Denture acrylic biofilms: microbial composition, interactions and prevention

Biofilms are defined as communities of microorganisms that are generally attached to a surface and embedded inside an extracellular polysaccharide matrix. Biofilms appear to be the preferred mode of growth of microorganisms in natural environments, and recent estimates associate biofilms with over 65% of hospital-acquired infections. Within the oral cavity, biofilms are present as dental plaque on teeth, as well as on the surfaces soft tissues, and prosthodontic and orthodontic devices. Biofilm development on acrylic denture surfaces is facilitated by poor oral hygiene, the failure to remove the denture whilst sleeping, and poor denture cleansing. The significance of denture biofilms is that they are associated with the infection, denture stomatitis. The key microorganisms involved in denture stomatitis are believed to be fungi of the genus Candida although bacterial species may also contribute.

Whilst there are numerous studies investigating the microbiology of denture stomatitis, the majority are limited to the fungal component of the biofilm. A primary aim of this research is to thoroughly characterise denture biofilms, using not only cultural methods, but also new next generation sequencing methodology. Having identified the microbial components, in vitro biofilms will be generated on acrylic surfaces and the distribution of microbial species spatially characterised by confocal laser scanning microscopy and species-specific molecular probes. In addition, the effect of these biofilms on oral epithelial cells and resident macrophages will be assessed in an in vitro model.

A key management strategy in the treatment of denture stomatitis is appropriate cleansing of the denture using antimicrobial agents. Having established our biofilm model and measured the associated effects on tissues, research assessing the efficacy of several denture cleansing agents in both removing the biofilm and preventing damage to host tissue will be measured.