手用ProTaper器械预备弯曲根管的研究

目的 使用牙髓立体模型(Endodontic Cube)评价手用ProTaper预备不同弯曲根管的能力.方法 按纳入标准筛选离体牙样本,根据根管弯曲度(α)将根管分3组,A组0°≤α＜25°,B组25°≤α＜40°,C组40°≤α＜55°,每组18个根管.灌制Endodontic Cube模型,用低速锯将样本分为根管上、中、下段,组装模型,手用ProTaper预备根管,体视显微镜获取预备前、后根管的断面形态.统计学分析预备前后各段根管截面积之差AS、面积比、根管偏移距离X1、中心比CR值.结果 ①B、C组的牙本质切削量和预备前后根管截面积差比较大B组根中部△S为(0.46±0.25)mm2,C组根中部△S为(0.48±0.30)mm2],显著大于A组A组根中部AS为(0.28±0.13)mm2,P＜0.05];②C组的根管偏移距离最大,在根尖部(0.23±0.10)mm]、根中部(0.36±0.16)mm]及根上部(0.31±0.15)mm]均显著大于A组根尖部(0.19±0.07)mm、根中部(0.20±0.08)mm、根上部(0.18±0.08)mm,与C组相比P＜0.05],在根管中段的偏移距离显著大于B组(0.28±0.11)mm,P＜0.05];③C组根管中部的维持能力显著差于A、B组(P＜0.01).结论 随着根管弯曲度的增加,手用ProTaper对牙本质的切削量增加,定位中心的能力降低.

Evaluation of preparation of curved root canals using hand-used ProTaper

Objective To evaluate the shaping ability of hand-used ProTaper on curved canals using Endodontic Cube.Methods Fifty-four curved root canals in vitro were selected and dirided into three groups according to the Curved degree(α),group A:0°≤α＜25°,group B:25°≤α＜40°,group C:40°≤α＜55°.Endodontic Cube was assembled.and each sample was sectioned perpendicular to the axis of the tooth into four sections with Isomet-Buhler in low speed.Then the root canals were prepared with hand-used ProTaper.Before and after shaping,photograph of all the sections were taken under a stereomicroscope.Statistical analyses were performed.Results The dentin cutting quantity of the whole canal prepared with ProTaper in group B and C Was larger than that of group A.The deviation distance of the whole canal prepared by ProTaper in group C was significantly larger than that in group A,and the deviation distance in middle portion larger than that in group B.The maintaining ability in the middle portion ofgroup C by ProTaper wag worse than that of group A and B.Condusious The curvature of root canal mayincreasethe cutting quantity of the dentin and reduce the ability of remaining original canal shape prepared by ProTaper.