No! A root canal is not a black and white cure, it is a therapy with a high success rate. Sometimes the infection never clears up and tooth has to be either A) Retreated, B) have a retrofill (a retrofill is when we lay the gum tissue back, curette out the infection, and place a silver filling at the bottom or the root) or C) extract the tooth. The success or failure of a root canal can result from causes that are not under our control (such as, the anatomy of the tooth, breakage of endodontic files in the root or the patient’s own immune system).