Q. What are the success rates for root canal retreatment?
A. In terms of retreatment success, I can only report my experience. For me, nonsurgical endodontic retreatment success is about 85%. Virtually all failures can be successfully retreated nonsurgically, which means about 15% of my nonsurgical retreatment cases will continue to fail and will require either microsurgery or extraction. The reason there is a higher failure rate performing retreatment is because we're trying to overcome a variety of existing problems. In other words, I can't solve every problem case that presents in my office. In some instances I tell the patient, We might get 3, 4 or 5 years out of this treatment and if signs or symptoms manifest, we can always consider surgery or extraction. Appreciate that if we can get a few additional years out of our retreatment efforts, then new technologies, materials and techniques will inevitably be available in the future to more predictably manage these cases.
Q. Retreatment must address a multitude of circumstances to reach a successful outcome. What are the circumstances that will make retreatment successful?
A. Typically, endodontic retreatment involves accessing through a restorative, in other instances, sacrificing the dentistry, or employing techniques and devices to remove and save an existing restorative. Next, all core materials must be eliminated from the pulp chamber. With access and vision the pulp chamber is inspected to see if there have been any missed orifices/canals. Additionally, retreatment involves the removal of post and cores, broken instruments, and previously placed obturation materials. During retreatment we must be prepared to manage iatrogenic events such as negotiating blocked canals, bypassing ledges, repairing perforations and sealing apical transportations. When disassembly has been successfully completed then the root canal is negotiated and optimally shaped. A shaped canal facilitates removing all of the residual materials and irritants harbored within the root canal system. Cleaned and shaped canals can then be three-dimensionally packed. In fact, if there are no radicular fractures, if the tooth is not periodontally hopeless, and if the tooth is restorable, then we should be able to achieve success.