COMPARATIVE-STUDY IN-VIVO IN-VITRO OF THE BACTERIAL-COLONIZATION BY STREPTOCOCCUS-MUTANS ON DENTAL SURFACES IN GNOTOBIOTIC-RATS, AND IN AN ARTIFICIAL MOUTH MODEL

The study of bacterial colonization by Streptococcus mutans on dental surfaces of rat have been undertaken in vivo in gnotobiotic rat, and i n vitro in an artificial mouth model, in order to validate the suitabi lity of such a model. The study of colonization by Streptococcus mutan s with time showed a similar kinetic of the monobacterial plaque forma tion in the two experimentations. Three phases were observed. A logari thmic phase in the earliest hours after inoculation of bacterium, foll owed by an exponential phase, and finally a stabilization phase of the monobacterial plaque formed in this way from the third day. Neverthel ess, if the kinetic is the same, it is observed a more important colon ization of dental surfaces in rat. This phenomenon was explained by th e simplification of biological conditions encountered in the in vitro model. In particular, it is noticed the important saliva action. It is concluded that the in vitro model developed simulate suitably the con ditions of the oral environment encountered in vivo.