childhood.The maxillary left second premolar was extracted at anearly age, and the maxillary left first molar had driftedmesially. The prognathic mandible was responsible forthe dished-in face and the Class III malocclusion.

The patient had a Class III skeletal malocclusion withsevere mandibular prognathism, a low mandibularplane angle, and excessive lower facial height (especiallyfrom stomion to soft-tissue menton). The lips were in-competent, and the incisor-stomion distance was 2 mm.The lower lip was strained to compensate for the verti-cal discrepancy, and this stretch eliminated the labio-mental sulcus. Infraorbital rim positions appeared tobe in good relationship to the globe. Also noted werea paranasal depression and an acute nasolabial angle(Figs 1 and 3, Table).

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Fig 1. Pretreatment facial and intraoral photographs.

Fig 2. Pretreatment study models.

220 Tsai, Lin, and Wang

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Fig 3. Pretreatment lateral cephalometric and panoramicradiographs.

Table. Cephalometric summary

Measurement Pretreatment Posttreatment NormSkeletalSNA (�) 86 85.5 84.2 6 3.2SNB (�) 92 85 81.2 6 3.0ANB (�) �6 0.5 2.9 6 1.9NAPg (�) �12 2 5.4 6 4.9A-Nv (mm) 1 2 0 6 3.0Pg-Nv (mm) 16 4 �5.8 6 5.6Wits (mm) �15 �7 �1 6 1SN-OP (�) 6 18 16 6 2SN-MP (�) 22 26 27.8 6 6.2UFH/LFH (%) 43.5/56.5 44/56 45/55

Dental factorU1-SN (�) 120 106 110 6 5.6U1-NA (�/mm) 6/34 4.5/23 24/5U1-L1 (�) 157 128 121.9 6 10.5L1-NB (�/mm) 1.5/14 7/29 27/6L1-MP (�) 74 95 99.2 6 6.8

Soft tissueNLA (�) 84 102 92.9 6 7.4E-line (mm) �6 1 �0.67 6 1.8Upper lip/lower lip 0 1.5 0.93 6 2.16Sn-ST/ST-Me 20:48 22:46 1:2Chin throatlength (mm)

58 48 57 6 6

Tsai, Lin, and Wang 221

She had a dental Class III malocclusion with anoverbite of 3.5 mm and a negative overjet of 5 mm.Her maxillary incisors were tipped labially of theirbony base, and the mandibular incisors were tipped lin-gually. Bilateral posterior and anterior crossbites werepresent. The absence of the maxillary left second pre-molar aggravated the deviation of her maxillary dentalmidline. The mandibular midline was coincident withthe facial midline. The maxillary right second molarhad a large temporary restoration with subgingival car-ies. The periodontal tissues were healthy (Figs 1-3,Table).

TREATMENT OBJECTIVES

1. Maxilla. Rotate the maxillomandibular complex clock-wise, correct the insufficient dentogingival display andthe paranasal depression, eliminate the acute nasola-bial angle, and assist the sagittal coordination withmandible.

2. Mandible. Rotate the maxillomandibular complexclockwise, reduce the lower facial height, correctthe prognathism and the dental malocclusion, andshape the bilateral gonial angle because of thebony ledge after clockwise rotation of maxilloman-dibular complex.

American Journal of Orthodontics and Dentofacial Orthoped

3. Maxillary dentition. Substitute the maxillary rightthirdmolar for the largely decayedmaxillary right sec-ond molar, coordinate the facial and maxillary dentalmidlines, resolve the proclined incisor position, andachieve ideal overbite and overjet relationships.

4. Mandibular dentition. Remove dental compensa-tion by placing the mandibular incisors moreupright over the basal bone. Level, align, and coor-dinate with the maxillary arch.

TREATMENT ALTERNATIVES

The alternative treatment option was 1-jaw surgery,mandibular osteotomy only. However, it would compro-mise the facial esthetics. The patient rejected the 1-jawsurgery. A patient-oriented treatment plan would giveher the ultimate benefit. The success of treatment isnot just to achieve the defined treatment goal, butalso to fulfill the patient’s expectations.6

TREATMENT PROGRESS

Presurgical orthodontic preparation was performedwith preadjusted 0.022-in edgewise appliances. Afterextraction of the maxillary right second molar, and themaxillary left and mandibular right third molars, levelingand alignment proceeded smoothly and quickly. Spacewas closed in the maxillary arch on a 0.016 3 0.022-instainless steel archwire with elastic chain. The

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Fig 4. Presurgical facial and intraoral photographs.


mandibular dentition was decompensated without ex-traction. In the leveling and alignment stage, the arch-wires were coordinated. Preoperative preparation took5 months and was completed with maxillary and man-dibular 0.018 3 0.025-in stainless steel archwires (Figs4 and 5).

