Abstract
Fluoride from fluoridated water accumulates not only in the enamel of teeth but also in the skeleton. The effects of fluoridated water on the skeleton are not well understood, yet there is some evidence that fluoridated water consumption increases the incidence of fractures. In the present study, femoral bending strength was measured in rats on fluoride intakes that ranged from low levels to levels well above natural high fluoride drinking water. Bone strength followed a biphasic relationship with bone fluoride content. Fluoride had a positive effect on bone strength for lower fluoride intakes and a negative influence on bone strength for higher fluoride intakes. The vertebral fluoride content at which femoral strength was maximum was between 1,100 and 1,500 ppm. The increase in femoral strength at this fluoride level was not accompanied by an increase in femoral bone density. The optimal fluoride content is within the range of bone fluoride contents found in persons living in regions with fluoridated water (1 ppm) for greater than 10 years.
NOTE from FAN: In subsequent studies, Turner was unable to duplicate the beneficial effects on bone strength which he found at low doses in this study. As Turner noted in a more extensive, follow-up study: “the present results showed no evidence of increased bone strength resulting from fluoride levels below 16 ppm.” – Ref: J Dent Res; 1995; Vol 74: 1475-81.
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Effects of estrogen on bone composition in rats at low and high fluoride intake
Bone examinations were carried out on female rats which had received estradiol benzoate and drinking water containing either 0.55 or 50 ppm of fluoride (F). The estradiol benzoate was injected subcutaneously twice weekly and the rats were killed after 2, 4 and 6 weeks. The results showed that estrogen treatment
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On fluoride and bone strength
The recent paper by Einhorn et al. [1] drew the conclusion that fluoride incorporation into bone does not impair bone's mechanical properties. This result is in conflict with the results of others concerning fluoride and bone strength. For instance, several investigators--including ourselves--have shown that bone strength decreases as bone fluoride
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Correlation between longitudinal, circumferential, and radial moduli in cortical bone: effect of mineral content
Previous studies indicate that changes in the longitudinal elastic properties of bone due to changes in mineral content are related to the longitudinal strength of bone tissue. Changes in mineral content are expected to affect bone tissue mechanical properties along all directions, albeit to different extents. However, changes in tissue
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Combined effects of diets with reduced calcium and phosphate and increased fluoride intake on vertebral bone strength and histology in rats
Ingested fluoride is incorporated into bone apatite and can affect the structural integrity of bone. Fluoride absorption in the gut and incorporation into bone is affected by the presence of other ions, including calcium. We hypothesized that a low calcium phosphate diet combined with high fluoride intake would have independent
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Compressive properties of cortical bone: mineral-organic interfacial bonding
Bone tissue is an anisotropic non-homogeneous composite material composed of inorganic, bone mineral fibres (hydroxyapatite) embedded in an organic matrix (type I collagen and non-collagenous proteins). Factors contributing to the overall mechanical behaviour include constituent volume fraction, mechanical properties, orientation and interfacial bonding interactions. Interfacial bonding between the mineral and
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Skeletal Fluorosis: The Misdiagnosis Problem
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Mechanisms by which fluoride may reduce bone strength
Based on a large body of animal and human research, it is now known that fluoride ingestion can reduce bone strength and increase the rate of fracture. There are several plausible mechanisms by which fluoride can reduce bone strength. As discussed below, these mechanisms include: Reduction in Cortical Bone Density De-bonding of
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Fluoride & Osteoarthritis
While the osteoarthritic effects that occurred from fluoride exposure were once considered to be limited to those with skeletal fluorosis, recent research shows that fluoride can cause osteoarthritis in the absence of traditionally defined fluorosis. Conventional methods used for detecting skeletal fluorosis, therefore, will fail to detect the full range of people suffering from fluoride-induced osteoarthritis.
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"Pre-Skeletal" Fluorosis
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Fluoride Reduces Bone Strength Prior to Onset of Skeletal Fluorosis
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