Root Canal Treatment
A tooth maintains its health via dental pulp within. Dental pulp contains nerve and blood vessels which bring nutrients to the tooth.
Dental pulp may get infected due to untreated decay or might get injured due to trauma, where the nerves within the pulp die. This allows bacteria to gain access into the pulp causing infection which travels through the root canals into the bone causing an abscess. So, instead of extracting the tooth, a root canal is performed to remove the infected dead pulp and fill the pulp space to save the tooth. A root canal treated tooth often requires a crown.
You can discuss with your dentist to learn more.