Evaluation of Microbiologically Induced Corrosion in the Presence of Streptococcus Mutans

Abstract

Titanium and titanium alloys are used in biomedical implants such as dental screws due to their excellent mechanical strength and high resistance to corrosion. The corrosion resistance of these alloys is largely due to the formation of a passive oxide layer on the titanium surface when in contact with oxygen. For the application of use in dental implants, titanium’s ability to withstand corrosion in the presence of oral bacteria is of utmost importance, specifically in the presence of Streptococcus mutans, the most common plaque causing oral bacteria. Previous literature has explored the effects of the formation of a S. mutans biofilm on the corrosion resistance of commercially pure titanium [1]. A decrease in corrosion resistance is observed following the formation of the biofilm, however this decrease in corrosion resistance does not invalidate the viability of titanium for use in orthodontic systems. Due to the electrochemical and material similarities between titanium and zirconium, including the formation of a passive oxide layer on the zirconium surface and high material strength, there is evidence to suggest zirconium and zirconium alloys may be a viable alternative to titanium for these applications [2]. Previous literature has explored the use of titanium-zirconium alloys in such applications and found no decrease in their ability to withstand colonization and microbiologically induced corrosion in the presence of Streptococci species relative to commercially available titanium [3]. The aim of this current research is to begin the exploration of the feasibility of zirconium based materials in orthodontic applications by investigating the microbiologically induced corrosion of commercially pure zirconium and a zirconium-niobium alloy in the presence of S. mutans and compare them against commercially pure titanium.