Comparative evaluation of 2 skeletally anchored maxillary protraction protocols

Abstract

Introduction: The aim of this study was to evaluate and compare the effects of 2 protocols of bone-anchored maxillary protraction with an untreated control group.

Methods: Thirty growing Class III subjects with maxillary deficiency in the late mixed or early permanent dentition were included in the study. In group 1 (n = 10), skeletally anchored facemasks were used with miniplates placed at the zygomatic buttress. In group 2 (n = 10), the patients were treated with Class III elastics extending from infrazygomatic miniplates in the maxilla to symphyseal miniplates in the mandible. Group 3 (n = 10) was an untreated control group. Pretreatment and posttreatment cephalometric radiographs were analyzed.

Results: The treatment periods were 8 and 8.9 months in groups 1 and 2, respectively, and the untreated control group was observed for 9.4 months. The maxilla moved forward significantly in groups 1 and 2 compared with the untreated control group (4.87 mm in group 1, 5.81 mm in group 2); overjet and maxillary incisor display were improved without proclination or mesialization of the maxillary teeth relative to the maxillary base. Soft tissue harmony demonstrated the great improvement. However, group 1 showed more opening rotation of the mandible and lingual inclination of the mandibular incisors than did group 2.

Conclusions: The 2 skeletal anchorage protocols for maxillary protraction effectively resolved the severe maxillary deficiently in growing Class III patients. However, vertical changes and retroclination of the mandibular incisors were better controlled by Class III elastics extending from the infrazygomatic miniplates in the maxilla to the symphyseal miniplates in the mandible (group 2).