Mandibular setback by bilateral sagittal split osteotomy: a two-year three-dimensional study of condylar positional and morphological changes.

OBJECTIVE

To elucidate the pattern and extent of long-term condylar adaptation within the temporomandibular joint (TMJ) following mandibular setback by bilateral sagittal split osteotomy (BSSO) in patients with mandibular prognathism, with particular attention to subtle three-dimensional changes over time.

MATERIALS AND

METHODS

46 temporomandibular joints from 23 eligible patients (17 females, six males; mean age 22.7 ± 5.0 years) who underwent BSSO, with or without Le Fort I osteotomy, were analyzed. Computed tomography (CT) scans were obtained at three time points: preoperatively (T0), within 1 week postoperatively (T1), and at a 2-year follow-up (T2). Quantitative assessments of condylar position, inclination, linear dimensions, joint spaces, and volumetric joint space were performed using a standardized three-dimensional measurement protocol, and reconstructed imaging data were statistically compared across the three time intervals.

RESULTS

A statistically significant change in the right anterior joint space (AJS) was observed between T0 and T1 (p = 0.046), increasing from 1.55 ± 0.43 mm to 1.95 ± 0.65 mm. In contrast, no statistically significant changes were identified in the posterior, superior, or medial joint spaces on either side at any time point. Similarly, condylar inclination, position, and linear dimensions did not differ significantly between T0, T1, and T2 (p > 0.05). Volumetric joint space measurements remained stable throughout the observation period, with no statistically significant variation.

CONCLUSION

This comprehensive three-dimensional evaluation indicates that mandibular setback via BSSO does not induce short- or long-term condylar morphological alterations.