关键词: 儿童, 埋伏多生牙, 拔牙难度, 分级

Abstract: PURPOSE: To investigate the clinical classification of extration difficulty for embedded multiple teeth in children(EMTC). METHODS: Two hundred and fifty teeth of 178 children with embedded multiple teeth were examined by cone-beam CT(CBCT）. According to the relationship between adjacent embedded multiple teeth and permanent teeth, they were divided into 3 types. Type I:embedded multiple teeth located on the crown of permanent teeth; type Ⅱ: embedded multiple teeth located to the body of permanent teeth; type Ⅲ: embedded multiple teeth located to the root apex of the permanent teeth. The embedded multiple teeth were further divided into 2 classes. Class A: the angle of malformation was<90° with the axis of the crown and root, and the tooth was of straight deformity. Class B: the malformation angle was >90° with the crown-root axis, and the tooth was hook-shaped. The embedded multiple teeth were extracted accordingly based on the different type and class. RESULTS: ：One hundred and seventy-six teeth belonging to type Ⅰ, type Ⅱand class A were removed immediately when the adjacent permanent teeth were not fully developed. Twelve teeth belonging to type Ⅱ, class A, and 62 teeth belonging to type Ⅲ and class B were removed secondly when the adjacent permanent teeth were fully developed. All 250 teeth were removed without damage to the adjacent permanent teeth. CONCLUSIONS: This classification based on teeth morphology is of certain clinical usefulness in predicating extraction difficulty and guidance of operation.

Key words: Children Embedded multiple teeth；Extration difficulty, Classification