The purpose of the study was to evaluate the postoperative change in mandibular movement function and in joint noise in patients who underwent sagittal splitting ramus osteotomy (SSRO) for mandibular deformities. The following measurements were made in 22 patients before surgery and at 3, 6, and 12 months after surgery: the amount of maximum mouth opening, levels of electoromyographic activity ofmasseter muscle, and temporomandibular joint noise. At 3 months after surgery, the amount of maximum mouth opening and masseter muscle activity had not recovered sufficiently; at 6 months, both mouth opening and electromyogram activity began to increase; and at 12 months after surgery, the values of the two indices were almost the same when compared with those in normal groups. After surgery, the ratio of patients with temporomandibular joint noise decreased remarkably. Therewas no case of newly-recognized joint noise after surgery.
