We are performing root canals with the assumption that you will have them for life, and we have a very high rate of long term success (according to the literature, endodontists have a greater than 95% long term success rate), but there are root canals that fail.  Failures are usually due to either a fracture, recurrent decay, or difficulties with the tooth’s anatomy that do not allow a “seal” that prevents bacterial invasion of the space.  Sometimes the tooth can still be saved with a surgical procedure, and we will recommend this if it is the best option.  While saving your natural tooth is usually the best option, occasionally the only option will be to extract a tooth and replace it with either a bridge or implant.