Antimicrobial Action of Hypochlorite and Ricinus Communis Solutions

Objectives: This study evaluated, by in vitro and clinical assays, the antimicrobial action of sodium hypochlorite (SH) and Ricinus communis (RC) solutions against specific microorganisms.
Methods: Acrylic resin specimens were contaminated with Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, Bacillus subtilis, Escherichia coli, Streptococcus mutans, Enterococcus faecalis and Candida glabrata) and immersed (n=10; 20 minutes) in the following solutions: A: 0.25% SH; B: 0.5% SH; C: 10% RC and D: saline (Positive Control). Then, they were immersed in Letheen medium and the aliquots (50 uL) of the dilutions (10º to 10^-3) were seeded into appropriate selective media. In clinical assay, 64 complete denture wearers were instructed to brush their dentures and to soak them (20 minutes), once a day, in the above mentioned solutions. According to a randomized sequence, each solution was used for 7 days. For biofilm collection,the internal surfaces of upper dentures were brushed (saline) and the suspensions were collected. After dilutions (10⁰ to 10^-3), the aliquots (50 uL) were seeded into Streptococcus mutans, Candida spp. and gram negative appropriate selective media. In both assays, after incubation, the colonies were counted andthe CFU/mL calculated. Data were processed [log10 (CFU +1)] and statistically analyzed byStudent t (in vitro assay) (α=0.05), Friedman and Bonferroni tests (clinical assay) (α=0.05).
Results: In in vitro assay, SH (0.25% and 0.5%) eliminated all microorganisms; 10% RC eliminated B. subtilis, but had no effect on E. faecalis and showed moderate action against other strains (p <0.05). In clinical assay, there was significant difference between solutions (P <0.001); 0.5% SH had effective actionon all evaluated microorganisms and 0.25% SH and RC solutions had effective action on S. mutans and moderate on Candida spp..
Conclusions: 0.5% sodium hypochlorite was the most effective solution and may be useful as cleanser solution for complete dentures.