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| 4: J Dent Res. 1987 Nov;66(11):1658-62. |
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Comparison of the effects of fluoride and the ionophore
nigericin on acid production by Streptococcus mutans and the resultant in
vitro enamel demineralization.
Van Loveren C, Fielmich AM, Ten Brink B.
Department of Preventive Dentistry, University of Utrecht, Utrecht, The
Netherlands.
In an in vitro demineralization experiment with a plaque of S. mutans C180-2
over enamel, the effect of 0.5 mmol fluoride/L was compared with that of 10
nmol nigericin/L. Since the effects of both substances on the acid production
in a dense cell suspension were of the same magnitude, and since nigericin did
not affect the enamel solubility, the present demineralization experiment may
differentiate between the effect of fluoride on bacterial metabolism alone and
the combined effect of fluoride on both the bacterial metabolism and enamel
solubility. In our experiments, the effect on bacterial metabolism accounted
for 75% of the caries-inhibiting effect of fluoride. Microradiographic data
showed subsurface lesions in the control and nigericin group and a slight
surface-softening in the fluoride group. In addition, the effects of fluoride
and nigericin on the cellular internal pH during glycolysis were studied.
Analysis of these data suggested that glycolysis was inhibited when the
intracellular pH reached about pH 5.2, which supports the view that
acidification of the cell cytoplasm is a mechanism by which fluoride inhibits
glycolysis.
PMID: 10872402 [PubMed - indexed for MEDLINE]
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