Dental Anatomy of Human Teeth

A tooth is a hard structure set in the jaw and used to bite and grind food. Each tooth is divided into two main parts: the crown, the visible portion above the gum line, and the root, the part embedded in the bone of the jaw that anchors the tooth in place. The boundary between them, where the tooth narrows at the gum, is the neck. Although teeth appear simple, they are built from several distinct tissues arranged in layers.

The crown is covered by enamel, the hardest substance in the human body, which forms a protective outer shell. Beneath the enamel, and making up most of the tooth, is dentin, a slightly softer, bone-like tissue that supports the enamel and surrounds the central cavity. At the core lies the pulp, a soft tissue containing the nerves and blood vessels that nourish the tooth and give it sensitivity; the pulp extends down through canals in the roots. Over the surface of the root, in place of enamel, is a thin layer called cementum, to which fibres attach.

Teeth are held firmly in their sockets by the periodontal ligament, a set of fibres connecting the cementum of the root to the surrounding bone, while the gums cover and protect the underlying tissues. Humans develop two sets of teeth in a lifetime: a first set of baby, or deciduous, teeth that are later shed, followed by the permanent teeth. Decay of the enamel and dentin can reach the pulp and cause pain, which is why dental treatments such as fillings and root canal therapy are directed at these structures.

Frequently asked questions

What are the main parts of a tooth?

The crown above the gum line and the root embedded in the jaw, meeting at the neck. Internally a tooth has layers of enamel, dentin and pulp.

What is the hardest part of a tooth?

The enamel, which covers the crown. It is the hardest tissue in the human body and protects the softer dentin beneath.

What is inside the pulp of a tooth?

The pulp contains the nerves and blood vessels that nourish the tooth and make it sensitive. It runs through the centre and down into the roots.