Treatment effects of Reverse Twin-Block and Reverse Pull Face Mask on craniofacial morphology in early and late mixed dentition children

Abstract

Objective: Reverse Twin-Block (RTB) and Reverse Pull Face Mask (RPFM) appliances are used to correct Class III malocclusion in growing patients. Aim of this retrospective study was to compare and analyse craniofacial changes produced by RTB and RPFM in the early and late mixed dentition in Malay children with Class III malocclusion. Methods: Data consisted of pre- and post-treatment lateral cephalograms of 95 children, 49 patients with RTB and 46 patients with RPFM, divided into an early (8-9 year) and late (10-11 year) group. Treatment changes were assessed by the Ricketts analysis using CASSOS software, where 71 anatomic landmarks were identified in each cephalogram. Paired and independent t tests were performed for statistical comparison. Results: Paired t test revealed significant changes in facial axis, facial angle, MD plane to FH, lower facial height, mandibular arc, maxillary convexity, U1 to APog, L1 to APog, L1 to APog angle and upper lip to E-plane measurements in RPFM, whereas significant changes were found in facial taper, U1 to APog and lower lip to E-plane values with RTB in the early treatment group. Independent t test revealed significant changes in U1 to APog, L1 to APog and U6 to PtV values in the RTB group. Post-treatment comparison of RTB and RPFM showed significant differences in L1 to APog and L1 to APog angle values. Conclusions: RPFM revealed more favourable craniofacial changes than RTB, particularly in the late mixed dentition stage.