Unilateral maxillary molar distalization using zygoma-gear appliance

The aim of the present case report was to present the treatment of a patient with Class II subdivision using the zygoma-gear appliance (ZGA) for unilateral maxillary molar distalization and fixed appliances for the further treatment needs. The ZGA consisted of a miniplate, an inner bow and a sentalloy closed coil spring. Three weeks after the miniplate was placed on zygomathic buttress, a distalization force of 350 g was unilaterally applied to the maxillary left first molar through the sentalloy closed coil spring. After a distalization period of 6 months, a super Class I relationship was achieved and the maxillary left first molar moved 5 mm distally without anterior movement of the anchor premolars. In addition, the maxillary left molar slightly tipped distally (2.4΀), the maxillary incisors slightly retruded (about −5΀) and the overjet decreased (−1.4 mm). Then, preadjusted fixed appliances (0.022 Χ 0.028-in, Roth system) were placed in both arches and the maxillary premolar and canine were distalized using the miniplate anchorage after the leveling and alignment procedure. Class I molar and canine relationships, acceptable overjet and overbite were established in a total treatment time of 18 months.