title: Corrosion of dental alloys in artificial saliva with Streptococcus mutans.
abstract: A comparative study of the corrosion resistance of CoCr and NiCr alloys in artificial saliva (AS) containing tryptic soy broth (Solution 1) and Streptococcus mutans (S. mutans) species (Solution 2) was performed by electrochemical methods, including open circuit potential measurements, impedance spectroscopy, and potentiodynamic polarization. The adherence of S. mutans to the NiCr and CoCr alloy surfaces immersed in Solution 2 for 24 h was verified by scanning electron microscopy, while the results of electrochemical impedance spectroscopy confirmed the importance of biofilm formation for the corrosion process. The R(QR) equivalent circuit was successfully used to fit the data obtained for the AS mixture without S. mutans, while the R(Q(R(QR))) circuit was found to be more suitable for describing the biofilm properties after treatment with the AS containing S. mutans species. In addition, a negative shift of the open circuit potential with immersion time was observed for all samples regardless of the solution type. Both alloys exhibited higher charge transfer resistance after treatment with Solution 2, and lower corrosion current densities were detected for all samples in the presence of S. mutans. The obtained results suggest that the biofilm formation observed after 24 h of exposure to S. mutans bacteria might enhance the corrosion resistance of the studied samples by creating physical barriers that prevented oxygen interactions with the metal surfaces.
authors.affiliation: Yongjia Clinic, Shanghai Stomatological Hospital, Fudan University, Shanghai, People's Republic of China.|Stomatology Special Consultation Clinic, Ninth People's Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, People's Republic of China.
authors.forename: Chunhui
authors.initials: C
authors.lastname: Lu
authors.affiliation: Stomatology Special Consultation Clinic, Ninth People's Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, People's Republic of China.
authors.forename: Yuanli
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Yongjia Clinic, Shanghai Stomatological Hospital, Fudan University, Shanghai, People's Republic of China.
authors.forename: Qun
authors.initials: Q
authors.lastname: Zhong
mesh_terms: D001422:Bacterial Adhesion / Q000187:drug effects; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development; D002858:Chromium Alloys / Q000737:chemistry / Q000592:standards; D003035:Cobalt / Q000737:chemistry; D003343:Corrosion; D003722:Dental Alloys / Q000737:chemistry* / Q000592:standards; D058266:Dielectric Spectroscopy; D055664:Electrochemical Techniques; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing / Q000379:methods; D008855:Microscopy, Electron, Scanning; D009532:Nickel / Q000737:chemistry; D012464:Saliva, Artificial / Q000737:chemistry / Q000494:pharmacology*; D013295:Streptococcus mutans / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D013499:Surface Properties; D013997:Time Factors
chemical_list: D002858:Chromium Alloys; D003722:Dental Alloys; D012464:Saliva, Artificial; D003035:Cobalt; D009532:Nickel