Factors affecting adhesion of bacterial to a tooth in vitro.

The initial adhesion of oral bacteria to a tooth in vitro was examined. The organisms were grown in broth with and without sucrose, and suspensions made either in broth or a modified Ringer's solution. The tooth used was either dry or coated with natural or synthetic saliva. Adhesion was determined by counting organisms removed from the tooth surface by simple washing or by sonication. It was found that the firmest bonding occurred when a dry tooth was immersed in a suspension of bacteria in Ringer's solution; the prior growth of the organisms in the presence of sucrose did not affect adhesion. It was concluded that instantaneous irreversible adhesion of bacteria to a tooth occurs without the need for active metabolism, and that this process is inhibited by the presence of competing organic substances which probably produce a surface-conditioning film.