正畸牙移动早期牙根吸收的临床研究

目的 应用锥体束计算机断层(Cone beam computed tomography,CBCT)技术分析正畸牙移动早期牙根吸收的发生情况及其影响因素.方法 选择108例正畸患者,432颗上切牙,治疗前及治疗5～9个月,平均(6.9±1.24)个月后分别拍摄上颌4个切牙CBCT.记录患者性别、初诊年龄、拔牙与否、安氏分...

A study of root resorption during the initial stages of orthodontic treatment

Objective The purpose of this study was to measure the amount of external apical root resorption (EARR) by using cone beam computed tomography (CBCT) and to determine which factors were clinically relevant in predicting the extent of EARR at the initial stage of orthodontic treatment. Methods CBCT radiographs were taken before treatment (T1) and at the stage of (6.9±1.24) months of treatment (T2) in 432 teeth of 108 patients. Parameters about patient information such as gender, age at the beginning of treatment, extraction pattern, root shape and duration of follow-up were recorded. More than 1 mm of root resorption was considered to be clinically significant. Results Average root resorption of upper incisors was (0.45±0.49) mm, whereas the maximum amount of resorption was 4.58 mm. Clinically significant resorption was found in 13.8% of the incisors and 27.8% of the patients, only 2% of the incisors and 6.5% of the patients had the severe root resorption. Multivariate linear regression showed that the parameters recorded were not identified as risk factors to root resorption. Conclusions Root resorption of upper incisors is common at the initial stage of orthodontic treatment, but the resorption is usually slight. Individual susceptibility might be a major cause related with root resorption at the initial stage of treatment