Analysis of postsurgical relapse patterns in one-jaw surgery: skeletal factors and clustering analysis in patients with mandibular setback

Objectives: To compare presurgical skeletal factors and postsurgical relapse patterns between more relapsed (MR) and less relapsed (LR) groups.

Materials and methods: This study retrospectively examined patients who underwent mandibular setback surgery, classifying them into two groups based on the amount of relapse of the pogonion using K-means analysis. Comparisons were conducted by analyzing cephalometric radiographs presurgically (T0), at 1-month post-surgery (T1), and immediately after orthodontic treatment (T2).

Results: The MR group at T0 had a lower articular angle and AB to the mandibular plane angle (MPA), higher gonial angle, shorter anterior and posterior facial heights, and shorter Frankfort horizontal plane to the upper incisor and first molar. The articular angle in the MR group increased postoperatively. The Frankfort MPA (FMA) did not differ significantly between the MR and LR groups.

Conclusion: Acute articular angle and short facial height with a high gonial angle in the presurgical stage can predict surgical relapse regardless of the FMA.