RESUMEN
CONTEXT: Equisetum giganteum L. (Equisetaceae) is an endemic plant of Central and South America used in traditional medicine. Natural drugs have been frequently used in the treatment of a myriad of diseases, proving to be an alternative to synthetic chemicals, and have been intensively studied in the prevention of sicknesses, including oral diseases. OBJECTIVE: This study evaluated the in vitro antiadherent activity of E. giganteum extract against Candida albicans biofilms. MATERIALS AND METHODS: Crystal violet and colony-forming units assays were used to quantify the total biofilm biomass and biofilm living cells on a denture base acrylic resin pretreated with hydroethanolic extract of E. giganteum in different concentrations (50, 25, 16, 8, and 4 mg/mL), after 24 h of biofilm development. RESULTS: Equisetum giganteum affected biofilms by reduction of biomass and living cells per area of acrylic specimens. The results revealed reduction of 15-44% of the biofilm mass and reduction of numbers of colony-forming units (CFUs) present in biofilms (79%) compared to the untreated control (CTRL/PBS). At all concentrations, it demonstrated important antiadherent activity on Candida albicans biofilms, the main microbe in denture stomatitis. DISCUSSION AND CONCLUSION: The present findings show that E. giganteum antimicrobial effects may qualify the extract as a promising natural alternative for topical treatment or prevention of denture stomatitis. The usage of drugs made of natural products shows advantages in relation to synthetic drugs on the market, such as lower cost, lower toxicity, and in relation to the occurrence of microbial resistance.