Karen Tereza Altieri - Faculdade de Odontologia - Unesp

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(quantification of viable cells and XTT reduction method). For quantification
procedures, aliquots of suspensions were plated at dilutions (10 -3 to 10 -6 for PC
and 10 0 to 10 -3 for experimental groups) and incubated (37 °C/48 h). Colonies
counts (cfu/mL) were quantified. Dentures disinfected were also incubated at
37 °C for 7 days to verify the long-term effectiveness of disinfection. The viability
of cells in each group of specimens was evaluated by XTT reduction method. The
results showed that all dentures and specimens from the PC groups showed
substantial microbial growth. No evidence of microbial growth was observed on
plates of all disinfected dentures. After 7 days incubation, broth turbidity was
observed in all beakers containing the dentures disinfected by 1 % sodium
hypochlorite. In XTT assay, no evidence of microbial growth was observed in all
disinfected circular specimens. It was concluded that soaking in 1 % sodium
hypochlorite solution was effective for a short-term disinfection of dentures
contaminated with MRSA. Soaking in 2 % chlorhexidine gluconate solution for
10 min and microwave irradiation for 3 min at 650 W showed complete
disinfection of all dentures and circular specimens contaminated with MRSA.
From the present investigation, it can be concluded that microwave irradiation
and 2 % chlorhexidine gluconate are effective in inactivating MRSA present in
denture biofilms.
Key Words: Methicillin-resistant Staphylococcus aureus; disinfection;
disinfectants; microwaves; denture, complete.