Oral Biofilms: From Development to Assessment and Treatment

For years, microbiologists and infectious disease specialists have considered bacteria to be simple, independent, free-floating, single-cell living organisms. Based on this view, many of the strategies for controlling infections in human body have used laboratory models of free-floating microbes. In the past decade, however, scientists and clinicians have found that bacteria in natural environments often live in highly organized communities and have the ability to participate in a rudimentary form of communication. These communities are called biofilms. Oral biofilms are functionally and structurally organized polymicrobial communities that are embedded in an extracellular matrix of exopolymers on mucosal and dental surfaces. These biofilms are found naturally in health and provide benefits to the host. However, this relationship can break down, and disease can occur; disease is associated with a shift in the balance of the species within these biofilms. One promising approach to combating these biofilms is based on nanotechnology-tailored agents. Nanotechnology is the field of science which can guide our understanding of the role of interspecies interaction in the development of biofilm. Strategies to control caries could include inhibition of biofilm development (e.g., prevention of attachment of cariogenic bacteria, manipulation of cell signalling mechanisms, delivery of effective antimicrobials, etc.), or enhancement of the host defenses. Additionally, these more conventional approaches could be augmented by interference with the factors that enable the cariogenic bacteria to escape from the normal homeostatic mechanisms that restrict their growth in plaque and out compete the organisms associated with health. Nanotechnology application includes the use of quantum dots for labelling of bacterial cells, selective removal of cariogenic bacteria while preserving the normal oral flora and silver antimicrobial nanotechnology against pathogens associated with biofilms. The future also comprises a mouthwash full of smart nanomachines which can allow the harmless flora of mouth to flourish in a healthy ecosystem. This chapter is aimed at providing an understanding of the biofilm architecture within the oral cavity and predominantly focuses on recent research on the creation, characterization, and evaluation of nanoparticles for the prevention or treatment of biofilms in the oral cavity.