Apical surgery will be used when:

• The root canal access to the area of the persisting infection is blocked by a large post, a broken instrument, or calcified materials for which the continuing removal of the blockade can cause root perforation or weaken the affected root, thereby increasing the risk of root fracture.
• There is no sign of bone healing after 5 years OR the area of bone damage around the root enlarges although root canal treatment is done correctly without any missing/untreated portion of the root canals, caries, or leakage of the crown restoration.

Apical surgery: Apicoectomy and MT A retrograde fillings on the M and D roots

The patient presented with pain on a lower left tooth. Biting and percussion tests reproduced the pain from the tooth #19. Root canal treatment was completed previously by his dentist > 5 years ago with persisting lesions in the periapical bone around the M and D roots (red arrows). Due to a broken file (blue arrows) in the apical third of the M root and a large metal post placed near the furcal surface of the D root, the access for nonsurgical retreatment of the M and D roots was severely compromised. Apical surgery was completed to remove the infected M and D root ends and subsequent placement of the MTA retrograde fillings to seal the M and D roots.

Diagnosis: #19 Previously treated tooth with symptomatic apical periodontitis