For a 70-kg subject, the calcium mass represents about 1300 grams, 99% of which is in bone and teeth, mostly as hydroxyapatite.
Like other apatites it has a calcium and phosphate component in a ratio of 1.67 (Ca/P ration) but is associated with a hydroxyl group.
Hydroxyapatite is generally constitutes between 60 to 70 weight % of the bone, while the remaining part is collagen. The inorganic component provides compressive strength to the bone. Bone is continually remade as a balance of formation and breakdown.
Using artificial hydroxyapatite as a bone substitute is therefore the most obvious choice, as it replicates the mineral composition and the behavior of human bone.
Hydroxyapatite is highly biocompatible and osteoconductive; in fact, it promotes the formation of new bone by favoring the growth of osteoblast cells.
Hydroxyapatite in bone
