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[Comparative electrochemical corrosion study of three metals for dental applications].

OBJECTIVE
The aim of this study was to investigate the korrosionsneigung of three metal specimens for casing removable denture by means of electrochemical method.


METHODS
Three kinds of test specimens were prepared, including cobalt-chromium alloy, nickel-chrome alloy with titanium and pure titanium. Then they were analyzed via linear polarization in artificial saliva simulating oral environment. From this electrochemical test the polarization curves of these kinds of specimens were recorded. Then the scanning electron microscope (SEM) and X-ray diffractometer (XRD) were applied to assess the morphology and phase changes before and after electrochemical corrosion.


RESULTS
No typical Tafel curve had been recorded for pure titanium, other than cobalt-chromium alloy and nickel-chrome alloy with titanium. Nickel-chrome alloy with titanium got more negative corrosion potential and higher corrosion current than cobalt-chromium alloy. Via SEM, the obvious changes were observed on the morphology and phase before and after corrosion on cobalt-chromium and nickel-chrome alloy with titanium specimens while pure titanium having no change. The XRD provided us little changes on these all three materials.


CONCLUSION
The results confirm that the korrosionsneigung of the studied cobalt-chromium alloy in artificial saliva is lower than that nickel-chrome alloy with titanium. Pure titanium is the most stable one of the three materials and is extreme hard to be etched.