不锈钢K锉预备弯曲根管时根管不良形态形成的实验研究

目的:探讨弯曲根管预备时根管不良形态形成的特点与规律。方法:使用手用不锈钢K锉,按逐步后退法预备8个弯曲人工根管,根管预备过程中对根管及根尖孔进行微距摄影,用图像分析软件Image-ProPlus对根管的形态与位置变化进行测量、分析;实验数据采用SPSS10.0统计软件包进行统计学分析,选用配对t检验比较组间差异。结果:根管预备完毕,根管弯曲角度均值从预备前的36.21°(Schneider法)逐渐减小至21.98°,弯曲半径均值从6.28mm增大至11.35mm;根管长轴发生了偏移,与预备前原根管长轴形成2个交点,3个相交区。根管的连续锥度被破坏,并出现一系列预备缺陷。结论:弯曲根管预备时,根管器械在弯曲应力与切削力的共同作用下发生动态的根管偏移,是导致一系列根管不良形态的根本原因。

Experimental study of preparation errors during instrumentation of artificial curved root canals with stainless steel K files

PURPOSE: To investigate the features and rules of preparation errors developed from instrumentation of curved root canals. METHODS: 8 curved artificial root canals were prepared with stainless steel K files by the step-back technique,the root canals were digitally photographed,the images were analysed by the software Image-Pro Plus,the shapes and positions of the root canals were measured and analysed.SPSS 10.0 software package was used for statistical analysis, paired-samples t test was used to compare the difference of the means among sample groups. RESULTS: After root canal preparation,the mean value of the angles of canal curvature decreased from 36.21 degrees to 21.98 degrees , while the mean value of the radius of the canal curvature increased from 6.25mm to 11.35mm; the canal axes transported and intercrossed with the original axes at 2 points and created 3 intersection zones.The taper of the root canals was destroyed and a series of instrumentation defaults were created. CONCLUSION: The cause of preparation errors was the transportation of the root canal instruments leaded by the elastic force and cutting effects.