The sterilization effect of microwave irradiation in compare of sodium hypocholorite to disinfect the casts which are made of type III stone, which are infected by Pseudomonas aeroginosa and Staphylococcus aureus

Abstract

Transmission of microorganisms and cross-contamination is a serious risk in prosthodotics.1,2 The stone cast is a potential source of the transmission of infection between clinic and laboratory. Therefore to avoid the spreading of microbe, the sterilization and disinfection of casts has a special importance. Disinfection techniques of stone casts are categorized in two mean groups: chemical and physical methods. Because of some problems of chemical methods and based on results of microbiological studies, Microwave irradiation of stone casts can be a reliable alternative for chemical disinfection techniques. Methods and materials: The bullets which were made of type3 stone, were sank in microbial inoculum of Pseudomonas aeruginosa and Staphylococcus aureus individually . then from this prepared samples one group was sank in sodium hypochlorite at different concentration and time, and the other one was irradiated by microwave oven at different power levels and time. Next the disinfected samples were cultured and formed colonies were counted and the data was analyzed to compare antimicrobial effect of these two methods. Results: Microwave irradiation of all the specimens for 2-20 minutes at 300-600 W power level resulted in no growth for any microorganisms; furthermore, there was no growth in chemical disinfection at 0.06-0.5% concentrations of sodium hypochlorite after 2-3 minutes of immersion. Conclusion: Regarding to the findings, Because of some problems of chemical methods and based on results of microbiological studies, Microwave irradiation of stone casts can be a reliable alternative for chemical disinfection techniques.