The comparative investigation of the microbiological effectiveness of spray disinfectants used for impression material disinfection on different microorganisms

2.SUMMARY THK COMPARATIVE INVESTIGATION OF THE MICROBIOLOGICAL EFFECTIVENESS OF SPRAY DISINFECTANTS USED FOR IMPRESSION MATERIAL DISINFECTION ON DIFFERENT MICROORGANISMS Infection control in dentistry focuses on the prevention of cross-contamination among patients, dentists and dental personnel. Difficulties in sterilizing impression materials have led to chemical disinfection as an alternative. This study demonstrates the potential for cross contamination with microorganisms from impression materials and evaluates the efficacy of spray disinfection on dental impressions contaminated with Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Candida albicans. Impressions of typodont were made of contaminated acrylic resin models with a miccobial suspension (approximately 107cfu/ml) and then rinsed in running tap water for 15 seconds, sprayed, stored in sealed plastic bags for 15 minutes and then rinsed in running tap water again to remove access disinfectant. Samples were taken from each impression with sterile cotton applicators and plated on convenience mediums and incubated at 37°C for 24 hours. At the end of the incubation period colony counts were taken to determine the efficacy of the disinfectants used to remove the contamination. It was shown that sodium hypochlorite spray was the most effective in decontaminating the impressions whilst the control group showed high levels of microbial growth. Moreover, alginate appeared to carry significantly higher numbers of bacteria than other impression materials.