Abstract:Objective: To investigate the therapeutic effect of modified Twin-block appliance combined with micro-implant anchorage in patients with Angle Class II division 1 malocclusion. Methods: A retrospective analysis was conducted on the clinical data of 125 patients diagnosed with Angle Class II division 1 malocclusion. According to the treatment method, patients were divided into the control group (modified Twin-block appliance alone, n=61) and the observation group (modified Twin-block appliance combined with micro-implant anchorage, n=64). Clinical efficacy, cephalometric measurements of soft and hard tissues, severity of malocclusion, periodontal indicators, satisfaction, and complications were compared between the two groups. Results: The observation group demonstrated a significantly superior overall effective rate compared to the control group (95.31% vs. 81.97%, P<0.05).Post-treatment assessments revealed that the observation group exhibited smaller ANB, U1-NA, and U1-SN values, alongside larger L1-MP and Z-angle measurements. Furthermore, this group showed lower upper lip protrusion (ULP), lower lip protrusion (LLP), and Peer Assessment Rating (PAR) scores than the control group (P<0.05). The observation group reported a significantly higher satisfaction rate compared to the control group (96.88% vs. 80.33%, P<0.05). Conclusion: Modified Twin-block appliance combined with micro-implant anchorage is effective in treating Angle Class II division 1 malocclusion. It can effectively improve soft and hard tissue indicators and the severity of malocclusion, and enhance patient satisfaction.