Soft tissue effects of aesthetic and conventional twin block appliances in the treatment of skeletal class II malocclusion: a randomized controlled trial

Enhancement of facial profile represents one of the primary objectives of orthodontic treatment, particularly in the light of the growing aesthetic concerns among patients. This randomized controlled trial (RCT) aimed to evaluate and compare the effects of aesthetic (ATB) and conventional (CTB) Twin Block appliances on the facial soft tissues of patients with skeletal Class II Division 1 malocclusion. 52 pubertal patients were randomly assigned to two groups: 26 received ATB, and 26 received CTB. Pre- and post-treatment lateral cephalometric radiographs were used to assess 16 soft tissue variables. The data were analyzed via paired and independent t tests, with the significance level set at p < 0.05. Both ATB and CTB significantly improved facial convexity and mentolabial angles, with no significant difference between the groups (p < 0.05). The CTB group presented significant upper and lower lip retraction relative to the Ricketts' E-line, whereas the ATB group did not, with no significant difference between the groups (p < 0.05). Holdaway analysis indicated significant soft tissue improvement in both groups. Notably, the ATB group demonstrated greater advancement in the lower lip sulcus (p = 0.02) and less nasal prominence (p = 0.03) than did the CTB group. No serious harm was reported. Functional treatment with both appliances caused favorable soft tissue changes. However, The ATB appliance demonstrated more advantageous outcomes in enhancing the concavity of the lower labial sulcus.Trial Registration: NCT05418413 (14/06/2022).