We use our teeth to cut up food into smaller pieces that we can swallow. There are four main kinds of teeth, each with a different job. The sharp-edged, chisel-like incisors at the front of the mouth bite off pieces of food. The taller, pointed canines tear the food up. The wide premolars and molars at the back of the mouth squeeze and crush the food.

Kinds of teeth

By the age of three, children have 20 milk (or deciduous) teeth: four incisors, two canines and four molars in each jaw. Between 6 and 12 years, these teeth are shed and replaced by adult teeth. An adult person has 32 teeth. There are four incisors, two canines, four premolars and six molars in each jaw. The rearmost molars are called wisdom teeth.

Only a small part of a tooth, the crown, shows above the surface of the gum. Deep roots anchor the tooth to the jawbone. Most of the tooth is made of dentine, a hard, bone-like material. The tooth is hollow inside. At the centre, in what is called the pulp cavity, are blood vessels and nerve endings.

​​​​​​​Above the gum, the tooth is coated with a layer of enamel. This substance is even harder than bone. It protects the tooth from many years of crushing and grinding. But even enamel can be eaten away by acids released by mouth bacteria. These feed on food remains left on or between the teeth.