Endodontics deals with the root of your tooth and also the nerves and blood vessels within your tooth. If that tissue, called the pulp, becomes infected, then it can lead to severe pain, an abscess and the loss of the tooth.
If an infection occurs, and there is enough tooth structure to save and the decay is not too extensive, then a root canal can be performed to prevent extraction.
A root canal procedure involves removing the infected or dead nerve tissue, disinfecting the nerve space, and sealing that space. A crown is usually recommended after a root canal to prevent the tooth from fracturing over time.