正畸拔牙患者无托槽隐形矫治牙根吸收的研究

Evaluation of Root Resorption in Extraction Patients Treated with Clear Aligner

目的:采用锥形束CT(cone beam computed tomography,CBCT)三维重建技术研究正畸拔牙患者无托槽隐形矫治后上颌牙牙根吸收。方法:本回顾性研究纳入15例安氏Ⅱ类正畸拔牙病例,共计150颗观测牙,应用CBCT三维重建技术测量术前(T0)、术后(T1)牙根体积和牙根表面积(root surface area,RSA)的变化。结果:(1)所有患者牙根体积均减少(P<0.001),98%观测牙发生轻度到中度牙根吸收;(2)前后牙牙根吸收的严重程度无统计学差异(P>0.05);(3)所有患者RSA均减少(P<0.001),前后牙RSA变化无统计学差异(P>0.05);(4)切牙和第一磨牙中度和重度牙根吸收的发生率为23.33%~26.67%。结论:在安氏Ⅱ类正畸拔牙患者无托槽隐形矫治过程中,大部分观测牙发生轻度到中度牙根吸收,前后牙牙根体积和表面积的变化没有统计学差异,提示正畸医生不仅需要关注前牙的牙根吸收,也应关注后牙的牙根吸收风险。

Objective:To investigate the root resorption of maxillary teeth in extraction patients treated with clear aligner using three-dimensional reconstructed cone beam computed tomography(CBCT).Methods:One hundred and fifty teeth from 15 ClassⅡextraction treatment patients were selected.CBCT images were obtained at pretreatment(T0)and posttreatment(T1).Root volume and root surface area(RSA)were calculated by three-dimensional reconstruction of CBCT images.Results:The root volume was significantly decreased in all patients(P<0.001),and 98%of the measured teeth showed mild to moderate root resorption.There was no significant difference in the severity of root resorption between anterior and posterior teeth(P>0.05).The RSA was significantly decreased in all patients(P<0.001).There was no significant difference in RSA between anterior and posterior teeth(P>0.05).The incidence of moderate and severe root resorption in incisors and first molars was 23.33%-26.67%.Conclusion:During clear aligner therapy for ClassⅡextraction treatment patients,mild to moderate root resorption occurred in most of the measured teeth,and no statistical difference in the changes of volume and surface area of anterior and posterior teeth,suggesting that orthodontists should pay attention to the risk of root resorptions not only in the anterior teeth but also in the posterior teeth.