Whenever possible, it is best to save your natural tooth. Retreated teeth can function well for years, even for a lifetime.
As occasionally happens with any dental or medical procedure, a tooth may not heal as expected after initial endodontic therapy (root canal treatment) for a variety of reasons. If the infection did not heal properly, placement of the crown or other restoration was delayed, or new decay has formed, you may need endodontic retreatment in order to save your tooth.
Retreatment Procedure
Retreatment involves removal of the previous root canal filling material in order to allow reinstrumentation of the root system. After re-cleaning the canal walls, the endoodnist can then carefully examine the inside of your tooth using magnification and illumination, searching for any additional canals or unusual anatomy that may require treatment.
Once the canals have been re-cleaned, the roots are filled with a root filling material and a temporary filling is placed in the tooth. You will then need to return to your regular dentist as soon as possible to have a permanent filling and possibly a crown or other restoration placed on the tooth to protect and restore it to its full function.