Hydroxyapatite

The hydroxyapatite is a natural form of Apatite of calcium, of formula Ca5 (PO4) 3 (OH), usually written Ca10 (PO4) 6 (OH) 2 to underline the fact that the mesh of the crystalline structure includes/understands two molecules. The hydroxyapatite is the hydroxylated member apatite group. The Ion OH- can be replaced by the Fluor, the Chlore or the Carbonate.

The hydroxyapatite crystallizes in the hexagonal system. It has a specific gravity of 3,08 and one hardness of 5 on the scale of hardness Mohs. The pure powder of hydroxyapatite is white. Those which one finds in nature can however be of green color chestnut, yellow or. One can bring this closer to the discoloration observed in the dental Fluorose.

The word apatite drift of the Greek apatao - " I am fallacieux" in allusion to its appearance similar to the Gem S.

The hydroxyapatite is the mineral main component of the dental enamel, the Dentine and the Os.

Medical use

The hydroxyapatite can be used as substance of filling to replace a bone amputee or like coating to support the growth inside the prosthetic implants . Although there exists many other states with a similar chemical structure even identical, the body answers in a quite different way one or the other.

The skeleton of the Corail can be transformed into hydroxyapatite at high temperature. Its porous structure allows a relatively fast growth and the expansion of the initial mechanical force. Moreover, the high temperature makes it possible to burn the organic molecules like the Protéine S, thus preventing the rejection of Clerc's Office.

Some dental implants modern are coated with hydroxyapatite. It was suggested that this could support the Ostéo-integration, but there does not exist conclusive clinical trial on the subject.

External bonds

  • Material overview
  • International Mineralogical Association
  • ha one webmineral.com
  • ha one mindat.org
  • Dated from CAMD - Center for Advanced Microstructures and Devices, Louisiana State University

Reference

  • Wopenka, B. and J.D. Pasteris, has mineralogical perspective one the apatite in bone. Materials Science and Engineering: C. 25 (2): 131,2005

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