Mineral phases calcified tissues

Rey, C., Renugopalakrishnan, V., Shimizu, M., Collins, B. and Glimcher, M.J. 1991 A resolution-enhanced Fourier transform spectroscopic study of the environment of the COj ion in the mineral phase of enamel during its formation and maturation. Calcified Tissue International 49 259-268. 

Bone is a porous tissue composite material containing a fluid phase, a calcified bone mineral, hydroxyapatite (HA), and organic components (mainly, collagen type). The variety of cellular and noncellular components consist of approximately 69% organic and 22% inorganic material and 9% water. The principal constiments of bone tissue are calcium (Ca ), phosphate (PO ), and hydroxyl (OH ) ions and calcium carbonate. There are smaller quantities of sodium, magnesium, and fluoride. The major compound, HA, has the formula Caio(P04)g(OH)2 in its unit cell. The porosity of bone includes membrane-lined capillary blood vessels, which function to transport nutrients and ions in bone, canaliculi, and the lacunae occupied in vivo by bone cells (osteoblasts), and the micropores present in the matrix. 

A compilation of the phases occurring in the different calcified tissues or calculi is given in Table V. If more than one apatite phase is involved, these generally occur as domains in the same apatitic particles of the mineral and cannot be separated physically (53, 57). 

Phases occurring in the mineral of calcified tissues and dental calculus ( 5 3, 57)... 

The CaP phase as present in the inorganic mineral component of calcified tissue is referred to as apatite (Biltz and Pellegrino 1983). The general formula of synthetic CaP apatite is Ca5(P04)3X. When the X position is occupied by OH groups, the apatite is referred to as HA. HAs can be grouped into two categories (i) stoichiometric apatite (s-HA) or (ii) nonstoichiometric apatite (ns-HA) (Elliott 1994). 

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