骨性及功能性的Ⅲ类错大多表现为Ⅲ类骨面型，其中相当一部分患者的发病机制为上颌发育不足和下颌前突。对替牙晚期和恒牙早期的病例，临床上常用上颌前牵引以促进上颌骨的发育。但由于面框架的存在，患儿难以较好配合，致疗效不佳。笔者对Ricket's弓进行了改良，在双尖牙区加 Osseous and functional class III errors mostly manifested as type Ⅲ bone surface type, a considerable number of patients with the pathogenesis of maxillary hypoplasia and mandibular protrusion. In the early stage of tooth replacement and early permanent teeth, maxillary protraction is commonly used clinically to promote maxillary development. However, due to the presence of face frame, children with difficulty with better coordination, resulting in poor efficacy. The author of the Ricket's bow was improved in the canine area plus