Effects of fluoride, lithium, and strontium on intracellular polysaccharide accumulation in S. mutans and A. viscosus.

Fluoride (5 mg/l) consistently depressed the accumulation of intracellular iodophilic polysaccharides (IPS) in Streptococcus mutans strains BHT, FA-1, and GS-5 by over 90% and in Actinomyces viscosus strain RC-45 by over 50%. There was little further reduction in IPS content when fluoride was increased from 5 to 100 mg/l. Lithium (0 to 1 mg/l) neither enhanced nor inhibited IPS accumulation, nor did it modify the inhibitory effects of fluoride in three of the four strains tested. Strontium (0 to 100 mg/l) did not alter IPS accumulation in S. mutans GS-5 but decreased accumulation (less than 10%) in S. mutans FA-1 and BHT and significantly enhanced IPS accumulation in A. viscosus RC-45. Analysis of variance indicated no statistically significant interactions between fluoride and strontium, fluoride and lithium, or strontium and lithium.