Calcium apatite

T. Tanabe, T. Aoba, E.C. Moreno, M. Fukae, Effect of fluoride in the apatitic lattice on adsorption of enamel proteins onto calcium apatites, J. Dent. Res. 67 (1988) 536-542. C. Robinson, S. Connell, J. Kirkham, S.J. Brookes, R.C. Shore, A.M. Smith, The effect of fluoride on the developing tooth. Caries Res. 38 (2004) 268-276. 

Inorganic Chemistry of the Dissolution Phenomenon The Dissolution Mechanism of Calcium Apatites at the Atomic (ionic) Level (Dorozhkin, 1999)... 

Moreno. E. C. and Vanighese. K. (1981). Crystal growth of calcium apatite from dilute solutions. J. Crystal Growth. 53 20-30. 

Now, let us tackle the problem of calculating the chemical requirements for removing calcium apatite. Although calcium carbonate has a very high K,p that it would not be precipitating with the apatite, the natural alkalinity would have to be... 

It is easily identified by its optical or X-ray diffraction characteristics as it is always well crystallized. The apatite formed at low temperatures, however, is not well crystallized. For example, the phosphate species in the Phosphoria Formation of western US, though a calcium apatite containing a wide range of other elements, is very hne grained and associated with many other hne-grained or poorly crystalline materials, i.e., clays (Gulbrandson, 1966). It is this low-temperature, poorly crystalline form of calcium apatite that is found in biomineralized tissues. The bioapatite, predominantly a hydroxylapatite, has a formula that can be written as Ca5(P04,C03)3 (OH, F, Cl, CO3). 

Moreno EC, Kresak M, Hay DI Adsorption thermodynamics of acid proline-rich salivary proteins onto calcium apatites. J Biol Chem 1982 257 2981-2989. 

Royce, B.S.H. (1973) The effect of structure and ionic transport properties of calcium apatite. /. Rhys. Suppl., 34, 327-332. 

The interaction of the column anions suggests that binary and ternary calcium apatite phosphates are not mere additions of the end-member structures, but that structural adjustments must occur to accommodate mixed-anion columns. Table 2 depicts the distance between anion occupants of adjacent planes, and illustrates which adjacent neighbors are allowed with mixtures of the end-member structures. 

Moreno EC, Varaghese K (1981) Crystal growth of calcium apatites from dilute solutions. J Cryst Growth... 

Dorozhkin SV (2002) A review on the dissolution models of calcium apatites [Review]. Progr Crystal Growth Charact Mater 44 45-61... 

Osaka A, Mima Y, Takeuchi K, Asada M, Takahashi K (1991) Calcium apatite prepared from calcium hydroxide and orthophosphoric acid. J Mater Sci Mater in Med 2 51-55 Osaka A, Tsura K, lida H, Ohtsnki C, Hayakawa S, Miura Y (1997) Spray pyrolysis preparation of apatite-composite particles for biological application. J Sol-Gel Sci Technol 8 655-61 Otsuka M, Matsuda Y, Suwa Y, Fox JL, Higuchi W1 (1995) Effect of particle size of metastable calcium phosphates on mechanical strength of a novel self-setting bioactive calcium phosphate cement. J Biomed Mater Res 29 25-32... 

Shimoda S, Aoba T, Moreno EC, Miake Y (1990) Effect of solntion composition on morphological and stmctural features of carbonated calcium apatites. J Dent Res 69 1731-1740 Shinohara T, Gyo K, Saiki T, Yanagihara N (2000) Ossiculoplasty using hydroxylapatite prostheses long term results. Clin Otolaryngol 25 287-292... 

Location, soii type, texture, sampiing depth and totai phosphorus concentration of controi sites in these studies are given in Table 11.1. Mineral phosphate fertilizer (with single superphosphate, triple super phosphate, calcium apatite, or rock phosphate) unless stated otherwise. Carbon concentrations from Lehmann etal. (2001a). 

Biomaterials Bone cell regeneration Calcium apatites... 

X-ray diffraction studies of bones and enamel reveal that the salts contained in the tissues have a crystalline structure identical to that of apatite. Although the ultimate shape assumed by the crystal is not known, there is, according to Posner, no doubt that the unit cell of bone salts is identical to that of calcium apatite. 

Calcification involves the seeding of the calcium apatite crystal and the growth of the crystals. It would be more convenient to review the second of these mechanisms first. This can best be done by assuming for the moment that the bone matrix, connective or cartilaginous, is bathed in a medium supersaturated in calcium phosphate. Intrinsic to the matrix, there is a mechanism that precipitates calcium phosphate in the form of tiny apatite crystals. If there is no interference with the process of calcification, either by deficient absorption of calcium (vitamin D deficiency) or by active dissolution of the calcium crystals (parathormone), most of the process of mineralization can probably be explained by the physicochemical properties of the apatite crystals. Thus, the divalent cations and anions, PO4 and calcium, penetrate the hydration shell reaching the surface of the crystals where they are crystallized, thereby increasing the size of the crystals. As mineralization proceeds, the amount of bound... 

Mammalian organisms, including humans, have learned to deal with solutes by maintaining them in various levels of solubility. Thus, calcium crystallizes to form calcium apatite in a very organized fashion to build bones. Lipid molecules of the cell membranes exist in a fluid crystal structure and play a key role in their properties. 

High Velocity Oxy-Fuel Process (HVOF) Mixture of a combustible gas (such as propane) and oxygen ignited inside a combustion chamber to melt a coating material before it is accelerated via an inert carrier gas at high speeds toward a surfece, where the hot material forms a coating. Hydroxyapatite Naturally occurring mineral form of calcium apatite with the chemical formula Ca,o(PO,)e(OH),. 

Vertebrates construct their skeletal and dental hard parts from calcium phosphates with calcium carbonates being used for balance organs and egg shells. Bone, dentin, enamel, and mineralized cartilage aU contain crystalline calcium apatite phases but the crystals exhibit different sizes, compositions, and ulfrastructural organization. Apart from enamel they aU contain collagen fibers, and additional inorganic salts and biomolecules. 

Phosphate fertilizers have been known for more than 150 years. Phosphate rock contains minerals such as calcium fluorapatite, Ca5(P04)3F, which are generally too insoluble to be of much use for plant uptake. (See pp. 367 and 554 for several viewpoints on the role of the insoluble calcium apatites in bone and teeth structure.)... 

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