Department of Endodontics I, University of Rome "La Sapienza", Rome, Italy.
Int Endod J. 2010 Mar;43(3):226-30. doi: 10.1111/j.1365-2591.2009.01668.x.
To evaluate the cyclic fatigue resistance of five NiTi rotary systems in an abrupt apical curvature.
Cyclic fatigue testing was performed in stainless-steel artificial canals with a 2-mm radius of curvature and an angle of curvature of 90 degrees constructed to the dimensions of the instruments tested. The middle of the simulated curvature was 2.5 mm from the tip of the instrument that was placed at full working length. All instruments were new and 25 mm in length. Ten ProTaper Universal F2 (Dentsply Maillefer, Ballaigues, Switzerland); FlexMaster (VDW, Munich, Germany) tip size 25, taper 0.06; Mtwo (Sweden & Martina, Padova, Italy) tip size 25, taper 0.06; ProFile tip size 25, taper 0.06 from Dentsply Maillefer (Ballaigues, Switzerland); and ProFile tip size 25, taper 0.06 from Dentsply Tulsa (Tulsa, OK, USA) were rotated passively at 300 rpm until fracture occurred, and the number of cycles to failure (NCF) recorded. Length of the fractured tip was measured. Data were analysed by one-way anova and Tukey HSD test to determine any statistical difference amongst groups.
Mtwo had the highest fatigue resistance compared to the other instruments (NCF 124 +/- 25) (P < 0.001); there was no statistical difference between ProFile from the two different brands, although ProFile from Maillefer had the higher fatigue life (NCF 75 +/- 10) compared to ProFile from Tulsa (NCF 66 +/- 10). No difference was registered between FlexMaster (NCF 53 +/- 5) and ProFile from Tulsa; ProTaper F2 had a significantly (P < 0.001) lower fatigue life compared to the other instruments tested (NCF 29 +/- 5).
Lifespan registered for the instruments tested in an apical abrupt curvature was Mtwo > ProFile from Maillefer > ProFile from Tulsa > FlexMaster > ProTaper.
评估五种镍钛旋转系统在突然的根尖弯曲处的循环疲劳强度。
在半径为 2 毫米、弯曲角度为 90 度的不锈钢人工根管中进行循环疲劳试验，该根管的尺寸与所测试器械的尺寸相符。模拟弯曲的中点距离器械尖端 2.5 毫米，器械放置在全长工作长度处。所有器械均为全新，长度为 25 毫米。ProTaper Universal F2（Dentsply Maillefer，Ballaigues，瑞士）；FlexMaster（VDW，慕尼黑，德国）尖端尺寸 25，锥度 0.06；Mtwo（瑞典和 Martina，帕多瓦，意大利）尖端尺寸 25，锥度 0.06；ProFile 尖端尺寸 25，锥度 0.06 来自 Dentsply Maillefer（Ballaigues，瑞士）；ProFile 尖端尺寸 25，锥度 0.06 来自 Dentsply Tulsa（塔尔萨，俄克拉荷马州，美国）以 300rpm 的速度被动旋转直至断裂，并记录失效循环数（NCF）。测量断裂尖端的长度。采用单因素方差分析和 Tukey HSD 检验分析数据，以确定组间的任何统计学差异。
Mtwo 的疲劳强度最高，与其他器械相比（NCF 124 ± 25）（P < 0.001）；两个不同品牌的 ProFile 之间没有统计学差异，尽管 Maillefer 的 ProFile 具有更高的疲劳寿命（NCF 75 ± 10），而 Tulsa 的 ProFile 则（NCF 66 ± 10）。FlexMaster（NCF 53 ± 5）和 Tulsa 的 ProFile 之间没有差异；ProTaper F2 的疲劳寿命明显（P < 0.001）低于其他测试器械（NCF 29 ± 5）。
在突然的根尖弯曲处测试的器械的寿命为 Mtwo > Maillefer 的 ProFile > Tulsa 的 ProFile > FlexMaster > ProTaper。
