Hong Joon-Ki, Kim Seong-Kyun, Heo Seong-Joo, Koak Jai-Young
Department of Prosthodontics and Dental Research Institute, Seoul National University Dental Hospital, School of Dentistry, Seoul National University, 101 Daehak-ro, Jongno-gu, Seoul 03080, Korea.
Materials (Basel). 2020 Dec 16;13(24):5745. doi: 10.3390/ma13245745.
Cobalt-chromium (Co-Cr) metal is one of the widely used biomaterials in the fabrication of dental prosthesis. The purpose of this study was to investigate whether there are differences in the properties of metals and bond strength with ceramics depending on the manufacturing methods of Co-Cr alloy. Co-Cr alloy specimens were prepared in three different ways: casting, milling, and selective laser melting (SLM). The mechanical properties (elastic modulus, yield strength, and flexural strength) of the alloys were investigated by flexure method in three-point bending mode, and microstructures of the specimens were analyzed. After application of the veneering ceramic through the three-point bending test, bond strength of the Metal-Ceramic was investigated. The cracked surfaces were observed by means of energy dispersive X-ray (EDX) spectroscopy and scanning electron microscopy (SEM) with backscattered electron (BSE) images. In mechanical properties, the elastic modulus was highest for the casting group, and the yield strength and flexural strength were lowest for the milling group. The SLM group showed finer homogeneous crystalline-microstructure, and a layered structure was observed at the fractured surface. After the ceramic bond strength test, all groups showed a mixed failure pattern. The casting group showed the highest bond strengths, whereas there was no significant difference between the other two groups. However, all groups have met the standard of bond strength according to international standards organization (ISO) with the appropriate passing rate. The results of this study indicate that the SLM manufacturing method may have the potential to replace traditional techniques for fabricating dental prosthesis.
钴铬（Co-Cr）金属是牙科修复体制造中广泛使用的生物材料之一。本研究的目的是调查根据Co-Cr合金的制造方法，金属性能和与陶瓷的结合强度是否存在差异。Co-Cr合金试样通过三种不同方式制备：铸造、铣削和选择性激光熔化（SLM）。通过三点弯曲模式下的弯曲方法研究合金的力学性能（弹性模量、屈服强度和弯曲强度），并分析试样的微观结构。通过三点弯曲试验施加饰面陶瓷后，研究金属-陶瓷的结合强度。通过能量色散X射线（EDX）光谱和带有背散射电子（BSE）图像的扫描电子显微镜（SEM）观察裂纹表面。在力学性能方面，铸造组的弹性模量最高，铣削组的屈服强度和弯曲强度最低。SLM组显示出更细的均匀晶体微观结构，并且在断裂表面观察到分层结构。在陶瓷结合强度测试后，所有组均显示出混合破坏模式。铸造组的结合强度最高，而其他两组之间没有显著差异。然而，所有组均根据国际标准化组织（ISO）的标准，以适当的通过率达到了结合强度标准。本研究结果表明，SLM制造方法可能有潜力取代传统的牙科修复体制造技术。
