ORTHODONTIC AND ORTHOPEDIC EFFECTS OF ACTIVATOR, ACTIVATOR-HG COMBINATION, AND BASS APPLIANCES - A COMPARATIVE-STUDY

The orthodontic and orthopedic effects of the Activator, Activator-Hea dgear Combination (ACHG) and the Bass appliance systems were compared by analyzing the cephalometric records of 64 subjects, who were treate d for skeletal Class II malocclusion, with both conventional and Panch erz's methods. Differences between observations on the different occas ions (starting and ending values) were tested with Wilcoxon's matched pairs rank test. Kruskal-Wallis nonparametric analysis of variance was carried out in different situations among all three groups. If a leve l of significance less than 0.05 was observed, Scheffe's method of mul tiple comparisons was used to determine differences among groups. The results of this study showed that greater improvement in sagittal skel etal relationship (ANB angle) was obtained in both Bass and ACHG group s than in the Activator group. The differences between the groups were most pronounced for dental variables. The Bass appliance was found to be more effective in the control of the unwanted side effects (procli nation of lower incisors, retroclination of upper incisors). Unfavorab le labial tipping of the lower incisors was also prevented with the AC HG appliance.