| dc.description | Background
Titanium (Ti) and its alloys possess high biocompatibility and corrosion resistance due to Ti
ability to form a passive oxide film, i.e. TiO2, immediately after contact with oxygen. This
passive layer is considered stable during function in the oral cavity, however, emerging information
associate inflammatory peri-implantitis to vast increases in Ti corrosion products
around diseased implants as compared to healthy ones. Thus, it is imperative to identify
which factors in the peri-implant micro-environment may reduce Ti corrosion resistance.
Methods
The aim of this work is to simulate peri-implant inflammatory conditions in vitro to determine
which factors affect corrosion susceptibility of Ti-6Al-4V dental implants. The effects of
hydrogen peroxide (surrogate for reactive oxygen species, ROS, found during inflammation),
albumin (a protein typical of physiological fluids), deaeration (to simulate reduced pO2
conditions during inflammation), in an acidic environment (pH 3), which is typical of inflammation
condition, were investigated. Corrosion resistance of Ti-6Al-4V clinically-relevant
acid etched surfaces was investigated by electrochemical techniques: Open Circuit Potential;
Electrochemical Impedance Spectroscopy; and Anodic Polarization.
Results
Electrochemical tests confirmed that most aggressive conditions to the Ti-6Al-4V alloy were
those typical of occluded cells, i.e. oxidizing conditions (H2O2), in the presence of protein
and deaeration of the physiological medium.
Conclusions
Our results provide evidence that titanium???s corrosion resistance can be reduced by intense
inflammatory conditions. This observation indicates that the micro-environment to which the implant is exposed during peri-implant inflammation is highly aggressive and may lead to
TiO2 passive layer attack. Further investigation of the effect of these aggressive conditions
on titanium dissolution is warranted. | |
