Root canal therapy removes the nerves within the pulp of the tooth, the nerves that are a part of the tissue that formed the tooth. There are still millions of nerve fibers in the ligament that lines the socket of the tooth. The inflammation that began in the pulp of the tooth is a chemical cascade that spreads outside the tooth through the natural openings at the ends of the roots where the blood vessels enter. This inflammation is similar to a sunburn, where touch becomes painful instead of just the sensation of touch. As with a sunburn, time will heal the inflammation and the tooth will return to feeling normal.