Adhesion of oral bacteria to an antibacterial modified dental material

Objectives: Adhesion of oral bacteria plays a decisive role in dental plaque formation and subsequent diseases, e.g. caries and periodontitis. The aim of this study was to develop a composite with reduced susceptibility to oral bacteria and to investigate its bacterial adhesion in comparison to a commercial dental material.

Methods: A dental restorative composite was manufactured by adding custom made filler components. The fillers were modified by adapting an antibacterial Chitosan layer in 10% and 100% concentration. 45 specimens (diameter 10mm, thickness 2mm) were made of the experimental material and a commercial non-modified dental composite restoration material according to the manufacturer's instructions (40s, Elipar Triglight, 3M Espe, USA). A veneering composite (Sinfony, 3M Espe, USA) was used as a reference. The surface roughness was determined according to ASTM (Perthometer S6P, Perthen, G). The specimens were incubated for 2,5h at 37°C with i) Streptococcus mutans (DGMZ 20523), ii) S. oralis (DGMZ 20627) or iii) S. sanguinis (DGMZ 20068; all NCTC, G). After labelling the bacteria with Resazurin (Sigma, G) the fluorescence intensity of adhering streptococci was determined (Fluostar Optima, bmg, G). Low fluorescence corresponds with low bacterial adhesion. Statistics: Median (25/75); Mann-Whitney U-test (α=0.05).

Results: The bacterial adhesion to the experimental material was significantly reduced with increasing amount of Chitosan in comparison to the commercial composite.

Conclusion: The modification of the composite filler reduced the in-vitro bacterial adhesion to the tested streptococci significantly and is supposed to reduce the plaque susceptibility under clinical conditions.