Routine root canal therapy has a very high success rate of ~90-95%; a tooth that has had a prior root canal will likely never have to be redone. However, in some rare situations a prior infection will persist inside the previously root canal treated tooth or a new infection may contaminate and develop in the root canal filling. In these instances, retreatment of an existing root canal treated tooth is necessary to remove the infection. Retreatment can be a very predictable treatment option, but many factors need to be considered that will determine the overall success of your specific retreatment. Generally, retreatment has a success rate of greater than 85%.



Sometimes, the anatomy of the root canals of teeth can be very complicated; they may turn and twist like a narrow road in the middle of a rocky mountain range. When these challenging features exist, it reduces the Dentist’s ability to effectively clean and disinfect the root canal infection. There are also instances where the root canal spaces of the teeth may be “calcified”, or so narrow they appear to be blocked. These canals may be very difficult to clean with instruments. In both these cases, the original root canal infection may not be effectively removed, causing a persistent infection that may produce tooth and jaw pain.



In another type of scenario the original root canal therapy could have been performed successfully with the initial infection being completely removed. However, sometimes new dental decay (cavity), a crack in the tooth from trauma/grinding/clenching/oral habits, or leakage of saliva into a tooth through a broken filling can cause a new root canal infection to develop inside the tooth.



After gently numbing your tooth with special topical jelly and anesthetics, Dr. Kruszewski will isolate your tooth with a small rubber sheet (think of it as a “tooth poncho”). This ensures that there will be no contamination of the inside of the tooth from saliva (which naturally has much bacteria), and will protect you from the strong disinfectants, solvents, and materials used during treatment. A small hole will be made, or access opening, on the chewing surface of the tooth. This enables Dr. Kruszewski to reach the infected pulp space of your tooth. The old infected root canal filling will be removed and the inside of your pulp chamber and root canal areas will be cleaned and disinfected, removing the infection with special tiny instruments and disinfectant solutions.


An xray will be taken to verify the fit of the root canal fillings in your tooth and the inside of the root canals will then be dried. The inside of the root will be sealed with a permanent gutta percha filling, a special rubber-like material with a cement. A temporary filling will then be placed in the access opening and final xray will be taken.

Once retreatment is complete, it is recommended you return to your general dentist within ~2 weeks. Then, your general dentist will replace Dr. Kruszewski’s temporary filling with a permanent filling of their choice, called a core buildup. A new crown may be recommended after the core buildup is completed, but your general dentist will explain what is best for your tooth.

After treatment, you may have some mild discomfort when you chew on your tooth for a few days to 1 week while the area is healing. Dr. Kruszewski will explain which medications are appropriate to use during healing.

Your body will begin to heal the area in the bone where the abscess was located near the root tips. This process usually takes 1-2 years to occur, and in some cases may take up to ~4 years. Dr. Kruszewski will re-examine your tooth at appropriate times after treatment to ensure the bone is healing properly.