Emergency
Exposed tooth nerve
An exposed tooth nerve means the pulp inside the tooth is open to the mouth, often from deep decay or a crack. It can hurt and lead to infection.
The pulp is the jelly-like center of each tooth. It holds nerves and blood vessels. Cleveland Clinic says cavities and cracks can expose tooth pulp and lead to infection. The ADA's MouthHealthy site says bacteria that reach the pulp can lead to pulp death and an abscess.
Signs may include sharp pain with hot, cold, or biting, or constant pain. Sometimes there is little pain at first. Because the nerve is open, the tooth needs a dentist's attention. Treatment may include a filling, pulp cap, pulpotomy, or root canal therapy, depending on the case.
See tooth pulp and toothache. For a tooth with a visible nerve after an injury, call a dentist right away. The practice describes root canal care on the root canal page.