Selecting Anterior Segmental Osteotomy Versus Orthodontic Camouflage Treatment: Importance of the Incisor–Mandibular Plane Angle

Background: Temporary anchorage devices (TADs) have reduced the need for anterior segmental osteotomy (ASO) in Class I patients; however, ASO remains relevant in Class II patients. As previous studies were conducted before the usage of TADs, updated guidelines are required to determine the relationship between surgery and orthodontic treatment. We aimed to evaluate the hard tissue changes following ASO versus non-ASO (NASO) orthodontic treatment utilizing TADs with premolar extraction. Methods: This retrospective clinical study involved 67 patients diagnosed with skeletal Class II malocclusion. The patients were categorized into the ASO (n = 31) and NASO (n = 36) groups. Cephalometric analyses were conducted to compare initial and final records to assess the treatment effects. Results: Pre- and post-treatment changes in the ASO and NASO groups exhibited significant differences in ΔSNA, ΔSNB, ΔANB, ΔA to N-perp, ΔB to N-perp, ΔPog to N-perp, and ΔA to FH (p < 0.05). Both groups demonstrated normalized ANB, indicating significant skeletal improvement in Class II malocclusion. Specifically, the change in FMIA (ΔL1 to FH [°]) was 4.98° greater in the NASO group than in the ASO group (p < 0.05). Conclusions: Considering the IMPA change, NASO was recommended for treatment choice when a reduction of more than 10° was achievable.