Implications of resource-ratio theory for oral microbial ecology.

The ability to compete for the limited nutrients available to the microorganisms of dental plaque is a strong ecological determinant of the structure of the subgingival ecosystem. This paper introduces a new concept from the field of ecology, resource-ratio theory, and applies it to the dynamics of microbial dental plaque with emphasis on the putative periodontal pathogens. Resource-ratio theory is a mechanistic theory of resource competition that utilizes pairs of growth-limiting nutrients in a stoichiometric fashion to predict zones of competitive dominance, exclusion, and coexistence for organisms competing for these resources. Once these resource pairs are identified for plaque organisms, resource-ratio theory may provide predictions of changes in the microbial community structure of plaque based on directional changes in their resource supply ratios.