The effect of zigzag elastics in the treatment of Class II division 1 malocclusion subjects with hypo- and hyperdivergent growth patterns. A pilot study

The aim of this study was to investigate the effect of zigzag elastics in t he treatment of Class II division 1 malocclusion subjects with hypo- or hyp erdivergent growth patterns. Two groups were established, each consisting o f 10 subjects classified as hypo-or hyperdivergent according to their pre-t reatment SN-GoGn angle. The cephalometric radiographs taken before and afte r an elastic application period of approximately 4 months were used to gene rate 22 variables. In both groups, there were no statistically significant differences in the vertical position of the lower molars, the SN-GoGn angle or the inclination of the lower incisors, whereas the sagittal skeletal relationship was impr oved as a result of an increase in the SNB angle and the mandibular length (P < 0.01). Upper incisor extrusion was statistically significant in both g roups (P < 0.05). The downward rotation of the occlusal plane and the incre ase in overbite were found to be significant in the hypodivergent group (P < 0.05). Significant differences were observed between the groups in the ex trusion of the upper incisor, the inclination of the occlusal plane, and th e amount of overbite (P < 0.05). The results show that the zigzag elastic s ystem is preferable, especially in hyperdivergent Class II division 1 subje cts, as the use of such elastics does not cause an unfavourable effect on v ertical jaw base relationship.