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A natural mineral structure that the crystal lattice of bones and teeth (that is, amorphous hydroxyapatite) closely resembles; used in chromatography of nucleic acids; also found in pathologic calcifications (for example, atherosclerotic aortas).
Synonym(s): hydroxylapatite
Farlex Partner Medical Dictionary © Farlex 2012


, hydroxylapatite (hī-drok″sē-ap′ă-tīt″) (″sĭ-lap′ă-tīt″) [ hydro- + ²oxy- + apatite ]
Ca10(PO4)6(OH)2; the calcium- and phosphorus-containing compound that constitutes the bulk of the mineral structure of bones and teeth. In teeth it is soluble in the acids of soft drinks or carbohydrate fermentation, but it becomes decay-resistant fluoroapatite after combining with fluoride ions present in fluoridated water or fluoride toothpastes. Under some circumstances, it can deposit in and around joints, producing periarthritis or calcific tendinitis.
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References in periodicals archive ?
Chemical precipitation is mixed aqueous solution of certain concentration of calcium salt and phosphate salt, by controlling the pH value, produces chemical reaction, generates colloidal hydroxyapatite sediment, and gets its crystalline powder by calcining grinding.
Since the surface of Hydroxyapatite consists mainly of two functional groups a"Ca-OH and a"P=OH acting as the active sites [12].
In present work, hydroxyapatite (HA) powder has been prepared by suspension precipitation method.
The study was conducted to observe if there is any difference in the chemical structure of demineralized and remineralized enamel and hydroxyapatite using solid state 31P MAS NMR techniques.
Where is the intensity of (300) diffraction peak and the intensity of the hollow between (112) and (300) diffraction peaks of hydroxyapatite. The crystallite size (t) of hydroxyapatite powder has been calculated based on Scherrer's equation (Bouyer et al., 2000):
Among various phases of calcium phosphate, biphasic calcium phosphate (BCP) ceramic, an intimate mixture of hydroxyapatite (HA, [Ca.sub.10](P[O.sub.4])6[(OH).sub.2]) and [beta]- tricalcium phosphate ([beta]-TCP, [Ca.sub.3][(P[O.sub.4]).sub.2]), has been commonly used for biomedical applications for nearly three decades [1].
The best known member of the apatite family is hydroxyapatite (HAp).
As 25 KGy is the most common dose of gamma irradiation for serialization of biomedical products [13], in this study, after preparation of hydroxyapatite, copolymer, and their composite, they were submitted to 25 and 50 KGy gamma irradiation, and various properties including changes in molecular weight, thermal behavior, wettability, cell viability, and alkaline phosphatase activity of the composite and each of its ingredients were studied separately.
In this study, porous hydroxyapatite scaffolds coated with type-I-collagen-glycosaminoglycan (collagen-GAG) were prepared and characterized to achieve more rapid bone tissue regeneration of matrix.
In the last decades, a major attention has been given to a special material, hydroxyapatite (HAp) [[Ca.sub.10][(P[O.sub.4]).sub.6][(OH).sub.2]], due to its remarkable properties.
Tampieri, "Development of Sr and C[O.sub.3] co-substituted hydroxyapatites for biomedical applications," Acta Biomaterialia, vol.