Adhesion of Porphyromonas gingivalis and Tannerella forsythia to dentin and titanium with sandblasted and acid etched surface coated with serum and serum proteins - An in vitro study

Objective: To evaluate the adhesion of selected bacterial strains incl. expression of important virulence factors at dentin and titanium SLA surfaces coated with layers of serum proteins. Methods: Dentin-and moderately rough SLA titanium-discs were coated overnight with human serum, or IgG, or human serum albumin (HSA). Thereafter, Porphyromonas gingivalis, Tannerella forsythia, or a six species mixture were added for 4 h and 24 h. The number of adhered bacteria (colony forming units; CFU) was determined. Arg-gingipain activity of P. gingivalis and mRNA expressions of P. gingivalis and T forsythia proteases and T. forsythia protease inhibitor were measured. Results: Coating specimens never resulted in differences exceeding 1.1 log10 CFU, comparing to controls, irrespective the substrate. Counts of T forsythia were statistically significantly higher at titanium than dentin, the difference was up to 3.7 log10 CFU after 24 h (p = 0.002). No statistically significant variation regarding adhesion of the mixed culture was detected between surfaces or among coatings. Arggingipain activity of P. gingivalis was associated with 1og10 CFU but not with the surface or the coating. Titanium negatively influenced mRNA expression of T. forsythia protease inhibitor at 24 h (p = 0.026 uncoated, p = 0.009 with serum). Conclusions: The present findings indicate that: a) single bacterial species (T forsythia) can adhere more readily to titanium SLA than to dentin, b) low expression of T. forsythia protease inhibitor may influence the virulence of the species on titanium SLA surfaces in comparison with teeth, and c) surface properties (e.g. material and/or protein layers) do not appear to significantly influence multi-species adhesion. (C) 2016 Elsevier Ltd. All rights reserved