Journal of Dental Research, Vol 67, 447-449, Copyright © 1988 by International & American Associations for Dental Research Online Journals
Effects of inorganic orthophosphate and pyrophosphate on dissolution of calcium fluoride in water
F. Lagerlof, E. Saxegaard, P. Barkvoll and G. Rolla
NIOM, Scandinavian Institute of Dental Materials, Haslum, Norway.
Calcium and fluoride release from excess solid calcium fluoride was
monitored for 15-30 min in aqueous solutions containing various
concentrations of inorganic orthophosphate and pyrophosphate. Low
concentrations of these ions (1-10 mumol/L) considerably inhibited the rate
of dissolution of calcium fluoride. This inhibition was pH-dependent, being
reduced at pH values below 5. It is suggested that a reduced calcium
fluoride dissolution rate, in the presence of phosphate, can account for
the relatively slow loss of calcium fluoride from dental enamel observed in
recent clinical studies. It also appears that calcium fluoride coated with
phosphate may provide a pH-controlled slow release of fluoride that may be
of clinical significance and a major component of the cariostatic mechanism
of topically applied fluoride.
