In some cases, a tooth that has undergone root canal therapy may not heal as expected, or complications may arise after the procedure that threaten the tooth’s health. Root canal retreatment is designed to address these issues. The process involves removing the previous crown and filling material, thoroughly cleaning the root canals, and then refilling and re-crowning the tooth. Essentially, retreatment follows the same steps as the original procedure, with the main difference being the removal of existing restorative materials. The success rate for root canal retreatment is approximately 75%.

Root canal treatments and retreatments are usually preferable to tooth extraction. If a tooth has healthy gums, solid bone support, and an intact surface, it can often be saved. Retreatment is typically more cost-effective than alternatives such as dental implants, complex bridgework, or prosthetic teeth, which require ongoing maintenance and may not feel as natural as a preserved tooth.

Why Root Canal Retreatment Is Needed

Though the idea of additional endodontic work may seem daunting, retreatment is generally straightforward and can often be completed in 1–3 visits. Common reasons a root canal may fail include:

  • Cracked crown allowing filling material to leak
  • Narrow or curved canals left untreated in the original procedure
  • Delay in placing a permanent restoration after the initial treatment
  • New decay or fracture in the treated tooth
  • Saliva entering the restoration
  • Undetected complex canal anatomy

What Root Canal Retreatment Involves

On the day of the retreatment, a local anesthetic is typically administered. The tooth is isolated with a rubber dam to protect it from saliva and bacteria during the procedure. The extent of treatment in a single visit depends on inflammation and the complexity of the canals.

Step 1: Accessing the Tooth
If a crown or post is present, it will be removed to access the root canals.

Step 2: Removing Old Material
Previous filling material and any obstructions are removed using an ultrasonic handpiece, which vibrates unwanted material loose. Small instruments are then used to clean and reshape the canals. X-rays may be taken to ensure thorough cleaning. If canals are difficult to treat in one session, medicated packing material is placed, and the procedure is completed during a follow-up visit.

Step 3: Sealing the Canals
Once the canals are fully cleaned, gutta-percha, a biocompatible rubber-like material, is used to fill and seal the canals, preventing bacterial reinfection.

Step 4: Restoring the Tooth
A temporary crown or filling is applied immediately after retreatment. Once the tooth has stabilized, a permanent, color-matched crown is placed to restore full function and aesthetics.