With proper care most teeth that have had root canal treatment can last as long as other natural teeth.
In some cases, however, a tooth that has had treatment fails to heal.  Occasionally, the tooth becomes painful or diseased months or even years after successful treatment.
If your tooth has failed to heal or develops new problems, an additional endontic procedure may be able to save the tooth.  The following two procedures are employed to retreat teeth that have previously undergone root canal treatment.  The doctor recommends which one of these two procedures will best resolve your problem.

Conservative Retreatment

During a Conservative Retreatment, the endodontist reopens the tooth to gain access to the root canal filling material.  The filling is then removed, and the canals are cleaned.  The doctor will use a microscope to search for any additional canals which may have been left untreated.  He then cleans, fills and seals the canals.  A temporary filling is then placed in the tooth. After the retreatment is completed and the tooth is given some time to heal, you will need to return to your dentist to have the crown replaced or repaired.  Every effort is made to save existing crowns.

Endodontic Surgery
Although there are many surgical procedures that can be performed to save a tooth, the most common is call apicoectomy or root-end resection.  In this procedure, the endodontist opens the gum tissue near the tooth to see the underlying bone and to remove any inflamed or infected tissue.  The very end of the root is also removed.  A small filling may be placed to seal the end of the root canal and a few stitches or sutures are placed in the gum to help the tissue heal properly.  Over a period of months, the bone heals around the end of the root.
Bruce D. Schulman, D.D.S., P.A.