3种牙科铸造金属模拟唾液浸泡后粗糙度的变化

目的：通过考察钴铬合金、镍铬合金以及纯钛在不同pH值人工唾液中浸泡后表面粗糙度的变化，研究3种常用牙科金属的耐腐蚀能力。方法：将3种金属的标准铸造试件逐级打磨抛光后。浸泡于pH值分别为7．0和5．6的人工唾液中。3个月后检测试件表面粗糙度，并用金相显微镜观察试件表面。采用SPSS11．0软件包对数据进行单因素方差分析及t检验。结果：pH=5．6的人工唾液浸泡后，3种材料表面粗糙度有显著差异，镍铬合金〉钴铬合金〉纯钛金属（P〈0．01）。pH=7．0的人工唾液浸泡后，镍铬合金表面粗糙度大于钴铬合金和纯钛（P〈0．01），但钴铬合金和纯钛之间无统计学差异（p〉0．05）。pH=5．6人工唾液浸泡组的镍铬合金和钴铬合金表面粗糙度大于pH=7．0组的同种材料（P〈0．01）。各试验组表面粗糙度大小与显微镜观察到的材料表面腐蚀程度一致。结论：纯钛在酸性和中性环境下均有较强的耐腐蚀性，钴铬合金、镍铬合金在酸性介质中的耐腐蚀性较差。3种金属的耐腐蚀性由大到小排列为：纯钛金属〉钴铬合金〉镍铬合金。

Study on the surface roughness of three dental alloys soaked in artificial saliva

PURPOSE: The aim of this study was to investigate the corrosion behavior of three metal materials for dental use (Co-Cr alloy, Ni-Cr alloy, titanium) by measurement of their surface roughness after soaked in artificial saliva with two different pH values. METHODS: Standard samples were casted respectively from 3 different alloys and grided into the same roughness .Then the samples were exposed to artificial saliva with two different pH values. After three months,the surface roughness of the samples was tested, and the microstructure of surfaces was studied by metalloscope. The data were analyzed with SPSS11.0 software package for one-way ANOVA and t test. RESULTS: There was significant difference in surface roughness of three alloys after exposed to artificial saliva with pH5.6. The surface roughness values of three alloys were listed as follows: Ni-Cr alloy>Co-Cr alloy >titanium(P<0.01). When exposed to artificial saliva with pH7.0, Ni-Cr alloy was found rougher than Co-Cr alloy and titanium(P<0.01), while there was no significant difference in roughness between Co-Cr alloy and titanium(P>0.05).Ni-Cr alloy and Co-Cr alloy soaked in artificial saliva with pH5.6 were found rougher than the same material in artificial saliva with pH7.0(P<0.01).The microstructure of the samples' surface verified the results. CONCLUSION: Titanium was stable not only in neutral environment but also in acid environment. The corrosion resistance of Co-Cr alloy and Ni-Cr alloy was superior in neutral environment than in acid environment. The corrosion resistance of the three alloys was: Titanium >Co-Cr alloy >Ni-Cr alloy.