ABSTRACT
Disinfection of dental prostheses is important, so determining an appropriate disinfectant and the effective time for disinfection is necessary. The aim of this study was to evaluate of the disinfecting effect of 0.5% Sodium hypochlorite and 2% Glutaraldehyde on heat cure acrylic resin contaminated by two types of bacteria. In this experimental and In vitro study 90 acrylic resin samples, 6mmx17mm, were made using Acropars acrylic resin. The sterilized samples were divided into two groups. One group was exposed to a microbial suspension containing Streptococcus viridance and the other was exposed to a microbial suspension containing Bacillus subtilis. Two negative controls not contaminated with barteria were considered. Two samples from each group were used as the positive controls and were not disinfected. Each group was divided into two subgroups. The subgroups were immersed in either 2% glutaraldehyde or 0.5% sodium hypochlorite. After 30 min, 2h and 4h, seven samples were removed from each solution and transferred to individual tubes containing Brain Heart Inpusion [BHI] culture medium. The tubes were incubated for 24h at 37°C and then examined for turbidity. A sample of each tube was plated onto blood agar plate and the results were observed after 24h. Statistical analysis was made by Chi-Square tests [Fisher's exact test] and Kendalls tau-b. The difference between 3 time interval in all samples for hypochlorite solution [P=0.057] was not significant but it was significant for glutaraldehyde [P=0.021], Comparing 3 time intervals in the samples contaminated with Bacillus subtilis for hypochlorite solution [P=0.032] and glutaraldehyde [P=0.014] showed significant difference. The analysis was not made for Streptococcus viridance because all the results were negative. The difference between the disinfecting ability of the solutions after 30 min [P=1] and 2h [P=0.266] was not significant. The results indicate that both disinfecting solutions eliminated Streptococcus viridance after 30min but could not eliminate Bacillus subtilis until 4h immersion time. Within the number of the samples in this study there was no difference between the disinfecting ability of 0.5% sodium hypochlorite and 2% glutaraldehyde