Formation of biofilms by representatives of the oral microflora on the surfaces of basic materials
Authors: Rozhko S. M. , Kutsyk R. V. , Paliichuk I. V. 
Published: September 2021

The aim of the work is to conduct a comparative analysis of the biofilm formation by representatives of the oral microflora on the surfaces of basic materials.
Materials and methods. The process of biofilm formation was examined on 7 types of basic plastic samples: Polyan, Breflex, Nylon, Protakryl, Vinakryl, Biocryl, which were used for the manufacture of removable prosthetic basis constructions, and SYNMA, which was used for comparison. Biofilm formation was analyzed by the method Y. Zhang (2017) with minor modifications. The test sample was placed in a test tube with 2.0 ml of nutrient broth Brain Heart Infusion to model the biofilm growth of microorganisms (HiMedia Laboratories Pvt. Ltd., India) supplemented with 1 % glucose, pre-inoculated with test strains at a final concentration of 1 × 104 CFU/ml. The strains were cultivated for 24 hours at a temperature of 37 °C under continuous stirring in a shaker MR-1 (SIA BIOS AN, Latvia) at 20 rpm. Evaluation of the biofilm massiveness was performed after gentian violet staining followed by elution of the stain with ethanol and registration of the eluent optical density (OD). The OD was measured with a Synergy™ HTX S1LFTA microplate multimode photometer (BioTek Instruments, Inc., USA) at 595 nm wavelength using Gen5™ Data Analysis Software. The number of viable bacterial cells in the formed biofilms was determined by the method of ten-fold serial dilutions. The obtained results were converted per unit area of the sample tested.
Processing of the results was performed using a two-sample t-test with the software package Statistica 13.0 and Microsoft Office Excel, the differences were considered statistically significant at a P value of < 0.05. Statistical analysis of the obtained data was presented as mean values of measurements ± standard deviation for three independent experiments.
Results. According to the microbiological analysis results it was found that α-hemolytic streptococci S. oralis and S. sanguinis showed the ability to form biofilms on the surfaces of basic materials, namely Protacryl and Vinacryl, the total biomass of S. sanguinis biofilms was 47.7 % (P < 0.01) and 14.7 % (P > 0.05) greater, respectively, in comparison to a glass slide. Inhibition of biofilm formation processes was observed on the surfaces of Nylon and Biocryl basic materials. S. oralis and S. gordonii showed the highest ability to survive in biofilms. The intensity of C. albicans biofilms formation on Biocryl basic materials, comparative plastics SINMA and Breflex basic materials was greater than on glass slides by 48.3 %, 43.0 % and 34.9 % (P < 0.01), respectively. The least massive C. albicans biofilms were formed on Breflex surfaces and SINMA comparative plastics in comparison to glass slides by 33.6 % and 24.8 % (P < 0.01), respectively. Both Candida strains had the highest level of fungal viability in biofilms on Breflex, Polyan and Protacryl basic materials (P < 0.01), and C. tropicalis biofilms on Biocryl and Vinacryl basic materials (P < 0.05). Integral coefficients indicated the inhibition of the oral microflora ability to form biofilms on the surfaces of basic materials.
Conclusions. Oral α-hemolytic and β-hemolytic streptococci have the ability to intensive biofilm growth on the surfaces of the basic materials Protacryl and Vinacryl. Oral Candida albicans form massive biofilms on the surfaces of Biocryl and Vinacryl basic materials and comparative SYNMA plastics. The basic materials Breflex, Nylon and comparative plastics SYNMA are the most inert to biofilm formation by the oral microflora representatives.