Objective:

To evaluate the effect of synchronous water irrigation on the fatigue resistance of nickel-titanium instrument.

Methods:

A standardized cyclic fatigue test models were established, and five types of nickel-titanium instruments (PTU F1, WO, WOG, RE, and M3) were applied. Each instrument was randomly divided into two groups (N = 12). There was synchronous water irrigation in the experimental group, and no water irrigation in the control group. Besides, ProTaper Universal F1 was randomly divided into 10 groups (N = 20). In the static group, nickel-titanium instruments were divided into one control group (no irrigation, N = 20) and six experimental group (irrigation, N = 20) based on different flow rate, angle and position; while in the dynamic group, instruments were divided into one control group (no irrigation, N = 20) and two experimental group (irrigation, N = 20) based on different flow rate. The rotation time (Time to Failure, TtF) of instruments was recorded and analyzed.

Results:

According to the static experiments, the TtF of instruments in all experimental groups was significantly higher than that in the static control group. Besides, the dynamic tests of PTU F1 showed that the TtF in the experimental group was significantly higher than that in the dynamic control group. Compared with control group, the TtF in the experimental groups increased by at least about 30% and up to 160%. The static and dynamic tests of PTU F1 showed that the TtF of nickel-titanium instrument in all experimental groups was significantly higher than that in the control group. However, there was no significant difference between any two experimental groups.

Conclusion:

Regardless of dynamic or static model, TtF with irrigation was longer than that with non-irrigation, indicating that synchronous irrigation can increase the fatigue resistance of nickel-titanium instrument. However, different irrigation conditions may have the same effect on the fatigue resistance.

中文翻译：

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动态和静态模型中同步冲洗对镍钛仪器循环疲劳的影响

客观的：

评价同步灌水对镍钛仪器抗疲劳性能的影响。

方法：

建立了标准化循环疲劳试验模型，并应用了五种镍钛仪器（PTU F1、WO、WOG、RE和M3）。每台仪器随机分为两组（N  = 12）。实验组同步灌水，对照组不灌水。此外，ProTaper Universal F1 被随机分为 10 组（N  = 20）。 静态组镍钛器械根据流速、角度、位置不同分为1个对照组（不灌水，N  =20）和6个实验组（灌水，N =20）；而在动态组中，仪器分为一个对照组（不灌溉，N = 20）和两个实验组（灌溉，N  = 20）基于不同的流量。记录和分析仪器的旋转时间（故障时间，TtF）。

结果：

根据静态实验，所有实验组仪器的TtF均显着高于静态对照组。此外，PTU F1的动态测试表明，实验组的TtF显着高于动态对照组。与对照组相比，实验组的TtF至少增加了约30%，最高增加了160%。PTU F1的静态和动态测试表明，所有实验组的镍钛仪器的TtF均显着高于对照组。然而，任何两个实验组之间没有显着差异。

结论：

无论是动态模型还是静态模型，灌水的TtF都比不灌水的要长，说明同步灌水可以提高镍钛器械的抗疲劳性。然而，不同的灌溉条件可能对抗疲劳性有相同的影响。