Postsurgical stability in mandibular prognathism patients undergoing a surgery-first approach: influence of postoperative orthodontic approach using clear aligners vs fixed appliances.

Objectives: To compare the effect of postsurgical orthodontic treatment between using clear aligners (CA) or fixed appliances (FA) on the postsurgical stability of patients with mandibular prognathism in the surgery-first approach (SFA). Materials and Methods: This retrospective study included 54 patients with mandibular prognathism who underwent surgical orthodontic treatment with isolated mandibular setback surgery. The patients were divided into two groups according to the mechanics of postsurgical orthodontic treatment: the CA group included 27 patients treated with clear aligners, and the FA group included 27 patients treated with brackets during postoperative orthodontic treatment. Cone beam computed tomography scans were taken before, immediately after, and at 3, 6, and 12 months postsurgery to assess mandibular relapse. The measurements of postsurgical mandibular relapse including horizontal and vertical positions were compared according to the treatment progress and groups. Results: Total postsurgical mandibular relapse at pogonion was 3.2 mm in the CA group and 2.2 mm in the FA group. Relapse was higher at 3 months postsurgery in both groups, with an average forward movement of 1.4 mm in the CA group and 1.7 mm in the FA group. Relapse in the CA group showed no significant changes over time, indicating persistence beyond the initial period. In contrast, the FA group showed a significant reduction in relapse by 3 months. Overall, the CA group tended to have greater and more persistent relapse than the FA group. Conclusions: Careful consideration of skeletal relapse is needed in the postsurgical management of patients treated with clear aligners in SFA treatment.