Vallittu P K
Department of Prosthetics and Stomatognathic Physiology, University of Kuopio, Finland.
J Oral Rehabil. 1997 Jun;24(6):444-8. doi: 10.1046/j.1365-2842.1997.00514.x.
The aim of this study was to compare the resistance to deflection fatigue of a gold alloy used in porcelain-fused-to-metal restorations with and without a brazing joint. Pre-ceramic brazing filler metal was used to join the parent specimens of gold alloy together. The deflection fatigue test was carried out mainly with 0.4 m deflection of the test specimens (n = 5) but to obtain an S-N curve for the specimens, other magnitudes of deflection, i.e. the stress, were also used. When the fracture surface of the test specimens was examined by scanning electron microscopy (SEM), the results showed that the brazing joint in the gold alloy test specimen decreases the fatigue resistance considerably compared to that of specimens without a brazing joint (P = 0.002). SEM examination showed that the failure type of the brazing joint was cohesive and that the brazing filler metal had a more porous structure than the parent gold alloy. These results suggest that, due to the occlusal biting forces in situ, the brazing joints in fixed partial dentures can be fractured by metal fatigue.
本研究的目的是比较用于烤瓷熔附金属修复体的含和不含钎焊接头的金合金的抗挠曲疲劳性能。使用预陶瓷钎料将金合金的母材试样连接在一起。挠曲疲劳试验主要在试样产生0.4 m挠曲（n = 5）的情况下进行，但为了获得试样的S-N曲线，还使用了其他挠曲幅度，即应力。当通过扫描电子显微镜（SEM）检查试样的断裂表面时，结果表明，与没有钎焊接头的试样相比，金合金试样中的钎焊接头显著降低了疲劳抗性（P = 0.002）。SEM检查表明，钎焊接头的失效类型为内聚性，并且钎料的结构比母材金合金的结构孔隙更多。这些结果表明，由于原位咬合咬合力，固定局部义齿中的钎焊接头可能会因金属疲劳而断裂。
