3D assessment of root resorption and soft tissue adaptations in surgery-first vs. early orthognathic surgery: a randomized clinical trial.

OBJECTIVE: This study evaluated the effects of two orthognathic surgery-timing approaches on hard and soft tissues in skeletal Class III patients undergoing bimaxillary orthognathic surgery using cone beam computed tomography (CBCT) and stereophotogrammetry. METHODS: Patients undergoing non-extraction surgery were randomly assigned to either a surgery-first (SF) group (n = 12; 19.91 ± 2.60 years) or a surgery-early (SE) group (n = 12; 22.50 ± 2.90 years) for a total of 24 patients. Maxillary advancement was 3.64 ± 1.50 mm in the SF group and 3.47 ± 2.77 mm in the SE group, and mandibular setback was 2.25 ± 1.32 mm and 1.20 ± 1.75 mm, respectively. Millimetric (length, dehiscence, and fenestration), volumetric measurements, and soft tissue anthropometric assessments were collected using three-dimensional (3D) records obtained before treatment and after debonding. RESULTS: Following orthognathic surgery, a significant reduction in root length and volume measurements, and a significant increase in dehiscence were observed within the groups. Additionally, incisor teeth exhibited greater root resorption compared to other teeth. However, no significant differences were found between the groups regarding changes in hard or soft tissues. CONCLUSIONS: These findings suggest that changes in root length, alveolar bone, and soft tissues are similar in the SF and SE approaches, indicating that these changes occur independently of the surgical timing in comparable patients. THE TRIAL REGISTRATION NUMBER (TRN): is NCT06873451 (Date of registration: 13.02.2025; retrospectively registered).