Root Canal Retreatment
Occasionally, a tooth has previously had root canal treatment, and the tooth and infection does not initially respond to treatment. There are many reasons why teeth may not respond to primary root canal therapy –
One common reason that requires retreatment is inadequate debridement of the root canal system. This may be due to poor endodontic access, missed canals, complex tooth anatomy or inadequate shaping and disinfection of the root canal system. In these cases, retreating the root canal system may allow the tooth to respond.
If the internal portion of the tooth has been exposed to the oral environment because of new decay, exposure of the old root canal filling material to the oral environment may mean the tooth becomes recontaminated with bacteria. If complex and expensive restorative dentistry is planned in the future, then ideally the contaminated teeth are retreated to minimize the future risk of new infection.
Endodontic retreatment is technically demanding and can be time consuming procedure as meticulous care is required. Careful disassembly of the tooth is aided by the use of an operating microscope and ultrasonic instrumentation devices which allow precise removal of old materials.