A root canal is a treatment of the pulp of the tooth that is inflamed, infected or dead. The pulp is a soft substance in the center of the tooth that consists of the nerve, blood, vessels and connective tissue to the pulp chamber is the hollow part in the center of the tooth that contains the pulp, and it continues down canals that extend through the roots of teeth and into the surrounding bone. Some roots have more than one root canal, but all have at least one canal.

Root canal treatment (RCT) and endodontic treatment are the more correct terms for a procedure that treats the nerve of the tooth. Endodontics is a specialty of dentistry that deals specifically with the tooth pulp and tissues surrounding the root of the tooth. A root canal may be treated by an endodontist.

When the root canal is treated, the pulp of the tooth is removed and all the canals and pulp chamber of the tooth are filled and sealed with a material known as gutta-percha, this helps to keep the canals free of infection or contamination. In some cases, a post is placed into the root next to the gutta-percha until the tooth receives a permanent filling or a crown.