Glossary

Dentin

The layer of tooth structure lying under the enamel of the crown and cementum of the root, around the nerve and blood vessels of the pulp. Dentin is tubular in cross-section, porous, and permeable (fluid can move freely through it). Primary dentin is produced as the tooth develops in the jaw.

Throughout life, "secondary" dentin is continuously deposited on the inner walls of teeth by the "odontoblast" cells. In response to trauma (including tooth decay and drilling on the teeth), the formation of secondary dentin occurs at a more rapid rate, and is known as "reparative dentin".

When blood flow to the pulp increases after a traumatic event to the tooth, the dentin pores can be saturated with reddish-brown iron pigments from the blood, and the tooth can darken. Teeth that are sensitive generally have exposed dentin tubules, through which fluid moves, causing pressure changes in the tooth that are perceived as pain.
Learn more: Diagnoses › Intrinsic stains