Role of microbial communities in the pathogenesis of periodontal diseases and caries

: The microbiological characteristics of both caries and periodontal disease show significant change from those in health. In both instances, there is evidence of co-association of different organisms into consortia. Aim: We review and summarize a number of issues pertinent to the community organization and functional activity of the bacterial populations resident on supra-and subgingival tooth surface and the influence of these populations on disease. Methods: A literature review was undertaken with a particular emphasis on recent publications involving high-throughput, deep sequencing approaches to the analysis of microbial populations and their functional activity. Results: There is increasing evidence to suggest that both caries and periodontal disease represent dysbiotic states of the oral microbiome. The mode of acquisition of the oral microbial communities may be less passive than previously recognized but once established remains relatively stable within an individual although there are very significant site variations. A repertoire of stable dysbiotic states may occur in both caries and periodontitis involving different microbial community structures with potentially similar functional properties. Conclusions: The processes which underlie the development and stability of microbial populations in the healthy mouth are fundamental to understanding how these populations are transformed into a dysbiotic state in disease.