[Uptake and release of fluoride in enamel surface after fluoridation]

After one single application of a sodium monofluorophosphate or sodium fluoride solution (1%) in an in vitro study, the incorporation of fluoride into enamel platelets was determined. Compared with sodium fluoride the increase in the fluoride concentration following the application of sodium monofluorophosphate was significantly lower, whereas the loss of fluoride after four weeks of rinsing with an artificial saliva solution was markedly reduced. The duration of fluoride incorporation may be one of the factors governing the clinical equivalence of both substances. To determine the amount of enamel in which the fluoride content was measured, the elements calcium and phosphor were determined with the aid of nuclear emission spectrometry and compared with photometric phosphate measurements. All three methods produced identical results.