Abstract
A 17-year-old female with severe facial asymmetry and skeletal Class III malocclusion, whose skeletal growth was already complete, presented with left-sided mandibular prognathism, a 5 mm chin height discrepancy (higher on the right side), and a 7.6 mm chin deviation to the left, together with paranasal depression and a 4 mm cant of the maxillary occlusal plane, positioned higher on the right side. The patient exhibited significant dental asymmetry, including a Class III molar relationship (7 mm) and canine relationship on the right side and a Class II molar relationship (end-on) on the left, along with a left posterior crossbite. After evaluation by the oral and maxillofacial surgery team, it was determined that she required bimaxillary orthognathic surgery combined with chin border reduction. The treatment consisted of bimaxillary surgery and inferior chin border shaving, including a Le Fort I osteotomy for 5.5 mm of maxillary advancement, asymmetric intrusion (2 mm right-sided downward repositioning and 2 mm left-sided intrusion), and bilateral mandibular ramus osteotomies to achieve a 5.5° rotation to the right and counterclockwise mandibular rotation. The final positioning was adjusted according to the preoperative surgical plan, with careful verification of occlusal alignment, overjet, overbite, facial symmetry, and lip commissure level before rigid fixation was performed.