The ecological plaque hypothesis and the aetiology of dental caries. The diagram shows a dynamic relationship whereby an environmental change in the biofilm (e.g. low pH) drives a shift in the balance of the resident microflora, thereby shifting the balance towards enamel demineralization. Caries could be controlled by inhibiting the putative pathogens, e.g. mutans streptococci (MS) or other acid producers, by interfering with the environmental changes driving the ecological shift, e.g. by reducing the acid challenge by the use of sugar control, saliva stimulation and/or biofilm removal. (Adapted from Marsh, 1994.)