A root canal is a dental procedure used to treat and preserve teeth where the roots have been infected. The pulp of the tooth is the live portion that extends into the roots and contains nerve endings and tissues. When this part of the tooth becomes infected, patients can experience lingering pain to cold, swelling and even total tooth loss if the tooth is left untreated. When a tooth is treated with a root canal the damaged parts of the tooth as well as the infection are removed. Once the procedure is completed, the canals are sealed, and the tooth will be filled before restoring with a crown.