The effect of storage time and disinfection method on the activity of some dental stone disinfectants

Abstract EN

Background : It has been recommended that all materials returning from the laboratory be disinfected before placement in the patient’s mouth.

Various adverse reactions have been reported when using disinfectant solutions with impression materials.

Therefore, disinfection of dental cast may be effective in preventing cross infection.

This study was carried out to evaluate the effect of storage time on the antimicrobial activity of chlorhexidine, sodium hypochlorite, and madacide-1 solutions and to test the effect of spray, immersion and incorporation techniques on their activities.

Materials and Methods: Stone specimens were prepared in cylindrical blocks, under aseptic conditions, containing the three tested solutions applied by spray, immersion and incorporation methods.

These specimens were stored for (1½h, 1 day, 3days, 7days, and 10days) and then tested by using disk-diffusion plate method to estimate the release of disinfectant solutions against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa,and Candida albicans.

The zones of inhibition were measured with a ruler (in mm) after incubation, which was for 24h at 37°C aerobically.

Results : The results showed that all microorganisms were sensitive to chlorhexidine and sodium hypochlorite while E.coli and P.

aeruginosa were resistant to madacide.

Also it was shown that chlorhexidine was more effective than madacide and sodium hypochlorite as a long acting disinfectant while sodium hypochlorite was the most effective as a short acting one.

Conclusion : Immersion method had more inhibitory effect than the other methods representing (60 %) of all the tested specimens followed by incorporation method (25%) and the least percentage for spray method (15%).