Minerals of bones and teeth

Calcium Mineralization of bone and teeth synaptic transmission muscle contraction blood clotting Men women 1000 mg/d... 

Crystalline hydroxyapatites are the major mineral of bones and teeth in a matrix of the protein collagen. The hydroxyls reside in chaimels running along the crystal c-axis which provide easy access to the external environment. Hydroxyapatites in vivo are usually described as poorly crystalline, calcium deficient and containing carbonate substitutions. The carbonate substitutions can occur at both the hydroxyl and the phosphate... 

The action of vitamin D in human and animal organisms is primarily related to calcium metabolism and the mineralization of bones and teeth, although the mechanism of these processes has not yet been unequivocally confirmed. The cooperation of vitamins A and K is necessary for the proper functioning of vitamin... 

The most obvious requirement for calcium in the body is in the mineral of bones and teeth — a complex mixture of calcium carbonates and phosphates (hydroxyapatite) together with magnesium salts and fluorides. An adult has about 1.2 kg of calcium in the body, 99% of which is in the skeleton and teeth. This means that calcium requirements are especially high in times of rapid growth — during infancy and adolescence, and in pregnancy and lactation. 

Up to this point, we have focused on aqueous equilibria involving proton transfer. Now we apply the same principles to the equilibrium that exists between a solid salt and its dissolved ions in a saturated solution. We can use the equilibrium constant for the dissolution of a substance to predict the solubility of a salt and to control precipitate formation. These methods are used in the laboratory to separate and analyze mixtures of salts. They also have important practical applications in municipal wastewater treatment, the extraction of minerals from seawater, the formation and loss of bones and teeth, and the global carbon cycle. 

Concentrations of Na", C, and Cl in body fluids, and the physiological variables dependent on these (e. g. blood pressure), are subject to strict regulation. The principal site of action of the hormones involved is the kidneys, where hormones increase or reduce the resorption of ions and recovery of water (see pp. 326-331). The concentrations of Ca and phosphate, which form the mineral substance of bone and teeth, are also precisely regulated. 

Ninety five percent of the phosphorus on Earth belongs to the minerals of the apatite group. Apatites are inorganic constituents of bones and teeth of vertebrate and man, as well as a basis of many pathologic sohd formations. Minerals of the apatite group are the main raw materials in the production of phosphorus fertilizers, fodder and technical phosphates, elementary phosphorus, and phosphor-organic compounds. The mineral is sometimes substantially enriched in rare-earth elements (REE) making their extraction possible (Altshuller 1980). 

Biological issues (i) Mg bioavailabihty, metabolism and physiology . (ii) Cell proliferation and differentiation , (iii) Animal husbandry. (iv) Magnesium in blood . (v) Genetic regulation , (vi) Mineral phase composition of bone and teeth . (vii) Brain and nervous system , (viii) Renal handling of magnesium . 

The insoluble Ca(II) salts of weak acids, such as calcium phosphate, carbonate, and oxalate, serve as the hard structural material in bone, dentine, enamel, shells, etc. About 99% of the calcium found in the human body appears in mineral form in the bones and teeth. Calcium accounts for approximately 2% of body weight (18,19). The mineral in bones and teeth is mosdy hydroxyapatite [1306-06-5] having unit cell composition Ca10(PO4)6(OH)2. The mineralization process in bone follows prior protein matrix formation. A calcium pumping mechanism raises the concentrations of Ca(II) and phosphate within bone cells to the level of supersaturation. Granules of amorphous calcium phosphate precipitate and are released to the outside of the bone cell. There the amorphous calcium phosphate, which may make up as much as 30—40% of the mineral in adult bone, is recrystallized to crystallites of hydroxyapatite preferentially at bone collagen sites. These small crystallites do not exceed 10 nm in diameter (20). 

Archaeological fragments of bones and teeth take up fluorine from the surrounding soil and accumulate it in their mineral phase when they are exposed to a humid environment. Geological time spans are needed for this process to reach equilibrium and for the fluorine distribution to become uniform. In cortical parts of long bone diaphysis, an initially U-shaped fluorine concentration profile can be observed, which decreases from the outer surface and the marrow cavity towards the inner parts of the bone and carries information on the exposure duration of the buried object in its shape. The time dependence of the profile slope is usually described in a simplified way by a diffusion model. The quantitative mathematical evaluation of these profiles may provide information on the exposure duration and the physical condition of the samples. Therefore, several attempts to use fluorine profiling as a dating method have been undertaken [3,39], The distribution of... 

Few groups have dealt with the problem of ageing of bones and teeth. It is known that with time many physical and chemical properties of bones and teeth mineral components undergo different changes. Kuhn et al.131 employed 31P SS NMR to study the FIPO4 groups of young and old cancellous and cortical bovine bones. From these data, it was apparent that calcium phosphate in the form of carbonated apatite is the only bone mineral component. 

Minerals include sodium, potassium, calcium, phosphorus, magnesium, manganese, sulphur, cobalt and chlorine trace minerals include iron, zinc, copper, selenium, iodine, fluorine and chromium. Their roles may be generalised within the areas of providing structure in the formation of bones and teeth, maintenance of normal heart rhythm, muscle contractility, neural conductivity, acid-base balance and the regulation of cellular metabolism through their activ-ity/structural associations with enzymes and hormones. The daily requirements of minerals can be obtained from a well-balanced diet. 

