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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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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The effect of in vitro fluoride ion treatment on the ultrasonic properties of cortical bone
The mechanical properties of composites are influenced, in part, by the volume fraction, orientation, constituent mechanical properties, and interfacial bonding. Cortical bone tissue represents a short-fibered biological composite where the hydroxyapatite phase is embedded in an organic matrix composed of type I collagen and other noncollagenous proteins. Destructive mechanical testing
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Effects of different regimens of sodium fluoride treatment for osteoporosis on the structure, remodeling and mineralization of bone.
We compared initial and final bone histomorphometric findings in 66 osteoporotic patients treated with sodium fluoride (NaF) according to three regimens, and in 7 osteoporotic patients who did not receive NaF. Fourteen patients received continuous NaF 75 mg/day (high-dose) with calcium 1500 mg/day for a mean of 41 months. Twenty-six
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Effects of dialysate calcium and fluoride on bone disease during regular hemodialysis
A previous study indicated that, in patients maintained by hemodialysis, clinically and roentgenographically apparent bone disease appeared almost exclusively when the dialystate calcium concentration was less than 5.7 mg per 100 ml. In the present study, bone biopsy specimens from the iliac crest were studied at the beginning and end
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The role of ions and mineral-organic interfacial bonding on the compressive properties of cortical bone
Bone tissue is a composite material composed of an inorganic stiff mineral phase embedded in a compliant organic matrix. Similar to other composites, the mechanical properties of bone depend upon the properties, volume fraction, and orientation of its constituents as well as the bonding interactions. Interfacial bonding between the mineral
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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 & Rickets
One of fluoride's most well-defined effects on bone tissue is it's ability to increase the osteoid (unmineralized bone) content of bone. When bones have too much osteoid, they become soft and prone to fracture -- a condition known as osteomalacia. When osteomalacia develops during childhood, it is called "rickets." The potential for fluoride
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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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"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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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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