The cosmetic ‘brick’ of the bones

Minerals are essential for physical and mental wellbeing, in that they constitute the whole tissue structure and fluids of the human body. They play an important role in the production of hormones and antibodies, thus keeping the delicate hydric structure in balance.

All the minerals considered necessary for the body must be present in the diet as essential food substances which the body is either unable to synthesise at all or in insufficient quantities.

 Hydroxyapatite: an inside view

Hydroxyapatite is a nutritious element present in the body and food as an organic and non-organic component. Many tissues in the human body, mainly bone and teeth, are made of this element. Bone is constantly being formed by osteoblasts and is continually absorbed by active osteoclasts. The salt crystals which account for 70% of compact bone are composed mainly of calcium and phosphate (hydroxyapatite). Probably the first calcium salts which deposit are not crystals of hydroxyapatite but amorphous (non-crystalline) compounds. Even if most of these salts are restructured into hydroxyapatite crystals through different processes, it is very important that 20% to 30% of them remain permanently in the amorphous state so that they can be quickly absorbed in the extracellular fluid when necessary. Bones are the main source of this ‘exchangeable calcium pool’ and, as such, act as a buffer of the concentration of calcium ions in the extracellular fluid and consequently in the blood, thus contributing to the maintenance of all physiological processes.1 On this basis, scientific studies report hydroxyapatite medical use as a filler in amputated bones, as a coating to promote ossification in many modern implants or as a carrier for drugs and proteins2,3 and as a filler in aesthetic medicine. Moreover, 70% of dentine, one of the main components of the teeth, is composed of hydroxyapatite crystals, similar to those of the bone but much thicker, immersed in a robust reticulum of collagen fibres. Dentine hydroxyapatite crystals make it extremely resistant to pressure. Also 97% of enamel, that is the external surface of the tooth, is made up of hydroxyapatite as large very thick crystals on which carbonate, magnesium, sodium, potassium and other ions are adsorbed.1 Each day dental enamel is demineralised by acids present in the mouth and remineralised by the calcium and phosphate ions carried in saliva. Under normal conditions the dynamic balance between demineralisation and remineralisation is stable. This equilibrium results in healthy teeth which are not affected by caries, and are not eroded, decalcified or hypersensitive.4

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