Fluorine occurs in nature in minerals such as fluorite, Cap2 fluor-apatite, Ca.(PO )3F, which is a constituent of bones and teeth and cryolite, Na3AlF<. and in small quantities in sea water. Its name fluorine, from Latin finere, to flow, refers to the use of fluorite as a flux (a material which forms a melt with metal oxides). 

CALCIUM The most abundant of the body s minerals an important component of bones and teeth important participant in regulation of many metabolic processes. When bound to the regulatory protein calmodulin, calcium helps modulate the activities of many enzymes. Calcium is important for blood clotting, neural and muscular activity, cell motility, hormone actions, and other activities. 

Certain minerals, including calcium, phosphorus, magnesium, and fluorine, are components of bone and teeth. Deficiencies during the growing years cause growth to be stunted and bone tissue to be of poor quality. A continual adequate intake of minerals is essential for the maintenance of skeletal tissue in adulthood. 

As was briefly mentioned earlier in this chapter, the inorganic matter of bone and teeth in many ways resembles apatite minerals (Ca5(0H)(P04)3). Table 3.5 summarizes inorganic solid components of other biominerals. A detailed... 

Calcium and phosphorus are major minerals that are needed for the development of healthy bones and teeth. These two minerals are found in a crystalline calcium phosphate mineral known as hydroxyapatite, [Cajo(P04) (OH)2l, that makes up the mineral matrix of bone and teeth. In addition, calcium is required for normal blood clotting and muscle function. The RDA for calcium is 1200 mg/day for adults between nineteen and twenty-four years of age and 800 mg/day for adults over age twenty-five. Milk, cheese, canned salmon, and dark green leafy vegetables are all rich sources of dietary calcium. 

Collagen. Ossein. Mol wt about ]30,000. Polypeptide substance comprising one third of the total protein in mammalian organisms main constituent of skin, connective tissue, and the organic substance of bones and teeth. Prepd from bones by dissolving the mineral part of the bones with phosphoric acid Sciallano, Fr. pat. 688,104... 

Phosphorus has more known functions in the animal body than any other mineral element. Together with calcium, phosphorus plays a major role in the formation of bones and teeth, as well as eggshells. It is a component of nucleic acids, which control cell multiplication, growth and differentiation. In combination with other elements, phosphorus has a role in the maintenance of cellular osmotic pressure and the acid-base balance. Energy transfer processes in all living cells involve interconversion of the phosphate-containing nucleotides, adenosine diphosphate (ADP) and ATP, and thus phosphorus participates in all biological events. Other roles include its presence in phospholipids, where it functions in cell-wall structure, fatty acid transport and protein as well as amino acid formation. 

Calcium and phosphorus serve as structural components of bones and teeth and are thus required in relatively large quantities. Calcium (Ca ) plays many other roles in the body for example, it is involved in hormone action and blood clotting. Phosphorus is required for the formation of ATP and of phosphory-lated intermediates in metabolism. Magnesium activates many enzymes and also forms a complex with ATP. Iron is a particularly important mineral because it functions as a component of hemoglobin (the oxygen-carrying protein in the blood) and is part of many enzymes. Other minerals, such as zinc or molybdenum, are required in very small quantities (trace or ultra-trace amounts). 

As mentioned above, the mineral in bones and teeth contains COs ions so its solubility properties will not be the same as depicted for HAP in Figure 1. In fact, the presence of COs ions increases the solubility product and the rate of dissolution in acids significantly. Taking dental enamel because it is better crystallized than bone mineral, an activity product of 5.5 x 10 mol F (presumably at 25°C) has been reported (Patel and Brown 1975). This compares with 3.04 x 10 mol 1 at 25°C for stoichiometric HAP (McDowell et al. 1977). Both activity products are based on (Ca ) (P04 ) (OH ) where the parentheses indicate activities. In more recent studies, the activity of the C03 ion has been included in the calculation of activity product of enamel (Aoba and Moreno 1992). This necessitated making solubility measurements under controlled CO2 partial pressures. 

Herman H, Dallemagne MJ (1961) The main mineral constituent of bone and teeth. Arch Oral Biol 5 137-144... 

Because the natural mineral component of bones and teeth is carbonate-hydroxyl-apatite, the use of synthetic apatites as bone and tooth replacement materials has been extensively investigated. The first step in the manufacture of biomedical devices requires the ability to synthesize pure and reproducible apatite powders. 

Calcium phosphate can be crystallized into salts such as hydroxyapatite and 8-whitlockite depending on the Ca P ratio, presence of water, impurities, and temperature. In a wet environment and at lower temperatures (<900°C), it is more likely that hydroxyl- or hydroxyapatite will form, while in a dry atmosphere and at a higher temperature, /3-whitlockite will be formed [ Park and Lakes 1992]. Both forms are very tissue compatible and are used as bone substitutes in a granular form or a solid block. The apatite form of calcium phosphate is considered to be closely related to the mineral phase of bone and teeth. 

The mineral part of bone and teeth is made of a crystalline form of calcium phosphate similar to hydroxyapatite [Caio(P04)s(OH)2]. The apatite family of mineral [Aio(B04)eX2] crystallizes into... 

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