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.

OBJECTIVE: To evaluate and compare the treatment effect of Reverse Twin-Block (RTB) and Reverse Pull Face Mask (RPFM) on Pharyngeal Airway Space (PAS) in early and late mixed dentition Class III samples.

METHODS: Ninety-five mixed dentition Malay children with Class III malocclusion were included in this study. Data consists of 190 pre- and post-treatment lateral cephalograms of early (8-9 years) and late (10-11 years) mixed dentition Class III samples. forty-nine samples were under RTB and forty-six samples were under RPFM. Treatment changes were evaluated by McNamara airway analysis and changes in tongue and hyoid bone position.

RESULTS: Both upper and lower pharyngeal airway width were increased after treatment with RTB and RPFM ruling out the chance of airway constriction. There was also posterior positioning of the tongue and hyoid bone indicating mandibular retrusion. No significant treatment changes were found on the Pharyngeal Airway Space by the factor age, gender or type of appliance.