Method: Ti discs were anodically polarized in a standard 3-electrode setting within a controlled environment. Control specimens were not corroded. Specimens were treated with lipopolysaccharide in sterile/deionized water (1.5, 15 and 150 µg/ml) for 24 hours to evaluated lipopolysaccharide adherence. Discs were then transferred every 24 hours to fresh lipopolysaccharide-free water for up to 72 hours to investigate lipopolysaccharide elution. Ti surfaces were examined using white-light-interferometry microscopy and their surface roughness values were investigated. Data were analyzed by ANOVA, and T- tests and Tukey’s tests were further used as post-hoc techniques (α=.05).
Result: Acidic saliva increased the corrosion rate of cp-Ti and Ti-6Al-4V alloy, and promoted greater lipopolysaccharide adherence to Ti surfaces (P<.05). Ti-6Al-4V alloy exhibited greater lipopolysaccharide affinity compared to cp-Ti (P<.05). Lipopolysaccharide elution was greatest at 24-hour interval and reduced over time. However, even after 72 hours of elution, greater than 99.9% of initially adhering lipopolysaccharide remained on the Ti surfaces. The white-light-interferometry images of Ti surfaces showed higher surface changes at low pH level. The surface roughness of cp-Ti was not affected by the pH of saliva (P=.207), while significant effect was observed for Ti-6Al-4V alloy (P<.001). The surface roughness values were higher at acidic pH. Cp-Ti exhibited greater roughness value when compared to Ti-6Al-4V alloy (P<.05).
Conclusion: Corrosion process increased the lipopolysaccharide affinity for cp-Ti and Ti-6Al-4V alloy. Clinically, corrosion of Ti and its surface affinity for lipopolysaccharide could influence periimplant inflammation and implant prognosis.