With proper care, most teeth that have had root canal (endodontic) treatment can last as long as other natural teeth. In some cases, however, a tooth that has received endodontic treatment fails to heal. Occasionally, the tooth becomes painful or diseased months or even years after successful treatment. If your tooth has not healed or has developed new problems, you have a second chance. Another procedure, endodontic retreatment, may be able to save your tooth.