Anti-biofilm activity of commercial toothpastes against Staphylococcus aureus

Abstract

OBJECTIVES: To investigate the anti-biofilm activities of chlorhexidine digluconate (Against24 Deep Clean), herbal (Dentiste’ Plus White), Oxychlor (Therabreath Fresh Breath), sodium chlorite (Periotherapy Healthy Gums), and standard sodium fluoride (Colgate Anticavity) toothpastes against S. aureus biofilms. METHODS: Standardized inocula of S. aureus ATCC 25923 were prepared and transferred to Immuno MaxiSorp 96-peg plates (Nunc). Plates were incubated for 48 hours to establish mature biofilms. The pegs were rinsed to remove loosely adherent planktonic cells, and positioned into 96-well plates containing toothpaste preparations. Neutralizers were added after one minute and five minutes of exposure. Toothpaste-free biofilm cultures were used as controls. A standard 2,3-bis(2-methoxy-4-nitro-5-sulfo-phenyl) -2H-tetrazolium-5-carboxanilide reduction assay was used for quantitative determination of S. aureus biofilm metabolic activity. RESULTS: The herbal toothpaste (sage extract, chamomile extract, fennel extract, Glycyrrhiza extract, cinnamon bark extract, peppermint oil, clove oil, menthol, eucalyptus oil, vitamin C, silicone dioxide, xylitol) exhibited significantly greater anti-biofilm activity (>60% reduction in biofilm metabolic activity; p≤0.001) than the other toothpastes at an exposure time of one minute, with the exception of the chlorhexidine digluconate toothpaste, for which there was no significant difference. Equivalent anti-biofilm effects (>80% reduction in biofilm metabolic activity) between the herbal and chlorhexidine toothpaste were also observed at a five minute exposure time, and these were significantly greater than those observed for the sodium fluoride (p<0.001), Oxychlor (p<0.001), and sodium chlorite (p<0.001) toothpastes. CONCLUSIONS: Among the tested toothpastes, the herbal and chlorhexidine toothpastes exhibited the greatest anti-biofilm activities. Neither toothpaste, however, demonstrated complete eradication of mature S. aureus biofilms at an extended exposure time of five minutes.