Support for and implications of the specific plaque hypothesis.

The role of specific microorganisms in dental caries is reviewed. A considerable amount of evidence supports the association between organisms of the Streptococcus mutans group and caries incidence and prevalence. The cariogenic potential of S. mutans is probably due to the unique combination of properties with which this microorganism is endowed. The pathogenic potential can be modified by changes in the environment. Lactobacilli play a major role in the development of a lesion. The specific plaque hypothesis has important implications because the association between S. mutans, lactobacilli and dental caries can be used in diagnosis, treatment and prevention of the disease in groups of subjects as well as in the individual case.