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

INTRODUCTION

The aim of the study was to evaluate the dentoskeletal effects of the zygoma-gear appliance used for unilateral maxillary molar distalization in patients with Class II subdivision malocclusion.

METHODS

This prospective clinical study consisted of 21 patients (9 boys, 12 girls; mean age, 15.68 ± 2.18 years) 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.

RESULTS

The mean amount of distalization for the maxillary first molar was found to be 5.31 ± 2.46 mm (P <0.001) in 0.45 ± 0.12 years, showing an amount of 0.98 mm of distalization per month. It was also accompanied by a slight intrusion (0.76 ± 2.85 mm; 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 ± 1.90 mm (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 ± 0.63 mm, P <0.05; respectively) showing no anchorage loss. No statistically significant changes were found for the skeletal and soft tissue measurements (P >0.05).

CONCLUSIONS

The zygoma-gear appliance system is an effective method for unilateral maxillary molar distalization.