The surgery included bimaxillary procedures. A 1-pieceLeFort I osteotomywith advancement and clockwise rota-tion of the maxilla was performed. Bilateral sagittal splitosteotomies were performed with clockwise rotation andsetback to correct the sagittal maxillomandibular skeletaland dental relations and excessive lower facial height.Bilateral gonial angles were reduced due to the bony ledgeafter clockwise rotation of the maxillomandibularcomplex. Rigid fixation was used in the maxilla and themandible.

Four weeks after surgery, maxillary 0.018-in stainlesssteel and mandibular 0.016 3 0.022-in nickel-titaniumarchwires were used for finishing and detailing. Verticalintermaxillary and Class III elastics were used sparinglyto settle the final occlusion. Seven months of

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postoperative detailing and finishing were needed beforedebonding. The surgical segments were stable (Figs 6-8).The final occlusal relationship was retained with maxillaryand mandibular Hawley retainers. The patient wascooperative and highly motivated throughout thetreatment. The total treatment time was 12 months.

TREATMENT RESULTS

The posttreatment photographs show improvementin the facial profile and elimination of the excessivelower facial height (Fig 6). The superimposition of thecephalometric tracings shows that the maxilla was ad-vanced with the orthognathic surgery, and the mandibleexperienced clockwise rotation and setback (Fig 9). Theanterior segment of the maxilla was moved downward1 mm, the posterior segment of the maxilla wasimpacted 2.5 mm, and the mandible was moved poste-riorly by 10.5 mm. Cephalometric changes included anincrease of the ANB angle from �6� to 10.5� (Table).The mandibular incisor to mandibular plane angle

Journal of Orthodontics and Dentofacial Orthopedics

Fig 5. Presurgical cephalometric and panoramic radiographs.


increased from 74� to 95�. The maxillary incisor was up-righted by retraction during maxillary space closure andmoved forward to provide better upper lip support withthe maxillary advancement and clockwise rotation. Aconsiderable increase in the nasolabial angle was ob-served. The facial concavity decreased. Maxillary incisorexposure at rest was increased. The previous interproxi-mal enamel reduction of the mandibular incisors did notresult in a Bolton discrepancy. The occlusion was fin-ished with a Class I canine relationship. The overbiteand overjet relationships were ideal. The maxillary andmandibular dental midlines were coincident with thefacial midline. The results were stable at 10 months afterdebonding (Fig 10).

DISCUSSION

Surgical-orthodontic treatment of nongrowing ClassIII patients includes preoperative orthodontic treatmentto decompensate the malocclusion, followed by surgicaldetailing and finishing of the occlusion. Typical dentaldecompensation is to retract the proclined maxillary in-cisors and procline the retroclined mandibular incisors toa more normal axial inclination. This increases the


severity of the Class III dental malocclusion and often re-sults in the patient’s facial profile becoming less estheticbefore surgery.7 The preoperative dental decompensa-tion dictates the magnitude and type of surgical changeand is a major factor in the success of treatment. Lackof optimal dental decompensation compromises thequality and quantity of the orthognathic correction.8,9

This patient had proclined maxillary incisors andretroclined mandibular incisors. It took 5 months todecompensate the teeth by closing the residual spacein the maxillary arch and leveling the mandibular archwithout extractions. The overjet went from 5 to 7 mm.The increased overjet permitted the mandible to be setback by a greater amount.

Extraction of the decayed maxillary right second mo-lar and protraction of the maxillary right third molar notonly eliminated the need for prosthetic reconstruction,but also helped to decompensate the maxillary incisors.The amount of incisor retraction would be less, the fur-ther posterior that the extraction space is located. In thispatient, the amount of retraction of the maxillary inci-sors was 1 mm before surgery as stated by Proffit et al.10

Most dentofacial deformities can be corrected byconventional orthognathic treatment. It is important


Fig 6. Posttreatment facial and intraoral photographs.

Fig 7. Posttreatment study models.


February 2012 � Vol 141 � Issue 2 American Journal of Orthodontics and Dentofacial Orthopedics

Fig 8. Posttreatment cephalometric and panoramic radiographs.

Fig 9. Pretreatment (black line) and posttreatment (red line) cephalometric tracings, superimposed onA, sella-nasion plane at sella; B, palatal plane at ANS; and C, mandibular plane at menton.


to set the vertical position of maxilla first. Then autoro-tation of mandible changes the occlusal plane. Any an-teroposterior repositioning of the jaws should take placeaccording to the new occlusal plane. But, in this patient,


we planned the clockwise rotation of the maxilloman-dibular complex instead of a conventional approachfor esthetic reasons. The principle for rotation of themaxillomandibular complex is to alter the occlusal plane


Fig 10. Facial and intraoral photographs 10 months after debonding.


angle to the normal range (FH-OP 5 8� 6 4�).4,11-12

Rotation of the maxillomandibular complex in thispatient fulfilled the paranasal depression, normalizedthe nasolabial angle, reduced the prominent chin,altered the occlusal plane, and enhanced the curvatureof smile arc.

