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Efficacy of Microwave Disinfection on Moist and Dry Dental Stone Casts with Different Irradiation Times
Abstract
Objectives: Dental practice contains the use of instruments and multiuse items that should be sterilized or disinfected properly. The aim of the current study was to investigate the effect of microwave irradiation on dental stone cast disinfection in moist and dry condition.
Materials and Methods: In this in vitro study, 76 stone casts were prepared by a sterile method. The casts were contaminated by Pseudomonas aeruginosa (ATCC 9027), Staphylococcus aureus (ATCC 6538), Enterococcus faecalis (ATCC 29212) as well as Candida albicans (ATCC 10231). Half the samples were dried for two hours and the other half was studied while still moist. The samples were irradiated by a household microwave at 600 W for 3, 5 and 7 minutes. The microorganisms on the samples were extracted by immersion in tryptic soy broth and .001 ml of that was cultured in nutrient agar media, incubated overnight and counted and recorded as colony forming unit per milliliter (CFU/mL).
Results: The findings showed that microorganisms reduced to 4.87 logarithm of CFU/mL value on dental cast within seven minutes in comparison with positive control. Although microbial count reduction was observed as a result of exposure time increase, comparison between moist and dried samples showed no significant difference.
Conclusions: Seven-minute microwave irradiation at 600 W can effectively reduce the microbial load of dental stone casts. Wetting the casts does not seem to alter the efficacy of irradiation.
Keywords: Microwave Disinfection; Dental Stone Casts; Irradiation Times
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Mitchell DL, Hariri NM, Duncanson MG, Jacobsen NL, McCallum RE. Quantitative study of bacterial colonization of dental casts. The Journal of prosthetic dentistry. 1997;78(5):518-21.
Leung RL, Schonfeld SE. Gypsum casts as a potential source of microbial cross-contamination. J Prosthet Dent. 1983;49(2):210-1.
Chassot ALC, Poisl MIP, Samuel SMW. In vivo and in vitro evaluation of the efficacy of a peracetic acid-based disinfectant for decontamination of acrylic resins. Braz Dent J. 2006;17(2):117.
Wu G, Yu X, Gu Z. Ultrasonically nebulised electrolysed oxidising water: a promising new infection control programme for impressions, metals and gypsum casts used in dental hospitals. J Hosp Infect. 2008;68(4):348-54.
Taylor RL, Wright PS, Maryan C. Disinfection procedures: their effect on the dimensional accuracy and surface quality of irreversible hydrocolloid impression materials and gypsum casts. Dent Mater. 2002;18(2):103-10.
Owen C, Goolam R. Disinfection of impression materials to prevent viral cross contamination: a review and a protocol. Int J Prosthodont. 1993;6(5):480-94.
Kumar RN, Reddy SM, Karthigeyan S, Punithavathy R, Karthik KS, Manikandan R. The effect of repeated immersion of gypsum cast in sodium hypochlorite and glutaraldehyde on its physical properties: An in vitro study. J Pharm Bioallsci 2012;4:353-7
Sofou A, Larsen T, Fiehn NE, Öwall B. Contamination level of alginate impressions arriving at a dental laboratory. Clin Oral Investig. 2002;6(3):161-5.
Tate W, Goldschmidt M, Ward M, Grant R. Disinfection and sterilization of composite polishing instruments. Am J Dent. 1995;8(5):270-2.
Berg E, Nielsen O, Skaug N. High-level microwave disinfection of dental gypsum casts. Int J Prosthodont. 2005;18(6):520-5.
Rohrer M, Bulard R. Microwave sterilization. J Am Dent Assoc. 1985;110(2):194-8.
Consani R, Azevedo DD, Mesquita MF, Mendes WB, Saquy PC. Effect of repeated disinfections by microwave energy on the physical and mechanical properties of denture base acrylic resins. Braz Dent J. 2009;20(2):132-7.
Dovigo LN, Pavarina AC, Ribeiro DG, De Oliveira JA, Vergani CE, Machado AL. Microwave disinfection of complete dentures contaminated in vitro with selected bacteria. J Prosthodont. 2009;18(7):611-7.
Ribeiroa DG, Pavarina AC, Dovigoa LN, Spolidorio DMP, Giampaoloa ET, Vergania CE. Denture disinfection by microwave irradiation. A randomized clinical trial. .Journal of Dentistry 2009;37:666-72
Sanita PV, Vergani CE, Giampaolo ET, Pavarina AC, Machado AL. Growth of Candida species on complete dentures: effect of microwave disinfection. Mycoses. 2008;52(2):154-60.
Berg E, Nielsen O, Skaug N. Efficacy of high-level Microwave Disinfection of Dental gypsum casts: The effects of number and weight of casts. Int J Prosthodont. 2007;20(5):463-67.
Abass SM, Mahmood MA, Khalaf BS. Effect of microwave irradiation on disinfection, dimensional accuracy, and surface porosity of dental casts. Med J Dent. 2011;8(2):177-187
Bhat V, Shenoy K, Shetty S. Evaluation of efficacy of microwave oven irradiation in disinfection of patient derived dental cast. Int J Infect Control. 2012;8(3): doi: 10.3396/ijic.v8i3.027.12.
Luebke R, Chan K. Effect of microwave oven drying on surface hardness of dental gypsum products. J Prosthet Dent. 1985;54(3):431-7.
Tuncer N. Investigation on the compressive strength of several gypsum products dried by microwave oven with different programs. Int J Prosthodont. 1993;69(3):333-9.
Hersek N, Canay Ş, Akça K, Çiftçi Y. Tensile strength of type IV dental stones dried in a microwave oven. J Prosthet Dent. 2002;87(5):499-502.
Yap A, Yap SH, Teo J, Tay C, Ng K, Thean H. Microwave drying of high strength dental stone: effects on dimensional accuracy. Oper Dent. 2003;28(2):193-9.
Onizuka T, Kamimura N, Kajiwara H, Nakashima A, Suenaga K, Jimi T. Influence of boiling water treatment on surface roughness and surface microstructure of set gypsum (dental stone). Dent Mater J. 1995;14(2):245-50.
Fredrich EG, Philip LE. Microwave sterilization of Candida on underwear fabric. A preliminary report. J Reproduct Med 1988;33(5):421-2.
Tanaka Yi, Shoko Fujiwara S, Kataoka D, Takagaki T, Takano S et al. Warming and Sterilizing Towels by Microwave Irradiation. Yonago Acta medica 1998;41:83–88.
Najdovski L, Dragaš AZ, Kotnik V. The killing activity of microwaves on some non-sporogenic and sporogenic medically important bacterial strains. J Hosp Infect. 1991;19(4):239-47.
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