Effects of zygoma-gear appliance for unilateral maxillary molar distalization: A prospective clinical study.

Abstract

The aim of the study was to evaluate the dentoskeletal effects of the zygoma-gear appliance usedforunilateral maxillary molar distalization in patients with Class II subdivision malocclusion. This prospective clinical study consisted of 21 patients (9 boys, 12 girls; mean age, 15.68±2.18years) with unilateral Class II malocclusion treated using the unilateral zygoma-gear appliance supported by a zygomatic miniplate inserted on the Class II malocclusion side. The dentoskeletal effects of the system were evaluated using cephalometric lateral and panoramic films with a paired t test. The mean amount of distalization for the maxillary first molar was found to be 5.31±2.46mm(P<0.001) in 0.45±0.12years, showing an amount of 0.98mm of distalization per month. It was also accompanied by a slight intrusion (0.76±2.85mm; P>0.05) and distal tipping (6.39°±5.39°; P<0.001) of the maxillary molars. The maxillary premolar also spontaneously moved distally 1.63±1.90mm(P<0.01) with distal tipping (4.05°±3.47°; P<0.001). Moreover, the inclination of the maxillary incisors and overjet were decreased (-1.59°±1.45°, P<0.001; and -0.29±0.63mm, P<0.05; respectively) showing no anchorage loss. No statistically significant changes were found for the skeletal and soft tissue measurements (P>0.05). The zygoma-gear appliance system is an effective method for unilateral maxillary molardistalization.