apatite crystal


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apatite crystal

In dentistry, the hydroxyapatite crystal typical of calcified tissues; a complex of calcium phosphate and other elements, present in bone and in the cementum, dentin, and enamel layers of teeth. The most dense crystalline pattern is found in enamel, the hardest tissue of the body.
See also: crystal
References in periodicals archive ?
Studies with synthetic HAp showed that Zn2+ is readily acquired by the apatite as it competes with Ca2+ and can attain position on the apatite crystal, making the HAp resistant to the acid dissolution.29 Trace elements have their respective cariogenic effects (Table-1)30
For our study, we can conclude that serum-free cultured [MSCA-1.sup.+] JPCs form heterogeneous apatite crystals result in a wider hydroxyapatite peak that is generated from immature crystal structures [32].
In part, the disagreement involves how to interpret the record in the apatite crystals. In places, the helium data from Flowers' team and Lee's team are essentially identical; the difference is in how scientists infer a temperature history for the rock.
Indeed, abundant apatite crystals were identified in the lumens of loops of Henle.
The most dramatic piece (which has been named the "Apatite Sapo King") is a cluster of albite and muscovite crystals measuring 15 X 23 X 48 cm, richly coated with sharp apatite crystals up to 6 cm and, on top on the left side, one large bicolor apatite crystal (very pale tan with a dark green core) measuring 5 X 5 cm (habit 6; see below).
The bioactive glass ceramic containing two main crystal phases, mica and apatite, developed by Hoeland et al., showed a calcium phosphate rich interface layer with apatite crystals grown on solid state reaction between glass ceramic and bone.
At present, differences exist among the morphology, size, calcium and phosphorus ratio, and crystallinity of chemically synthesized nanoapatite granules and apatite crystals in natural bone tissue.
The Ti2p, Zr3d, and O1s peaks of each sensor were analyzed before apatite formation, and the Ca2p, P2p, and O1s peaks of apatite crystals on each sensor were analyzed after apatite formation.
A report in the Journal of Oral Implantology describes synthesis of a collagen-hydroxyapatite composite through mineralization of collagen fibrils with nanometer-sized apatite crystals. The biological properties of the composite were evaluated by culturing with mouse and human mesenchymal stem cells.
Hydroxy apatite crystals are in shape of needles and plates 27A[degrees]--75A[degrees] thick, 44A [degrees]--75A[degrees] wide and 50A[degrees]--400A[degrees] long.
Dental enamel is arranged in the form of hexagonal apatite crystals. Calcium salts that enter the structure of the enamel collect and crystallize, gradually dissolving into the organic tooth outline.
The apatite crystals were sealed in epoxy resin, polished, etched with a 2.5% HN[O.sub.3] solution for 70 s at 22 [degrees]C to enable visibility of the spontaneous fission tracks, fitted with a muscovite external detector (Miller et al., 1993) and irradiated in a nuclear reactor (Oregon State University Radiation Center) by thermal neutrons.