Campbell S D, Kelly J R
Int J Prosthodont. 1989 Sep-Oct;2(5):459-66.
The effect of three surface preparations on the flexural strength of a cast glass-ceramic (Dicor) was studied. The microstructure of the external and fracture surfaces was evaluated using electron microscopy. It was found that there was no difference in strength for the "as-cast/cerammed," acid-etched, or glazed shading porcelain specimens. A significant increase in strength (twofold) was observed when the "ceram layer" was mechanically removed from the surface of the ceramic. Scanning electron microscopy revealed that the "ceram layer" was 25 to 100 microns thick and consisted of crystal "whiskers" oriented perpendicular to the external surfaces. It was observed in both the laboratory and the clinically failed specimens that a zone of strength-limiting porosity was associated with this "ceram layer." Potential origins of the crystal "whiskers" and the porosity were discussed.
研究了三种表面处理对铸态玻璃陶瓷（Dicor）抗弯强度的影响。使用电子显微镜评估了外部和断裂表面的微观结构。结果发现，“铸态/陶瓷化”、酸蚀或釉面遮色瓷试样的强度没有差异。当从陶瓷表面机械去除“陶瓷层”时，观察到强度显著增加（两倍）。扫描电子显微镜显示，“陶瓷层”厚度为25至100微米，由垂直于外表面取向的晶体“晶须”组成。在实验室和临床失效的试样中均观察到，强度限制孔隙区域与该“陶瓷层”相关。讨论了晶体“晶须”和孔隙的潜在来源。
