Orthognathic treatment for a patient with facial asymmetry … · 2017. 12. 11. · Orthognathic treatment for a patient with facial ... black line in Fig 4) ... a lingual arch appliance

CASE REPORT

Orthognathic treatment for a patient with facialasymmetry associated with unilateral scissors-biteand a collapsed mandibular arch

Naoto Suda,a Naoko Tominaga,b Yasufumi Niinaka,c Teruo Amagasa,d and Keiji Moriyamae

Saitama, Tokyo, and Yamanashi, Japan

aProfeFostebCliniDivisiand DcAssisMedicdProfeconstGraduUniveeProfeRecon

94

Subapical mandibular surgeries have been used to correct vertical malocclusion and interdental problems as-sociated with mandibular deformity. Subapical surgery to the anterior part of the mandible is applicable in manypatients with anterior open bite and deepbite. Surgery of the posterior part of themandible is needed less frequentlythan surgery of the anterior part. This case report describes the surgical-orthodontic treatment of a 21-year-oldwoman who underwent posterior subapical mandibular surgery. Her chief complaint was facial asymmetry, andshe had a collapsedmandibular arch with a scissors-bite of the right premolars and molars. After subapical osteot-omy, surgically assisted correction of the collapsed right mandibular arch was performed with a lingual arch appli-ance. Comprehensive orthodontic treatment was initiated in both arches after this correction. Le Fort I osteotomyand sagittal split ramus osteotomy were used to correct the facial asymmetry. Her facial appearance and tempo-romandibular problems were markedly improved, and she achieved a functional and stable occlusion after thesetreatments. This case report demonstrates the efficiency of posterior subapical mandibular surgery for a patientwith a collapsed mandibular arch and a scissors-bite. (Am J Orthod Dentofacial Orthop 2012;141:94-104)

Anterior subapical mandibular surgery was firstdescribed by K€ole1 and was mainly applied topatients with anterior open bite and deepbite.This surgery is frequently used to correct vertical prob-lems, but it can also advance or retrude a dentoalveolarsegment. Total subapical mandibular surgery was firstdescribed by MacIntosh.2 This involves moving the totalmandibular dentoalveolus in an anterior, posterior, or su-perior direction.3 Compared with these 2 subapical sur-geries, posterior subapical mandibular surgery has beenless frequently used. This is mainly due to the risk of in-juring the inferior alveolar neurovascular bundles.4

This case report describes the surgical-orthodontictreatment of a 21-year-old woman with a unilateral col-lapsed mandibular arch and a scissors-bite. Posteriorsubapical mandibular surgery was applied, and

ssor, Division of Orthodontics, Department of Human Development andring, Meikai University School of Dentistry, Saitama, Japan.cal fellow, Department of Maxillofacial Reconstruction and Function,on of Maxillofacial/Neck Reconstruction, Graduate School of Medicalental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.tant professor, Department of Oral and Maxillofacial Surgery, Faculty ofine, University of Yamanashi, Yamanashi, Japan.ssor and chair, Maxillofacial Surgery, Department of Maxillofacial Re-ruction and Function, Division of Maxillofacial/Neck Reconstruction,ate School of Medical and Dental Sciences, Tokyo Medical and Dentalrsity, Tokyo, Japan.ssor and chair, Maxillofacial Orthognathics, Department of Maxillofacialstruction and Function, Division of Maxillofacial/Neck Reconstruction,

surgically assisted correction of the mandibular archwas performed. This report demonstrates the efficiencyof posterior subapical mandibular surgery to treat a se-verely collapsed or narrowed arch.

DIAGNOSIS AND ETIOLOGY

A Japanese girl was born to healthy parents withouta facial deformity. She had been having difficulty withocclusion from her youth but did not seek treatment.She visited our dental hospital at 21 years 0 months ofage with a chief complaint of facial asymmetry (Figs 1-3).

