Clinical Study on Orthodontic Treatment without Extraction of Angle Class II Malocclusion with Moderate Crowding

Objective To investigate morphologic changes of Angle class II moderate crowding patients treated orthodontically without extraction and to analyze the mechanism. Methods Twelve patients with Angle class II moderate crowding were recruited. The lateral cephalometric radiographs were evaluated at every stage before treatment, after molar distalization, and after treatment in order that the changes in skeletal, dental and soft tissues were determined. Results The distal movement and the distal angulation of the maxillary molars, mesial angulation of the maxillary incisors, and mesial movement of the maxilla were significant after molar distalization stage. Conclusion The upper molars' distalization can be achieved by removable appliance. The class I molar relationship can be obtained by the differential growth of jaws and the differential movement of upper and lower molars.