Endodontics is a combination of the Greek words "Endo," which means "inside" and "odont," which means "tooth." Endodontic treatment involves treating the inside of the tooth. The other terminology for endodontic treatment is root canal therapy. This name comes from the fact that the treatment is to the root part of the tooth and, more specifically, in the canal part of the root where the nerve, blood vessels, and connective tissue of the tooth reside.

To understand endodontic treatment, it helps to know something about the anatomy of a tooth. Inside the tooth, under the white enamel and a hard layer called the dentin, is a soft tissue called the pulp. The pulp contains blood vessels, nerves, and connective tissue and creates the surrounding hard tissue of the tooth during development.

The pulp extends from the crown of the tooth to the tip of the roots where it connects to the tissues surrounding the root. The pulp is important during a tooth's growth and development. However, once a tooth is fully mature, it can survive without the pulp because the tooth continues to be nourished by the tissue surrounding it.