Berzins A, Shah B, Weinans H, Sumner D R
Department of Orthopedic Surgery, Rush Arthritis and Orthopedics Institute, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612, USA.
J Biomed Mater Res. 1997 Mar 5;34(3):337-40. doi: 10.1002/(sici)1097-4636(19970305)34:3<337::aid-jbm8>3.0.co;2-l.
Push-out and pull-out tests are used for destructive evaluation of implant-bone interface strength. Because nondestructive mechanical tests would allow maintenance of an intact interface for subsequent morphological study, we developed such a test to determine the shear modulus of the interface by measuring the shear deformation of a thin layer adjacent to the implant. A polyurethane foam model was used to test the experimental setup on a group of nine cylindrical implants with three different lengths (15-48 mm) and three different diameters (5-9.7 mm). The shear modulus of the interface, as calculated from the pull-out test, was validated against the shear modulus of the foam derived from tensile tests. The two values of shear modulus were well correlated (R2 = 0.8, p < 0.001), thus encouraging further application of the setup for tests of implant-bone interface mechanics. In addition, we also examined the effects of implant length and diameter. The length of the implants had a significant influence on the interface shear modulus (p < 0.05), indicating that comparisons of the variable should only be made of implants with the same length. The length and diameter of the implants were not critical parameters for the ultimate fixation strength.
推出试验和拔出试验用于对种植体-骨界面强度进行破坏性评估。由于无损力学试验能够使界面保持完整以便后续进行形态学研究，因此我们开发了一种通过测量种植体相邻薄层的剪切变形来确定界面剪切模量的试验。使用聚氨酯泡沫模型对一组九个圆柱形种植体进行试验装置测试，这些种植体具有三种不同长度（15 - 48毫米）和三种不同直径（5 - 9.7毫米）。根据拔出试验计算得出的界面剪切模量，与通过拉伸试验得出的泡沫剪切模量进行了验证。两种剪切模量值具有良好的相关性（R2 = 0.8，p < 0.001），这促使该试验装置在种植体-骨界面力学测试中得到进一步应用。此外，我们还研究了种植体长度和直径的影响。种植体长度对界面剪切模量有显著影响（p < 0.05），这表明仅应对相同长度的种植体进行该变量的比较。种植体的长度和直径并非最终固定强度的关键参数。
