Objective. Studying the species composition of microorganisms of bacterial plaque, improving oral hygiene and increasing the resistance of hard tooth tissues in patients with estrogen imbalance. Materials and methods. For microbiological evaluation of the effect of the coating to increase the resistance of dental hard tissues on the in vivo microbial colonization process, a number of representatives of the oral bacterial microflora were isolated, cultured and identified. Bacteriological examination was subject to 60 patients aged 40 to 50 years who had an imbalance of estrogen. We investigated soft plaque from the surface of the teeth. Bacteriological research was carried out on the 28-th day after the start of observation. A qualitative or specific study of the microflora of the oral cavity was carried out using the technique of aerobic cultivation. For the identification of anaerobic bacteria, a biochemical identification system for anaerobic bacteria «ANAERotest 23» by LACHEMA was used. To confirm the imbalance of estrogen, all patients underwent a study on the level of estrogen (estradiol) in the body. All patients were in the period of menopause, that is, they did not have cyclic fluctuations in hormone levels. The study was conducted three times: at the beginning of treatment, on days 14 and 28. Results. The obtained results indicate the diversity of microbial associations in plaque in the comparison group with a predominance of aerobic ones, the study of the microbial landscape of which showed the most frequent isolation of Staphylococcus aureus golden and epidermal (79.8 %) in monocultures or associations with other types of microorganisms. Streptococcus was 17.2 %, the remaining aerobes were represented by proteom and pseudomonads in isolated cases. In the main group, the prevalence of aerobic associations of microflora with the predominance of cultures of Streptococcus mutans (43.4 %) and Staphylococcus epidermidis in 35.6 % was found. Among non-spore-forming anaerobes, Fusobacterium (24.3 %), Peptococcus (22.8 %), Veilonella (17.4 %), Prevotella (13.5 %), Bacteroides (11.3 %) were the leaders. Other types of anaerobes were determined less frequently: Propionibacterium, Porphyromonas, Actinomices. Anaerobic bacteria isolated from 47.5 % of the examined are presented both in monocultures and in associations, which corresponds to the literature. Most often, anaerobic associations are represented by two species (62.0 %). The most threatening patients in patients with estrogen imbalance is aerobic-anaerobic associations, due to the complex effect of pathogenicity factors of these groups of microorganisms. Conclusions. In patients of the main group, the microbial spectrum of aerobic microflora of plaque differs from that in the comparison group. There is a decrease in the detection of Staphylococcus aureus in relation to the comparison group (2.6 % and 46.1 %, respectively). When using coatings in the main group to increase the resistance of hard tooth tissues, the detection of anaerobic microorganisms was observed to be 2.73 times less compared to the comparison group. In this case, a predominance of non-pathogenic saprophytic microflora, similar to the microflora of the oral cavity, is normal. Key words: caries prophylaxis, estrogen imbalance, decamethoxin, microbiological examination.