高压灭菌对不同镍钛锉抗扭力性能和切割效力的影响

Effect of sterilization on the torque resistance and cutting efficiency of two different types of nickel-titanium rotary instruments

目的评价反复高压灭菌对两种镍钛锉抗扭力性能和切割效率的影响。方法新的ProTaperF1锉和Mtwo20#锉各60支,分为3组:对照组(未高压灭菌)、A组(连续高压灭菌7次)和B组(连续高压灭菌14次)。分别随机取3组中ProTaperF1锉和Mtwo20#锉各10支进行抗扭力性能试验,测定其在同转速和同扭距下的折断时间;分别取3组中ProTaperF1锉和Mtwo20#锉另外各10支进行切割效率测定。结果 A、B组与对照组的ProTaperF1锉和Mtwo20#锉在扭力作用的折断时间差异均无统计学意义(P>0.05);与对照组相比,A组的ProTaperF1锉和Mtwo20#锉切割力分别下降20.34%和15.34%,B组的ProTaper F1锉和Mtwo20#锉切割力分别下降46.39%和35.89%。结论高压灭菌并未增加镍钛锉折断的可能性,但可以降低镍钛锉的切割效率。

Objective To evaluate the torque resistance and cutting efficiency of two different types of nickel-titanium rotary instruments under repeated sterilization cycles. Methods 60 new ProTaper F1 and 60 new Mtwo 20# were divided into 3 groups. Each group has 20 ProTaper F1 and 20 Mtwo 20# respectively. Samples in group A were exposed to 7 consecutive sterilization cycles in a steam autoclave. Samples in group B were exposed to 14 consecutive sterilization cycles; the control group samples were not sterilized. The torque resistance and cutting efficiency of ProTaper F1 and Mtwo 20# of each group were tested. Results Compared with the control group, the time of fracture of instruments under repeated sterilization cycles was shortened, but there is no significant difference （P〉0.05, ANONA test）; the cutting efficiency of ProTaper F1 and Mtwo 20# in group A were decreased by 20.34% and 15.34% respectively, while those in group B were decreased by 46.39% and 35.89% respectively. Each of these differences was statistically significant （P〈0.05, ANONA test）. Conclusions Repeated sterilization in autoclave does not increase the likelihood of instrument fracture, but reduces the cutting efficiency of nickel-titanium rotary instruments.