@2021 JCO, Inc. May not be distributed without permission. www.jco-online.com CASE REPORT Surgical-Orthodontic Treatment of a Patient with Severely Asymmetrical Skeletal Class III Dentofacial Deformity JIYU SONG, MDS XINGFU BAO, DDS, PhD LI CHEN CHENMENG LU, MDS GUOMIN WU, DDS, PhD MIN HU, DDS, PhD YI ZHANG, DDS, PhD ompared with a typical skel­ mandibular height in the vertical etal Class III mandibular pro­ dimension, and inconsistency of Ctrusion, an asymmetrical the maxillary and mandibular skeletal Class III is a more complex widths in the transverse dimen­ three­dimensional craniomaxillary sion.1,2 Comprehensive treatment deformity, involving unilateral ex­ including presurgical orthodontics, cessive mandibular growth or de­ orthognathic surgery, and post­ ficient maxillary growth in the sag­ surgical orthodontics is required ittal dimension, bilateral for these defects to be completely inconsistency of maxillary and resolved.3 Drs. Song and Lu are residents, Drs. Bao and Zhang are Lecturers and staff orthodontists, and Dr. Hu is Dean and Professor, Department of Ortho- dontics; Mrs. Chen is a diagnostic technician, Department of Oral Radiology; and Dr. Wu is Dean and Professor, Plastic Aesthetic Center, School and Hospital of Stomatology, Jilin University, Changchun, Jilin, China. E-mail Dr. Zhang at [email protected]. JCO/JULY 2021 © 2021 JCO, Inc. 210701 TREATMENT OF A PATIENT WITH SEVERELY ASYMMETRICAL SKELETAL CLASS III The long-term stability of conventional sur- The panoramic radiograph indicated general- gical-orthodontic treatment for a severely asym- ized horizontal bone loss in both arches, with the metrical skeletal Class III dentofacial deformity root of the upper left premolar shorter than normal. has been considered problematic because of the Cephalometric analysis (Table 2) confirmed a skel- possible inadequacy of dental decompensation be- etal Class III relationship (ANB = −4.2°, Wits ap- fore surgery, along with complications due to con- praisal = −13.5mm, APDI = 96.4°), a hyperdiver- dylar changes, airway conditions, and muscle pull gent pattern (SN-MP = 44.9°, FMA = 29.1°, and function.4 Considering these factors, it is im- S-Go/N-Me = 58.3%, y-axis = 74.7°, ODI = 46.7°), portant to carefully evaluate such a skeletal defor- and a skeletal open-bite tendency (ALFH/PLFH = mity and the dental compensation mechanisms to 1.9). The Ricketts frontal cephalometric analysis plan presurgical orthodontics that can achieve the indicated skeletal asymmetry of the mandible and desired goals and ensure stability. The magnitude dental asymmetry of the mandibular arch (Table 3). and amount of surgical correction will largely de- Cone-beam computed tomography (CBCT) pend on the efficacy of the presurgical orthodontic showed inconsistency in the morphology of the decompensation, which should be planned in all TMJ and widening of the anterior space on the left three planes of space.5,6 In the sagittal dimension, (Fig. 2). Functional examination found no signs of the proclined upper incisors and retroclined lower TMD, although the mandible deflected to the right incisors must be decompensated to place them in when opening. ideal positions with respect to the jaw; in the trans- The diagnosis was a skeletal Class III dento- verse dimension, the arches must be coordinated facial deformity with facial asymmetry, attribut- while controlling the torque of the posterior seg- able to abnormal development of the maxilla and ments; in the vertical dimension, the overerupted mandible in three dimensions; a congenitally miss- teeth must be intruded to establish an appropriate ing upper right first premolar; an abnormality in vertical anterior tooth display after surgery.3,7 the upper left second molar; and chronic general- This case report demonstrates comprehensive ized periodontitis. surgical-orthodontic treatment of a patient with Treatment objectives were to correct the severe skeletal discrepancies in all three planes: asymmetrical skeletal Class III deformity, thus sagittal (Class III malocclusion), transverse (facial achieving a harmonious facial appearance; align asymmetry), and vertical (long face and open bite). the dental midlines with each other and with the facial midline; establish ideal overjet and overbite Diagnosis and Treatment Plan with proper interdigitation of the posterior teeth; improve the periodontal condition; and facilitate A 27-year-old male presented with an asym- good oral hygiene. metrical face, with the chin shifted to the left, a Combined surgical-orthodontic treatment concave profile, and excessive lower facial height was the only viable approach to achieve these ob- (Fig. 1). He reported that a mild mandibular trauma jectives. Presurgical orthodontics would decom- had occurred a month