Many studies have reported secondary morphologicchanges in the nose, including alar flaring after a LeFortI osteotomy. This is extremely important, particularly forthe Asian population, because their noses are wider andflatter than those of European Americans, whereas theoverall prevalence of patients with severe skeletal ClassIII requiring orthognathic surgery is apparently high.13

The changes might be advantageous for patients witha narrow nose, but they can have a negative effect onthe overall esthetics of the face in those with a wide ornormal width as in this patient. To prevent wideningof the nose during surgery, a concomitant alar basecinch suture and anterior nasal spine ostectomy wereused in this patient.

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Smile arcs are preferred not only by laypersons, butalso by orthdontists.14 To obtain a favorable smile arc,Sarver15 recommended inclining the occlusal plane be-cause it is 1 method that can improve the flat curvatureof the maxillary anterior teeth. We observed the same re-sult in our patient by clockwise rotation of the maxillo-mandibular complex.

The stability of clockwise rotation of the maxilloman-dibular complex was discussed by Reyneke et al16 andChemello et al.17 In their studies, clockwise rotation ofthe maxillomandibular complex, counterclockwise rota-tion of the maxillomandibular complex, and conventionaltreatment all had good long-term stability. In this patient,the stable occlusion and skeletal relationship wereobserved after a 10-month follow-up period (Fig 10).

CONCLUSIONS

This case report demonstrates that clockwise rotationof the maxillomandibular complex can be satisfactory in

Journal of Orthodontics and Dentofacial Orthopedics


patients with Class III malocclusion, paranasal depression,and lowmandibular plane angle. Theorthodontic-surgicalprotocol provided goodmaxillary incisor exposure and ex-cellent facial balance. The patient responded well physio-logically and psychologically and was quite pleased withthe treatment outcome.

REFERENCES

1. Arnett GW, Bergman RT. Facial keys to orthodontic diagnosis andtreatment planning—part II. Am J Orthod Dentofacial Orthop1993;103:395-411.

2. Arnett GW, Bergman RT. Facial keys to orthodontic diagnosis andtreatment planning. Part I. Am J Orthod Dentofacial Orthop 1993;103:299-312.

3. Arnett GW, Worley CM Jr. The treatment motivation survey: defin-ing patient motivation for treatment. Am J Orthod DentofacialOrthop 1999;115:233-8.

4. Reyneke JP, Bryant RS, Suuronen R, Becker PJ. Postoperative skel-etal stability following clockwise and counter-clockwise rotationof the maxillomandibular complex compared to conventional or-thognathic treatment. Br J Oral Maxillofac Surg 2007;45:56-64.

5. Wolford LM, Chemello PD, Hilliard F. Occlusal plane alteration inorthognathic surgery—part I: effects on function and esthetics.Am J Orthod Dentofacial Orthop 1994;106:304-16.

6. Phillips C. Patient-centered outcomes in surgical and orthodontictreatment. Semin Orthod 1999;5:223-30.

7. Worms FW, Isaacson RJ, Speidel TM. Surgical orthodontic treat-ment planning: profile analysis and mandibular surgery. Angle Or-thod 1976;46:1-25.


8. Johnston C, Burden D, Kennedy D, Harradine N, Stevenson M.Class III surgical-orthodontic treatment: a cephalometric study.Am J Orthod Dentofacial Orthop 2006;130:300-9.

9. Tompach PC, Wheeler JJ, Fridrich KL. Orthodontic considerationsin orthognathic surgery. Int J Adult Orthod Orthognath Surg 1995;10:97-107.

10. Proffit WR, Fields HW, Sarver DM. Contemporary orthodontics. 4thed. St Louis: Mosby Elsevier; 2007. p. 283, 600.

11. Wolford LM, Chemello PD, Hilliard FW. Occlusal plane alteration inorthognathic surgery. J Oral Maxillofac Surg 1993;51:730-40.

12. Reyneke JP. Surgical manipulation of the occlusal plane: new con-cepts in geometry. Int J Adult Orthod Orthognath Surg 1998;13:307-16.

13. Farkas LG, Katic MJ, Forrest CR, Alt KW, Bagic I, Baltadjiev G,et al. International anthropometric study of facial morphologyin various ethnic groups/races. J Craniofac Surg 2005;16:615-46.

14. Parekh S, Fields HW, Beck FM, Rosenstiel SF. The acceptability ofvariations in smile arc and buccal corridor space. Orthod CraniofacRes 2007;10:15-21.

15. Sarver DM. The importance of incisor positioning in the estheticsmile: the smile arc. Am J Orthod Dentofacial Orthop 2001;120:98-111.

16. Reyneke JP, Bryant RS, Suuronen R, Becker PJ. Postoperativeskeletal stability following clockwise and counter-clockwiserotation of the maxillomandibular complex compared to conven-tional orthognathic treatment. Br J Oral Maxillofac Surg 2007;45:56-64.

17. Chemello PD, Wolford LM, Buschang PH. Occlusal plane alterationin orthognathic surgery—part II: long-term stability of results. AmJ Orthod Dentofacial Orthop 1994;106:434-40.


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