An Electrochemical Study On Corrosion Behavior Of Two Alloys RPD In Artificial Salial With Different PH

Objective: To study the effect on the corrosion resistance of cpTi RPD in the artificial saliva with different pH value (pH5. 6 and pH6. 8) in vitro, compared with Co-Cr alloy RPD. Methods: The electrochemical corrosion behavior of cpTi and Co-Cr alloy RPD in artificial saliva at pH=5. 6, 6. 8respectively to determine the corrosion potential (Ecorr) and self-corrosion current density (Icorr) , at the first?14th?28th days. Surface microstructures were observed by Scanning Electron Microscope (SEM) . Results: Compared with two alloys RPD, the corrosion resistance of cpTi was better than Co-Cr alloy(P<0.05). The value of Icorr was lower than Co-Cr alloy. The pH value in the artificial saliva was decreased, the Icorr value of two types of alloy increased, the Rpvalue of two types of alloy decreased. But the changes of cpTi was smaller than that of Co-Cr alloy(P<0.05). The scanning results of SEM showed that Co-Cr alloy appeared crystal lattice corrosion in artificial saliva. the corrosion of cpTi was not significant. Conclusion: 1) The corrosion resistance of cpTi was superior to that of Co-Cr alloy. Comparing among two dental alloys, cpTi had the slowest corrosion speed, the best corrosion resistance, and the smallest influence following pH alteration. Hence, when selecting dental alloys from Co-Cr alloy and cpTi in clinical practice, cpTi was the best choice. In the acid artificial saliva, the corrosion resistance of two types of alloy descended evidently. 2. Following with increasing acidity of medium, the corrosion potentials of two alloys shifted in negative direction, polarization resistance was decreased and corrosion current density was increased as well. This phenomenon proved that dental alloys were more easily corrupted and had bigger corrosion speed in acidity environment. The Icorr value of two types of alloy increased, the Rp value of two types of alloy decreased.