Journal of Dental Research, Vol 65, 30-33, Copyright © 1986 by International & American Associations for Dental Research Online Journals
Inhibition of acid production from oral bacteria by fluorapatite-derived fluoride
D. S. Harper and W. J. Loesche
The inhibitory effect of fluorapatite (FAP)-derived fluoride upon resting
cell suspensions of Streptococcus mutans incubated at pH 4.5 and 6.5 was
studied using lactic acid production from 0.1% sucrose as an indicator of
fermentation activity. Cells incubated with FAP produced significantly less
lactic acid than did cells incubated with hydroxyapatite (HAP). Addition of
HAP to cell suspensions containing FAP reduced this inhibition, suggesting
that dissolution of the FAP was necessary for inhibition. Incubation with
low concentrations of NaF showed significant inhibition in cell suspensions
incubated with as little as 0.45 micrograms/mL F at pH 5.0. These results
provide further support to the hypothesis that fluoride levels in plaque
and enamel, achievable through use of fluoridated water and/or fluoride
dentifrices, may produce appreciable inhibition of glycolysis at the acidic
pH levels which are readily achieved in plaque. Thus, bacterial acid
production may activate plaque and enamel-bound fluoride, resulting in
inhibition of further acid production, and thereby contribute substantially
to the other cariostatic mechanisms of fluoride.
