A 23-year-old female with chief complaints of gummy smile and facial asymmetry visited our OPD for orthodontic treatment evaluation. She denied any contributory systemic disease, with no known drug or food allergy. In the functional examination, she denied any TMJ symptoms and signs or other para-function. Pre-treatment data Extraoral examination
The Frontal view revealed obvious facial asymmetry with chin deviation to right, mild lip canting with right side upward and mild mentalis muscle strain when closing her mouth (Figure 1)
. From smiling view, regional anterior cross-bite, about 4 mm gingival exposure from anterior to posterior, and upper gingival marginal discrepancy were found on her full smile. Relatively to facial midline, upper dental midline shift to her right side for 1 mm, while the lower dental midline shifted to her right for 4 mm. From lateral view, she had a convex profile, more protrusive lower lip, and shallow labial mental fold with inadequate chin projection. Intraoral examination
The overbite was 1 mm; meanwhile, her bilateral upper lateral incisors were block-in and lower left central incisor had cross-bite with upper central incisors. The lower dental midline to upper dental midline was shifted to her right by 3 mm. The upper arch form was asymmetrical ovoid with moderate crowding, while the lower arch form was tapered with minimal crowding and 2 mm depth of curve of Spee bilaterally. The buccal segment revealed upper and lower right second premolar had lingual cross-bite, Class I canine and molar relationship at the right side, and Class III canine and molar relationship at left side. Radiographic examination
In the panoramic X-ray, the morphology of bilateral condyles and ramus were asymmetrical with right side larger than the left side in width, and the four wisdom teeth were noted. From PA cephalometric analysis, the left mandibular body was longer than the right, and the chin and lower dental midline deviated to the right side for 4 mm. The occlusal plane was canting with right side upward 1.5 mm. From the lateral cephalometric analysis, the patient exhibited a skeletal class III facial pattern with mandibular prognathism, normal mandibular plane angle, and proclined upper incisors with retroclined lower incisors. Diagnosis
Skeletally, the patient had a Class III jaw relationship with mandibular prognathism and normal mandibular plane angle; facial asymmetry with occlusal canting and chin deviation to the right side. Dentally, she had Angle Class III malocclusion with regional anterior cross-bite. The upper and lower dentition were crowding and midline shifting. Upper and lower right second premolars had lingual cross-bite. In soft tissue aspect, she had a convex profile and gummy smile; the soft tissue chin deviated and the lips were mild canting. Treatment goal and treatment plan
The treatment goals for this patient were as the followings:
Sagittal: correct the mandibular prognathism and chin retrusion
Transverse: correct the mandibular asymmetry and maxillary yawing
Vertical: correct the gummy smile and maxillary canting
Dental: achieve canine Class I and molar Class II relationship; upper and lower midline coincidence; and establish proper overbite and overjet.
According to the diagnosis and chief complaints of this patient, we proposed her the treatment plan of orthodontic treatment combined with 2-jaw surgery.
