目的 探究不同角度的弯曲根管模型中,不同尖端直径的Woride KS(WKS)、Protaper Gold(PTG)及Hyflex CM(HCM)机用镍钛器械抗循环疲劳性能的差异,为临床上预备弯曲根管时有针对性地选用合适的镍钛器械提供参考.方法 选取不同尖端直径20#、25#(0.20 mm、0.25 mm)的3种全新镍钛锉,WKS(20/0.06)、WKS(25/0.06)、PTG(20/0.07)、PTG(25/0.08)、HCM(20/0.06)、HCM(25/0.06)各 20 支.根据推荐设置马达的转速和扭矩,于30°和60°的不锈钢根管模型中测试镍钛锉的抗循环疲劳性能,用摄像机及计时器记录镍钛锉从开始旋转到疲劳折断的时间(time from ratation to fatigue fracture,TTF),用游标卡尺测量并记录折断碎片的长度(fragment length,FL).结果 同种锉的TTF比较,①WKS:尖端同直径锉在30°弯曲根管中的TTF均长于60°(P<0.05),同角度弯曲根管中25#锉的TTF均长于20#锉(P<0.05);②PTG:20#锉在30°弯曲根管中的TTF长于60°(P<0.05),25#锉在30°弯曲根管中的TTF与60°无统计学差异(P>0.05),在30°弯曲根管中的20#锉TTF长于25#锉(P<0.05),在60°弯曲根管中20#锉的TTF与25#锉无统计学差异(P>0.05);③HCM:尖端同直径锉在30°弯曲根管中的TTF均长于60°(P<0.05),同角度弯曲根管中20#锉的TTF均长于25#锉.不同锉的TTF比较:在30°弯曲根管中,3种20#锉的TTF无统计学差异(P>0.05),25#WKS的TTF长于其他锉(P<0.05);在60°弯曲根管中,20#HCM的TTF长于尖端同直径的其他锉(P<0.05),25#WKS的TTF长于尖端同直径的HCM(P<0.05).20#PTG、25#PTG、20#HCM在30°的弯曲根管模型中FL均分别显著长于60°(P<0.05),20#WKS、25#WKS、25#HCM在30°及60°的弯曲根管模型中FL无统计学差异.结论 WKS镍钛锉的抗循环疲劳性能在30°模拟弯曲根管内较PTG及HCM镍钛锉有明显优势;而在60°模拟弯曲根管内,20#镍钛锉中HCM镍钛锉的抗循环疲劳性能较其他锉有明显优势,25#镍钛锉中仅WKS镍钛锉的抗循环疲劳性能较HCM镍钛锉有明显优势.
Objective The purpose of this study was to investigate the differences in the anti cyclic fatigue perfor-mance of Woride KS(WKS),Proteper Gold(PTG),and Hyflex CM(HCM)nickel titanium instruments with different tip diameters in curved root canal models,and to provide reference for the targeted selection of suitable nickel titanium in-struments in clinical preparation of curved root canals.Methods Three kinds of new nickel titanium files with 20#and 25#(0.20 mm and 0.25 mm)tip diameters were selected,including WKS(20/0.06),WKS(25/0.06),PTG(20/0.07),PTG(25/0.08),HCM(20/0.06),and HCM(25/0.06),each with 20 files.According to the recommended speed and torque of the motor,the anti cycle fatigue performance of the nickel titanium file was tested in 30° and 60° stainless steel root canal models.The time from rotation to fatigue fracture(TTF)of the nickel titanium file was recorded with a camera and timer,and the fragment length(FL)was measured and recorded with a Vernier scale.Results Com-parison of TTF of the same type of file.① WKS:the TTF of files with the same tip diameter in a 30° curved root canal was longer than 60°(P<0.05);The TTF of 25# nickel titanium files in the same angle curved root canal was longer than that of 20# nickel titanium files(P<0.05).②PTG:the 20# nickel titanium files had a TTF longer than 60° in a 30° curved root canal(P<0.05),while the 25# nickel titanium files had no statistically significant difference in TTF be-tween the 30° curved root canal and 60° curved root canal(P>0.05);In a 30° curved root canal,the TTF of 20# nickel titanium files was longer than that of 25# nickel titanium files(P<0.05).In a 60° curved root canal,there were no sta-tistically significant difference between the TTF of 20# nickel titanium files and 25# nickel titanium files(P>0.05).③HCM:the TTF of files with the same tip diameter in a 30° curved root canal was longer than 60°(P<0.05);The TTF of 20# nickel titanium files in the same angle curved root canal is longer than that of 25# nickel titanium filea.Compari-son of TTF of different files:in a 30° curved root canal,there was no statistically significant difference in TTF among the three types of 20# nickel titanium files(P>0.05).The TTF of 25# WKS was longer than that of other files(P<0.05);In a 60 ° curved root canal,the TTF of 20# HCM was longer than other files with the same tip diameter(P<0.05),and the TTF of 25# WKS was longer than HCM with the same tip diameter(P<0.05).The FL of 20# PTG,25#PTG,and 20# HCM in the 30° curved root canal model is significantly longer than that of 60°(P<0.05),while there is no statistical difference in FL among 20# WKS,25# WKS,and 25# HCM in the 30° and 60° curved root canal models.Conclusion The anti cyclic fatigue performance of WKS is significantly superior to PTG and HCM in a 30° curved root canal.In a 60° curved root canal,20# HCM had a significant advantage in terms of anti cyclic fatigue performance compared to other files,while only 25# WKS had a significant advantage in anti cyclic fatigue performance compared to HCM.