With proper care, most teeth that have had endodontic (root canal) treatment can last as long as other natural teeth. In some cases, however, a tooth that has received endodontic treatment fails to heal or the pain continues. Occasionally, the tooth becomes painful or diseased months or even years after successful treatment. If your tooth has failed to heal or has developed new problems, you have a second chance. Another endodontic procedure may be able to save your tooth.