Abstract

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 were used to study these fracture surfaces during various chemical treatments. Significant topographical changes were observed following exposure to aqueous solutions of ethylenediaminetetraacetic acid (EDTA) or highly concentrated sodium fluoride (NaF). Both treatments resulted in the apparent loss of the hydroxyapatite mineral platelets on a timescale of a few seconds. Collagen fibrils situated beneath the overlying mineral platelets were clearly exposed and could be resolved with high spatial resolution in the acquired AFM images. Time-dependent mass loss experiments revealed that the applied agents (NaF or EDTA) had very different resulting effects. Despite the fact that the two treatments exhibited nearly identical results following examination by AFM, bulk bone samples treated with EDTA exhibited a ~70% mass loss after 72 h, whereas for the NaF-treated samples, the mass loss was only of the order of ~10%. These results support those obtained from previous mechanical testing experiments, suggesting that enhanced formation of superficial fluoroapatite dramatically weakens the protein-hydroxyapatite interfaces. Additionally, we discovered that treatment with aqueous solutions of NaF resulted in the effective extraction of noncollagenous proteins from bone powder.

• Related Studies :

  • 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

  • Varying the mechanical properties of bone tissue by changing the amount of its structurally effective bone mineral content

    The effect of fluoride ions on the mechanical properties of bone tissue in tension was investigated with an in vitro model. Structurally effective Bone Mineral Content (BMC) of bovine bone tissue was changed by fluoride ion treatment. First, bovine cortical bone specimens were treated with a detergent solution in order

  • 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

  • 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

  • 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

• Related FAN Content :

  • 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

  • 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

  • "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.

  • 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

  • Skeletal Fluorosis: The Misdiagnosis Problem

    It is a virtual certainty that there are individuals in the general population unknowingly suffering from some form of skeletal fluorosis as a result of a doctor's failure to consider fluoride as a cause of their symptoms. Proof that this is the case can be found in the following case reports of skeletal fluorosis written by doctors in the U.S. and other western countries. As can be seen, a consistent feature of these reports is that fluorosis patients--even those with crippling skeletal fluorosis--are misdiagnosed for years by multiple teams of doctors who routinely fail to consider fluoride as a possible cause of their disease.