TEETH

Anchored firmly in the jawbones are the teeth. Our teeth are used to tear, chop, and grind food to make it soft enough to swallow and easier to digest.

WHAT ARE TEETH MADE OF?

The white, outer shell of a tooth is made of enamel, the hardest substance in the body. Under the enamel is a softer substance called dentine, and inside this is the soft, living heart of the tooth, called the pulp cavity.

INSIDE A TOOTH

Beneath the hard outer surface, dentine forms the body of a tooth. Nerves (green) and blood vessels (red and blue) run through the tissue of the pulp cavity and out through root canals at the base of the tooth.

WHY DO TEETH DECAY?

If teeth are not properly cleaned, a mixture of bacteria and food, called plaque, builds up on them. As the bacteria feed on the sugary food debris, they produce an acid that dissolves the calcium minerals in enamel and dentine, forming a cavity. If the sensitive dentine layer is exposed, hot and cold foods can cause pain.

PLAQUE

A sticky deposit called plaque builds up on teeth that are not cleaned regularly. Plaque consists of mucus, food debris, and bacteria that cause tooth decay.

FIND OUT MORE

Digestion
Microorganisms

Copyright © 2007 Dorling Kindersley