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.

Objective To investigate the clinical effect of internal rigid fixation with miniature titanium plate for mandibular condylar fracture under endoscope. Methods Twenty-two cases with mandibular condylar fractures were treated with transcutaneous puncturing and internal rigid fixation with miniature titanium plate under endoscope. Results All cases obtained a good recovery both of facial contour and bone healing. Mandibular movement was normal in 21 cases and biting function good in 20.Conclusions Under endoscope, the internal rigid fixation for mandibular condylar fracture is a good method with little trauma, accurate reduction and stable fixation but without complication and can be used for treatment of fractures of mandibular condylar neck or subcondylar condyle.