An individual tooth consists of that portion that is exposed above the gum line called the crown.
The part of the tooth that is buried in the gum and jaw is called the root.
The crown is covered by an outer layer of an especially hard substance related to bone called enamel.
Beneath the enamel, and sometimes exposed to the surface if the enamel is missing, is an intermediate layer of material called dentine, which is also similar to bone but is not nearly as hard as enamel. It surrounds an inner pulp cavity filled with pulp. The pulp or is a living vascular and well innervated tissue.
Blood vessels and nerves reach the pulp cavity through a channel called the root canal that penetrates the root.
An additional layer of bony material called cementum usually surrounds the root.