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F Feagin

Publications and source records attributed to F Feagin.

6 recordsLinked to original sources
PubMed1979

Effects of magnesium and fluoride on ion exchange and acid resistance of enamel.

Labial surfaces of bovine incisor enamel, after weak acid demineralization, were exposed for 24 h in solutions that contained trace levels of calcium as 45Ca, 0.4 mM NaF, and 1.0 mM MgCl2 at pH 7.0. The solutions approached saturation with apatites in the absence of NaF, and saturation with fluorapatites in the presence of NaF. NaF greatly increased the exchange of 45Ca. MgCl2 decreased 45Ca exchange, but had no effect on F- exchange in the surface minerals. MgCl2 decreased, while NaF increased the acid resistance of the exchanged surface minerals on later exposure to 10 mM acetic acid at pH 4.5. These results indicated that magnesium in oral fluids and tooth minerals may promote caries.

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PubMed1979

Fluoride action on acid resistance of unaltered human surface enamel.

Unaltered surface enamel of extracted human teeth was subjected to tests of resistance to dissolution in 10 mM acetic acid at pH 4.0 and 10 mM EDTA at pH 7.4 in a miniature continuous flow system. Fluoride in EDTA had no effect on enamel dissolution. Inclusion of 0.25, 0.50 and 5.0 mM NaF in the acid at pH 4.0 greatly increased the resistance of the enamel to dissolution. The 0.5 mM NaF in the acid almost instantly reduced enamel dissolution and the effect persisted through the 1 h experiments. These results suggested that the acid labile fluoride in plaque and tooth minerals may provide the primary beneficial effect of all types of enamel fluoridation.

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PubMed1977

The carbonate and fluoride in surfaces of remineralized enamel.

Analyses were made of samples of surface enamel collected before and after acid demineralization and after subsequent remineralization in solutions containing calcium and phosphate and various levels of bicarbonate and fluoride ions. Demineralization caused a preferential loss of carbonates. Remineralization was increased by both fluoride and bicarbonate ions. With no bicarbonate in the calcifying solution, 0.25 to 4.0 mM NaF increased mineral formation and thereby caused a relative reduction of its carbonate content. With 0.5 mM NaF (10 ppm F-) and 5, 15, and 25 mM HCO-3 in remineralizing solutions more carbonate was deposited than in the absence of NaF. Five and 15 mM HCO-3 increased, but 25 mM HCO-3 decreased, deposit of fluoride in enamel.

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