Sometimes teeth that have had root canal therapy do not heal properly, which can lead to pain and reinfection of the affected tooth. A root canal re-treatment procedure can be done to remove the infection and save the tooth. Initial root canal treatment may not fully heal due to several causes, which may include tooth decay or trauma, where bacteria is allowed to seep back into the root canal and reinfect the tooth during a root canal. During the re-treatment procedure, your doctor first removes any existing restorative materials in order to regain access to the root canal. Once the restorative material is removed, the canals are thoroughly cleaned and examined for any additional or misshaped canals that may require treatment. Next, the root is refilled with a special sealing material, and the opening at the top of the tooth is also refilled and sealed. Once the root canal re-treatment is complete and the infection removed, your doctor will design and place a new crown over the tooth, restoring it to proper form and function.