Microbiologically induced intergranular corrosion of 316L stainless steel dental material in saliva

The release of certain metallic constituents within some dental implants could contribute to peri-implantitis and mucositis. While the release rate into surrounding bones and tissues may be dependent on the biocompatibility of dental materials and their designs, the patient's oral hygiene and even the prevalence of certain resident oral bacteria may also affect the service lives of these dental implants by altering their gross corrosion rates. In this study, the levels of Fe, Cr, and Ni released during microbiologically induced intergranular corrosion of medical grade 316L stainless-steel dental material are measured across defined culture durations. Porphyromonas gingivalis, a prominent component of the oral microbiome known to associate with periodontitis and peri-implantitis, is the test bacterium in this study. From the evidence obtained from electrochemical and surface investigations in artificial salivary culture media, dental substates corroded significantly upon maturation of bacterial growth. Corrosion was accompanied by higher levels of metal ion release at extended culture duration. About 1.5 and 9.5 μg/cm2 of Ni and Cr were leached from the metal alloy after a 30-day exposure to the bacterial culture relative to the control; Fe was released 30 times more in the former. This study highlights how oral metal contact influences the corrosion of metallic dental implants (e.g., stainless-steel crowns) in patients infected by certain resident oral bacterium.