Abstract
This study examined the relationship between transient peak plasma fluoride levels (subcutaneous injections) as well as lower but relatively constant levels (subcutaneous constant infusion) and the occurrence of disturbances in the enamel mineralization of the rat incisor as determined microradiographically. The fluoride doses were administered for 1 week, and the animals were killed 2 weeks later. Once daily peak plasma fluoride levels of 10 µM were uniformly associated with disturbances in the mineralization of the enamel, but once daily peak levels of 5 µM were not. Neither were twice daily 5-µM peaks. Relatively constant plasma fluoride levels, which averaged 3.3 µM, were associated with an increased incidence of changes in enamel formation and levels of 4.7 µM consistently associated with disturbances in enamel mineralization. These findings suggest that (1) the rat is a better model for the study of human enamel fluorosis than previously believed, and (2) slightly elevated but relatively constant plasma fluoride levels are more likely to be associated with the occurrence of fluorotic disturbances in the mineralization of enamel than are the more rare high and transient peak levels.
*Abstract online at https://europepmc.org/article/MED/6956449
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Developmental and post-eruptive defects in molar enamel of free-ranging Eastern Grey kangaroos (Macropus giganteus) exposed to high environmental levels of fluoride
Dental fluorosis has recently been diagnosed in wild marsupials inhabiting a high-fluoride area in Victoria, Australia. Information on the histopathology of fluorotic marsupial enamel has thus far not been available. This study analyzed the developmental and post-eruptive defects in fluorotic molar enamel of eastern grey kangaroos (Macropus giganteus) from the
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Barrier formation: potential molecular mechanism of enamel fluorosis
Enamel fluorosis is an irreversible structural enamel defect following exposure to supraoptimal levels of fluoride during amelogenesis. We hypothesized that fluorosis is associated with excess release of protons during formation of hypermineralized lines in the mineralizing enamel matrix. We tested this concept by analyzing fluorotic enamel defects in wild-type mice
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Micromolar fluoride alters ameloblast lineage cells in vitro.
Fluorosed enamel is caused by exposure to fluoride during tooth formation. The objective of this study was to determine whether epithelial ameloblast-lineage cells, derived from the human enamel organ, are directly affected by micromolar concentrations of fluoride. Cells were cultured in the presence of fluoride, and proliferation was measured by
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Fluoride-induced ultrastructural changes in exocrine pancreas cells of rats: fluoride disrupts the export of zymogens from the rough endoplasmic reticulum (rER).
Influence of fluoride on exocrine pancreas cells was examined morphologically with traditional and prolonged osmium fixation techniques for electron microscopy in the enamel fluorosis model rats injected subcutaneously twice a day with 20 mg/kg body weight of sodium fluoride. Although the rough endoplasmic reticulum (rER) of exocrine pancreas cells in
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The effects of chronic high fluoride levels on forming enamel in the rat.
Sixty-gramme rats were given either 0, 75, 100 or 150 parts/10(6) fluoride in their drinking water. After five weeks, the fluoride, the phosphorus and the protein contents of the enamel were compared in control and experimental animals at three stages of enamel development. The mineral content was reduced in pigmented
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