Her facial photographs showed an asymmetricmandible and chin. Her philtrum and lip were inclinedin the frontal facial view. The mandibular right secondpremolar and 3 molars had collapsed lingually, and

Graduate School of Medical and Dental Sciences, Tokyo Medical and DentalUniversity, Tokyo, Japan.The authors report no commercial, proprietary, or financial interest in theproducts or companies described in this article.Reprint requests to: Naoto Suda, Department of Maxillofacial Reconstructionand Function, Division of Maxillofacial/Neck Reconstruction, Graduate Schoolof Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan; e-mail, [email protected], December 2009; revised and accepted, February 2010.0889-5406/$36.00Copyright � 2012 by the American Association of Orthodontists.doi:10.1016/j.ajodo.2010.02.042

mailto:[email protected]

Fig 1. Pretreatment facial and intraoral photographs, age 21 years 0 months.

Fig 2. Pretreatment cast model.

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American Journal of Orthodontics and Dentofacial Orthopedics January 2012 � Vol 141 � Issue 1

Fig 3. Pretreatment posteroanterior and lateral cephalograms and panoramic radiograph.

Fig 4. Cephalometric tracing of the pretreatment poster-oanterior cephalogram. Lo,7 Right latero-orbitale; Lo0, leftlatero-orbitale; Nc,7 neck of crista galli.

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a scissors-bite was noted. There was premature contactbecause of this collapsed mandibular arch, and a func-tional shift was noted toward the left. She occasionallyhad pain in both temporomandibular joints and fre-quently had clicking sounds on the right side. Her over-bite and overjet were both 2 mm, and the midline of themandibular central incisors was 4 mm to the left.

A panoramic radiograph showed that the mandibularthird molars were present on both sides. A posteroante-rior cephalogram showed an inclined maxilla andmandible in the frontal dimension (Fig 3). The cephalo-metric tracing showed that the maxillary occlusal planeinclined by 7.5�, and menton was located 11.0 mm tothe left (Fig 4; Table I). The SNA, SNB, and mandibularplane angles were comparable with Japanese norms(Table II), and the skeletal disharmony was not apparentin the sagittal or vertical dimension.

TREATMENT OBJECTIVES

The treatment objectives were to correct her chiefcomplaint of facial asymmetry, the collapsed right man-dibular arch, and the scissors-bite. For these corrections,

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Table I. Analysis of posteroanterior cephalograms

Pretreatment(21 y 0 mo)

Immediately beforeLe Fort I osteotomy andSSRO (23 y 6 mo)

Immediately afteractive orthodontic

treatment (24 y 8 mo)

One year after activeorthodontic treatment

(25 y 8 mo)Inclination of maxillary occlusal plane (�) 7.5 7.5 1.0 1.0Deviation of menton (mm) 11.0 8.0 2.5 2.5

SSRO, Sagittal split ramus osteotomy. Inclination of maxillary occlusal plane represents the angle between the line running through Lo-Lo0 (solidblack line in Fig 4) and the line running through the buccal cusps of the maxillary right and left first molars (solid red line in Fig 4). Deviation ofmenton is represented by the distance between menton and the skeletal midline (dotted red line in Fig 4) that runs through Nc and perpendicular tothe solid black line.

Table II. Analytic measurements

Angle (�)Japanese

norm8 6 SDPretreatment(21 y 0 mo)

Immediately beforeLe Fort I osteotomy and

SSRO (23 y 6 mo)

Immediately after activeorthodontic treatment

(24 y 8mo)

One year after activeorthodontic treatment

(25 y 8 mo)SNA 82.3 6 3.5 79.4 79.4 80.0 79.6SNB 78.9 6 3.5 78.3 77.0 77.7 77.2ANB 3.4 6 1.8 1.1 2.4 2.3 2.2U-1 to FH plane 111.1 6 5.5 114.5 116.2 116.8 117.0L-1 to mandibular plane 96.3 6 5.8 97.5 101.7 97.5 97.2Mandibular plane 28.8 6 5.2 27.4 29.2 30.0 30.2Gonial 122.2 6 4.4 126.4 126.4 126.5 125.2

SSRO, Sagittal split ramus osteotomy; S, sella turcica; N, nasion; A, Point A; SNA, angle between SN and NA; B, Point B; SNB, angle between SNand NB; U-1, long axis of the maxillary central incisor; U-1 to FH plane, angle between U-1 and the Frankfort horizontal (FH) plane; L-1, long axisof the mandibular central incisor; L-1 to mandibular plane, angle between L-1 and the mandibular plane; Mandibular plane, angle between themandibular plane and the FH plane; Gonial, angle between the mandibular plane and the ramus plane.

