Department of Conservative Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, São Paulo, Brazil.
Aust Endod J. 2021 Aug;47(2):265-272. doi: 10.1111/aej.12474. Epub 2020 Dec 9.
This study investigated the cyclic fatigue, bending, torsional resistance and angular deflection of Pro-R 25.08, Logic RT 25.08, MK Retreatment 25.08 (MK RT) and ProTaper Retreatment D2 instruments. Cyclic fatigue test was performed until fracture in a custom stainless-steel device with water bath equipment to simulate body temperature. Fracture time was recorded. A number of cycles were calculated. Resistance to bending at 45°, torsional resistance and angular deflection were evaluated. The fracture surfaces were examined by scanning electron microscopy. Statistical analysis was performed with one-way ANOVA and Tukey and Kruskal-Wallis and Dunn tests. Pro-R and Logic RT presented the highest cyclic fatigue (P < 0.05). D2 had higher strength to bend than Pro-R and Logic RT (P < 0.05). Logic RT showed the highest torque and angular deflection (P < 0.05), without differences when compared to D2 (P > 0.05). Instrument performances were dependent on their geometrical features and heat treatments.
本研究调查了 Pro-R 25.08、Logic RT 25.08、MK Retreatment 25.08（MK RT）和 ProTaper Retreatment D2 器械的循环疲劳、弯曲、抗扭和角度偏转。在具有水浴设备的定制不锈钢装置中进行循环疲劳测试，直至发生断裂，以模拟体温。记录断裂时间。计算了一定数量的循环次数。评估了 45°弯曲阻力、抗扭阻力和角度偏转。通过扫描电子显微镜检查断裂表面。采用单因素方差分析和 Tukey、Kruskal-Wallis 和 Dunn 检验进行统计分析。Pro-R 和 Logic RT 表现出最高的循环疲劳（P < 0.05）。D2 的弯曲强度高于 Pro-R 和 Logic RT（P < 0.05）。Logic RT 显示出最高的扭矩和角度偏转（P < 0.05），与 D2 相比没有差异（P > 0.05）。器械性能取决于其几何特征和热处理。
