Author(s): Fina Navi, Mohammad Hosein Kalantar Motamedi, Fariba Fayaz, Morteza Shabani and Amin Shams
Background and aim: Dentists and healthcare workers are commonly in contact with microorganisms present in blood and saliva which may potentially transfer infectious diseases. Use of methods to remove and or decrease the number of contaminants on instruments and tabletops are of paramount importance. Important properties of a good disinfectant aside from the ability to kill microbes include being safe, noncorrosive or damaging to instruments, odorless, colorless, economical and eco-friendly. This study was done to assess effectiveness and longevity of 2% hydrogen peroxide-silver for disinfection.
Materials and methods: Using sterilized physiological serum a spore suspension of Bacillus subtilis of 1×10 cfu/ ml was prepared on McFarland standard media. A sterilized capped tube was used for preparation of the suspension; 2 ml of a newly opened bottle of 2% hydrogen peroxide silver was poured in the test tube using a sterilized pipette and the tube was recapped. Then, 1 ml of the spore suspension was added to the test tube (test group).On the first day eight cultures were taken (at 30’, 60’, 120’, 180’, 240’, 300’, 360’ and 420’) and repeated twice each time. Also the same number of cultures was taken from the suspension at all the aforementioned time points without addition of hydrogen peroxide silver (control group). Then the samples were transferred to the culture medium after the required time points elapsed. All cultures were placed in the incubator for 24 hours at 37°C and assessed for growth. This procedure was the repeated using the same batch of 2%hydrogen peroxide silver until it was no longer effective on the organism.
Results: The batch of 2% hydrogen peroxide silver re-opened daily was effective on Bacillus subtilis up to 4 days of repeated daily use after contact for 180 min. There was no effect on day 4. All controls showed viability and growth of Bacillus subtilis.
Conclusion: Instruments should be soaked in 2% hydrogen peroxide –silver for at least 3 hours before being sterilized in an autoclave; 2% hydrogen peroxide silver will not disinfect after 3 days of use. A fresh bottle should be used daily for greater guarantee of disinfection.
