UDC 611.31.018:616-008.87

The experiment investigated the qualitative and quantitative composition of bacterial groups in the microbiotopes of the oral cavity of intact rats (20) for twenty-eight days. The material for microscopic and bacteriological studies was the microflora from the biotope of the oral cavity of animals, in particular, from microbiotopes of the tooth surface in the gingival margin, mucous membrane of oral vestibule and mucous membrane of oral cavity proper. During the experiment, stable microbiocenoses were formed from the gram-positive and gram-negative microorganisms of different species common to all intact animals in the studied biotope, however, they differed in quantitative composition in different microbiotopes of the oral cavity. The quantitative indicator of α hemolytic streptococci significantly decreased in the microbiotopes of the mucous membrane of oral vestibule and of oral cavity proper, compared with the corresponding indicator of the microbiotope of the tooth surface in the gingival margin during the experiment, which testified to the initial stages of formation of dental biofilm in this nishe of the oral cavity. The qualitative and quantitative composition of normal and opportunistic microbiota in the population of rats kept under standard conditions stabilized on the twenty-eighth day of the experiment.