常规消毒对ProTaper镍钛根管锉抗拉强度的影响

目的 探讨超声清洗时间和消毒灭菌频率对镍钛根管锉的抗拉性能的影响,以了解超声清洗和高温高压消毒灭菌法在镍钛根管锉灭菌中应用的安全性和可行性.方法 采用全新的ProTaper S2锉和F2锉各25支,分为5组:标准组(未处理)、对照组(未超声-高压灭菌)、A组(超声震荡50 min+高压灭菌5次)、B组(超声震荡100 min+高压灭菌10次)、C组(超声震荡150 min+高压灭菌15次),分别用万能测试仪对其进行抗拉伸强度的性能试验.结果 S2及F2的标准组之间的抗拉伸强度差异无统计学意义(P>0.05),提示样本间不存在差异性;经不同时间超声清洗及不同次数高温高压处理的S2镍钛锉抗拉伸强度测试结果显示:对照组、A组、B组、C组分别为(76.58±4.87)MPa、(71.00±5.39)MPa、(72.33±3.43)MPa、(66.81±4.08)MPa;F2镍钛锉抗拉伸强度结果分别为:(111.75±6.83)MPa、(110.46±3.88)MPa、(107.29±3.89)MPa、(94.53±6.61)MPa;A、B组与对照组的ProTaper S2锉和F2锉的抗拉强度差异均无统计学意义(P>0.05),即镍钛锉经超声震荡50 min+高压灭菌5次及超声震荡100 min+高压灭菌10次消毒后,其抗拉伸强度无明显影响;C组与对照组间差异存在统计学意义(P<0.05),即镍钛锉经超声震荡150 min+高压灭菌15次消毒后,对其抗拉伸强度有影响.结论 常规超声-高压灭菌消毒超过一定频率可能增加ProTaper系统镍钛根管锉折断可能性.

Effect of routine disinfection on tensile strength of proTaper Ni-Ti root canal files

Objective The study aimed to investigate the influence of ultrasonic cleaning time and disinfecting frequency on tensile strength of Ni-Ti root canal files in order to understand the safety and feasibility of ultrasonic cleaning and high temperature and high pressure disinfection for Ni-Ti root canal files. Methods 25 new ProTaper S2 files and F2 files were used, which were divided into five groups:the standard group without any treatment, the control group without ultrasonic and high pressure sterilization, group A with ultrasonic oscillator 50 minutes plus high pressure sterilization 5 times and group B with ultrasonic oscillator 100 minutes plus high pressure sterilization 10 times, group C with ultrasonic oscillator 150 minutes plus high pressure sterilization 15 times, respectively. The tensile strength was measured by universal tester. Results There is no statistical significance between S2 and F2 standard group (Sig.(2-tailed) > 0.05), suggesting that there is no difference between samples. The tensile strength (MPa) of S2 Ni-Ti files with different treatment was as follows:76.58±4.87 in the control group, 71.00±5.39 in group A, 72.33±3.43 in group B and 66.81±4.08 in group C treated with ultrasonic cleaning at different times and treated with high temperature and pressure treatment at different times. The tensile strength (MPa) of F2 Ni-Ti files were 111.75±6.83, 110.46±3.88, 107.29±3.89, 94.53±6.61, respectively. There was no significant difference in the tensile strength of ProTaper S2 files and F2 files between group A, group B and the control group (P>0.05), that is, the tensile strength of Ni-Ti files was not significantly affected by ultrasonic vibration for 50 min + autoclaving for 5 times and ultrasonic vibration for 100 min + autoclaving for 10 times. There was statistical difference between group C and the control group (P<0.05), that is, the tensile strength of Ni-Ti files was affected by ultrasonic shock for 150 minutes and autoclave sterilization for 15 times. Conclusion Above a certain frequency time of ultrasonic cleaning and high temperature and high pressure, the physical property of Ni-Ti root canal files maybe influenced.