Comparison between spray of 5.25% sodium hypochlorite and 1% virkon in disinfection of the type III dental stone casts contaminated with microbial strains (Pseudomonas aeroginosa, Staphylococcus aureus)

Abstract

There is a close contact between dental casts and impression materials as well as other items potentially contaminated by saliva and blood from a patientEs mouth. Consequently dental casts are one of the important items lead to cross-contamination. To interrupt the cross-contamination cycle, several methods have been applied so far, more dominantly chemical disinfection procedures either by immersion or surface spray methods. Virkon is a unique powder product for the safe and rapid disinfection of surfaces and equipment in a wide variety of situations. It is dissolved in water for use, providing a safe working solution with a faint lemon odour. The objective of the present study is to evaluate the antimicrobial activities of virkon 1% and hypochlorite 0.525% on dental casts made of type III dental stone using spraying method . Staphylococcus aureus and Pseudomonas aeroginosa as test organisms were used to contaminate the dental casts intentionally. Material and methods: Different concentrations of virkon and hypochlorite were prepared, using distilled water and then were sprayed on the surface of the dental casts contaminated with Staphylococcus aureus and Pseudomonas aeroginosa.Pour plate method was used to evaluate the antimicrobial efficacy of each solution. Microbiocidal effect (ME) was calculated according to log of control colony count values minus. log of remaining colony count after antimicrobial procedure. Results: Virkon showed total killing effect against gram positive Staphylococcus aureus in the concentrations (3%, 2%, 1%, 0/5%)as well as contact times ( 2 and 5 min) used in this study. Furthermore the results pertaining to the antimicrobial test of Virkon against gram negative Pseudomonas aeroginosa showed compele bactericididal effect (ME=6.69 or sterilization) in the concentration of 1% using our test procedure. Conclusion: According to our results Virkon can be considered as a bactericidal agent against both gram negative bacterim of Pseudomonas aeroginosa as well as gram positive bacterim of Staphylococcus aureus and based on its low toxicity and good enviromental compatibility, may be advised as a low level antimicrobial agent for dental stone casts as non-critical items.