[Comparative in vivo and in vitro study of bacterial colonization by Streptococcus mutans on dental surfaces in axenic rats and in an artificial model of the oral cavity].

The study of bacterial colonization by Streptococcus mutans on dental surfaces of rat have been undertaken in vivo in gnotobiotic rat, and in vitro in an artificial mouth model, in order to validate the suitability of such a model. The study of colonization by Streptococcus mutans with time showed a similar kinetic of the monobacterial plaque formation in the two experimentations. Three phases were observed. A logarithmic phase in the earliest hours after inoculation of bacterium, followed by an exponential phase, and finally a stabilization phase of the monobacterial plaque formed in this way from the third day. Nevertheless, if the kinetic is the same, it is observed a more important colonization of dental surfaces in rat. This phenomenon was explained by the 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 conditions of the oral environment encountered in vivo.