镍钛根管锉的横截面与根管壁微裂纹产生的相关性分析的体外研究

摘要

比较机用MTwo、TF、S3、ProTaper Next镍钛锉根管预备后,根管壁微裂纹的发生率.选用100例因正畸治疗拔出的直根单根管的前磨牙,去除牙冠,自凝树脂和藻酸盐印膜材料包埋牙根.样本随机分5组(n=20),对照组不予处理,实验组均预备根管至25号0.06锥度.预备完成后,分别与距根尖3、6、9 mm处与垂直于牙长轴将样本切开,体式显微镜下观察并记录各横截面上根管壁微裂纹的产生情况.结果显示对照组未发现根管壁微裂纹,机用MTwo、TF、S3、ProTaper Next组根管壁微裂纹的发生率分别为30%、20%、10%、5%,前3组的发生率之间差异无统计学意义,机用MTwo、ProTaper Next组发生率之间差异有统计学意义(P=0.03).结果表明:机用ProTaper Next镍钛锉根管预备后根管壁微裂纹的发生率较机用MTwo、TF、S3镍钛锉低;机用镍钛器械的横截面接触根管壁的点数目及位置分布与根管壁微裂纹的产生有相关性.%To compare the incidences of root cracks after root canal preparation with the MTwo,the TF Ni-Ti,the S3 Ni-Ti and ProTaper Next Ni-Ti machine files.One hundred simple root with straight root canal premolars were selected and randomly divided into five groups (n=20).One group was left unprepared and served as a negative control;all experiment groups prepared root canal up to number 25,taper 0.06.All of the roots were sectioned perpendicular to the long axis at 3,6,and 9 mm from the apex,and the sections were then observed under a Stereo-microscope.The absence of cracks was recorded.The results showed no cracks were observed in the negative control group.The incidence rate of the MTwo,TF Ni-Ti,S3 and ProTaper Next Ni-Ti machine files group micro cracks on root tube wall respectively is 30%,20%,10%,5%,there were no significant differences among the three former group,there were significant differences between the MTwo and ProTaper Next group.The results showed that: The ProTaperNext Ni-Ti machine system is not more likely to lead to micro cracks on root tube wall than the MTwo,TF,S3 Ni-Ti machine files;the number and position of cross section of Ni-Ti root canal preparation instrument has correlation with the occurrence of micro cracks on root tube wall.