全瓷修复体饰瓷疲劳损伤的初步分析

目的：通过对临床损伤失效的全瓷修复体的损伤形貌观察，分析全瓷修复体饰瓷疲劳损伤的机制和过程，以及缺陷与饰瓷损伤的关系。方法：收集断裂或破碎的全瓷修复体，体式显微镜和扫描电子显微镜 (scanning electron microscope, SEM) 观察其断裂面和咬合面微观形貌以及饰瓷的缺陷，X线衍射能谱分析（energy-dispersive X-ray spectroscopy ，EDS）饰瓷内不均质部分的化学成分。运用陶瓷损伤形貌分析的方法，分析全瓷修复体的断裂方式和损伤特征。结果：全瓷修复体的最终损伤失效包括完全断裂、饰瓷崩瓷和饰瓷脱瓷3种方式。氧化铝全瓷冠发生了完全断裂，氧化锆全瓷冠发生饰瓷崩瓷或饰瓷脱瓷。饰瓷疲劳损伤包括表面磨损、锥状裂纹和饰瓷脱瓷3种模式。饰瓷表面发现气孔和污染颗粒缺陷。结论：全瓷修复体应设计多点咬合接触，分散咬合应力。饰瓷脱瓷发生于饰瓷层过薄的情况，适当的饰瓷厚度保证饰瓷的抗疲劳损伤能力。临床需严格控制饰瓷烧结过程的环境污染。

Fatigue damage analysis of porcelain in all-ceramic crowns

Objective:To investigate the fatigue damage mechanism of porcelain,and its relation with the microscopic defects in clinically failed all-ceramic crowns.Methods: Collecting the bilayered all-ceramic crowns failed in vivo.The fractured surfaces and occlusial surfaces of failed crowns were examined by an optical microscope followed by detailed fractography investigations using a field emission scanning electron microscope.When chemical impurities were of concern,energy-dispersive X-ray spectroscopy analysis w...