Journal of Dental Research, Vol 72, 1593-1598, Copyright © 1993 by International & American Associations for Dental Research Online Journals
Effect of intermittent delivery of fluoride to solution on root hard-tissue de- and remineralization measured by 125I absorptiometry
H. Almqvist and F. Lagerlof
Department of Cariology, Karolinska Institutet, School of Dentistry, Huddinge, Sweden.
The effect of intermittent fluoride levels on root hard-tissue de- and
remineralization was studied once daily for 21 days in a pH-cycling caries
model with simulated fluoride clearance curves. Four root hard-tissue
blocks, from each of 12 human teeth, were cut out parallel to the cementum
surface. During a daily 15-hour period, the blocks were subjected 12 times
to pH changes similar to those which occur in plaque after a carbohydrate
intake. The fluoride was delivered immediately before a daily nine-hour
remineralization period. Four experiments were independently carried out:
One block from each tooth was subjected to pH-cycling without and with
fluoride delivery, simulating a rinse with 0.025, 0.2, and 1.0% sodium
fluoride (NaF), respectively. The mineral change in the blocks was
monitored by 125I absorptiometry and expressed as the change in
transmission (delta T). The surface between the data points (delta T
values) and the x axis (time points) was used as a summary measure, i.e.,
the area under the curve (AUC). When no fluoride was delivered, the delta T
increased over 21 days, indicating loss of mineral. The AUC was, on
average, 5.85 +/- 0.68 (mean +/- S.E.) %.day. In the 0.025% NaF-rinse
experiment, there was a marked reduction in mineral loss, indicated by an
average AUC of 1.66 +/- 0.59%.day. In both the 0.2 and 1.0% NaF-rinse
experiments, a decrease in delta T, indicating gain of mineral, was
observed from day 2. Negative delta T values occurred after 7 and 3 days,
respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
