Evaluation of the Efficacy of Chemical Disinfectants for Disinfection of Heat-polymerised Acrylic Resin

Objective: This study evaluated the efficacy of disinfectants on the internal aspect of heat-polymerised acrylic resin contaminated with microbial strains.

Background: Dentures absorb oral fluids and become contaminated by different microorganisms.

Methods: Two hundred and fifty rectangular specimens were made of heat-polymerised acrylic resin, and then divided into five groups corresponding to the microbial strains (Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, S. mutans and Enterococcus faecalis). After contamination, the specimens were immersed in 1 and 2% sodium hypochlorite and 2% glutaraldehyde for periods of 5, 10 and 15 min. The specimens were placed into tubes containing different broths and incubated at 35°C and then visually analysed. Turbidity in the medium indicated microbial growth. The Fisher's exact test was used in the analysis of the results.

Results: The strain E. faecalis was the most resistant to the disinfectant solutions, and among them, glutaraldehyde was more effective than 2 and 1% hypochlorite for disinfection for 5 min; in the 10-min period there were no differences between the disinfectants. In 15 min of immersion, 1% hypochlorite and glutaraldehyde were more effective than 2% hypochlorite.

Conclusions: Disinfection for 10 min with 1% hypochlorite and glutaraldehyde is effective in disinfecting the internal aspect of heat-polymerised acrylic resin.