The structure of a human tooth

Teeth are primarily made up of dentine (inside) and the particularly hard enamel (outside) (figures 1-2).

Enamel in particular is made up almost exclusively of hydroxyapatite, Ca 5 (PO 4 ) 3 (OH).

Enamel is comprised of needle-like hydroxyapatite crystallites that are bundled in parallel ordered prisms

This special microstructure makes enamel the hardest substance in the human body.

Dentine contains a larger protein content in addition to hydroxyapatite. Dentinal canaliculi (so-called tubules) can also be found in dentine. When dentine is exposed in the oral cavity, this can lead to pain-sensitive teeth.

In summary, it can be said that teeth are hierarchical biocomposites with special properties:

• Hardness
• Fracture strength
• Self-repair mechanism by means of remineralisation from saliva