Chemical, Electrochemical, and Surface Study on Microbial Attack of CoCrMo Dental Alloy by Streptococcus mutans

Abstract

Abstract: In this investigation, the objective of our research was to evaluate the influence of the corrosion behavior of CoCrMo dental alloy in the presence of the oral bacteria Streptococcus mutans (Streptococcus mutans) and its growth byproducts. The corrosion resistance of the dental alloy CoCrMo followed a comparative study in the sterilized Fusayama's artificial saliva (FAS) containing Trypticase soy broth (TSB) (medium 1) and Streptococcus mutans mixed with (TSB) and (FAS) (medium 2). To perform this study, electrochemical corrosion tests including open circuit potential (OCP), potentiodynamic polarization (PDP), and impedance spectroscopy (EIS) measurements and inductively coupled plasma atomic emission spectrometry (ICP-AES) were used. The formed films biomass was observed by an optical microscope, after 216 h (9 days) of exposition to medium containing Streptococcus mutans; then, it was verified by SEM-EDS analysis. The results of the electrochemical corrosion showed a significant shift of the corrosion potential and an increase in the corrosion current density (icorr) and the corrosion resistance (Rp) after 24 h of immersion of the alloys in the medium containing Streptococcus mutans. This led to alter the formation of the passive film which reveals the high reactivity of CoCrMo in the presence of Streptococcus mutans, whereas the surface analysis confirmed the biofilm formation once the contact of Streptococcus mutans to CoCrMo alloy surfaces was insured. Graphic Abstract: [Figure not available: see fulltext.]