Journal of Dental Research, Vol 69, 1261-1265, Copyright © 1990 by International & American Associations for Dental Research Online Journals
Assessment of loosely-bound and firmly-bound fluoride uptake by tooth enamel from topically applied fluoride treatments
B. Sieck, S. Takagi and L. C. Chow
American Dental Association Health Foundation, Paffenbarger Research Center, National Institute of Standards and Technology, Gaithersburg, Maryland 20899.
The amounts of loosely-bound fluoride (F) deposited on human enamel by two
topical F treatments were measured with use of a constant-composition F
washing method. Enamel biopsies conducted before treatment and after the
washing were used for determination of the firmly-bound F uptake. The
results showed that (1) the washing system did not remove F from untreated
enamel surface, (2) a four-minute application of an acidulated phosphate
fluoride (APF) gel deposited 27.2 (2.4) (mean, S.E.) micrograms of
loosely-bound F per cm2 of enamel surface and 186 (111) ppm of firmly-bound
F in the outer 10 microns of enamel, and (3) a four-minute application of a
pH-2.1 dicalcium phosphate dihydrate (DCPD)-forming solution followed by
APF produced 44.9 (3.1) micrograms/cm2 of loosely-bound F and 1280 (354)
ppm of firmly-bound F in the outer 10 microns of enamel. The results showed
that the DCPD pre-treatment effectively enhanced the enamel reactivity with
F, so that the DCPD-APF treated enamel acquired greater amounts of both
loosely-bound F and firmly-bound F than did samples treated with APF alone.
