Root canal retreatment for a previously treated tooth

Why can a previously treated tooth develop problems?

Possible causes include complex or missed canal anatomy, bacterial re-entry through a compromised restoration, new decay, a crack, or other structural problems. Problems can appear soon after the original treatment or many years later, and are sometimes found only on a routine X-ray.

What happens during retreatment?

Following a diagnostic assessment, the existing root filling material is removed where this can be done safely and appropriately. Posts and, occasionally, fractured instruments may also need to be removed.

Under magnification, the canal system is carefully reassessed for previously untreated anatomy or other contributing factors. The canals are then cleaned, disinfected and sealed again.

Some cases require more than one appointment; an antibacterial dressing is often placed between visits to help the surrounding tissues settle.

When surgery may be considered instead

If the canals cannot be reached through the crown of the tooth — for example when a large post cannot be removed safely — endodontic microsurgery may be recommended instead of, or in addition to, retreatment. We explain which approach gives your tooth the better outlook.

Benefits

• an opportunity to preserve a previously treated tooth;
• renewed cleaning and disinfection of the root canal system;
• improved visualisation of complex anatomy under magnification;
• an alternative to extraction in appropriately selected cases.

Where a tooth is fractured or has too little structure left to restore, we will say so and help you and your dentist plan the next step.