不同根管预备方法对椭圆形根管预备效果的影响

The effects of different techniques for preparing oval-shaped canals

目的:比较4种不同的根管预备方法对椭圆形根管的预备效果。方法:选取1颗离体椭圆形单根管的上颌第二前磨牙,以此为原型获取80颗3D打印模型牙,随机分成4组,分别使用机用ProTaper镍钛锉、机用ProTaper镍钛锉结合20#手用H锉、机用ProTaper镍钛锉结合25#手用H锉、机用ProTaper镍钛锉结合30#手用H锉按冠向下法进行预备。对所有3D打印牙进行术前、术后Micro-CT扫描并重建三维图像,测量根管体积增量百分比、牙体硬组织去除量百分比、根管表面积增量百分比及未预备根管壁面积百分比。结果:80颗3D打印牙预备前管体积及根管表面积无显著差异(P>0.05)。机用ProTaper镍钛锉结合30#手用H锉组的根管体积增量百分比(40.02±0.79)%、牙体硬组织去除量百分比(3.47%±1.17)%、根管表面积增量百分比(14.23±1.19)%最大(P<0.05),未预备根管壁面积百分比(5.24±0.98)%最小(P<0.05)。结论:ProTaper镍钛锉结合30#H锉可更充分地预备椭圆形根管。

Objective: To compare the shaping ability of four different root canal preparation methods on the oval-shaped root canals.Methods: An extracted maxillary second premolar with a single oval-shaped canal was selected and eighty 3D printed teeth were produced based on this tooth. 3D printed teeth were randomly divided into 4 groups and shaped with ProTaper NiTi instruments;ProTaper NiTi instruments and size 20 hand-use H-files;ProTaper NiTi instruments and size 25 hand-use H-files;ProTaper NiTi instruments and size 30 hand-use H-files in a crown-down technique. Before and after root canal preparations, all samples were scanned by micro-computed tomography scanner and three-dimensional images were reconstructed. Images recorded were evaluated for morphometric measures regarding increase in the percentage of canal volume, dental hard tissue removed, canal surface area and untouched canal walls.Results: When comparing among groups, there was no significant difference regarding the canal volumes and canal surface areas before preparing root canals(P>0.05). The teeth shaped with ProTaper NiTi instruments and size 30 hand-use H-files showed the most increases in canal volume(40.02± 0.79)%, dental hard tissue removed(3.47% ± 1.17)% and canal surface area(14.23±1.19)%(P<0.05), while showed the least percentage of untouched canal walls(5.24±0.98)%(P<0.05).Conclusions: ProTaper NiTi instruments combined with size 30 H-files presented the best cleaning ability in the oval-shaped root canals.