Comparison of Orthodontics-First and Surgery-First Approach in Positional Changes of the Condyle After Mandibular Setback Surgery Using Three-Dimensional Analysis.

PURPOSE: To examine and compare the 3-dimensional (3D) postoperative changes of the condylar position after mandibular setback surgery using the orthodontics-first approach (OFA) and surgery-first approach (SFA).

MATERIALS AND

METHODS

This retrospective cohort study included patients who had undergone bilateral sagittal split ramus osteotomy for mandibular prognathism using OFA or SFA. Computed tomography images were obtained and analyzed preoperatively (T0), postoperatively (T1), and at the 6-month follow-up visit (T2). The bodily shift of the condylar center and rotational movement of the condylar head were measured using the 3D coordinate system between each time point and compared between the OFA and SFA groups. Repeated measures analysis of variance with a Bonferroni post hoc test was used to compare the time course changes of the condylar position for the 2 surgical-orthodontic approaches.

RESULTS

A total of 55 patients (mean age 21.9 years; 31 males, 24 females) were evaluated. Of the 55 patients, 29 had undergone OFA and 26, SFA. In both groups, the condyle showed perioperative lateral and inferior displacement with inward rotation, followed by returning to its preoperative position during the 6 months postoperatively. No significant difference was found between the 2 groups in the time course change of the condylar position.

CONCLUSIONS

Regardless of the timing of the operation (OFA vs SFA), the perioperative and postoperative changes of the condylar position after mandibular setback surgery are equivalent.