Root canal therapy is usually performed to alleviate a painful toothache when the inner tissues within a patient’s teeth roots become infected. This tissue causes pain, swelling, and tooth loss if left untreated, as it spreads infection to surrounding tissues. During root canal therapy, a small hole is made at the top of the tooth to drain out the infection and remove nerves and blood vessels, and then the inside of the tooth is cleaned. The final step is to fill the tooth and cover it with a dental crown. A root canal allows you to keep your tooth, maintain the bone, and preserve your natural chewing motion.