Journal of Dental Research, Vol 66, 19-22, Copyright © 1987 by International & American Associations for Dental Research Online Journals
A comparison of the effects of continuous and periodic fluoride delivery on fluoride levels in plasma, enamel, and bones of nursing rats
C. R. Drinkard, T. G. Deaton and J. W. Bawden
The purpose of this study was to determine and compare the F levels in
plasma, enamel, and bones of nursing rat pups that received the same daily
dose of F by continuous or periodic delivery during enamel development. The
hypothesis was that F delivered continuously would result in enamel F
levels higher than those attained when F was delivered periodically. For
continuous delivery, copolymer devices (Southern Research Institute) that
provide slow release of F were implanted in the backs of four-day-old rat
pups. For periodic delivery, rat pups received F by intraperitoneal
injection or gastric intubation. The doses were 0.01, 0.02, or 0.04 mg
F/day. The rats were killed at 13 days of age, 24 hours after the last
periodic delivery. Plasma was collected, femur and calvaria bones were
removed, and enamel was scraped from developing first molars. Fluoride
assay was by the microdiffusion method of Taves, with a F electrode. For
the 0.02 mg F/day dose, plasma levels in control, implanted, injected, and
gastric-intubated rats were 0.004, 0.020, 0.011, and 0.009 ppm,
respectively. Enamel F levels were 1.1, 61.9, 54.0, and 42.3 ppm,
respectively. Femur F levels were 2.2, 81.2, 84.8, and 68.1 ppm,
respectively. Calvaria F levels were 2.5, 79.3, 80.1, and 67.9 ppm,
respectively. The results showed that there was no significant difference
in the enamel F levels or in the bone F levels in rat pups that received
continuous or periodic, by injection, delivery of F at the same daily
dose.(ABSTRACT TRUNCATED AT 250 WORDS)
