Disinfection of impression materials: an evaluation of products and procedures

Purpose: The purpose of this study was to evaluate the antimicrobial properties of 6 commercially available disinfectants and their efficacy for bacterial removal from dental impression materials. Methods: Using Dentaforms and three impression materials (Impregum, Jeltrate Plus and Affinis), quadrant dental impressions were taken (n=780). The impressions were then contaminated with human saliva for 5 minutes, and disinfected by either a spray or immersion technique using the following disinfectants: Birex, Cavicide, Biocide, Cidex Plus, Sanitex Plus and ProEz. The impressions were allowed to sit at room temperature for 2, 5, 7, 10, 15, 30, 60 or 120 minutes and then rinsed with tap water for 1, 5, 7, 10, or 30 minutes. Samples were taken from each impression with sterile cotton applicators and plated on blood agar plates and incubated at 35°C for 24, 48, or 72 hours. At the end of the incubation period, colony counts were taken with a Bel-Art Colony Counter to determine the efficacy of the various solutions and protocols used to remove the contamination introduced by human saliva. Results: The protocol for both spray and immersion techniques demonstrated that the Jeltrate Plus, because of its added antimicrobial properties, showed no growth after contamination. Significant growth was determined (colony counts >100) for Impregum and Affinis after being disinfected with several of the tested products. Impregum and Affinis showed limited growth (colony counts <100) with the disinfectant Cidex Plus and Sanitex Plus for both the spray and immersion techniques. Conclusion: Under the test conditions, Jeltrate Plus was the only impression material that showed no growth in both techniques and with all disinfectant products. Impregum showed the best results with the immersion technique using Cidex Plus and Sanitex Plus. Affinis proved to be best disinfected with Cidex Plus and Sanitex Plus in both the spray and immersion techniques.