Titanium Corrosion is a Modifier of Peri-implant Health

Abstract

Dental implants are highly successful at replacing missing teeth and restoring Oral-Health Related quality of life. Despite a high rate of success, however, there remain a significant number of patients who develop peri-implant mucositis and peri-implantitis. The definition of success for implants extends beyond merely implant survival; in addition to lack of mobility “success” encompasses the maintenance of health of the peri-implant tissues and supporting bone despite the constant microbial challenge in the oral environment. It is well documented that the titanium dioxide (TiO2) passive layer is responsible for the biocompatibility of titanium dental implants and that weakening this layer leads to titanium dissolution and corrosion. Recent data support the implication of titanium corrosion as a factor in peri-implantitis and preliminary data support that certain oral taxa may cause bio-corrosion in vitro. It remains unknown whether titanium corrosion is related to differences in the peri-implant microbiome. It is also unknown whether titanium corrosion affects a change in the peri-implant health is by affecting site-specific changes in pro-inflammatory gene expression. This thesis explores the role of titanium corrosive particles in peri-implant disease and explores pathways that have plausibility for being affected by titanium. The subsequent pages are an examination of the prevalence and risk factors associated with peri-implantitis and the role of titanium as a modulator of the oral microbiome and host response. They will provide evidence of the significance of the problem of peri-implant disease in a United States population and the risk of implant failure associated with patient specific factors such as diabetes and periodontal disease. Next, they will provide evidence that titanium corrosion products, and not the disease status, shape the peri-implant microbiome suggesting that dissolved titanium creates a unique niche in the oral cavity causing a shift of the composition of the peri-implant microbiome. In addition, the relationship between methylation levels, titanium particles, and peri-implantitis was assessed. The results show that Global DNA Methylation levels in the peri-implant crevicular fluid are greater in peri-implantitis cases when compared to controls, and independently associated to higher plaque-adjusted titanium quantities. In summary, these findings unveil the role of titanium as a dysregulator of peri-implant health, support the consideration of peri-implantitis as a distinct entity from periodontitis and highlight the importance of maintaining titanium surface biocompatibility during maintenance, and disease management.