Transverse decompensation in surgery-first approach vs conventional orthognathic surgery in mandibular prognathism patients.

Objectives: To investigate transverse treatment outcomes in patients with skeletal Class III malocclusion treated with a surgery-first orthognathic approach (SFA) vs conventional orthognathic surgery (COS).

Materials and methods: This retrospective cohort study included 128 patients, divided into four groups of 32 based on the inclusion of presurgical treatment and extraction of the maxillary premolars: (1) COS with extraction, (2) COS without extraction, (3) SFA with extraction, and (4) SFA without extraction. CBCT scans were taken before and after treatment, with an additional scan after presurgical orthodontic treatment for the COS group only. The primary outcome variable was transverse decompensation, assessed through changes in maxillary and mandibular molar inclination and intermolar width. Predictor variables included treatment approach (SFA vs COS) and extraction status (extraction vs nonextraction). Transverse measurements were compared among the four groups throughout the treatment process.

Results: Maxillary molar inclination relative to the occlusal plane increased after treatment, whereas the mandibular molar inclination decreased after treatment, indicating transverse decompensation in the COS and SFA groups, and the extraction and nonextraction groups. There were no statistically significant differences in transverse changes between the COS and SFA groups.

Conclusions: Although the difference in transverse decompensation between the COS and SFA groups was not statistically significant, clinicians may still need to consider careful management of transverse decompensation during postsurgical treatment, particularly in SFA cases.