Department of Mechanical Engineering, Instituto Superior Técnico, Technical University of Lisbon, Lisbon, Portugal.
J Endod. 2011 Aug;37(8):1158-61. doi: 10.1016/j.joen.2011.05.018.
This article aims to evaluate how different superelastic nickel-titanium (NiTi) alloys determine the static mechanical performance of endodontic files during bending and torsion.
Two NiTi rotary instruments with similar geometries and equal cross sections, ProFile GT (GT) and a GT Series X (GTX), were selected. The latter file is made from M-Wire, a NiTi alloy that, according to its manufacturer, has been thermomechanically processed to have larger flexibility at body temperature. The mechanical response was studied for a series of static bending and torsional loads by using finite element (FE) models. The materials were characterized according to previously published stress-strain curves.
For the same load and boundary conditions, the GTX material significantly increased the instrument's performance. For instance, the deflection for a 1N force at the tip of the file was found to be 28.5% larger for the GTX file, whereas the maximum stress decreased 13.2%.
Although not fully reflective of the instrument's behavior in a dynamic rotation intracanal system, the static results showed that the GTX file is more flexible and capable of stress relief at the most critical sections than the GT file, suggesting that it has a lower risk of fracture inside the root canals during its clinical use.
本文旨在评估不同超弹性镍钛（NiTi）合金如何在弯曲和扭转过程中确定根管锉的静态机械性能。
选择了两种具有相似几何形状和相等横截面的 NiTi 旋转器械，ProFile GT（GT）和 GT Series X（GTX）。后者的锉丝由 M-Wire 制成，据制造商称，该合金经过热机械处理，使其在体温下具有更大的柔韧性。通过有限元（FE）模型研究了一系列静态弯曲和扭转载荷下的力学响应。根据先前发表的应力-应变曲线对材料进行了表征。
对于相同的载荷和边界条件，GTX 材料显著提高了器械的性能。例如，对于尖端施加 1N 力的情况下，GTX 锉的挠曲度增加了 28.5%，而最大应力降低了 13.2%。
尽管不完全反映动态旋转根管系统内器械的行为，但静态结果表明，GTX 锉比 GT 锉更柔韧，能够在最关键部位缓解应力，这表明在临床使用过程中，它在根管内断裂的风险较低。
