Adaptation of soft tissue following bilateral sagittal split ramus osteotomy in skeletal class III patients with facial asymmetry: A retrospective study

Purpose

This retrospective study aimed to evaluate sequential changes in soft tissue thickness after bilateral sagittal split ramus osteotomy (BSSRO) in skeletal class III patients with facial asymmetry and to explore their correlation with surgical movements for optimal postoperative facial symmetry and esthetic outcomes.

Material and Methods

This study included 37 patients with class III malocclusion and > 4 mm Menton (Me) deviation who underwent BSSRO. Posteroanterior cephalograms were captured at preoperative (T0), 6 weeks (T1), 6 months (T2), and 1 year (T3) postoperative intervals to analyze changes in Me deviation, fronto-ramal inclination (FRI), and soft tissue thickness. Statistical analysis was conducted to assess the changes in soft tissue thickness over time and the effects of surgical correction.

Results

Significant improvements in facial asymmetry were noted after surgery, with reductions in Me deviation and FRI on both the deviated side (DS) and non-deviated side (NDS). An increase in soft tissue thickness was observed on both the DS and NDS after surgery, with the NDS showing a continued increase between 6 months and 1 year, indicating an ongoing compensation for symmetry restoration. The study also identified a positive correlation between the surgical movement of the FRI and the increase in soft tissue width on the NDS after 6 months.

Conclusion

This study established that soft tissue thickness continues to adapt and change up to 1 year after BSSRO, underscoring the need for a long-term evaluative approach in orthognathic surgery for patients with facial asymmetry.