Influence of different lingual split patterns on skeletal stability after bilateral sagittal split osteotomy in patients with skeletal Class III malocclusion.

Abstract

This retrospective cohort study investigated the influence of differences in the pattern of lingual split on skeletal stability after bilateral sagittal split osteotomy (BSSO) in patients with skeletal Class III malocclusion. The study sample comprised patients who underwent double surgery between November 2016 and December 2024 and presented with the same type of postoperative bilateral lingual split fracture, classified according to the Lingual Split Scale (LSS). Lateral cephalograms were evaluated at three-time points: preoperative (T0), one week postoperative (T1), and six months postoperative (T2). Analyses of variance (ANOVA) and chi-square (χ²) tests were employed to compare skeletal stability among the groups. The study included 159 patients, with 88 (55.35 %) in the LSS1 group, 43 (27.04 %) in the LSS2 group, and 28 (17.61 %) in the LSS3 group. Postoperative analysis revealed a counterclockwise relapse of the mandible. The maxilla showed good skeletal stability after BSSO, while the LSS2 group presented more severe forward mandibular relapse than the LSS1 and LSS3 groups (P = 0.011). Notably, the Frankfort mandibular plane angle (FMA) increased more significantly in the LSS2 group postoperatively (P = 0.003). Significant intergroup differences were observed regarding the influence of different lingual split patterns on skeletal stability after BSSO in patients with skeletal Class III malocclusions. Notably, the LSS2 group exhibited a more severe relapse compared to both the LSS1 and LSS3 groups.