三种运动方式对TF单根镍钛器械在磨牙弯曲根管预备能力的比较研究

摘要

目的:比较3种不同运动方式下TF镍钛系统单根锉预备根管的能力. 方法:收集临床新鲜拔除的上、下颌磨牙(弯曲度20°~35°)90个(含根管105个),并将其随机分为3组(n=30个牙,35个根管):A组为连续旋转500 r/min、B 组为往复旋转300 r/min、C 组为连续旋转300 r/min;设定机用马达恒定扭矩3 N·cm,用TF镍钛锉(#25/06)冠向下技术对各组根管进行预备;CBCT拍摄3 组根管预备前后的横截面影像,测定根管偏移量和定心比率值,并比较各组根管预备所需时间,显微镜观察各组器械的损耗情况. 结果:3组 根管预备后,在根管中下段,根管偏移量A组最小、B组最大(P<0. 05);定心比率值C组较好、B组较差(P<0. 05);在根尖和根管中上段两者较一致(P>0. 05); B组预备根管的时间长于A、C组(P<0. 05); B组使用寿命约是A、C组的2倍. 结论:TF单根锉(#25/06)配合往复旋转运动模式行根管预备时,用时相对较长,但其安全性也更高;在300、500 r/min连续旋转速度下的操作效果无明显差异.%AIM:To evaluate the endodontic preparation ability of single TF nickel-titanium instrument with different operation mode in the preparation of curved root canal. METHODS:90 intact molars with 105 root canals were divided into 3 groups(n=30 molars with 35canals), the canals of the molars were prepared by the instrument with continuous rotation at 500 r/min( group A ) ,reciprocating movement at 300 r/min ( group B ) and continuous rota-tion at 300 r/min( group C ) respectively . The CBCT images of the root canal sections were recorded, the root transpor-tation and centering ratio were measured before and after instrumentation. The preparation time, wearing and tearing degree of the instrument were compared. RESULTS:At 3. 0 mm from the anatomic apex, root transportation of group B was significantly greater than that of group A (P<0. 05), centering ratio of group C was significantly better than that of group B (P<0. 05). There was no significant difference in root transportation and centering ratio among 3 groups at the distances of 1. 5 mm and 6 mm from the anatomic apex. The preparation time of group B was significantly longer than that of group A and C (P<0. 05). The lifespan of group B was about 2 times of group A and C. CONCLU-SION:TF single nickel-titanium instrument(#25/06) used with reciprocating mode may produce lower efficiency but higher security. When it is used with continues rotation mode, there is no significant difference between the speeds of 300 r/min and 500 r/min except that the speed of 300 r/min may shorten the lifespan of the instrument.