Root canal retreatment, also called endodontic retreatment, involves removing the previously filled root canal filling material or remaining tissue located in the center of the tooth and its root or roots (called the canal). Root canal retreatment is intended to allow you to keep a tooth that would otherwise require extraction. This treatment is being recommended for you in order to resolve the problems related to the diagnosis above.

Retreatment involves creating an opening through the biting surface of the tooth or crown to expose the previously filled root canal filling material, which is then removed from each canal that can be located. Medications and solutions may be used during treatment to disinfect the interior of the tooth in order to resist further infection. Each empty canal within the root is then re-filled, and the opening in the tooth is closed with a temporary restoration. Retreatment usually requires one or two visits, but more appointments may be required. During the course of treatment, x-rays will need to be taken.

Once the root canal retreatment is completed, it is essential to return promptly to your general dentist to permanently restore the treated tooth. A new crown is oftentimes necessary. The permanent restoration should be initiated within four weeks, but preferably as soon as possible. If your tooth already has an existing crown, it will need to be permanently repaired by your general dentist after the root canal retreatment is completed.

This procedure will not prevent future tooth decay, tooth fracture or gum disease, and occasionally a tooth that has had root canal re-treatment may require endodontic surgery or tooth extraction.

Risks are unlikely but may occur. They might include but are not limited to:

• Should anesthesia be necessary there is a possibility of numbness occurring in the tongue, lips, teeth, jaws and/or facial tissues resulting from either the anesthetic administration and or treatment procedures. Numbness is usually temporary but may be permanent.
• When retreatment is necessary, the removal of the previous root canal filling material may involve difficulties such as pulp chamber or root perforation, root fracture, or other complications. This may even require the extraction of the tooth.
• Instrument separation may occur. Because of the small diameter and fragility of root canal instruments, there is a possibility of an instrument separating. Many times the separated part of the instrument can be removed or even retained without causing problems. No matter how carefully instruments are manipulated the possibility of separation exists.
• A previously root canal treated tooth may subsequently become infected. Should this occur, it may be difficult to control the infection with retreatment only of the root canal and/or administration of antibiotics. The tooth may require a procedure called an apicoectomy that entails surgical removal of the end of the root and placement of filling material. In most instances, this treatment will take care of the problem. However, at times this procedure may not produce the desired result and preservation of the tooth.
• A retreated tooth may become brittle. Because of the loss of vital tissue in the pulp chamber and root canal, a tooth may become excessively brittle and break (fracture). At times, this could occur subsequent to retreatment. In such cases, the tooth may be preserved with a crown buildup and a crown to restore the tooth unless the fracture is too severe or too extensive. Should the fracture be too extensive for a crown buildup or extend below the level of supporting bone, the tooth may need extraction. 
• Should extraction be required, a replacement could be made with some type of prostheses such as a fixed bridge, a removable bridge, or an implant.