Structure of Teeth
The tooth has two anatomical parts; the crown and the root. The crown is the part of the tooth that is normally visible in the mouth (above the gum line). The shape of the crown determines the function of the tooth. The root of a tooth is the part embedded in the jaw. It anchors the tooth in its bony socket and is normally not visible (below the gum line). The gum line is where the tooth and gums meet. The anatomy of teeth and the mouth structures which surround and support them are described below.
Structures of the tooth
Enamel The hard outer layer of the crown. Enamel is the hardest substance in the body yet it can decay if teeth are not cared for properly.
Dentine Not as hard as enamel, forms the bulk of the tooth and can be sensitive if the protection of the enamel is lost.
Pulp Soft tissue containing the blood and nerve supply of the tooth. The pulp extends from the crown to the tip of the root where it connects to the nerves and blood supply of the mouth. The pulp enables sensations of tooth sensitivity or pain.
Cementum The layer of bone-like tissue covering the root. It is not as hard as enamel.
Structures around the tooth
Periodontal ligament: The periodontal ligament is responsible for attaching the tooth to the jaw bone. It is made up of thousands of fibres which fasten the cementum to the bony socket. These fibres anchor the tooth to the jaw bone and act as shock absorbers for the tooth, which is subjected to heavy forces during chewing.
Gingivae (gums): Soft tissue that immediately surrounds the teeth and bone. It protects the bone and the roots of the teeth and provides an easily lubricated surface.
Bone: Provides a socket to surround and support the roots of the teeth.
Nerves and blood supply: Each tooth and periodontal ligament has a nerve supply and the teeth are sensitive to a wide variety of stimuli. The blood supply is necessary to maintain the vitality of the tooth.