三种机用镍钛锉预备弯曲根管的中心定位能力比较研究

目的　评价M3-Pro 2018、M3-L铂金版及ProTaper universal三种机用镍钛锉预备弯曲根管的中心定位能力。方法　收集2018年10月至2019年3月在常州市第一人民医院口腔科拔除的上颌第一磨牙，筛选出30个近中颊根管弯曲度为20 ~ 40°的近中颊根，随机分成3组，分别为M3-Pro组、M3-L组和ProTaper组，每组10个样本，分别使用M3-Pro 2018机用镍钛锉、M3-L铂金版单支锉系统及ProTaper universal机用镍钛锉预备根管。各样本在处理前后均使用CBCT扫描并利用软件mimics17.0测算距根尖5 mm范围内每毫米处的根管偏移量及轴中心率。结果　距根尖1 mm区域，M3-Pro组、M3-L组和ProTaper组的根管偏移量均值分别为0.06、0.16和0.22 mm，轴中心率均值分别为0.86、0.71和0.49，3组间差异均有统计学意义（F值分别为3.404和3.499，均P < 0.05）。距根尖3 mm区域，M3-Pro组、M3-L组和ProTaper组的根管偏移量均值分别为0.13、0.19和0.26 mm，轴中心率均值分别为0.63、0.51和0.32，3组间差异均有统计学意义（F值分别为7.567和3.996，均P < 0.05）。进一步两两比较发现，距根尖1 mm和3 mm处M3-Pro组与ProTaper组的根管偏移量及轴中心率的差异有统计学意义（P < 0.05）；距根尖3 mm处M3-L组与ProTaper组的根管偏移量差异有统计学意义（P < 0.05），而两组的轴中心率差异无统计学意义（P > 0.05）。其余观测面上的根管偏移量和轴中心率在3组之间的差异均无统计学意义（均P > 0.05）。结论 M3-Pro 2018机用镍钛锉在弯曲根管的根尖区预备中能更好地顺应根管形状，减小根管偏移量，中心定位能力优于其他两种镍钛锉。

Center orientation in curved root canals after the preparation by three nickel-titanium rotary instruments

Objective To evaluate the center orientation of M3-Pro 2018,M3-L and Pro Taper universal in the preparation of curved root canals. Methods Totally 30 mesial buccal roots of the first maxillary molar whose curvature was20-40°were randomly divided into three groups with 10 in each group,namely group M3-Pro,group M3-L and group Pro Taper. Three groups were prepared by M3-Pro 2018,M3-L and Pro Taper universal,respectively. CBCT and mimics17.0 software were used to calculate the canal offset and center rate of each sample in the range of 5 mm from the apex before and after preparation. Results The average canal offset of group M3-Pro,group M3-L and group Pro Taper at1 mm from apex were 0.06 mm,0.16 mm and 0.22 mm,respectively. The average center rate of group M3-Pro,group M3-L and group Pro Taper at 1 mm from apex were 0.86,0.71 and 0.49,respectively. There was significant difference among the three groups(the corresponding values of F were 3.404 and 3.499,P < 0.05). The average canal offset of group M3-Pro,group M3-L and group Pro Taper at 3 mm from apex were 0.13 mm、0.19 mm、0.26 mm,respectively. The average center rate of group M3-Pro,group M3-L and group Pro Taper at 3 mm from apex were 0.63、0.51、0.32,respectively. There was significant difference among the threegroups(the corresponding values of F were 7.567 and 3.996,P < 0.05). Further pairwise comparisons revealed that there was significant difference between group M3-Pro and group Pro Taper at 1 mm and 3 mm from apex in the aspect of canal offset and center rate(P < 0.05). There was significant difference between group M3-L and group Pro Taper at 3 mm from apex in the aspect of canal offset(P < 0.05),while there was no significant difference between these two groups concerning the center rate(P > 0.05). There was no significant difference among the 3 groups in the aspect of canal offset and center rate in other observation area except the area 1 mm and 3 mm from the apex(P > 0.05). Conclusion M3-Pro2018 complys with the canal well;it can reduce the canal offset and its ability of center orientation is better than the other two instruments in the preparation of curved canals.