Root canal treatment involves one to three visits. During treatment, your general dentist or endodontist (a dentist who specializes in problems with the nerves of the teeth) removes the affected tissue. Next, the tissue will be removed, and the interior of the tooth will be cleaned and sealed. Finally, the tooth is filled with a dental composite. If your tooth has extensive decay, your doctor may suggest placing a crown to strengthen and protect the tooth from breaking. As long as you continue to care for your teeth and gums with regular brushing, flossing, and checkups, your restored tooth can last a lifetime.