Fig 5. Intraoral photographs at the posterior subapical mandibular surgery: A, design of the surgicalincisal line; B, exposed alveolar surface; C, osteotomy to the posterior subapical mandibular segment;D, a lingual arch appliance was placed 1 day after the surgery.

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posterior subapical mandibular surgery was planned togenerate the segment including the mandibular rightfirst and second molars. Since the surgical incisional

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line was designed to run through the mandibular rightsecond premolar, this tooth had to be extracted beforesurgery. After the surgery, we planned to move the

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Fig 6. Facial and intraoral photographs just before the Le Fort I osteotomy and sagittal split ramus os-teotomy, age 23 years 6 months.

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collapsed mandibular segment bucally using an appli-ance during comprehensive orthodontic treatment.

Since there was an inclination of the maxilla in thefrontal dimension (Table I), it was expected that her fa-cial appearance would not become satisfactory solelythrough this surgery. Thus, we also planned to performa Le Fort I osteotomy and a sagittal split ramus osteot-omy if she were not satisfied with her facial appearanceafter the correction of the scissors-bite.

TREATMENT ALTERNATIVES

As treatment alternatives, the following 2 plans wereconsidered. First, the correction of the collapsed rightmandibular arch was considered without surgery. Thisplan could exclude the posterior subapical mandibularsurgery because of a potential risk of injuring the neuro-vascular bundle and the extraction of the mandibularright second premolar. But the patient was an adult,and the collapse of the mandibular arch was quite severe.Thus, it would be extremely difficult to correct the col-lapsed arch without surgical intervention.

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Second, posterior subapical mandibular surgery wasplanned to relocate the segment including not onlythe mandibular right first and second molars but alsothe third molar. This plan had an advantage in upright-ing the mandibular right third molar. However, the neu-rovascular bundle was located close to the apex of thethird molar, and a high risk of injury would be possible.We expected that both plans would include a Le Fort Iosteotomy and a sagittal split ramus osteotomy for a bet-ter treatment outcome.

Considering all advantages and disadvantages, it wasmore practical and safer to use the posterior subapicalmandibular surgery and relocate the segment includingthe mandibular right first and second molars. The seg-ment was to be moved with an appliance. Optionally,a Le Fort I osteotomy and a sagittal split ramus osteot-omy could be arranged afterward.

TREATMENT PROGRESS

To correct the collapsed mandibular right arch,posterior subapical mandibular surgery was performed,

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Fig 7. Posteroanterior and lateral cephalograms and panoramic radiograph just before the Le Fort Iosteotomy and sagittal split ramus osteotomy.

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and the mandibular right second premolar was ex-tracted (Fig 5, A-C). The lingual arch appliance wasplaced 1 day after surgery (Fig 5, D). The appliancewas activated gradually, and a total of 7 months wasrequired for the correction of the collapsed mandibularsegment and the scissors-bite. During this time, a bite-plate was placed in the maxillary arch for effectivecorrection.

After correction of the scissors-bite, an edgewisemulti-bracket appliance was placed, and comprehensiveorthodontic treatment was performed in both arches.The patient achieved a functional occlusion with thistreatment and did not complain of any temporomandib-ular joint pain after correction of the scissors-bite. At thisstage, the SNB angle was slightly decreased because of anincrease in the mandibular plane with the correction ofthe scissors-bite (Table II). The inclination of her maxillaryocclusal plane did not change, but the position ofmentonwas improved by 3 mm (Table I). Her facial appearancehad improved (Figs 6 and 7), but she still complained offacial asymmetry. It was decided to perform a Le Fort I

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osteotomy and a sagittal split ramus osteotomy for fur-ther correction of the facial disharmony.

