Antimicrobial and physical properties of alginate impression material incorporated with silver nanoparticles

Background: Self‑disinfecting impression materials would reduce time and energy needed for impression disinfecting process in clinic. The aim of this study was to evaluate the antimicrobial effect of alginate mixed with nanosilver solution at a concentration of 500 ppm and 1000 ppm on common oral microorganisms and assess changes in working time, setting time, and surface detail reproduction. Materials and Methods: In this in vitro study, three groups were assigned. The first group was alginate, the second group was alginate mixed with 500 ppm nanosilver, and the third group was alginate mixed with 1000 ppm nanosilver. Antimicrobial effect on Escherichia coli, Staphylococcus aureus, and Candida albicans was studied using direct contact test in each group (n = 10). Working time (n = 10), setting time (n = 10), and surface detail reproduction (n = 10) were evaluated separately using the ISO 21563 protocol. Descriptive tables were used to describe the data. Kruskal–Wallis test used to determine significant differences in the number of colonies was counted in antimicrobial test (α = 0.05). Results: No adverse effects observed in working time, setting time, and surface detail reproduction of alginate impressions. Alginate mixed with silver nanoparticles showed no inhibitory effect on S. aureus and C. albicans, but the number of E. coli colonies were counted in the group 1000 ppm was significantly lower than 500 ppm (P = 0.001). Conclusion: Antimicrobial effect of alginate mixed with silver nanoparticles is not clinically indicated. Nevertheless, its physical features did not change significantly. Key Words: Dental impression materials, microbiologic, nanotechnology