Illustration depicting the interior structure of a human tooth. Each tooth has two major regions; the crown and the root. The enameled covered crown is the part of the tooth visible above the gum. The portion of the tooth embedded in the jaw is the root. Dentin, a bonelike material, forms the bulk of a tooth. It surrounds a central pulp cavity, which contains a number of soft tissue structures (connective tissue, blood vessels, and nerve fibers) collectively called the pulp. Pulp supplies nutrients to the tooth and provides for tooth sensation.