Abstract: Objective To observe the change of facial soft tissue after mandibular angle osteotomy. Methods Comuterized tomography (CT) examination was performed on 130 patients treated by mandibular angle ostemomy before operation and 6 months after operation, respectively. Intra-oral incision were used for correcting prominent mandibular angle (PMA).①ratio of the height from lobule to mandibular angle&the height of lower face, ②ratio of the distance between the two sides of mandibular angle&the distance between the two sides of zygometic arch and ③the degree of mandibular angle were all calculated pre-and postoperatively to evaluate the change of facial soft tissue. Results The preoperative ratio of the height from lobule to mandibular angle&the height of lower face was 1∶(1.5±0.12), while the postoperative was 1∶(1.92±0.15);The preoperative ratio of the distance between the two sides of mandibular angle & the distance between the two sides of zygometic arch was 1∶(1.03±0.11), while the postoperative was 1∶(1.2±0.21);The preoperative mandibular angle was (109±1.7) °, while the postoperative was (121 ±2.1) ° . Conclusion Six months after mandibular angle osteotomy, the patients with mandibular angle hypertrophy could obtain better quantitative improvement of facial shape.

Key words: Mandibular angle osteotomy, Computerized tomography, Three-dimensional imaging