title: Evaluation and comparison of high-level microwave oven disinfection with chemical disinfection of dental gypsum casts.
abstract: BACKGROUND
  The aim of this study was to evaluate and compare microwave disinfection with chemical disinfection of dental gypsum casts.
  
  
  METHODS
  A total of 120 casts were prepared from a silicone mold using Type III dental stone. Of the 120 casts, 60 casts were contaminated with 1 ml suspension of Staphylococcus aureus and 60 casts were contaminated with 1 ml suspension of Pseudomonas aeruginosa. Then, the casts were disinfected with microwave irradiation and chemical disinfection using the microwave oven and 0.5% sodium hypochlorite. Bacteriologic procedures were performed; the cfu/ml for each cast was calculated as a weighted mean. The results were analyzed using Kruskal-Wallis test and Mann-Whitney test.
  
  
  RESULTS
  The untreated casts showed Brain heart infusion broth counts of 106 log cfu/ml compared to irradiated and chemically disinfected casts, in which 105 log reduction of cfu/ml was seen. These results satisfied the requirements of current infection control guidelines for the dental laboratory. The results obtained for chemical disinfection were in equivalence with microwave disinfection.
  
  
  CONCLUSIONS
  Within the limitation of this in vitro study, it was found that microwave disinfection of casts for 5 min at 900 W gives high-level disinfection that complies with the current infection control guidelines for the dental laboratory and microwave disinfection method is an effective and validated method as chemical disinfection. How to cite the article: Meghashri K, Kumar P, Prasad DK, Hegde R. Evaluation and comparison of high-level microwave oven disinfection with chemical disinfection of dental gypsum casts. J Int Oral Health 2014;6(3):56-60 .
authors.affiliation: Department of Prosthodontics, Kurunji Venkatramana Gowda Dental College and Hospital, Sullia, Karnataka, India.
authors.forename: K
authors.initials: K
authors.lastname: Meghashri
authors.affiliation: Department of Oral and Maxillofacial Surgery, Kurunji Venkatramana Gowda Dental College and Hospital, Sullia, Karnataka, India.
authors.forename: Prasanna
authors.initials: P
authors.lastname: Kumar
authors.affiliation: Department of Prosthodontics A.B. Shetty Memorial Institute of Dental Sciences, Deralakatte, Mangalore, Karnataka, India.
authors.forename: D Krishna
authors.initials: DK
authors.lastname: Prasad
authors.affiliation: Department of Prosthodontics, A.B. Shetty Memorial Institute of Dental Sciences, Deralakatte, Mangalore, Karnataka, India.
authors.forename: Rakshit
authors.initials: R
authors.lastname: Hegde
keywords: Chemical disinfection; dental gypsum cast; microwave disinfection
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