The project is intended to study the implantation of Strep. mutans in the oral cavity of animals and man. Factors affecting the implantation process will be determined and examined in detail. Because implantation studies in humans present several difficulties at present and are hence currently limited, initial investigation will be limited to colonization studies regarding the implantation of various serotypes of Strep. mutans in gnotobiotic rats. Factors under investigation include the effect of simultaneous introduction of multiple serotypes, the effect of different sugar diets, the effect of prior induction of antibodies to Strep. mutans, and the effect of sequential introduction of each serotype on the implantation of Strep. mutans in gnotobiotic rats. Fluorescent Antibody conjugate reagents specific for each serotype of Strep. mutans are employed in monitoring the presence and level of antibodies to Strep. mutans and the proportion of Strep. mutans in animal specimens.