Yan Min, Wei Chung-Kai, Lin Yuh-Yih, Hu Suh-Woan, Ding Shinn-Jyh
Institute of Oral Science, Chung Shan Medical University, Taichung City 402, Taiwan.
Department of Dentistry, Chung Shan Medical University Hospital, Taichung City 402, Taiwan.
Materials (Basel). 2015 Jul 20;8(7):4479-4490. doi: 10.3390/ma8074479.
Biomechanics play a critical role in influencing the clinical applications of all-ceramic dental restorations. The restorative biomaterials have to demonstrate mechanical durability in the oral environment because they are always exposed to a variety of oral environments. This study was designed to evaluate the effect of soaking time, notch and saliva pH values on the impact energy of three commonly used all-ceramic materials for CAD/CAM. The leucite-reinforced glass ceramic (ProCAD), lithium disilicate glass ceramic (IPS e.max CAD) and zirconia-based ceramic materials (IPS e.max ZirCAD) were used. The experimental results indicated that the impact energy of ProCAD decreased with an increase in soaking time, but not for IPS e.max CAD and IPS e.max ZirCAD. The impact energy of the zirconia system was higher than leucite-reinforced and lithium disilicate-based ceramic systems. When subjected to preformed 0.5 mm U-shape notch on the bar specimen of 3 mm thick, the impact energy of the all-ceramic restorations revealed a markedly reduction of about 80%-90%, almost irrespective of dental compositions, which indicated the effect of flaw to a great degree. No statistically significant influence ( > 0.05) of pH values (4, 7 and 9) on impact energy was found for each group. It is concluded that the no matter which all-ceramic materials were used, it was appreciably sensitive to the presence of notches. The ceramic composition and microstructure have been shown to affect mechanical durability.
生物力学在影响全瓷牙修复体的临床应用方面起着关键作用。修复性生物材料必须在口腔环境中表现出机械耐久性，因为它们始终暴露于各种口腔环境中。本研究旨在评估浸泡时间、缺口和唾液pH值对三种常用于CAD/CAM的全瓷材料冲击能量的影响。使用了白榴石增强玻璃陶瓷（ProCAD）、二硅酸锂玻璃陶瓷（IPS e.max CAD）和氧化锆基陶瓷材料（IPS e.max ZirCAD）。实验结果表明，ProCAD的冲击能量随浸泡时间的增加而降低，但IPS e.max CAD和IPS e.max ZirCAD并非如此。氧化锆体系的冲击能量高于白榴石增强和二硅酸锂基陶瓷体系。当在3mm厚的棒状试样上预制0.5mm U形缺口时，全瓷修复体的冲击能量显著降低约80%-90%，几乎与牙科组合物无关，这在很大程度上表明了缺陷的影响。对于每组，未发现pH值（4、7和9）对冲击能量有统计学显著影响（>0.05）。得出的结论是，无论使用哪种全瓷材料，它对缺口的存在都相当敏感。陶瓷成分和微观结构已被证明会影响机械耐久性。
