title: In vitro corrosion of dental Ag-based alloys in polyvinylpyrrolidone iodine solution.
abstract: The corrosion and tarnish behaviors of three Ag-based alloys (Ag-Pd-Cu-Au alloy, Ag-In alloy, and Ag-Sn-Zn alloy) in polyvinylpyrrolidone iodine (povidone-iodine) solution were examined. The degree of tarnish was evaluated by visible-ray spectrocolorimetry. Corrosion potential measurements and analyses of corrosion products by X-ray diffractometry were carried out to elucidate the corrosion mechanism. The corrosion rate of the three Ag-based alloys in povidone-iodine solution at its practical concentration used as a gargle solution was so fast that the alloys tarnished within 10 seconds of immersion with the formation of AgI. Thermodynamic consideration and the results of surface analysis by X-ray diffractometry revealed that the main anodic and cathodic reactions were Ag + I(-)-->AgI + e- and I2 + 2e(-)-->2I- respectively.
authors.affiliation: Department of Fixed Prosthodontics, School of Dentistry, Health Sciences University of Hokkaido, 1757 Kanazawa, Ishikari-Tobetsu, Hokkaido 061-0293, Japan. ochident@hoku-iryo-u.ac.jp
authors.forename: Morio
authors.initials: M
authors.lastname: Ochi
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Endo
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ohno
authors.forename: Norio
authors.initials: N
authors.lastname: Takasusuki
authors.forename: Hideki
authors.initials: H
authors.lastname: Matsubara
authors.forename: Takeo
authors.initials: T
authors.lastname: Maida
mesh_terms: D000891:Anti-Infective Agents, Local / Q000737:chemistry*; D003124:Colorimetry; D003300:Copper / Q000737:chemistry; D003343:Corrosion; D003722:Dental Alloys / Q000737:chemistry*; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D007204:Indium / Q000737:chemistry; D007454:Iodides / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010165:Palladium / Q000737:chemistry; D011206:Povidone-Iodine / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D018030:Silver Compounds / Q000737:chemistry; D013053:Spectrophotometry; D013499:Surface Properties; D013997:Time Factors; D014001:Tin / Q000737:chemistry; D014961:X-Ray Diffraction; D015032:Zinc / Q000737:chemistry
chemical_list: D000891:Anti-Infective Agents, Local; D003722:Dental Alloys; D006047:Gold Alloys; D007454:Iodides; D018030:Silver Compounds; D007204:Indium; D012834:Silver; D010165:Palladium; D014001:Tin; D003300:Copper; C030584:silver iodide; D011206:Povidone-Iodine; D015032:Zinc