Inhibitory effect of sodium fluoride and clorhexidine on the growth of lactobacilli

AHUMADA MARIA,; WIESSE BIRGITT,; MARIA ELENA FÁTIMA NADER

CANADIAN JOURNAL OF MICROBIOLOGY

The National Research Council of Canada

Lugar: Otawa. Canadá; Año: 2005 vol. 51 p. 133 - 140

0008-4166

The accumulation of microorganisms in the dental plaque is related to the etiology of caries and periodontal disease, with high prevalence in the whole world. The prophylactic measures included the use of chemical agents as sodium fluoride (NaF) and chlorhexidine (CHX). Lactic acid bacteria are part of the normal microbiota of the oral cavity, without being defined yet their beneficial or detrimental effect. The present study was performed to determine the growth of some species of Lactobacillus at different concentrations of NaF and CHX. The strains were isolated from both healthy and non-healthy patients. Their growth parameters was evaluated by the application of Gompertz model to the experimental data of optical density (O.D.) as a measurement of growth. The degree of inhibition of the growth of all the lactobacilli studied was different, depending on each particular strain. 1mM NaF inhibited between 5 and 46%, at 5mM between 13 and 65% and at 20mM between 57 and 84%. CHX at higher concentrations (197 and 98mM) showed a complete inhibition of some of the strains. The significance of the results was evaluated by the application of a multivariate analysis, and also compared with the inhibition of  pathogenic Streptococcus mutans