Our teeth are actually hollow inside. The center of our teeth have a space called the pulp chamber, which contains nerve tissue and blood vessels. This space continues down into the root of the tooth, where it is called the root canal.
When cavities are very deep, or when there is trauma to a tooth, the tissue inside the pulp chamber can become inflamed and painful, or it can die and become infected. In either case, the tooth will need root canal therapy.
During root canal therapy, the dentist will make an access opening into the pulp chamber, and remove the inflamed or dead tissue. The canals, which usually number between 1 and 4 depending on the tooth, are then cleaned and shaped with small files. After all tissue has been removed from the canals, they are disinfected, and then sealed. A temporary filling is then placed in the tooth. The tooth will need to be restored with a crown as soon as possible.
While a tooth that needs root canal often hurts, there is usually very limited pain after the root canal therapy is completed, although soreness for a day or two is common.