What is Endodontic Retreatment?

Even the best root canals can need retreatment. Nothing can be guaranteed and nothing lasts forever. Although several studies report root canal success rates above 90-95%, sometimes a previous root canal needs to be retreated (redone).

Some common reasons for retreatment are:

1. Poor access to the root canal system
2. Procedural errors (perforation and/or fractured instruments)
3. Untreated (missed) canal – second most common
4. Inadequate (time) disinfection of the canal
5. Not shaped enough
6. Entire canal not instrumented
7. Poorly obturated (sealed) canal
8. Too short or long sealing
9. Failing restoration (filling, crown, and/or bridge) – most common reason! Usually because of caries (a cavity).

The retreatment of a previous root canal therapy is very similar to root canal therapy, but may take two appointments. The previous root canal is dissembled, with different medicines. Once everything is removed, the root canal system is disinfected, and a new filling material is inserted. Prior to initiating retreatment, each case is presented to the patient. Sometimes a tooth is retreated to look for a crack on the inside of the root with a surgical microscope. The difficultly depends on what and how much needs to be dissembled.