Haikel Y, Gasser P, Allemann C
Department of Restorative Dentistry and Endodontics, Faculty of Dentistry, University Louis Pasteur, Strasbourg, France.
J Endod. 1991 May;17(5):217-20. doi: 10.1016/S0099-2399(06)81924-2.
The purpose of this study was to analyze in vitro the dynamic fracture of some endodontic hand instruments. The K file and H file were tested as reference traditional files; the K-Flex, Flexofile, Unifile, and Helifile were tested as newly developed hybrid instruments. The files were mounted in a lathe and rotated with cyclical axial motion in the lumen of a curved tempered steel groove until failure occurred. The results showed that the life span of instruments, the distance between the instrument tip and the rupture point, and the resistance to fracture were dependent on the size and design of the instruments. Moreover, scanning electron microscopic photographs revealed two types of breakage patterns. The K file, H file, Unifile, and Helifile showed a distinct fracture starting point with crack striations and ductile fractures. The K-Flex and Flexofile showed only plastic deformations and axial fissures.
本研究的目的是在体外分析一些根管治疗手动器械的动态断裂情况。将K锉和H锉作为传统参考锉进行测试；将K-Flex锉、Flexofile锉、Unifile锉和Helifile锉作为新开发的混合器械进行测试。将这些锉安装在车床上，并在弯曲的回火钢槽管腔内进行周期性轴向运动旋转，直至器械失效。结果表明，器械的使用寿命、器械尖端与断裂点之间的距离以及抗断裂能力取决于器械的尺寸和设计。此外，扫描电子显微镜照片显示了两种断裂模式。K锉、H锉、Unifile锉和Helifile锉显示出具有裂纹条纹和韧性断裂的明显断裂起始点。K-Flex锉和Flexofile锉仅显示塑性变形和轴向裂缝。
