ABSTRACT
Objective To design a mandibular protraction appliance and to observe its effect in the treatment of mandibular retrognathia with malocclusion of Angle class II and division I. Methods 30 cases of mandibular retrognathia with Angle class II and division I malocclusion were treated with the mandibular protraction and edgewise appliance. Cephalometric radiograph and measurement were taken before and after treatment. Statistical analysis were performed. Results After treatment, maxillary and mandibular anterior teeth were arranged in dental arch neatly. Molar relationship and overjet and overbite were returned normal. SNB, ANB angle and Co-Po, Iis-SP, Mis-SP were remarkably changed. Conclusion The mandibular protraction appliance is an orthopedic force applicance. It can effectively induce forward movement of mandible and in the meantime restrain maxillary growth. It is feasible for the treatment of mandibular retrognathia.