不同牙根发育阶段与正畸治疗中牙根吸收关系的临床研究

目的探讨不同牙根发育阶段的牙齿与正畸治疗中出现的牙根吸收的关系。方法选择运用直丝弓矫治技术矫治完成的患者112例，其中成人患者32例，青少年患者80例。青少年患者按正畸治疗前牙根是否发育完成又分为牙根发育完成组和牙根发育未完成组两组。分别在其矫治前后的曲面断层片上对448颗双尖牙进行牙根形态观察以确定其正畸治疗前后牙根发育状况及牙根吸收等级。利用SPSS11．0软件对所得资料进行统计分析。结果正畸治疗前牙根发育未完成组的牙齿多数在正畸治疗中牙根继续发育完成，牙根形态正常，较少出现根吸收。青少年牙根发育完成组及成人组的牙齿在正畸治疗后出现不同比例的牙根吸收，三组间的组问差异有统计学意义（P〈0．01），而青少年牙根发育完成组与成人组正畸治疗后牙根吸收差异无统计学意义（P〉0．05），所出现的根吸收多为轻度根吸收。结论正畸治疗前牙根是否发育完成对正畸治疗中牙根是否出现吸收有明显的影响。牙根一旦发育完成无论青少年或成人正畸治疗的根吸收风险均增加，但根吸收的程度较轻。

Clinic study of the relationship between the stage of root development and the root resorption during orthodontic treatment

Objective To investigate the relationship between the stage of root development and the root resorption during orthodontic treatment. Methods One hundred and twelve patients （32adult, 80 adolescents） treated by straight wire appliances were selected. The adolescents were subdivided into the developing group and the developed group according to the stage of root development at the beginning of the treatment. The stage of root development and the level of root resorption of 448 premolars were detected in the panoramic radiographs before and after the orthodontic treatment. The data were analysed by SPSS11.0 software package. Results The roots of most of the teeth in developing group continued to develop during orthodontic treatment and the shape of root was normal with no resorption after treatment. Root resorption oecured in developed group and adult group after orthodontic treatment with different proportion. The score of root resorption among three groups differed significantly （P 〈0. 01 ）, whereas the differenee of root resorption between the developed group and adult group after orthodontic treatment was not found （P 〉 0. 05） and most of the root resorption were slight. Contusion The stage of root development at the beginning of treatment have significant influence on the root resorption during orthodontic treatment. Not only the adult but also the adolescent suffer the same susceptibility to root resorption in the orthodontic treatment once the root was developed, but the level of root resorption is slight.