Methods:Sixty cases were randomly selected after fixatio-orthodontic treatment at least 12 months.Each of the pat ients had clear film of orthopanotomography.

• 方法随机选择至少经过12个月固定正畸治疗,矫治前后有清晰的全口曲面断层片的病例60例,用根吸收分级评估法记录矫治前后上中切牙牙根吸收的情况,并进行统计分析。