Abstract
Fluoride stimulates trabecular bone formation, whereas bisphosphonates reduce bone resorption and turnover. Fracture prevention has not been convincingly demonstrated for either treatment so far. We compared the effects of 1-yr treatment of 9-mo-old minipigs with sodium fluoride (NaF, 2 mg/kg/d p.o.) or alendronate (ALN, 4 amino-1-hydroxybutylidene bisphosphonate monosodium, 1 mg/kg/d p.o.) on the biomechanical and histomorphometric properties of pig bones. As expected, NaF increased and ALN decreased bone turnover, but in these normal animals neither changed mean bone volume. NaF reduced the strength of cancellous bone from the L4 vertebra, relative to control animals, and the stiffness (resistance to deformation) of the femora, relative to the ALN group. In the ALN-treated animals, there was a strong positive correlation between bone strength and L5 cancellous bone volume, but no such correlation was observed in the NaF group. Furthermore, the modulus (resistance to deformation of the tissue) was inversely related to NaF content and there was a relative decrease in bone strength above 0.25 mg NaF/g bone. Moreover, within the range of changes measured in this study, there was an inverse correlation between bone turnover, estimated as the percentage of osteoid surface, and modulus. These findings have relevant implications regarding the use of these agents for osteoporosis therapy.
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Bone disease in hemodialysis patients with particular reference to the effect of fluoride
Forty-one patients on our chronic hemodialysis program were assessed for the degree of progression of bone disease over an average period of 46 months. Seven patients were using a fluoridated dialysate. Four of these seven patients developed a marked increase in osteoid as judged by bone biopsy, while in the
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Bone response to fluoride exposure is influenced by genetics
Genetic factors influence the effects of fluoride (F) on amelogenesis and bone homeostasis but the underlying molecular mechanisms remain undefined. A label-free proteomics approach was employed to identify and evaluate changes in bone protein expression in two mouse strains having different susceptibilities to develop dental fluorosis and to alter bone
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[Histomorphometric profile of bone fluorosis induced by prolonged ingestion of Vichy Saint-Yorre water. Comparison with bone fluorine levels].
Nine transiliac bone biopsies from 7 patients with skeletal fluorosis due to prolonged ingestion of often high quantities of Vichy Saint-Yorre water were analyzed. Four of these patients also suffered from a chronic renal failure. A histomorphometric study was possible in 8 out of the 9 biopsies. The measurement of bone fluoride
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Fluoride reduces bone strength in older rats
In response to recent concerns about the effect of water fluoridation on hip fracture rates, we studied the influence of fluoride intake on bone strength. Four groups of rats were fed a low-fluoride diet ad libitum and received 0, 5, 15, or 50 ppm of fluoride in their drinking water.
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Osteoporosis Treatments Affect Bone Matrix Maturation in a Rat Model of Induced Cortical Remodeling.
The example of sodium fluoride (NaF) clearly demonstrates an instance where increasing bone mass while altering maturation can negatively affect drug efficacy. NaF was a promising osteoporosis treatment because it increased BMD.5 However, it became evident that the treated patients were at increased risk of fracture,6, 7 which was later
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"Pre-Skeletal" Fluorosis
As demonstrated by the studies below, skeletal fluorosis may produce adverse symptoms, including arthritic pains, clinical osteoarthritis, gastrointestinal disturbances, and bone fragility, before the classic bone change of fluorosis (i.e., osteosclerosis in the spine and pelvis) is detectable by x-ray. Relying on x-rays, therefore, to diagnosis skeletal fluorosis will invariably fail to protect those individuals who are suffering from the pre-skeletal phase of the disease. Moreover, some individuals with clinical skeletal fluorosis will not develop an increase in bone density, let alone osteosclerosis, of the spine. Thus, relying on unusual increases in spinal bone density will under-detect the rate of skeletal fluoride poisoning in a population.
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Fluoride Exposure Increases Metabolic Requirement for Calcium & Vitamin D
It is well known that individuals with nutrient deficiencies are more susceptible to fluoride toxicity, including fluoride's bone effects. As discussed in the following studies, fluoride increases the skeleton's need for calcium (and vitamin D) by increasing the amount of unmineralized tissue (osteoid) in the bone. When insufficient calcium and
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Fluoride Reduces Bone Strength Prior to Onset of Skeletal Fluorosis
The majority of animal studies investigating fluoride's impact on bone strength have found that fluoride has either no effect, or a detrimental effect, on bone strength. Importantly, several of the animal studies that have found fluoride reductes bone strength have reported that this reduction in strength occurs before signs of skeletal fluorosis
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The Relationship Between Fluoride, Bone Density, and Bone Strength
Although fluoride has generally been found to reduce the bone density of cortical bone, it is well documented that fluoride can increase the density of trabecular bone (aka cancellous bone). Trabecular bone is the primary bone of the spine, whereas cortical bone is the primary bone of the legs and arms. While increases in
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In Vitro Studies on Fluoride & Bone Strength
The "in vitro" research on fluoride and bone strength confirms what has repeatedly been found in animal and human studies: the more fluoride a bone has, the weaker the bone becomes. In an in vitro bone study, the researcher directly exposes a human or animal bone to a fluoride solution
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