Antimicrobial Efficacy of Denture Cleansers Against Specific Microorganisms

Objectives: This in vitro study evaluated the antimicrobial efficacy of alkaline hypochlorite (0.20% and 0.10%) and Ricinus communis (8%) solutions against specific microorganisms.
Methods: Acrylic resin specimens (Lucitone 550; n=360) were obtained from square metal matrix (10 mm x 10mm x 2 mm) and were sterilized with microwave (650W, for 6 minutes), contaminated by eight microorganisms (Staphylococcus aureus - Sa, Pseudomonas aeruginosa - Pa, Candida albicans - Ca, Bacilus subtilis - Bs, Escherichia coli - Ec, Streptococcus mutans - Sm, Enterococcus faecalis – Ef and Candida glabrata - Cg) and immersed (20 minutes) in the solutions (n=10): HS1: 0.10% Sodium Hypochlorite; HS2: 0.20% Sodium hypochlorite; RC: 8% Ricinus communis; PC (Positive Control):Saline; NC (Negative Control): no contamination and immersed in saline (n=5). The specimens were washed in saline solution and immersed in Letheen broth. Dilutions were obtained, seeded into selective solid medium and incubated (98,6 F/24 hours).The colonies were counted. Data were transformed by the formula log10 and statistically analyzed using the Student t (α= 0.05) (Ca, Pa, Sm, and Ef) and Mann Whitneytests (α= 0.05) (Cg, Ec and Sa).
Results: The results showed that HS1 and HS2 eliminated completely all microorganisms. For RC it was observed a complete elimination ofBacillus subtilis and a significant difference in the CFU counts for Pa (p = 0.003), Sm (p = 0.026),Ef (p <0.001), Cg (p <0.001); Ec (p = 0.002) and Sa (p <0.001) as well as no action against Candida albicans (p=0,109),when compared to PC.
Conclusions: It was concluded that the solutions may control the biofilm, once HS1 and HS2 eliminated all evaluated microorganisms and RC showed moderate antimicrobial action against S. aureus, S. mutans, E. faecalis, E. coli, P. aeruginosa and C. glabrata and effective action against B. subtilis. Grant: 303002/2012-3