The pattern of experimental colonization of a human and a rodent strain of the bacterium Actinomyces viscosus on the dentition of the rat

Samples were taken from mesial, buccal, lingual and approximal sites and from fissures. Initially, most A. viscosus were recovered from the retention sites. With the exception of lingual sites during the period of exponential growth, the apparent doubling times calculated for A. viscosus Nyl SR remained within narrow limits for all locations. After cessation of exponentional growth, both strains had colonized all surfaces. However, the rodent strain A. viscosus Nyl SR had formed 30–800 times larger populations on the smooth surfaces than the human strain A. viscosus Ut2. On the retention sites, the populations of both strains were not significantly different.