Biofilm forming-bacteria on acrylic resin dentures

Abstract

It is well documented that bacteria possessing biofilm phenotype cause persistent infections. Recent studies have indicated that denture plaque can cause not only denture-induced stomatitis, but also systemic infections such as pneumonia and endocarditis. Our previous studies disclosed that exopolysaccharides produced by biofilm-forming bacteria may contribute to pathogenicity. However, little is known about the distribution of these bacteria. In this study, we attempted to isolate and identify biofilm-forming bacteria to understand the proportional distribution of these bacteria in denture plaque. We used scanning electron microscopy to demonstrate the existence of the extracellular matrix materials which are observed as meshwork-like structures around the cells. We found that 42.6% of all isolates from denture plaques showed meshwork-like structures around the cells. We identified these bacteria as Streptococcus salivarius, Streptococcus parasanguis, Streptococcus mitis, Prevotella denticola, Lactobacillus rhamnosus, Streptococcus anginosus and Streptococcus pneumoniae by 16S ribosomal RNA gene sequencing. This study showed that common denture plaque bacteria can form a biofilm on acrylic resin dentures during routine use. These results suggest that denture plaques can act as reservoirs of biofilm-forming bacteria that cause chronic systemic infections.