Yamashita J, Takakuda K, Shiozawa I, Nagasawa M, Miyairi H
Department of Prosthodontics, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, Texas 78284, USA.
Int J Prosthodont. 2000 Jul-Aug;13(4):321-6.
Fatigue behavior of luting cement film between model fixed partial dentures (FPD) and their dies was investigated to gain a better understanding of the mechanical properties of zinc-phosphate cement.
Fifty-six brass dies were made, half of them with grooves and half without grooves. A cantilever FPD for each die was cast in Au-Pd-Ag alloy. Four linear strain gauges were attached to the marginal portions of each retainer. The FPDs were cemented to the dies using zinc-phosphate cement. A fatigue test machine was used to cyclically load the specimens with 50 or 100 N for 5.5 x 10(5) cycles (1 Hz) in 37 degrees C water. During the fatigue test, strain measurements were made after every 0.5 x 10(5) load cycles to discover if strain response was altered. After completion of the fatigue test, ultimate tensile strength of each specimen was measured and statistically analyzed by 2-way analysis of variance.
With or without grooves, strain responses were the same at every periodic strain measurement throughout the 50-N fatigue test. For the 100-N fatigue test, strain responses for the specimens without grooves were different before and after cyclic testing, but there was no difference for the specimens with grooves. There were no significant differences in tensile strength among the specimens after the fatigue tests.
No fatigue fracture was observed in zinc-phosphate cement film after repetitive loading. Repetitive loading may improve stress transmission within the zinc-phosphate cement film.
研究模型固定局部义齿（FPD）与其代型之间粘固水门汀薄膜的疲劳行为，以更好地了解磷酸锌水门汀的机械性能。
制作56个黄铜代型，其中一半有凹槽，一半没有凹槽。为每个代型铸造一个悬臂式FPD，采用金-钯-银合金。在每个固位体的边缘部分粘贴四个线性应变片。使用磷酸锌水门汀将FPD粘固到代型上。使用疲劳试验机在37℃水中以50或100 N的力对试件进行5.5×10⁵次循环（1 Hz）的循环加载。在疲劳试验期间，每进行0.5×10⁵次加载循环后测量应变，以发现应变响应是否发生改变。疲劳试验完成后，测量每个试件的极限拉伸强度，并通过双向方差分析进行统计分析。
在50 N疲劳试验的整个过程中，无论有无凹槽，每次定期应变测量时的应变响应均相同。对于100 N疲劳试验，无凹槽试件在循环试验前后的应变响应不同，但有凹槽试件则无差异。疲劳试验后，各试件的拉伸强度无显著差异。
磷酸锌水门汀薄膜在反复加载后未观察到疲劳断裂。反复加载可能会改善磷酸锌水门汀薄膜内的应力传递。
