Читать книгу Good Teeth - Mandy Collins - Страница 9

To best understand what you’re doing when taking care of your teeth, it helps to have some knowledge of their basic anatomy. Your teeth have a complex, multilayered structure, as well as a supply of nerves and blood.

The tooth is divided into three main parts: the crown, the neck and the root. Enamel covers the crown of the tooth, and this smooth, hard coating is the hardest tissue in the body. It is not sensitive at all, and is usually translucent-white in colour. The main substance of the crown, neck and root of the tooth is dentine. This is a yellow-white colour, and is very sensitive, as it houses the tooth’s nerve supply.

The gums, or gingiva, are the link between the teeth and the rest of the mouth. The tiny space between the teeth and the gums is known as the gingival sulcus, and is usually no thicker than 2mm (0.08in). However, as small as it is, this space is a common source of infection. The tooth is connected to the bone in your jaw by thin fibres (periodontal ligaments), which act as shock absorbers for your teeth. The periodontal ligaments attach to the thin layer covering the root, called cementum.

ANATOMY OF A TOOTH

THE ORAL CAVITY

Inside each tooth is a nerve cavity that houses the tooth’s blood vessels and nerves. Blood vessels are vital because they transport essential nutrients to the tooth, and the nerves make the tooth sensitive, which is sometimes a good thing and at other times extremely painful. The nerves and blood vessels pass through the tooth into the nerve cavity by means of small channels called root canals.

Adults have 32 teeth, including four wisdom teeth, which can be divided into four types. Each of the four types has a different structure, position and function.

The eight incisors occur near the front of the mouth, and are typically used for biting. Moving outward from the centre, your canine teeth are sharper and more pointed than incisors, and help to tear off and hold your food while you are eating. They are also commonly called eye-teeth.

The premolars are next, and have two raised points that help to crush your food during chewing. Molars are a larger version of the premolars, and are used for grinding and pulping food. There are eight premolars and eight molars, plus the wisdom teeth that are simply an additional set of molars.