kalciumhydroxylapatit

Kalciumhydroxylapatit, commonly referred to as calcium hydroxyapatite (Ca10(PO4)6(OH)2), is a calcium phosphate compound that occurs both naturally and synthetically. It is a major inorganic component of vertebrate bone and teeth and belongs to the apatite family. In biological apatite, substitutions of carbonate, fluoride and other ions are common, which influence solubility, crystallinity and biological behavior.

Structure and properties: Pure hydroxyapatite forms a crystalline lattice with calcium, phosphate and hydroxide ions. It is biocompatible and bioactive, capable of bonding to bone tissue. It is osteoconductive, providing a scaffold for bone growth, while its mechanical properties depend on crystallinity, porosity and particle size. Higher crystallinity generally reduces resorption.

Synthesis and forms: Kalciumhydroxylapatit can be synthesized by precipitation from calcium and phosphate solutions or via hydrothermal methods. It is available as powders, porous blocks, granules, coatings for implants and composites with polymers or metals. Doping with silicate, calcium, magnesium or other ions can modify solubility and mechanical performance.

Applications: It is used as a bone graft substitute in orthopedics and dentistry, as a coating on metallic implants to improve osseointegration, and as a filler for periodontal defects. In some dental products, nano-hydroxyapatite is marketed for remineralization and tooth repair, reflecting its chemical similarity to natural tooth mineral.

Safety and limitations: Kalciumhydroxylapatit is generally regarded as biocompatible, but its brittleness and limited fracture toughness as a ceramic require careful design in load-bearing applications.