OBJECTIVE: Aim: To study the main differences in the intensity of growth of microbial strains of oral origin when they are cultivated in the presence of base resins that are widely used in the clinic of prosthetic dentistry. PATIENTS AND METHODS: Materials and Methods: 3 types of base resin samples were used to evaluate the impact on the growth of microorganisms. Strains of opportunistic pathogens representing the facultative anaerobic transient microflora of the oral cavity were used for the research. Microbial cultures were isolated from the oral mucosa of the patients with removable dentures. The optical density of the culture was determined using a multi-mode photometer. Control growth of the cultures was evaluated under similar cultivation conditions in test tubes with a nutrient medium without resin samples. RESULTS: Results: All resins reduced the intensity of polyantibiotic-resistant S. aureus MRSA growth compared to control samples. The impact on S. epedermidis growth was different. Thus, Vertex and Вreflex reduced the growth intensity insignificantly, and Villacryl increased it to the level of 1.104 ±0.026 CU in comparison with glass constituting 1.178 ±0.033 CU. All studied resins inhibited the growth of polyantibiotic-resistant S. aureus MRSA. Villacryl resin had the least impact on the growth of S. epedermidis. Villacryl resin inhibited C. albicans growth only by 13.70%, and the other two resins inhibited it by 25% on average. CONCLUSION: Conclusions: The conducted microbiological studies showed the diverse influence of base materials on such important indicators as the optical density of cultures grown in the presence of base resins and the growth inhibition index of cultures.