What is dentin?

Dentin is a hard tissue that forms the bulk of a tooth and surrounds the pulp chamber, which contains the tooth's nerve and blood supply. This vital structure plays an essential role in protecting the pulp and serves as a supportive framework for the enamel and cementum. Dentin has a composition that allows it to be somewhat resilient yet strong, containing microscopic tubules that can transmit sensations, such as pain or temperature changes, to the pulp.

In contrast to the other options, the hard substance that covers the root is referred to as cementum, not dentin. The soft tissue surrounding the tooth typically refers to the periodontal ligament or the gums, which are distinct from dentin. The protective layer of the gums pertains to gingiva, which covers the underlying bone and is separate from the hard tissues of the tooth itself. Understanding these definitions highlights the role of dentin as a critical component of dental anatomy and its relationship with the rest of the tooth structure.