In some cases, a tooth that has received endodontic (root canal) 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, called a retreatment, may be able to save your tooth. Retreatment can be more challenging so many dentists refer patients needing retreatment to endodontists.