Fluoride accumulation by oral microorganisms.

Ten laboratory strains of oral microorganisms and 17 recent clinical isolates were examined for their ability to concentrate fluoride from a 1 ppm (0.05 mM NaF( fluoride solution. The laboratory strains concentrated the ion from two- to six-fold over the surrounding media. Clinical isolates of Actinomyces concentrated the ion to similar levels to the laboratory strains of this organism; however, clinical isolates of Streptococcus mutans and S. sanguis concentrated the fluoride significantly less than any of the laboratory strains examined.