Anatomy and conditions
Dentin
The yellowish layer under the enamel that makes up most of a tooth and surrounds the nerve.
Dentin is the layer of tooth that lies beneath the enamel and above the pulp. It is softer than enamel and contains tiny channels that lead toward the nerve. When decay or wear exposes dentin, teeth can become sensitive to hot, cold or sweet things. Most of the tooth structure is dentin. Knowing this helps the front desk understand why a patient might report sensitivity before any visible hole.
Example at the front desk
He says cold drinks hurt, which the dentist said may be exposed dentin.