Antibacterial and antifungal impacts of combined silver, zinc oxide, and chitosan nanoparticles within tissue conditioners of complete dentures in vitro.

BACKGROUND: Tissue conditioners are suitable places for colonization of microorganisms. A combination of tissue conditioners with antibacterial and antifungal materials inhibits the growth of microorganisms. AIMS: Here, we aimed to investigate the antibacterial and antifungal effects of silver (Ag), zinc oxide (ZnO), and chitosan nanoparticles on tissue conditioners in complete dentures. METHODS: The growth of four microorganisms in six different concentrations of Ag, ZnO, and chitosan nanoparticles was investigated after 24 and 48 h. Nanoparticles were synthesized using optical sequestration and approved by scanning electron microscope, x-ray diffraction, and infrared (FT-IR) methods. Nanoparticles were combined at 0.5, 0.25, and 0.25 ratios (chitosan, Ag, and ZnO, respectively) with 0.625, 1.25, 2.5, 5, 10, and 20 mass percentages. Tissue conditioners with nanoparticles were entered to test tubes containing microorganisms, and the growth rate was measured using the turbidity method by spectrophotometer after 24 and 48 h of incubation at 37 °C. RESULTS: Growth inhibition of Candida albicans occurred at 2.5% concentration. However, the growth inhibition of Streptococcus mutans, Enterococcus faecalis, and Pseudomonas aeruginosa occurred at 5% after both 24 and 48 h. Also, the optimum nanoparticle concentration for Candida albicans was found to be 1.25% for both timings. On the other hand, the optimum nanoparticle concentration for Streptococcus mutans, Enterococcus faecalis, and Pseudomonas aeruginosa was 2.5% for both time scales. CONCLUSIONS: The combination of Ag, ZnO, and chitosan nanoparticles inhibited the growth of fungi and bacteria in tissue conditioners. These nanoparticles inhibited the growth of fungi more effectively than bacteria.

Evaluation of antibacterial and antifungal properties of a tissue conditioner used in complete dentures after incorporation of ZnO‒Ag nanoparticles.

Background . Incorporation of antifungal and antimicrobial agents into tissue conditioners might inhibit the formation of microbial plaque and prevent complications such as denture stomatitis. The present study was carried out to evaluate the antibacterial and antifungal properties of a tissue conditioner after incorporation of ZnO‒Ag nanoparticles into their structure. Methods . In this in vitro study, 4 microorganisms were evaluated at 6 concentrations of ZnO‒Ag nanoparticles at 24- and 48-hour intervals, using 168 samples. The nanoparticles were mixed at a ratio of 50% Ag and 50% ZnO and were homogenized with the tissue conditioner at 0.625, 1.25, 2.5, 5, 10 and 20 wt% according to the MIC technique principles. After culturing the microorganisms, a spectrophotometer was used for determining proliferation of microorganisms with the use of turbidity after 24 and 48 hours of incubation at 37ºC. Results . Complete inhibition of the proliferation of Candida albicans, Enterococcus faecalis and Pseudomonas aeruginosa was observed at 24- and 48-hour intervals at a concentration of 10%; such inhibition was observed at 20% concentration of nanoparticles with Streptococcus mutans. In addition, the most effective concentration of ZnO‒Ag nanoparticles at both 24- and 48-hour intervals was 5% with C. albicans and 2.5% with E. faecalis. In addition, the most effective concentration at 24- hour interval with S. mutans was 10% and with P. aeruginosa they were 5% at 24-hour and 2.5% at 48-hour intervals. Conclusion . Incorporation of ZnO‒Ag nanoparticles into tissue conditioners resulted in the inhibition of bacterial proliferation.