These procedures were performed at age 23 years 6months. After surgery, her facial appearance was mark-edly improved, and the philtrum and the lip achievedsymmetrical positions (Figs 8 and 9). After 14 monthsof postsurgical orthodontic treatment, a functional andstable occlusion was achieved (Figs 10-12). Because ofthe surgical incisional line of the sagittal split ramusosteotomy, the mandibular right third molar had to beextracted. To make the maxillary right second molarocclude with the mandibular second molar, aninterdental space was created between the mandibularfirst and second molars, and the restoration of themandibular second molar was remade.

TREATMENT RESULTS

Retention was initiated by using circumferentialHawley retainers in the maxillary and mandibular arches.After all treatment had been completed, there was

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Fig 8. Posttreatment facial and intraoral photographs after surgery and the end of active treatment, age24 years 8 months.

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marked improvement in the inclination of the maxillaryocclusal plane (from 7.5� to 1.0�; Table I). The patientwas satisfied with her facial appearance. A stable andfunctional occlusion was still maintained 1 year after ac-tive treatment. The pretreatment mandibular arch wasexpanded by 3.9 and 8.2 mm at the mandibular firstpremolars and first molars, respectively (Table III). Theposition of menton moved closer to the skeletal midline(from 8.0 to 2.5 mm). There was no sensory or motorparalysis.

All SNA, SNB, and mandibular plane angles werecomparable with Japanese norms after active treatment.A posteroanterior cephalogram showed no relapse in thefrontal dimension. There was remodeling of the mandib-ular plane. A panoramic radiograph showed that theroots of the incisors were slightly resorbed. The maxillaryincisors elongated through preoperative orthodontics.We planned to correct the inclined maxilla in the frontaldimension with a Le Fort I osteotomy. However, therewas also counterclockwise rotation of the whole maxillathrough this operation.

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DISCUSSION

Posterior subapical mandibular surgery can be ap-plied for the following treatments4: (1) to upright pos-terior teeth that are positioned lingually or bucally, (2)to upright posterior teeth that are positioned severelytoward the mesial aspect, (3) to close interdental spacesbetween the premolars or molars, and (4) to level super-erupted posterior teeth. This surgery is known to involvea risk of injuring the inferior alveolar neurovascularbundle, and a sufficient vascular supply to the dissectedsegment is crucial for the treatment outcome. Thus, it isless common to perform this surgery compared with an-terior subapical mandibular surgery. However, it can besuccessfully done with a proper incisional design anda careful surgical technique.4 This patient had a satisfac-tory treatment outcome with no sensory or motor paral-ysis after surgery, demonstrating the efficiency of thissurgical approach without complications or clinicalproblems.

After the posterior subapical mandibular osteot-omy, it was possible to move the segment and fix its

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Fig 9. Posttreatment posteroanterior and lateral cephalograms and panoramic radiograph.

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position by using an occlusal splint, as previously de-scribed.4 Alternatively, we decided to move the seg-ment bucally with a lingual arch appliance. This wasperformed by using a distraction osteogenesis-typeof movement to facilitate new bone formation in thealveolus. Another advantage of this movement wasthat it was easier to achieve the appropriate amountof buccal movement required for a desirable occlusion.After the treatment, integrity of the mandibular boneand satisfactory occlusion were achieved, demonstrat-ing that our treatment planning was appropriate forthis patient.

Posterior crossbite has been associated with tempo-romandibular joint disorders.5,6 In such cases, anasymmetric functional shift is regarded as a majorcause of the disorder. Our patient had a scissors-biteon the right side and temporomandibular joint painbefore treatment. After correction of the scissors-bite,the functional shift disappeared, and she did not com-plain of temporomandibular joint sounds or pain. It islikely that her scissors-bite on the right side was asso-ciated with her pretreatment temporomandibular joint

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disorders, and the correction of the malocclusion im-proved this condition.

