In the present study, the effects of Class II activator on dentofacial structures were evaluated considering three pubertal growth periods, to ascertain the most favorable treatment timing. Pre and post-treatment lateral cephalometric and hand wrist films, which were obtained from 36 individuals (1 st group: 12 pre-pubertal, 2 nd group: 12 pubertal and 3 rd group: 12 post-pubertal) having Class II, division 1 malocclusion were selected from the orthodontic department archive. Grouping was done considering growth periods according to hand wrist maturation criteria. All the treatments were managed by using conventional type Class II activator. Comparison of skeletal and dentoalveolar responses achieved with treatment between the groups were evaluated by analysis of variance (ANOVA) and Tukey tests. Similar reduction was observed in the ANB angle among the groups. Increases in GoGn/SN angle (p<0.05) and in posterior lower alveolar height (mean 2.3 mm) were found in the pubertal group. The largest overjet (mean , −7.2 mm) and upper incisor tip (UIT) (mean ,−12.1°) reductions were obtained in the pubertal group which was significantly different from the other groups (p<0.01 and p<0.5, respectively). An increase in mandibular length (Co-Pg) was observed in each group and pubertal group showed the highest increase in the mandibular length (mean, 4.8 mm). As a result, it can be suggested that considering differential effects of functional treatment on dentofacial structures, the most appropriate treatment time for functional treatment is the maximum pubertal growth period.

Keywords: Class II malocclusion, functional treatment, treatment timing