With proper care, most teeth that have had endodontic (root canal) treatment can last as long as other natural teeth. Root canals have a 98% success rate. In some cases, however, a tooth that has received endodontic treatment fails to heal. Occasionally, after may years a root canal can begin to flare up again. This is generally a sign the root canal has failed and may need to be retreated.

Why do I need retreatment?

As occasionally happens with any dental or medical procedure, a tooth may not heal as expected after initial treatment for a variety of reasons:

• Narrow or curved canals were not treated during the initial procedure.
• Complicated canal anatomy went undetected in the first procedure.
• The placement of the crown or another restoration was delayed following the endodontic treatment.
• The restoration did not prevent salivary contamination to the inside of the tooth.
• Fracture in the root tooth.

For example:

New decay can expose the root canal filling material to bacteria, causing a new infection in the tooth. A loose, cracked or broken crown or filling can expose the tooth to a new infection. A tooth sustains a fracture. Retreatment is performed in two visits and involves the following:

• At the initial visit the dentist will examine the tooth, take x-rays and discuss your treatment options. If you and your dentist choose retreatment, the retreatment will be scheduled at that time for a future date.
• At the retreatment appointment the dentist will administer local anesthetic to numb the tooth. After the tooth is numb, the dentist will reopen your tooth to gain access to the root canal filling material. In many cases, complex restorative materials (crown, post and core material) must be disassembled and removed to permit access to the root canals.
• After removing the canal filling, the dentist can clean the canals and carefully examine the inside of your tooth using a microscope, searching for any additional canals or unusual anatomy that requires treatment.
• After cleaning the canals, the dentist will fill and seal the canals and place a temporary filling in the tooth. Post space may also be prepared at this time.
• After your dentist completes retreatment, you will need to return to have a new crown or other restoration placed on the tooth to protect and restore it to full function.
• If the canals are unusually narrow or blocked, your dentist may recommend endodontic surgery or extraction.