在正畸治疗中拔牙的部位、数目、时间均根据错牙合的类型 ,患者牙弓中各个牙的牙体 ,牙周情况及患者要求等条件而定。由于拔牙减数比扩大牙弓、片切牙邻面减径保持牙列完整的矫治效果要稳定 ,不易复发 ,所以被临床广泛应用。通常首选拔除第一双尖牙 ,同时拔除四个第一双尖牙矫 In the orthodontic treatment of tooth extraction site, the number of time are based on the type of malocclusion, dental arch teeth of each tooth, periodontal conditions and patient requirements and other conditions may be. Due to the reduction in dental extraction than to expand the dental arch, the reduction of the adjacent facets of the incisors to keep dentures intact orthodontic effect should be stable, not easy to relapse, it is widely used in clinical. It is usually preferred to remove the first pair of canines, while removing the first four pairs of canines