It is always best to save your tooth if possible. "Retreated" teeth can function well for many years, even for a lifetime.
Occasionally a tooth may not heal as expected after initial endodontic therapy (root canal treatment) for a variety of reasons. These include the infection not healing properly, a delay in placement of the crown or other restoration, or the formation of new decay. If this happens, your dentist may recommend endodontic retreatment in order to save your tooth.
The Endodontic Retreatment Procedure
If you and your endodontist decide retreatment is the right approach, your endodontist will reopen your tooth to gain access to the root canal filling material. He or she will then remove the restoration and filling materials to allow access to blocked canals.
The endodontist will then clean the canals and carefully examine the inside of your tooth to identify any additional canals or unusual anatomy that requires treatment.
Your endodontist will clean the canals, seal them, and place a filling in the tooth. If the canals are unusually narrow or blocked, your endodontist may recommend endodontic surgery.
After your endodontist completes retreatment, you will need to return to your dentist as soon as possible to have a new crown or other restoration placed on the tooth to protect and restore it to its full function.