Change of masseter muscle after the angle-grinding ostectomy for the enlarged mandibular angle

Objective To study the change of masseter muscle after the anglegrinding ostectomy for the treatment of the mild enlarged mandibular angle, and provide reference for the clinic. Methods The masseter thickness of 60 female patients were bilaterally measured under both rest and maximal contracted positions by highfrequency superficial ultrasonic imaging before operation and every 4 weeks postoperatively and compared. Results The mean thickness of masseter muscle on postoperative week 24 became thinner and more atrophied markedly than that before operation (P0.05). There was no obvious difference in the thickness of masseter muscle between postoperative week 24 and week 32 (P0.05). Conclusion After the anglegrinding ostectomy, the hypertrophic masseter muscle can get atrophied itself in 24 weeks postoperatively without particular treatment, but no more changes happen thereafter. The patients with mild enlarged mandibular angle can be treated with anglegrinding ostectomy only.