铸造和切削钴铬合金与瓷结合强度的比较

Comparison of the bond strength of milled and cast Cobalt- Chromium alloys to porcelain

目的比较铸造和切削钴铬合金与瓷的结合强度。方法分别使用失蜡铸造法和计算机数字控制切削法制作钴铬合金试件(25 mm×3 mm×0.5 mm),在试件表面中心区域熔附8 mm×3 mm×1.1 mm的瓷,使用ISO 9693规定的三点弯曲测试对金瓷试件进行金瓷结合强度测定。使用佩有X线能谱分析的扫描电镜观察试件的显微特征,元素扩散以及开裂试件开裂模式、残留瓷面积分数。结合强度、残留瓷面积分数数据使用独立样本t检验进行统计学分析(α=0.05)。结果铸造钴铬合金与瓷的结合强度为(31.46±3.61)MPa,切削钴铬合金与瓷的结合强度为(31.74±3.33)MPa,两组间差异没有统计学意义(t=-0.204,P=0.738),三点弯曲测试后,铸造组和切削组所有开裂试件都为混合开裂模式,铸造组和切削组的残留瓷面积分数分别为0.32±0.06和0.45±0.08,两组间差异有统计学意义(t=-4.67,P<0.001),切削组合金表面比铸造组有更多的瓷残留。结论铸造法和切削法制作的钴铬合金金瓷结合强度没有差异。

Objective To compare the bond strength of milled and cast Cobalt-Chromium（Co-Cr）alloys to porcelain. Methods Co-Cr alloy specimens（25 mm × 3 mm × 0.5 mm）were prepared using either a cast or computer numerical control milling methods. An 8 mm × 3 mm × 1.1 mm ceramic layer was fused to the central portion（8 mm × 3 mm）of the surface of the metal specimen. The bond strengths of the metal-ceramic specimens were tested using a three-point bending test according to the ISO 9693 standard.Scanning electron microscopy and energy dispersive spectroscopy were used to determine the morphologies and elemental diffusion,and failure types,and area fraction of adherence porcelain. The data of metalceramic bond strength and area fraction of adherence porcelain were analyzed using independent sample t-test（α = 0.05）. Results The metal-ceramic bond strength of cast and milled Co-Cr alloy were（31.46 ±3.61）and（31.74 ± 3.33）MPa,respectively. No statistical difference was found between two groups（t =-0.204,P = 0.738）. After three-point bending test,a mixture of adhesive- and cohesive-failure types was observed in all specimens. The area fraction of adherence porcelain of cast and milled Co-Cr alloy were（0.32 ± 0.06）and（0.45 ± 0.08）,respectively. Significant differences were found between two groups（t =-4.67,P〈0.001）,the porcelain-debonded milled alloy surface had larger area of residual ceramic.Conclusion No difference was found in the metal-ceramic bond strength between milled and cast Co-Cr alloy.