上颌前突强支抗内收后上切牙牙根外吸收的锥形束CT研究

External root resorption of upper incisors after retraction with maximum anchorage in maxillary protrusion cases:a cone beam CT study

目的定量对比分析成人及青少年上颌前突拔牙强支抗内收后上切牙牙根外吸收情况。方法本研究为回顾性病例对照研究,收集符合纳入标准的成人及青少年患者矫治前后头颅侧位片及锥形束CT影像数据,测量上切牙切缘内收量、内收角度、压低量及牙根吸收量与吸收率。结果前牙内收后,中切牙根吸收量成人(1.47±0.72)mm,较青少年(1.16±0.45)mm,差异有统计学意义(P=0.006);侧切牙根吸收量成人(1.68±0.78)mm,虽然较青少年(1.49±0.74)mm,但差异无统计学意义(P=0.193)。同组患者不同牙位相比,成人侧切牙根吸收量(1.68±0.78)mm较中切牙(1.47±0.72)mm高,差异有统计学意义(P=0.025);青少年侧切牙牙根吸收量(1.49±0.74)mm同样高于中切牙(1.16±0.45)mm,差异仍具有统计学意义(P=0.001)。相关分析表明,牙根吸收量与年龄及牙位的相关性分别为0.168(P=0.010)和0.195(P=0.003),差异均具有统计学意义;牙根吸收率与年龄及牙位的相关性分别为0.217(P=0.001)和0.238(P<0.001),差异仍均具有统计学意义。对根吸收部位进行分析发现中、重度根吸收多发生于根尖1/3的腭侧及远中。结论上颌前突拔牙强支抗内收后,成人牙根外吸收发生的风险及量高于青少年,侧切牙高于中切牙。

Objective Quantitative comparative analysis of external root resorption of upper incisors after retraction with maximum anchorage in maxillary protrusion between adults and adolescents.Methods This study is a retrospective case-control study.Lateral cephalograms and cone beam CT of adults and adolescents who met the inclusion criteria were collected before and after treatment;the angle and amount of upper incisal retraction and amount of incisal were analyzed,as well as the amount and rate of root resorption.Results After anterior retraction,the amount of upper central incisal root resorption of adults(1.47±0.72)mm was more than adolescents(1.16±0.45)mm,and the difference was significant(P=0.006).The amount of root resorption in lateral incisors in adults(1.68±0.78)mm was more than that in adolescents(1.49±0.74)mm,but the difference was not significant(P=0.193).Compared with the same group of different teeth,the reduction of length of lateral incisors in adults(1.68±0.78)mm was more than the centrals(1.47±0.72)mm,and the difference was significant(P=0.025).The reduction of lateral incisors in adolescents(1.49±0.74)mm was also more than centrals(1.16±0.45)mm,and the difference was still significant(P=0.001).The correlation between the amount of root resorption and the age and site was 0.168(P=0.010)and 0.195(P=0.003),respectively,and the differences were all significant.The correlation of root resorption rate with age and tooth position were 0.217(P=0.001)and 0.238(P<0.001),respectively,and the difference were still significant.According to the analysis of root resorption site,it was found that moderate and severe root resorption mostly occurred in the palatal and distal of the apex.Conclusions For patients with maxillary protrusion,after treated by extraction and retraction with maximum anchorage,adults were at a higher risk of root resorption than the adolescents;and the laterals were more likely to happen than the centrals.