Facial asymmetry affects more frequently on the lower face than the upper face. Significant facial asymmetry compromises both occlusal function and facial esthetics. The etiology of facial asymmetry may be skeletal, dental, and soft tissue components of dentofacial structures. Correct diagnosis and appropriate treatment planning are very important in the management of the orthodontic patients with the chief complaint of facial asymmetry. Facial asymmetry in lower face can be clearly detected through the examination on chin deviation and asymmetry of bilateral gonial angle regions. The amount and the direction of deviation usually reveals the dental compensation in the transverse aspect before treatment. Thus the dental axis correction is more complicated in patients with asymmetric mandible. Herein we report a case presenting chin deviation and obvious asymmetry of bilateral gonial angles. The contour of gonial angle is more prominent at the ipsilateral side compared to the chin deviation. This is a case of 22-year-old male, who complained about facial asymmetry and chin protrusion. Clinical examination revealed acute nasolabial angle, mandible prognathism, chin deviation to right side. The prominent gonial angle was much more prominent at the right side, which was ipsilateral to the side of chin deviation. Cephalomatric analysis showed skeletal Class III malocclusion with mandible prognathism and mild dental compensation. Postero-anterior cephalomatric analysis showed mandible deviation to the right side and obvious asymmetry at bilateral ramus and gonial angle. The mild occlusal plane canting was noted. The treatment plan included non-extraction full-mouth orthodontic treatment and bilateral sagittal split osteotomy (BSSO) mandibular surgery for setback and side shift. Upper arch distalization by upper bilateral miniscrews was conducted to retract upper incisor for decompensation in the pre-surgical orthodontic treatment. The dental compensation in the transverse aspect was eliminated with the cross-elastics and the bucco-lingual torque correction of posterior teeth. In mandibular surgery, over-correction of mandible side-shift movement to the left side was done for more correction of chin deviation. The treatment outcome showed stable occlusion and obvious improvement of facial asymmetry.

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Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.