earlier. Intraoral examina- pensate the dentition to achieve a maximum skel- tion found a more-than-full-cusp Class III molar etal correction and stable postsurgical occlusion. A relationship, anterior and posterior crossbites, and Le Fort I osteotomy was planned to advance, slight- an open bite. The patient also exhibited gingival ly rotate, and center the maxilla, with the advance- swelling with bleeding and recession. ment more pronounced on the left and the impac- Analysis of the study casts showed an overjet tion on the right and in the posterior regions. In of −4.4mm to −8.07mm and generalized spacing addition, a bilateral sagittal split ramus osteotomy in the upper and lower anterior segments (Table would set back and rotate the entire mandible 1). The upper right first premolar was congenital- counter clockwise, with more movement on the right ly missing, and the upper left second molar was to level the mandible with the maxilla. Postsurgical abnormal. orthodontics would finish and detail the occlusion. JCO/JULY 2021 210702 TREATMENT OF A PATIENT WITH SEVERELY ASYMMETRICAL SKELETAL CLASS III The presurgical orthodontic decompensation rior teeth were corrected by buccal root-torquing was carefully planned to coordinate with the bends. Occlusal interferences were removed by planned surgical movements (Table 4). Maxillary grinding the lingual marginal ridges of the upper premolars are commonly extracted to help decom- canines. pensate proclined upper incisors and coordinate After 24 months of presurgical preparation, the midline between the upper dentition and the the teeth were properly positioned relative to the maxilla. In this patient, because of the missing jaws, and the upper arch was coordinated with the maxillary right first premolar, the upper dental lower arch (Fig. 3). midline was deviated to the right compared with A visual treatment objective and model sur- the maxillary midline. This was a challenging sit- gery were used to plan a Le Fort I osteotomy, bi- uation, since the upper dental midline and facial lateral sagittal split ramus osteotomy, and genio- midline typically deviate to the same side. We de- plasty (Fig. 4). The maxilla was advanced by 5mm cided to extract the upper left first premolar and to and drifted to the right by 2.5mm, with a .5mm retract the upper left incisors with strong anchor- impaction on the right side and 4mm extrusion on age from a miniscrew in the left maxilla. The pa- the left, as well as a slight clockwise rotation to tient agreed to this plan and to extraction of the correct the open bite. The mandible was set back lower left and right third molars, followed by two- by 2mm on the left and 9mm on the right, and jaw surgery to correct his skeletal deformity. pogonion was advanced by 4mm. Rigid fixation was used in both the maxilla and the mandible, Treatment Progress with no intermaxillary fixation. The patient was closely monitored for two Before orthodontic treatment, the patient un- months after surgery. Postsurgical orthodontic derwent periodontal therapy, including scaling and treatment was then initiated, using .019" × .025" root planing, to control plaque and eliminate in- stainless steel archwires to finish and detail the flammation. Periodic periodontal maintenance occlusion. visits were scheduled during orthodontic treat- After a total 31 months of treatment, all ap- ment. pliances were removed. Considering the typical Presurgical orthodontics began with direct bilateral discrepancy in masticatory muscle tension bonding of .022" × .028" Victory Series brackets* in a patient with asymmetrical skeletal Class III in both arches; the lower anterior brackets were dentofacial deformity, we designed special remov- rotated 180° to effectively procline the retroclined able acrylic retainers for nighttime wear to help lower incisors. A customized orthodontic band was prevent relapse (Fig. 5). used to control the abnormal upper left second molar. Treatment Results After leveling and alignment of both arches, the diastema was closed with sliding mechanics on Post-treatment records confirmed good es- .019" × .025" stainless steel archwires. Self-tapping thetic and occlusal results (Fig. 6). Cephalometric miniscrews** were placed buccally between the analysis (Tables 2,3) and superimpositions showed roots of the upper first and second molars to pro- significant improvement in the soft and hard tis- vide strong anchorage for retraction of the upper sues. The interdigitation in the left molar area was left incisors and midline alignment. To expand the still unsatisfactory because of the abnormal upper upper arch and coordinate it with the lower arch, left second molar (Fig. 7). irrespective of the occlusal plane inclination, the inclinations of the upper posterior