替牙期牵引上颌埋伏阻生中切牙对牙根发育影响的初步研究

A preliminary study of efficacy on root development of orthodontic traction for impacted maxillary central incisor in mixed dentition

目的 评价替牙期牵引上颌埋伏阻生中切牙对其牙根发育的影响.方法 选取9名8～11岁上颌中切牙埋伏阻生患者进行牵引治疗,应用CBCT进行牵引前后的牙根长度、根管壁厚度、牙根弯曲程度的测量,计算冠根比,比较阻生牙牵引前后、阻生牙与对侧对照牙牙根发育的差异.结果 9颗阻生牙经牵引均达到牵引到位标准,根管壁厚度与对照牙无显著性差异.经牵引治疗的埋伏阻生中切牙牙根继续发育,牵引后的牙根长度均长于牵引前,但短于对照牙,冠根比优于治疗前,但不及对照牙;替牙期牵引治疗可能无法改变原有的牙根弯曲,而新发育的牙根有可能在牵引过程中形成新的弯曲.结论 上颌埋伏阻生中切牙经牵引矫治能获得良好的临床效果,牙根继续发育,但需要谨慎选择替牙期牵引的适应证.

Objective To evaluate the efficacy on root development of orthodontic traction for impacted maxillary central incisor in mixed dentition.Methods 9 cases of 8 to 11 years old impacted maxillary central incisor patients were treated with traction.CBCT measurement on root length,root canal wall thickness,and degree of root bending and the ratio of crown and root of the impacted teeth were implemented,and compared with the contralateral counterpart tooth.Results 9 teeth were treated to standard place.After traction,incisor root continues development,but root length is shorter than the control teeth.Crown root ratio and root wall thickness presented no significant difference compared to control teeth.Orthodontic treatment may not be able to change the original root dilaceration,and may cause new dilaceration during traction process.Conclusions Impacted maxillary central incisor after orthodontic traction can achieve satisfied clinical results,but indications for traction during mixed dentition should be carefully evaluated.