Root_CanalEndodontically treated teeth can last a lifetime. Some of these teeth, however, may not heal properly or may develop new problems months, or even years, after they were initially treated. An additional endodontic treatment, called a retreatment (a second root canal procedure), can be performed, which could again, allow a patient to keep his or her tooth for a lifetime.

Root canal treatment is like any other medical or dental procedure. It may not heal or respond to treatment, as expected for many different reasons:

  • Often times, the permanent or temporary restoration may not have prevented salivary contamination inside the tooth.
  • There may have been an extended period of time between when the crown or other restoration was placed, and when the root canal treatment was completed. Most endodontists and studies agree that a definitive restoration should be placed within one month following an endodontic procedure.
  • There may be canals that were undetected, or canals that were too narrow, or calcified, to negotiate for the original practitioner.

There are occasions when a new problem arises with a tooth that has been treated previously that may compromise the original endodontic procedure:

  • If a tooth develops a vertical fracture after endodontic therapy, it is no longer a viable tooth to keep in the oral cavity.
  • A new cavity could develop in the tooth and expose the root canal to recontamination with bacteria.
  • The restoration that was placed in or on the tooth after the endodontic treatment was complete can break down, creating microleakage of bacteria into the canals, which can cause recontamination.

Before endodontic retreatment is started, the endodontist may want to take a CBCT of the tooth. A CBCT is a 3-dimensional X-ray that allows the endodontist to look at the tooth in all planes to help diagnose a pattern of bone loss that may be indicative of a vertical fracture, canal anatomy that may not have been addressed in the original endodontic therapy, and other factors that will help your endodontist determine the best treatment for the tooth.

Even though a CBCT may offer more information about why a retreatment may be necessary, sometimes the endodontist must go back into the tooth and look for a potential cause that prevented the original root canal from healing.

A retreatment procedure consists of removal of the original contents of the crown and canals and exploration of the tooth and internal root structure that remains. If any canals were missed, they are addressed at that time. If a fracture exists, then the tooth will ultimately need an extraction, and may be removed at that time or may be removed at some point in the future by another practitioner. Once these issues are addressed, and once the canals are free of their filling material, they are disinfected, and an antibacterial paste is placed in each of them. This paste may be left in the tooth for several weeks until the tooth is symptom-free, and all other clinical signs of infection have disappeared. At that point, the patient returns, and the root canals would once again be filled with the endodontic filling material and a restoration crown would top the tooth. Most endodontists will evaluate the tooth for proper healing for several years after a retreatment is performed.

Although the goal of primary endodontic therapy is to save the natural tooth for a lifetime, there may be factors that can affect that overall outcome. When this happens, other treatments can save a natural tooth for a lifetime.