Recent studies of bone mineral: Is the amorphous calcium phosphate theory valid?

Glimcher, Melvin J.; Bonar, Laurence C.; Grynpas, Marc D.; Landis, William J.; Roufosse, A.

doi:10.1016/0022-0248(81)90058-0

Cited by 157 publications

(108 citation statements)

References 44 publications

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“…This conclusion was drawn from the following facts: (1) when CaPO 4 are prepared by rapid precipitation from aqueous solutions containing ions of calcium and orthophosphate at pH [ 8.5, the initial solid phase is amorphous; (2) mature bone mineral is composed of a mixture of ion-substituted ACP and poorly crystallized ionsubstituted CDHA; (3) early bone mineral has a lower crystallinity than mature bone and the observed improvement in crystallinity with the age of the bone mineral is a result of a progressive reduction in the ACP content (Elliott 2002;Eanes et al 1965;Termine and Posner 1966a, b;Harper and Posner 1966;Posner 1969Posner , 1973Posner , 1978Boskey and Posner 1976;Glimcher et al 1981). Interestingly, thermodynamic data prove that the transition of freshly precipitated ACP into CDHA involves intermediate formation of OCP (Meyer and Eanes 1978a, b).…”

Section: Bonementioning

confidence: 99%

Calcium orthophosphates (CaPO 4 ): Occurrence and properties

Dorozhkin¹

2017

Morphologie

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Section: Bonementioning

confidence: 99%

Calcium orthophosphates (CaPO 4 ): Occurrence and properties

Dorozhkin¹

2017

Morphologie

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“…In such extreme cases, a situation with heterogeneous supersaturation distribution may even be reached where both OCP and HAP can coexist. It should be noted that OCP phase has never (up to present time) been identified by X-ray diffraction in bones 11,12 and only HAP was found. However, most studies were done by XRD and low quantities of OCP are difficult to detect because only special cameras are able to catch the (1 0 0) reflection around 18 -19 Å (Cu radiation) and the other reflections superimpose with HAP.…”

Section: Biological Samples: Bone and Cardiac Valvementioning

confidence: 89%

Model of the mechanism of Ca loss by bones under microgravity and earth conditions

Suvorova

Buffat

2002

J. Biomed. Mater. Res.

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A comparative characterization of crystal structure, morphology, sizes, and orientation in Ca phosphate precipitation from aqueous solutions, the mineral phase in bones, and mineral deposits on cardiac valves has been performed by high-resolution transmission electron microscopy to model possible mechanisms of Ca loss by bones. Physiological changes occurring in organisms can lead to deep perturbations of the natural calcium phosphate supersaturation and its local distribution, which in turn influences the phase composition, morphology, and organization of the mineral phase. Formation of crystals with larger size or of two distinct phases instead of the single hydroxyapatite one can result in the deterioration of the Ca balance in bone and tissue destruction as well as the possible misorientation (or spread of orientation) between HAP crystals newly formed in the bone.

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“…[1][2][3][4][5][6][7] The primary reaction product of most CPCs after being implanted for a while is various kinds of apatite, 8) a calcium phosphate compound which is the main inorganic component of human bones and teeth. 9,10) Tetracalcium phosphate (TTCP), a member of the calcium phosphate family, is known to have a high chemical activity and reacts at room temperature with aqueous solution.…”

Section: Introductionmentioning

confidence: 99%

Transmission Electron Microscopic Study of Tetracalcium Phosphate Surface-Treated in Diammonium Hydrogen Phosphate Solution

Wang

Lin

2005

Mater. Trans.

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The present study investigates the changes in microstructure and microchemistry (particularly Ca/P ratio) during whisker formation on the surface of a monolithic TTCP powder in a basic phosphoric acid solution. The XRD results indicate that when TTCP powder was treated for 10 min or less in (NH 4 ) 2 HPO 4 solution, the monolithic TTCP phase remains unchanged. When treated for 30 min, apatite whiskers appear, which continue to grow with treating time. When treated for 24 h, the apatite phase becomes dominant. TEM results show that on the surface of 1 min-treated TTCP are observed a large amount of globular-shaped fine particles which are substantially amorphous with an average Ca/P ratio of about 1.2. When treated for 10 min, whiskers primarily having a crystal structure of TTCP with an average Ca/P ratio of about 2.1 are observed to grow radially from TTCP surface. With time the whiskers continue to grow in length and width. The whiskers on 24 h-treated surface become Ca-rich apatite with an average Ca/P ratio of about 1.8. Both TTCP and apatite whiskers are essentially non-stoichiometric in chemistry.

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Recent studies of bone mineral: Is the amorphous calcium phosphate theory valid?

Cited by 157 publications

References 44 publications

Calcium orthophosphates (CaPO 4 ): Occurrence and properties

Calcium orthophosphates (CaPO 4 ): Occurrence and properties

Model of the mechanism of Ca loss by bones under microgravity and earth conditions

Transmission Electron Microscopic Study of Tetracalcium Phosphate Surface-Treated in Diammonium Hydrogen Phosphate Solution

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