A tooth is made up of two distinct parts. The part we can see above the gum is called the Crown and the part we usually cannot see below the gum is called the Root.
Front teeth usually have one root and back teeth have multiple roots. The purpose of the root is to anchor the tooth to the jaw bone.
Teeth are kept alive and healthy by a supply of nerves and blood vessels. These pass through the jaw bone and enter the tooth via the root canal in the centre of the root.