Combining endodontic retreatment with endodontic surgery

Endodontic failure happens on occasion due to improper canal filling or persistent bacteria. It then becomes necessary to look at both surgical and nonsurgical treatment options.

We’ll first briefly discuss what causes endodontic failure and then touch on scenarios best suited for endodontic retreatment, endodontic surgery or a combination of the two.

Determining the source of bacteria

Proper retreatment of a failed root canal begins with determining how bacteria first entered the canal system or periradicular tissues, and then removing the infection. Successfully identifying the cause requires ruling out other issues, such as fractures or periodontal disease.

This diagnosis may include:

• Diagnostic testing
• Radiographic imagery
• Assessment by the clinician

Nonsurgical treatment is preferable

Whenever possible, saving the tooth with nonsurgical retreatment is the first choice. Although some challenges may appear during complex restorations, such as with post or canal obturators, they can be alleviated through skillful technique coupled with the use of magnification and lighting.

When endodontic surgery is necessary

There are a number of cases where nonsurgical retreatment may not be effective. Consider endodontic surgery when:

• Intracanal impediments exist
• Large restorations or posts must be removed
• Separated instruments in the apical third cannot be bypassed
• The canal is ledged or otherwise inaccessible

Taking a combined approach

Sometimes a two-pronged strategy using both nonsurgical and surgical techniques is required. Bacteria in the periradicular tissues necessitate surgical removal, meaning that patients with etiology in both the canal and the periradicular space may need to undergo both procedures to stop a persisting disease.

A combined tactic may also be required when one or more of the following is present:

• Large lesions
• Canal transportation
• Zipping
• Overfills
• Perforations