RESUMEN
PURPOSE: The efficacy of a propolis solution against denture biofilm was evaluated by means of an in vitro assessment and a cross-over randomized clinical trial. METHODS: Acrylic resin specimens were contaminated by Staphylococcus aureus, Streptococcus mutans, Escherichia coli, Candida albicans, Candida glabrata, Candida parapsilosis, immersed in a (A) propolis solution, (B) saline or (C) alkaline peroxide, applied onto Petri plates with culture medium and after incubation the number of colonies was counted. For the clinical trial, 30 complete denture wearers were randomly assigned to groups (A) propolis solution, and (B) saline, following one of the sequences (I)A/B or (II) B/A. After each intervention, biofilm was quantified by means of digital photos taken from the intaglio surface and a microbiological quantification of Candida spp. and mutans streptococci was conducted. RESULTS: Both propolis solution and alkaline peroxide reduced the microbial counts for S. mutans and C. albicans with significant and greater effect for group C (P< 0.05). However, no difference was found clinically between the interventions. The propolis solution showed an intermediate antimicrobial effect against S. mutans and C. albicans. Also, it did not exert an immediate effect on denture biofilm. CLINICAL SIGNIFICANCE: A commercially available propolis-based cleanser solution was evaluated in vitro and clinically for the treatment of denture stomatitis. Although an immediate effect on denture biofilm was not observed after a single application, It showed antimicrobial effect against S. mutans and C. albicans.