Fujii K
Dent Mater J. 1989 Dec;8(2):243-59. doi: 10.4012/dmj.8.243.
Observations were made of fractured surfaces caused by flexural and tensile fatigue tests made in polymethyl methacrylate denture base resins (PMMA). In addition, the changes in dynamic viscoelastic and tensile properties of the materials along with fatigue propagation were investigated. In the tensile and flexural fatigue tests, both the fractured surfaces, which had striations on their surfaces and cracks near the fractured section, closely resembled each other in appearance. On the other hand, all of the tensile properties, such as elastic modulus, toughness and tensile strength, decreased with the increase of the number of stress cycles in the fatigue test. The storage modulus (E') of the material decreased gradually along with fatigue propagation over the whole range of temperatures tested. The loss modulus (E") and mechanical loss tangent (tan delta) increased slightly. The fatigue limit of four commercial denture base resins varied widely from one product to another.
对聚甲基丙烯酸甲酯义齿基托树脂（PMMA）进行弯曲和拉伸疲劳试验所产生的断裂表面进行了观察。此外，还研究了材料的动态粘弹性和拉伸性能随疲劳扩展的变化。在拉伸和弯曲疲劳试验中，两个断裂表面在外观上非常相似，其表面有条纹，在断裂截面附近有裂纹。另一方面，在疲劳试验中，所有拉伸性能，如弹性模量、韧性和拉伸强度，都随着应力循环次数的增加而降低。在整个测试温度范围内，材料的储能模量（E'）随着疲劳扩展而逐渐降低。损耗模量（E"）和力学损耗角正切（tan δ）略有增加。四种商用义齿基托树脂的疲劳极限因产品而异，差异很大。
