Journal of Dental Research, Vol 63, 885-889, Copyright © 1984 by International & American Associations for Dental Research Online Journals
Experimental osteo-fluorosis in the domestic pig: a histomorphometric study of vertebral trabecular bone
J. Kragstrup, A. Richards and O. Fejerskov
The experiment aimed at describing effects of fluoride on structure and
remodeling of vertebral trabecular bone in pigs. Eight animals receiving a
supplement of 2 mg F-/kg b.w. per day from age eight to 14 mo were compared
with eight controls. Plasma fluoride increased from 0.7 +/- 0.1 microM/1 to
12.7 +/- 2.0 microM/1 in pigs receiving fluoride. At slaughter, the
concentration of fluoride in dry fat-free bone was 149.3 +/- 10.5 mM/kg for
fluorotic animals and 9.5 +/- 0.9 mM/kg for controls. Morphologic changes
were assessed in un-decalcified specimens of the fourth lumbar vertebra by
quantitative histology using fluorochromes as intra-vital tissue time
markers. The volume of trabecular bone tissue (bone + marrow) was unchanged
in fluorotic animals, but the volume density of bone was increased by 17%.
Surface densities of cancellous bone were almost unchanged, whereas the
thickness of trabeculae increased in fluorosis. Fluoride enhanced
remodeling of trabecular surfaces: The fraction of surface occupied by
resorption lacunae increased 40%, and the formative surface approximately
30%. No changes were demonstrated at surface points undergoing formation:
Osteoid thickness, calcification rate, lamellar thickness, and completed
wall thickness were normal. It is concluded that the observed findings
cannot be explained by fluoride-induced changes in a single cell. Fluoride
appears to affect all cells involved in remodeling by direct or indirect
mechanisms.
