[Comparison of the efficacy of Twin block and Myobrace in the treatment of skeletal Class Ⅱ malocclusion].

To evaluate the effects of Twin block appliance and Myobrace myofunctional appliance on craniofacial hard and soft tissues in the early treatment of skeletal Class Ⅱ malocclusion in children and to compare the therapeutic outcomes between the two appliances. Twenty-eight children with skeletal Class Ⅱ malocclusion who received early functional treatment in Lishui People's Hospital from September 2022 to September 2024 were enrolled in this study. Fourteen patients received treatment with Twin block appliance (Twin block group) and fourteen with Myobrace myofunctional appliance (Myobrace group). Lateral cephalometric radiographs were taken before treatment (T0) and after treatment (T1), respectively. Cephalometric measurements were performed using Uceph 4.2.1 software to compare the differences in the changes of maxillofacial hard and soft tissues between the two groups before and after treatment. In Twin block group, SNB, FMA, IMPA, NP-FH, nasolabial angle, FH-Ns-Pos, and Z angle increased, while SNA, ANB, FMIA, U1-SN, U1-L1, overjet, UL-EP, and LL-EP decreased, the differences were statistically significant (P＜0.05). In Myobrace group, SNB, IMPA, overjet, NP-FH, nasolabial angle, FH-Ns-Pos, and Z angle increased, while ANB, FMIA, U1-SN, and LL-EP decreased, the differences were statistically significant (P＜0.05). There were no significant differences in the changes of cephalometric indices between the two groups before and after treatment (P＞0.05). Both Twin block appliance and Myobrace myofunction appliance can effectively improve skeletal Class Ⅱ malocclusion in children, with essentially the same efficacy of early orthodontic treatment for the two devices.