中文摘要：

目的通过对上颌过小侧切牙患者x线头影测量分析，了解其颌面形态发育特征。方法选择120例上颌过小侧切牙患者作为研究对象，分为2组：A组为I型锥形侧切牙60例，B组为Ⅱ型过小牙60例，拍摄X线头颅侧位片，对其进行x线头影测量分析。结果A组患者SNA、ANB、Ptm—A（mm）、U1-SN、L1-NB、UL—EP值减小，SNB、PP—GoGn、SN—MP、Y轴、U1-L1、U1-NA、L1-MP、Z角增大；B组SNB、PP—GoGn、SN—MP、SN—MP、Y轴、U1-L1、Z角值减小，ANB、L1-NB、L1-MP值增大，差异均有统计学意义（P〈0．05）。结论多数上颌I型锥形侧切牙患者表现为上颌骨发育不足，上颌后缩；多数上颌Ⅱ型过小侧切牙患者表现为下颌骨发育不足，下颌后缩。两型过小侧切牙患者具有截然不同的颌面形态特征。

英文摘要：

Objective To analyze the maxillofacial morphological characteristiesof patients with abnormalupper lateral incisors. Methods 120 patients with abnormal upper lateral incisors were divided into two groupsand were analyzed cephalometrically：group A：60 cases of type I peg-shaped upper lateralincisors; group B：60 cases of type II microdontia upper lateralincisors. Students＇t-test was used for data analysis. Results Group A showed significantly smaller SNA, ANB, Ptm-A （ram） , U1-SN, L1-NB, UL-EP and increased SNB,PP-GoGn,SN-MP,Y axis,U1-L1 ,U1-NA、L1-MP and Z angle （P 〈 0.05 ）while Group B showed significantly smaller SNB,PP-GoGn,SN-MP,SN-MP,Y axis,U1-L1 ,angle and increased ANB,L1-NB,L1-MP（P 〈0.05）. Conclusions Most patients with Type I peg-shaped upper lateralincisors showed Class III skeletal patternwith retrusive maxilla and most patients with Type II micr- odontia upper lateralincisorsshowed Class II skeletal patternwith retrusive mandible. Patients with the two types of abnormal upper lateral incisors showed different maxillofacial morphological characteristics.