A root canal is a tooth treatment that attempts to save a decayed or infected tooth. The nerve and pulp of the tooth is removed and the area is sealed to prevent an abscess. Your tooth or teeth may be damaged due to tooth injury or filling problems, or because of other things. Symptoms of problems that may require a root canal include severe toothache, swelling, discoloration, tooth sensitivity, and more. The procedure may be somewhat painful, and afterwards, the tooth may be sensitive for a while. Your dentist will explain how to care for your teeth following the procedure.