Department of Surgery, University of Catania, Catania, Italy.
J Endod. 2011 Aug;37(8):1139-42. doi: 10.1016/j.joen.2011.04.008. Epub 2011 May 31.
The purpose of this study was to assess the resistance to cyclic fatigue of three nickel-titanium (NiTi) files after the immersion in sodium hypochlorite (NaOCl) solution in conditions similar to those used in clinical practice.
A total of 150 new Twisted Files (SybronEndo, Orange, CA), Revo S SU files (Micro Mega, Besancon, France), and Mtwo files (Sweden and Martina, Padova, Italy), size 25.06, were tested. Fifty files of the same brand were randomly assigned to five groups (n = 10) and submitted to the following immersion protocol in 5% NaOCl at 37°C for 16 mm: no immersion (control), 5 minutes statically, 1 minute statically, 5 minutes dynamically (300 rpm/min), and 1 minute dynamically. Resistance to cyclic fatigue was determined by counting the numbers of cycles to failure in a 60° curve with a 5-mm radius. Data were analyzed by two-way analyses of variance.
Resistance to cyclic fatigue of the same NiTi file was not significantly affected by immersion in NaOCl (P > .05). The Twisted File showed a higher resistance in all groups than Revo S SU (P < .001). The comparison between the same groups of Twisted Files and Mtwo files or between Mtwo and Revo S files did not show significant differences (P > .05) except for two cases: group 2 of the Twisted Files and Mtwo files and group 5 of the Mtwo and Revo S SU files (P < .05).
Static or dynamic immersion in NaOCl for 1 minute or 5 minutes did not reduce the cyclic fatigue resistance of NiTi significantly. However, the type of instrument influences cyclic fatigue resistance. In our study, Twisted Files were more resistant followed by Mtwo and Revo S SU files.
本研究的目的是评估三种镍钛（NiTi）锉在临床使用条件下浸泡于次氯酸钠（NaOCl）溶液中的抗循环疲劳性能。
共测试了 150 个新的 Twisted Files（SybronEndo，Orange，CA）、Revo S SU 锉（Micro Mega，Besancon，法国）和 Mtwo 锉（瑞典和 Martina，Padova，意大利），规格为 25.06。将 50 个相同品牌的锉随机分配到 5 个组（n = 10），并按照以下方案在 37°C 下用 5%的 NaOCl 浸泡 16 毫米：不浸泡（对照）、静态浸泡 5 分钟、静态浸泡 1 分钟、动态浸泡 5 分钟（300rpm/min）和动态浸泡 1 分钟。通过在半径为 5 毫米的 60°曲线上计数失效循环次数来确定抗循环疲劳性能。数据采用双因素方差分析进行分析。
NiTi 锉浸泡于次氯酸钠溶液中，其抗循环疲劳性能无显著差异（P >.05）。在所有组中，Twisted File 的抗疲劳性能均高于 Revo S SU（P <.001）。Twisted File 与 Mtwo 锉或 Mtwo 锉与 Revo S SU 锉在相同组之间的比较没有显著差异（P >.05），除了两种情况：Twisted File 组 2 与 Mtwo 锉和 Mtwo 锉组 5 与 Revo S SU（P <.05）。
静态或动态浸泡于 NaOCl 中 1 分钟或 5 分钟并未显著降低 NiTi 的抗循环疲劳性能。然而，器械类型影响抗循环疲劳性能。在我们的研究中，Twisted File 更具抗疲劳性，其次是 Mtwo 锉和 Revo S SU 锉。
