the effect of silver nano particles on candida albicans and streptococcus mutans in denture acrylic resins

introduction: denture stomatitis is a common complication in patients wearing dentures and preventing the proliferation of related microorganisms and their induced infections is noteworthy. the aim of the present study was to assess the antimicrobial effect of acrylic resins containing various concentrations of silver nanoparticles, on candida albicans and streptococcus mutans. materials and methods: in this in vitro study, the effect of four different concentrations of silver nanoparticles in 160 acrylic samples (10mm *4mm) on standard and hospital isolated strains of two different microorganisms were investigated. the samples were soaked (containing silver nanoparticles and control) in bacterial suspension and the antimicrobial tests were performed after 0, 1, 6 and 24 hours. mean and standard deviation were used to describe the data and one-way variance analysis test was performed to compare groups. results: results have shown that in concentration of 2.5% the highest mean difference for standard s. mutans, after 24h of exposure was 540.0±14.4 (p< 0.001), while in 5% ,this value for standard c.albicans after 6h of exposure was 953.0±87.0 (p< 0.001). however in concentration of 10% the highest mean difference of 1000.0±24.9 in standard c.albicans after an exposure period of 24h (p< 0.001) was observed, which was indicative of the significant  effect of the highest concentration of silver nanoparticles. conclusion: 1. in acrylic resins, increase in silver nanoparticle concentration leads to a greater antimicrobial effect.  2.  acrylic resins containing silver nanoparticles have a stronger antimicrobial property on standard c.albicans and generally less effect on hospital isolated strains. 3.  the longer time elapsed after exposure of bacterial suspension with acrylic resins containing silver nanoparticles, the less the residual antimicrobial effect.