Remineralization in human premolars of different posteruptive age.

In human premolars with posteruptive ages varying from 6 months to 4 years demineralized enamel was remineralized for 3 days at 37 degrees C in a recalcifying medium containing 2 mM Ca2+, 1.2 mM phosphate, 0.05 mMF- and 150 mM NaCl (pH = 7). The Ca, P and Ca/P molar ratio of the mineral gained were determined at various distances from the enamel surface. Whereas, particularly at 30 micrometers from the surface remineralization was higher and more extensive in young demineralized enamel, no difference could be found in Ca/P molar ratio, suggesting precipitation of an apatitic mineral in both young and old demineralized human enamel. The probable nature of the precipitate is that of a fluoridated hydroxyapatite.