Comparison of the skeletal and dentoalveolar effects of twinblock and clear aligners with mandibular advancement in patients with class II division 1 malocclusion

Objective: The aim of this study was to compare the skeletal, dentoalveolar, and soft tissue effects of the Twinblock appliance and clear aligners with mandibular advancement (MA) in patients with Class II Division 1 malocclusion. Materials and Methods: The study included growing patients diagnosed with Class II Division 1 malocclusion. Participants were divided into twinblock and mandibular advancement (MA) clear aligner groups. Lateral cephalometric radiographs taken before (T0) and after treatment (T1) were analyzed to assess skeletal angular, skeletal linear, dental angular, dental linear, and soft tissue parameters. Statistical analyses were performed, and intergroup comparisons were conducted. Results: Both treatment modalities produced statistically significant improvements in the correction of Class II Division 1 malocclusion (p<0.05). In the Twinblock group, mandibular sagittal growth showed statistically significant increases in SNB (p<0.001) and Co–Gn (p=0.001) measurements, and a significant forward advancement of the soft tissue pogonion was also observed (p<0.001). In the clear aligner group (MA), dentoalveolar changes were more pronounced, with statistically significant reductions observed in L1-MP, U6-OLP, overjet, and overbite measurements (p<0.001). Conclusion: While the Twinblock appliance exhibited stronger skeletal effects, mandibular advancement with clear aligners provided more controlled dentoalveolar changes and higher patient comfort. Therefore, treatment planning should consider not only skeletal and dental parameters but also patient cooperation, esthetic expectations, and lifestyle factors. Key Words: Functional appliance, Mandibular advancement, Class II Division 1 malocclusion, Clear aligner, Twinblock.