Ⅱ类1分类在人群中约占15—20%,因其骨骼和牙的明显异常,大部分患者要求治疗,故临床上此类错(牙合)约占49%。用头颈装置机械方法作为治疗Ⅱ类l分类的常规,常产生满意效果而不需拔除恒牙。但在某些病例、则需拔除一定的牙才能获得稳定疗效。头颈装置对上颌的生长起到抑制作用同时使下颌向着与上颌相适应的形式和方向生长,是取 The Class II and Class 1 classification accounts for about 15-20% of the population. Most patients require treatment because of significant abnormalities in their bones and teeth. Clinically, this type of occlusion accounts for about 49%. Mechanical treatment of head and neck as a treatment of Class II l routine, often produce satisfactory results without removing the permanent teeth. However, in some cases, you need to remove a certain tooth in order to obtain a stable effect. Head and neck device to inhibit the growth of the maxillary while allowing the mandibular to adapt to the upper jaw in the form and direction of growth is to take