Endodontic Retreatment and Surgical Endodontics
Retreatment and Surgical Endodontics tests why endodontic treatment fails and how to choose between non-surgical retreatment, surgery, or extraction.
Core rules
- Diagnose the cause before re-entering: missed canal, inadequate cleaning, coronal leakage, perforation, separated instrument, or persistent infection.
- Non-surgical retreatment is usually first when the canal is accessible and the tooth is restorable; it removes old filling material and addresses anatomy.
- Remove gutta-percha with rotary or ultrasonic instruments and solvent as needed; preserve canal walls and avoid pushing material apically.
- Surgery is considered when retreatment is impossible or has failed, with apical surgery, root-end resection, and retrofill using bioceramic material.
- CBCT is valuable for planning but must be justified; assess sinus, nerve, and root proximity.
Worked example
A previously treated molar is symptomatic with a short fill and an untreated MB2. The tooth is restorable and the canal is accessible, so non-surgical retreatment is planned: remove the crown restoration, retrieve gutta-percha, locate MB2, clean and shape, then re-obturate. Surgery would not address the untreated canal and would be premature.
Traps that cost marks
Operating without a diagnosis; choosing surgery for a missed canal; bypassing a separated instrument without assessing risk; perforating the furcation during post removal; and ignoring coronal leakage as the cause of failure.