In-vitro evaluation of the effect of nicotine, cotinine and caffeine on oral microorganisms / Avaliação in vitro do efeito da nicotina, cotinina e cafeina sobre microrganismos orais




There are significant evidences that subgingival accumulation of bacterial biofilm is the etiologic agent in periodontal diseases. Cigarette smoking might result in progression of periodontitis and in impaired response to periodontal therapy. Some studiesindicated a strong relationship between cigarette smoking and coffee drinking. However, the mechanisms by which smoking and coffee consumption affect the periodontium are not clear. The purpose of this in-vitro study was to evaluate the effects of nicotine, cotinine, and caffeine on the viability of some bacterial species from the oral microbiota. Single-species biofilms of Streptococcus gordonii, Porphyromonas gingivalis, and Fusobacterium nucleatum and dual-species biofilms of S. gordonii + F. nucleatum and F. nucleatum + P. gingivalis were grown on hydroxyapatite discs. Seven species were studied as planktonic cells, including Streptococcus oralis, Streptococcus mitis, Propionibacterium acnes, Actinomyces naeslundii, and the species mentioned above. Bacteria were incubated in either O or 0.37 to 400 µg/mL of nicotine, cotinine or caffeine for planktonic cells and O or 400 µg/mL for biofilm. The viability of planktonic cells and biofilms was analyzed by susceptibility tests and time-kill assays, respectively. "Susceptibility Tese showed that nicotine reduced the growth of S. gordonii (400 µg/mL) and S. oralis (0.37-400µg/mL); cotinine stimulated the growth of A. naeslundii (0.37 µg/mL) and F. nucleatum (0.37 -400 µg/mL) and reduced the growth of S. oralis (400 µg/mL), and caffeine stimulated the growth of F. nucleatum (400 µlg/mL). Results of "Killing Assays" showed an enhanced growth of F. nucleatum in single-species biofilm and a reduced viability of S. gordonii in single-species biofilm, 24 h and 48 h after exposure to cotinine and caffeine, respectively. These findings indicated that nicotine, cotinine and caffeine could slightly affect the growth and viability of some oral bacterial strains


crescimento bacteriano biofilme doença periodontal periodontal disease bacterial growth biofilms

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