The patient’s chief complaint was her asymmetric fa-cial appearance. We expected her facial appearance toimprove after correction of the functional guidance.Since her pretreatment maxillary occlusal plane was in-clined by 7.5�, we also expected that she might not besatisfied with her facial appearance after the posteriorsubapical mandibular surgery, and that a Le Fort I os-teotomy and a sagittal split ramus osteotomy would berequired for further correction. It would have been pos-sible to perform the Le Fort I osteotomy and the sagittalsplit ramus osteotomy together with the subapical sur-gery. However, considering the possibility that she wouldbe satisfied with her facial appearance and not requestmore surgery after the subapical surgery, we decidedto perform the Le Fort I osteotomy and the sagittal splitramus osteotomy after the subapical surgery. As shownin Table I and the facial photographs, the Le Fort I os-teotomy and the sagittal split ramus osteotomy cor-rected her asymmetric skeletal pattern and markedlyimproved her appearance.

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Fig 10. Facial and intraoral photographs 1 year after active treatment, age 25 years 8 months.

Fig 11. Dental casts 1 year after active treatment.

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Fig 12. Posteroanterior and lateral cephalograms and panoramic radiograph 1 year after active treatment.

Table III. Analysis of cast models

Pretreatment(21 y 0 mo)

One year after activeorthodontic treatment (25 y 8 mo)

Maxillary first premolars (mm) 43.8 44.3Maxillary first molars (mm) 55.0 54.7Mandibular first premolars (mm) 36.2 40.1Mandibular first molars (mm) 36.0 44.2

Maxillary first premolars, Distance between the buccal cusps of the maxillary right and left first premolars; Maxillary first molars, distance be-tween the mesiobuccal cusps of the maxillary right and left first molars; Mandibular first premolars, distance between the buccal cusps of themandibular right and left first premolars;Mandibular first molars, distance between the mesiobuccal cusps of the mandibular right and left firstmolars.

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CONCLUSIONS

Posterior mandibular subapical osteotomy was per-formed on a 21-year-old woman, whose chief complaintwas facial asymmetry. Her collapsed mandibular rightpremolars and molars were moved by using a lingualarch appliance after the subapical osteotomy. Le Fort Iosteotomy and sagittal split ramus osteotomy were per-formed to correct her facial asymmetry. After these treat-ments, she achieved a satisfactory occlusion and a more

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symmetric facial appearance. This case report highlightsthe efficacy of posterior subapical mandibular surgeryfor the correction of a collapsed arch and a scissors-bite.

REFERENCES

1. K€ole H. Surgical operations on the alveolar ridge to correct occlusalabnormalities. Oral Surg 1959;12:277-88.

2. MacIntosh RB. Total mandibular osteotomy: encouraging experi-ences with an infrequently indicated procedure. J Maxillofac Surg1974;2:210-8.

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3. BuckleyMJ, Turvey TA. Total mandibular subapical osteotomy: a re-port on long-term stability and surgical technique. Int J Adult Or-thod Orthognath Surg 1987;2:121-30.

4. Epker BN, Wolford LM. Posterior subapical mandibular surgery. In:Epker BN, Wolford LM, editors. Dentofacial deformities, surgical-orthodontic correction. St Louis: Mosby; 1980. p. 16-25.

5. Kennedy DB, OsepchookM. Unilateral posterior crossbite with man-dibular shift. J Can Dent Assoc 2005;71:569-73.

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6. Egermark-Ericksson I, Carlsson GE, Magnusson T, Thilander B. Alongitudinal study on malocclusion in relation to signs and symp-toms of cranio-mandibular disorders in children and adolescents.Eur J Orthod 1990;12:399-407.

7. Sassouni V. Orthodontics in dental practice. St Louis: Mosby; 1971:p. 330-7.

8. Iizuka T. Roentgencephalometric analysis of craniofacial growth inJapanese children. J Stomatol Soc Jpn 1958;25:18-30.

Journal of Orthodontics and Dentofacial Orthopedics

Orthognathic treatment for a patient with facial asymmetry associated with unilateral scissors-bite and a collapsed mandibu ...Diagnosis and etiologyTreatment objectivesTreatment alternativesTreatment progressTreatment resultsDiscussionConclusionsReferences