The pre-surgical orthodontic treatment plan:
The upper and lower dentition need leveling, alignment, decompensation, and occlusal plane flattening. Four wisdom teeth were planned to be extracted before orthognathic surgery. The orthognathic surgical plan:
The maxilla needs asymmetrical impaction at the anterior and posterior part to correct the gummy smile and occlusal plane canting; therefore, LeFort I with multi-pieces osteotomy and 14, 24 extractions during the surgery was planned. The mandible needs bilateral sagittal split osteotomy and an asymmetrical setback to correct the mandibular prognathism and asymmetry. The chin may need genioplasty to correct the menton deviation and control the lower anterior facial height. The post-surgical orthodontic treatment plan:
The finishing stage needs detailing the dental arch and settling the occlusion. Treatment Progress Pre-surgical orthodontic treatment
After consultation with this patient, fixed 0.022x0.028-in preadjusted appliances were placed. The upper and lower dentition were through leveling and alignment from round NiTi wire to rectangle stainless steel wire. Four wisdom teeth were all extracted by oral surgeon. Before the surgery, segmented archwires were inserted from canine to canine and from the second premolar to each second molar in the maxillary arch for the anterior segmental osteotomy and bilateral first premolar extractions. Pre-surgical clinical examination
The presurgical phase took 17 months. The pre-op clinical examination showed the occlusal plane was canting with right side upward 1.5mm; the incisor show at rest was 6 mm, and the gummy smile was about 4 mm. The upper dental midline relative to facial midline shifted to the right for 1mm and lower shifted to the right for 3.5mm. The overbite was 2 mm and the overjet was 2.5 mm (Figure 2)
The cephalometric analysis and superimposition tracing of initial to pre-op showed the upper incisors were flared with control tipping and upper molars became tip-back due to the leveling and alignment; the inclination of lower incisors and the position of lower molars were maintained. Orthognathic surgery
Following the surgical plan made by the orthodontist, in the maxilla, LeFort I with 3-piece osteotomy and 14, 24 extractions during the surgery were performed; the anterior segment was advanced 2.5 mm, impacted 3 mm with clockwise rotation, and the dental midline was coincident with the facial midline; the posterior 2-piece segments were both advanced to close the extraction space and asymmetrical impaction (R: 1 mm; L: 2.5 mm).
In the mandible, BSSO to perform asymmetric setback (average 6 mm) and yaw rotation to center the lower dental midline to upper midline; the genioplasty was for centering the chin (4 mm shift to the left side) and chin augmentation, and maintaining the lower anterior facial height. A rigid fixation with miniplates and miniscrews fixed the maxillary segments in the final position. No interocclusal splint or postoperative maxillomandibular fixation was used. Post-surgical orthodontic treatment
Through the postoperative orthodontic treatment, the occlusal steps between the anterior and posterior segments of the anterior segmental osteotomy were leveled and aligned through NiTi wire and 3/16-inch, 6 oz vertical intermaxillary elastics wearing the whole day except meals and tooth brushing. The root divergence between upper canines and 2nd
premolars were corrected by bracket repositioning. After finishing and detailing at the post-op stage for 10 months, the full mouth fixed appliances were debonded with Hawley retainers delivery. The total treatment period was 28 months. Treatment Results
Posttreatment records showed that all treatment objectives were achieved with good esthetic and occlusal results: the facial asymmetry had an obvious improvement, and the chin point was aligned with the facial midline (Figure 3)
. The patient was also satisfied with the excessively reduction of the gummy smile and the consonant smile arc. Dentally, proper overbite and overjet with canine class I and molar class II relationship were achieved. The occlusion had good interdigitation. The upper and lower dental midlines were coincident with the facial midline. No any dysfunction of TMJ or masticatory muscle appeared after treatment. The panoramic showed well bone healing and improved root parallelism, especially the upper canines and 2nd
premolars, from post-op to debonding. The cephalometric analysis showed that successful dental decompensation and surgical correction of the skeletal Class III jaw discrepancy were achieved: the ANB angle and the Wits appraisal increased from -1º to 4.5º and from -8 to 0 mm, respectively; the mandibular incisors were proclined from 90º to 93º relative to the mandibular plane (IMPA); the maxillary incisors were uprighted from 120º to 98º with respect to SN (U1 to SN); and the mandibular plane angle (SN-MPA, FMA) was maintained (Table 1)
. The cephalometric superimpositions of pretreatment and posttreatment radiographs showed that the maxilla moved forward and upward both 2mm, and the mandible moved back 6 mm (Figure 5)
. Dental movements included upper incisal uprighting, mesial movement of the maxillary molars, and proclination of the mandibular incisors. The facial profile was improved with upper and lower lips retraction, labiomental fold deepening, and final convexity increased.
Overall superimposition of initial, pre-op and finish cephalometric tracings. View Hi-Res Image