Abstract
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 has revealed that fluoride ion treatment significantly lowers the Z-axis tensile and compressive properties of cortical bone through a constituent interfacial debonding mechanism. The present ultrasonic data indicates that fluoride ion treatment significantly alters the longitudinal velocity in the Z-axis as well as the circumferential and radial axes of cortical bone. This suggests that the distribution of constituents and interfacial bonding amongst them may contribute to the anisotropic nature of bone tissue.
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The effect of fluoride treatment on bone mineral in rabbits
Fluoride therapy has been used clinically for many years, but its use remains controversial and many basic questions remain unanswered. Accordingly, this study returns to an animal model to study the effects of high doses of fluoride on bone mineral in rabbits. Twelve rabbits, aged 3(1/2) months at the start
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In situ observation of fluoride-ion-induced hydroxyapatite-collagen detachment on bone fracture surfaces by atomic force microscopy
The topography of freshly fractured bovine and human bone surfaces was determined by the use of atomic force microscopy (AFM). Fracture surfaces from both kinds of samples exhibited complex landscapes formed by hydroxyapatite mineral platelets with lateral dimensions ranging from ~90 nm × 60 nm to ~20 nm × 20 nm. Novel AFM techniques
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Fluoride ion effect on interfacial bonding and mechanical properties of bone
The mechanical properties of composite material (such as bone) rely on the properties of its constituents as well as the interfacial bonding between them. Bone tissue is a porous mineralized matrix composite of inorganic bone mineral and organic constituents (collagen and non-collagenous proteins). The porosity of bone is due in
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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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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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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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Skeletal Fluorosis Causes Bones to be Brittle & Prone to Fracture
It has been known since as the early as the 1930s that patients with skeletal fluorosis have bone that is more brittle and prone to fracture. More recently, however, researchers have found that fluoride can reduce bone strength before the onset of skeletal fluorosis. Included below are some of the
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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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"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 Reduces Bone Strength in Animals
Most animal studies investigating how fluoride effects bone strength have found either a detrimental effect, or no effect. Few animal studies have found a beneficial effect. In fact, one of the few studies that found a beneficial effect was unable to be repeated by the same authors in a later
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