If the root canal has failed for whatever reason, is it worth the time, effort, cost and slightly reduced prognosis of having another go? Well, it depends. A high percentage of the re-root treated teeth will be successful the second time around so if you can afford it, I certainly would.
If I had done a root canal on a patient that failed, I am not sure that I would do, or see anything different if I was to attempt it again and for this reason, I personally would refer the case to an endodontist. Perhaps they may be able to identify something I have missed- maybe an extra canal for example. This isn't always a possibility in some more remote rural areas- so some dentists may try again themselves.
The process for a re-root canal treatment is almost exactly the same- the only difference being the initial stage involves trying to remove all of the gutta percha from each of the canals instead of the nerve. Strong solutions are used to soften and partially dissolve the set material in the canal and then a range of instruments used to help remove this.
If a post
has been placed in the tooth to provide support for a crown, this makes a re-root canal treatment considerably more difficult and sometimes impossible. In order to re- sterilise the canal, the post must be first removed and this can be a real pain in the neck and
you can risk fracturing the root in the process. Not fun all round. If it is an anterior (front) tooth, an apisectomy can be performed. This is incredibly tough, in fact, almost pointless in molar teeth so it may be better to wave good bye and plan a replacement for the tooth