title: Effect of (-)-epigallocatechin gallate on electrochemical behavior and surface film composition of Co-Cr alloy used in dental restorations.
abstract: The aim of this study was to investigate the electrochemical behavior of Co-Cr alloy in artificial saliva containing (-)-epigallocatechin gallate (EGCG) and to characterize the composition and structure of the passive film formed by potentiodynamic polarization.Electrochemical measurements ranked the corrosion resistance of Co-Cr dental cast alloy as follows when exposed to artificial saliva containing different concentrations of EGCG: 4.0 g/L<2.0 g/L<0 g/L<0.5 g/L<1.0 g/L. This showed that the concentration of EGCG in artificial saliva affected the corrosion behavior of Co-Cr alloy. X-ray photoelectron spectroscopy (XPS) results revealed that the outermost surface layer on Co-Cr alloy was mainly composed of Cr2O3 and EGCG-Cr (III) ion complex, which were formed by redox and complex formation reactions respectively. When the redox reaction was dominant, Co-Cr alloy exhibited high corrosion resistance in EGCG-containing artificial saliva. On the contrary, when the complex formation reaction was dominant, Co-Cr alloy exhibited low corrosion resistance.
authors.affiliation: Department of Prosthodontics, School of Stomatology, Tongji University, Shanghai, China. g_y_qiao@126.com
authors.forename: Guangyan
authors.initials: G
authors.lastname: Qiao
authors.forename: Jiansheng
authors.initials: J
authors.lastname: Su
authors.forename: Meifeng
authors.initials: M
authors.lastname: He
mesh_terms: D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D002858:Chromium Alloys / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry; D003343:Corrosion; D058266:Dielectric Spectroscopy; D055664:Electrochemical Techniques; D056951:Photoelectron Spectroscopy; D012464:Saliva, Artificial; D013054:Spectrophotometry, Atomic; D013499:Surface Properties; D013662:Tea / Q000737:chemistry*
chemical_list: D002858:Chromium Alloys; D012464:Saliva, Artificial; D013662:Tea; D003035:Cobalt; D002392:Catechin; C045651:epigallocatechin gallate