Retreatment
Occasionally a tooth that has undergone endodontic, treatment fails to heal or pain continues despite therapy. Although rare, sometimes a tooth initially responds to root canal therapy but becomes painful or diseased months or years later. When either of these situations occur, the tooth often can be maintained with a second endodontic treatment. Our doctors perform a comprehensive examination to ensure that root canal retreatment is your best option.
https://www.aae.org/patients/root-canal-treatment/endodontic-treatment-options/endodontic-retreatment/endodontic-retreatment-explained/
At this point, you will need to return to your dentist as soon as possible in order to have a new crown or restoration placed on the tooth to restore full functionality.