Department of Conservative Dentistry, School of Dentistry, Pusan National University, Busan, Korea.
J Endod. 2010 Jan;36(1):147-52. doi: 10.1016/j.joen.2009.09.037.
The purposes of this study were to compare the fatigue resistance of traditional, ground nickel-titanium rotary instruments with the Twisted File and to examine the fracture characteristics of the fatigued fragment.
Size #25, 0.06 tapered, TF (SybronEndo), RaCe (FKG Dentaire), Helix (DiaDent), and ProTaper F1 (Dentsply Maillefer) were examined with scanning electron microscope for surface characteristics before subjected to a cyclic (rotational bending) fatigue test. The time until fracture was recorded to calculate the number of revolutions for each instrument. The data were compared for differences by using analysis of variance and post hoc Scheffé test. The fragments were examined with scanning electron microscope both in lateral view and fractographically.
TF showed a significantly higher resistance to cyclic fatigue than other nickel-titanium files that were manufactured with a grinding process (P < .05). The path of crack propagation appeared to be different for electropolished (TF and RaCe) versus non-electropolished (Helix and ProTaper) instruments.
Although all specimens showed similar fractographic appearance, which indicated a similar fracture mechanism, instruments with abundant machining grooves seemed to have a higher risk of fatigue.
本研究旨在比较传统的镍钛旋转器械与 TwistFile（TF）的抗疲劳性能，并观察疲劳断裂的特征。
对 #25 号、0.06 锥度的 TF（登士柏 SybronEndo）、RaCe（菲格 FKG Dentaire）、Helix（登士柏 DiaDent）和 ProTaper F1（登士柏 Maillefer）进行表面特征的扫描电子显微镜检查，然后进行循环（旋转弯曲）疲劳试验。记录每种器械发生断裂的时间，以计算每个器械的旋转次数。使用方差分析和事后 Scheffé 检验比较数据差异。通过扫描电子显微镜以侧视和断口形貌学观察断裂碎片。
TF 显示出比其他采用研磨工艺制造的镍钛锉（RaCe、Helix 和 ProTaper F1）更高的抗循环疲劳性能（P<0.05）。电抛光（TF 和 RaCe）器械的裂纹扩展路径似乎与非电抛光（Helix 和 ProTaper F1）器械不同。
尽管所有样本的断口形貌学表现相似，表明有相似的断裂机制，但具有丰富加工槽的器械似乎更容易发生疲劳。
