Electrochemical impedance investigation of Ni-free Co-Cr-Mo and Co-Cr-Mo-Ni dental casting alloy for partial removable dental prosthesis frameworks

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• 作者：Chao Qian ; MDS^a ; Xingchen Wu ; MDS^b ; Fuqiang Zhang ; DDS^c ; Weiqiang Yu ; DDS^d ; ^{ywqhuai@126.com" class="auth_mail" title="E-mail the corresponding author}
• 刊名：The Journal of Prosthetic Dentistry
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：116
• 期：1
• 页码：112-118
• 全文大小：3897 K

文摘

The pH level of the oral environment influences corrosion in dental materials. Corrosion behaviors of Co-Cr-Mo and Co-Cr-Mo-Ni alloys in different pH environments remain undetermined.

Purpose

The purpose of this in vitro study was to evaluate the surface properties and corrosion behaviors of Co-Cr-Mo and Co-Cr-Mo-Ni dental casting alloys in artificial saliva at pH values of 5.0 and 2.5.

Material and methods

Fifty specimens were divided into 2 groups according to the alloy composition. The surface compositions, hardness values, and microstructures of the alloys were measured before immersion in artificial saliva. The corrosion behaviors of the specimens in artificial saliva at pH values of 5.0 and 2.5 were studied using electrochemical impedance spectroscopy (EIS). The microstructures were examined again after a 7-day immersion test. Data were analyzed by a 1-way analysis of variance (ANOVA) test (α=.05).

Results

As expected, the relative levels of Co and Cr of the surface composition were higher in the Co-Cr-Mo alloy. The Co-Cr-Mo alloy had statistically higher surface hardness than the Co-Cr-Mo-Ni alloy (P<.05). In the pH 2.5 environment, both of the alloys showed decreased corrosion resistance (P<.05). The microstructure of the Co-Cr-Mo-Ni alloy corroded more than that of the Co-Cr-Mo alloy in the pH 2.5 environment. The oxide-layer corrosion resistance of the Co-Cr-Mo alloy was better than that of the Co-Cr-Mo-Ni alloy in Fusayama artificial saliva solutions at pH values of both 5.0 and 2.5 (P<.05).

Conclusions

The corrosion resistance of the Co-Cr-Mo alloy was better in the oral environment, especially at a low pH value.