Effect of application time of APF and NaF gels on microhardness and fluoride uptake of in vitro enamel caries
Delbem, A.C.B.; Cury, J.A.
American Journal of Dentistry 15(3): 169-172
2002
ISSN/ISBN: 0894-8275 PMID: 12469754 Document Number: 541254
To evaluate the effect of time of fluoride application gel, acidulated or neutral, on in vitro enamel resistance to demineralization and fluoride uptake. One hundred and ninety-two human enamel blocks were used in this study and 144 were treated with fluoride gel, acidulated or neutral, for 1 or 4 minutes. Ninety-six blocks treated with fluoride and 24 control blocks were submitted to a high cariogenic challenge. After the pH-cycling, enamel demineralization was assessed by surface and cross-sectional microhardness. Fluoride in the enamel blocks was also determined after removing an enamel layer by etching acid. Acidulated fluoride gel formed more fluoride in enamel than neutral gel (P<0.05), and it was also more efficient in reducing the demineralization of the enamel blocks submitted to a cariogenic challenge than the neutral one (P<0.05). It was found that the time of application was significant in terms of fluoride uptake, but it did not render the enamel more resistant to demineralization.