Dentin

Dentin is a tissue of the body and along with enamel, cementum and pulp is one of the four major components of teeth. It is covered by enamel on the crown and cementum on the root and surrounds the entire pulp.  Dentin, which is less mineralized and less brittle than enamel, is necessary for the support of enamel and consists of microscopic channels, called dentinal tubules, which radiate outward through the dentin from the pulp to the exterior cementum or enamel.

The formation of dentin begins prior to the formation of enamel and is initiated by the factors of the pulp. Unlike enamel, dentin continues to form throughout life and can be initiated in response to stimuli, such as tooth decay or attrition.

Primary dentin forms most of the tooth. Secondary dentin develops after root formation is complete and forms much slower than primary dentin.