Dentures' Biofilm Eradicated by CHG, Microwave Irradiation

Researchers in Brazil say that biofilms growing on dentures can be eradicated by a dip in CHG and by microwave irradiation. Methicillin-resistant Staphylococcus aureus (MRSA) biofilm on dentures can be aspirated, thus causing infections such as aspiration pneumonia. The researchers evaluated the efficacy of two disinfectant solutions and microwave irradiation in disinfecting complete dentures contaminated with MRSA.

The researchers contaminated 36 simulated complete dentures with MRSA and divided them into four equal groups: a positive control group consisting of dentures that were not disinfected; a group that soaked in 1 percent sodium hypochlorite for 10 minutes; a group that soaked in 2 percent chlorhexidine gluconate for 10 minutes; and a group that underwent microwave irradiation at 650 watts for three minutes. The authors quantified colony counts and evaluated the long-term effectiveness of disinfection.

All dentures from the control group showed substantial microbial growth on the plates (6.24 log(10) colony-forming units per milliliter). The researchers observed no evidence of microbial growth on plates of any disinfected dentures. After seven days' incubation, the researchers observed broth turbidity in all beakers containing the dentures disinfected with 1 percent sodium hypochlorite.

The researchers concluded that soaking in chlorhexidine gluconate solution and microwave irradiation resulted in complete disinfection of all dentures contaminated with MRSA in both the short and the long term. Soaking in sodium hypochlorite solution was effective only as a short-term disinfectant. They add that microwave irradiation and 2 percent chlorhexidine gluconate may have a disinfective application in dental offices and institutions in which denture wearers are treated, thus improving the longevity and quality of life of patients and reducing the burden of disease caused by MRSA.

Reference: Altieri KT, Sanitá PV, Machado AL, Giampaolo ET, Pavarina AC, Vergani CE.Effectiveness of two disinfectant solutions and microwave irradiation in disinfecting complete dentures contaminated with methicillin-resistant Staphylococcus aureus. J Am Dent Assoc. 2012 Mar;143(3):270-7.