Impact Behavior of Three Notched All-Ceramic Restorations after Soaking in Artificial Saliva
Impact Behavior of Three Notched All-Ceramic Restorations after Soaking in Artificial Saliva
复制标题
三缺口全瓷修复体人工唾液浸泡后的冲击行为
作者：
Min Yan;Chung;Yuh;Suh;S. Ding
生物力学是影响全瓷口腔修复体临床应用的重要因素。由于生物修复材料经常暴露在各种口腔环境中，因此必须在口腔环境中表现出机械耐久性。本研究旨在评估浸泡时间、缺口和唾液pH值对三种CAD/CAM常用全陶瓷材料冲击能的影响。采用白晶石增强玻璃陶瓷（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的冲击能随保温时间的延长而降低，而IPS e.max CAD和IPS e.max ZirCAD的冲击能则不降低。氧化锆体系的冲击能高于白矿石增强和二硅酸锂基陶瓷体系。当在3 mm厚的棒材试样上预制0.5 mm的u型缺口时，全瓷修复体的冲击能显著降低约80%-90%，几乎与牙体成分无关，这在很大程度上表明了缺陷的影响。各组pH值（4、7、9）对冲击能的影响均无统计学意义（p > 0.05）。结果表明，无论采用何种全陶瓷材料，其对缺口的存在都非常敏感。陶瓷成分和显微组织对机械耐久性有影响。
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 (p > 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.