Objective: The aim of this study was to examine the effect of plasma protein coat on oral bacterial adhesion to modified Ti surface.
Methods: Oral bacterial adhesion to Ti was examined on three surface modifications: Machined, Acid etched and Acid etched & blasted surface, with and without human plasma albumin or fibronectin coat. Roughness parameters were determined using Atomic Force Microscope (AFM). Streptococcus mutans (S.m) and Porphyromonas gingivalis (P.g) adhesion to the Ti discs was visualized through Scanning Electron Microscopy. Confocal scanning laser microscope was used to investigate protein coat and bacterial adhesion and their interrelationships. Quantitative assessment of bacterial adhesion was done by DNA analysis using Nano Drop instruments.
Results: The roughness parameter "Ra" was measured as follows: 53.54 (±8.81), 70.65 (±13.54) and 183.22 (±31.66) nm, for the Machined, Acid etched and Acid etched & blasted surfaces respectively. The acid etched & blasted surfaces exhibited significantly higher amounts of bacterial adhesion as compared to the other surfaces. While Human plasma albumin coat significantly reduced the adhesion of S.m to all surfaces, it had no influence on the adhesion of P.g . However, Fibronectin coat induced P.g adhesion to all the examined surfaces.
Conclusions: Bacterial adhesion to Ti surfaces was found to be roughness depended. Furthermore, human plasma proteins were found to have varying influences on the adhesion of oral bacteria. These findings point to the complexity of the interactions between constituents of serum, oral bacteria and implant surfaces. Further studies, on the mechanism of these relationships in the vicinity of the implants are underway.