The effects of a modified protraction headgear on maxilla

Abstract

Protraction headgears are commonly used in the treatment of Class III malocclusion characterized by maxillary retrognathism. The upward and forward rotation of the maxilla during protraction is a major unwanted side effect. The aim of this study was to eliminate the upward and forward rotation of maxilla while protracting. Seventeen patients with Class III malocclusion as a result of maxillary retrognathism were treated for 3 months; their average age was 12.81 years. A full coverage acrylic cap splint-type rapid maxillary expansion appliance was cemented and activated twice a day for 5 days. After sutural separation, a maxillary modified protraction headgear was worn and 750 g of force was applied. Wilcoxon signed rank test was carried out to evaluate 42 parameters measured on cephalometric radiographs. The maxilla was displaced anteriorly by downward and backward rotation. The mandible was displaced downward and backward due to anterior elongation of the maxilla. Extrusion and lingual tipping of the upper incisors and intrusion of upper molars and downward and backward rotation of functional occlusal plane were observed, The aim of our study was achieved, which was to avoid upward and forward rotation while protracting the maxilla. In conclusion, maxillary modified protraction headgear (MMPH) can be used effectively in Class III patients with retrognathic maxilla and anterior open bite tendency.