Comparison of the effects of monoblock and twin block appliances in class II division 1 and class II division 2 patients

Objective: The aim of this study was to compare the skeletal, dental and soft tissue effects of monoblock and 'twin block with expansion screw' appliances in patients with Class II Division 1 and Class II Division 2 malocclusions in pubertal period. Method: In this study records of patients with mandibular retrognathia whose functional treatment applied between the years, 2013-2018 were examined. Among these patients accordance with the inclusion criteria, 43 monoblock and 34 twin block patients were identified. After examination of cephalometric radiographs; who have Class 2 Division 1 malocclusion monoblock applied 24 patients (CII/D1-MA), twin block applied 18 patients (CII/D1-TA); who have Class II Division 2 malocclusion monoblock applied 19 patients (CII/D2-MA), twin block applied 16 patients (CII/D2-MA) included. Intragroup changes in cephalometric measurements were performed by paired t-test, independence t-test was used to compare intergroup changes. Results: It was determined that maxillary growth was restricted and mandibular growth was stimulated in all groups. When upper incisors evaluated; in CII/D1-MA and CII/D1-TA groups retrusion; in CII/D2-MA and CII/D2-TA groups protrusion were determined. Lower incisors' protrusion were observed in all groups. Lower incisors' protrusion were significantly higher in Class II Division 1 patients with twin block appliance. Conclusion: In different malocclusion groups, monoblock and twin block appliances induced similiar skeletal and soft tissue changes. Different dental effects were observed between the appliance and malocclusion groups. Key Words: mandibular retrognathia, monoblock, twin block, Class II Division 1, Class II Division 2