New aspects and new concepts of maintaining “microbiological” health

The human mouth is host to a diverse collection of microorganisms including bacteria, viruses, fungi and protozoa. Recent advances using molecular methods for the analysis of complex bacterial communities have demonstrated the richness of the oral bacterial biota and the presence of numerous previously undescribed lineages. Dental plaque forms in a structured way with pioneer species able to colonise pellicle-coated enamel followed by secondary plaque formers such as Fusobacterium nucleatum that have the capability of coaggregating with a range of other genera and species. The mature plaque biofilm has many features of multicellular organisms with the constituent organisms cooperating to make nutrients available and resist environmental stresses, and communicating to regulate their overall numbers. Control of the oral microbiota to prevent disease has conventionally been by mechanical means augmented with toothpastes and mouthrinses, but improved knowledge of oral microbial ecology is allowing the development of preand pro-biotic approaches. Other possibilities include interference with the plaque formation process and the perturbation of bacterial communication networks.