Method: Standardised alginate blocks were fabricated and contaminated using suspensions of each of the following test organisms: Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus mutans and Bacillus subtilis spores. Contaminated blocks were either placed in 20ml sterile distilled water (control) or disinfected by immersion in 48ppm Aseptrol® solution (test blocks) for 30 seconds, one minute, three minutes and five minutes. Two hundred microlitres of skim milk had been added to the disinfectant as organic material. After disinfection, the test blocks were placed in sterile 20ml 0.5% sodium thiosulphate neutraliser solution to harvest surviving organisms. Samples from the control and test suspensions were plated on their respective media, incubated for 24 to 48 hours, and thereafter colony forming units (CFUs) were counted. Both counts were later used to quantify the percentage kill for each organism and exposure time.
Results: The results showed that 30-seconds immersion in solutions containing 48ppm Aseptrol®, consistently produced a 99.99% or greater reduction in CFUs of C. albicans, Staph. aureus, P. aeruginosa, and S. mutans. The same concentration of the disinfectant required 3 minutes to produce a 99.99% reduction of B. subtilis spores.
Conclusion: Aseptrol® is a promising disinfectant for impression materials, as immersion for 3 minutes is unlikely to cause any dimensional change. Further research is required to assess its effect, if any, on any surface quality of the resultant gypsum casts.
Supported in part by WayLo Trading CC