Octacalcium phosphate
Octacalcium phosphate (sometimes referred to as OCP) is a calcium phosphate with a formula Ca8H2(PO4)6.5H2O. OCP may be a precursor in creation of the tooth enamel, dentine and bones in living organisms.
OCP has been shown to be a precursor of hydroxylapatite (HAP), an inorganic biomineral that is very important in bone growth. Determinations of the crystal structures of OCP and acidic apatite thus appear to be a pre-requisite to an understanding of the formation and chemical properties of skeletal tissues. OCP could one day replace HAP in bone grafts and implants because of the similar apatite structure. OCP is an intermediate complex before the synthesis of HAP. When mixed with boiling water the crystal structure morphs to one that is very similar to apatitic structure of HAP. OCP has similar domains to HAP and has an apatite crystal structure. This makes it ideal to fill in calcium pores in teeth and bones. The morphology of tooth and bone crystallites, as seen in their micrographs, strongly indicates that OCP is involved in the formation of these tissues. There have been studies that have shown the advantages of using OCP in tooth enamel repair to stimulate the regrowth of the enamel because the crystal structure fits into the pores of tooth enamel. Studies have been done with titanium plates and bone implants with a coating of OCP. The implants and plates with coatings of OCP were accepted and integrated more quickly and fully than those without OCP because of the apatite crystal structure of OCP that is similar to the crystal structure of bone. OCP shows very promising signs of replacing HAP in bone and tooth repair and growth in grafts and implants and will likely be used more widespread in the healthcare fields.