安氏Ⅱ1类错牙合是常见的错畸牙合形,典型症状为磨牙远中关系、前牙深覆牙合、深覆盖、下颌后缩等。下颌骨发育不足或功能性后缩为其主要发病机制之一[1],对此类替牙期或恒牙早期患者,促进下颌发育是改善上下颌间关系的关键。Twinblock矫治器是一种功能性矫治器,由正畸教授Clar Class Ⅱ 1 malocclusion is a common malocclusion, the typical symptoms of molar distal relationship, anterior deep overbite, deep coverage, mandibular retraction and so on. Mandibular hypoplasia or functional retraction is one of its main pathogenesis [1], for such patients or patients with early permanent dentition, the promotion of mandibular development is the key to improve the relationship between the mandible. The Twinblock appliance is a functional appliance, taught by orthodontist Clar