Effect of "surgery first" orthognathic approach on temporomandibular symptoms and function: a comparison with "orthodontic first" approach.

Objective: The aim of this study was to comparatively evaluate the effects of the surgery-first approach (SFA) and the orthodontics-first approach (OFA) on temporomandibular joint (TMJ) function and maximum mouth opening.

Study Design: This retrospective study investigated the outcomes of patients with diagnosed skeletal class III dentofacial deformities. Twenty-four patients were enrolled in the OFA group, and 23 patients were enrolled in the SFA group. All patients were examined in the same manner 4 times: before surgery and at 1, 3, 6, and 12 months after surgery. Range of mouth opening (ROM) was measured between the maxillary and mandibular central incisors. Symptoms were evaluated subjectively by using a questionnaire with items pertaining to pain on mandibular movements, TMJ sounds, and pain in masticatory muscles region.

Results: No severe complications or relapse occurred in either group during the 12-month follow-up period. Postoperative changes in ROM showed similar tendencies, but there was no significant difference in ROM during the follow-up period between the OFA and SFA groups (P < .05). The percentage reduction was nearly 45% at 1 month postoperatively and 20% at 3 months postoperatively compared with the preoperative situation. After 6 months postoperatively, the ROM was almost the same as before surgery. The number of patients with such sounds increased with time until 12-month postoperative examinations in the OFA group but increased slightly during this period in the SFA group. During the first 3 months postoperatively, less than 10% of patients in both groups had newly detected pain of TMJ and/or muscles. At 6 and 12 months postoperatively, only 1 patient in the SFA group had pain.

Conclusions: No significant differences in TMJ symptoms or function were observed during a 12-month follow-up period between patients with skeletal class III malocclusion treated with the SFA and those treated with the OFA.