After initial root canal therapy, a patient has a persistent sinus tract and tenderness. What is the most likely cause and next step?

After initial root canal therapy, a patient has a persistent sinus tract and tenderness. What is the most likely cause and next step?

• A. The sinus tract is a normal aftercare finding; continue routine follow-up.
• B. Possible missed canal or persistent infection; obtain updated imaging and consider retreatment or surgical endodontics (apicoectomy) based on anatomy.
• C. Extraction should be planned immediately.
• D. Antibiotics should be continued indefinitely.

Answer: (B)

Persistent sinus drainage after root canal therapy signals ongoing infection at the periradicular area. The most likely cause is a missed canal or incomplete debridement/obturation in a tooth with complex anatomy, so the infection hasn’t fully resolved. The next step is to obtain updated imaging, preferably a CBCT, to reassess the canal system and periapical status for hidden or accessory canals. Based on what the imaging shows, retreatment to locate and thoroughly clean and refit the canal is typically the best course; if retreatment isn’t feasible or the lesion persists at the apex, surgical endodontics (apicoectomy with retrograde filling) may be considered depending on anatomy and access. Antibiotics alone won’t resolve the drainage, and extraction is not the immediate plan unless the tooth is non-restorable.

Persistent sinus drainage after root canal therapy signals ongoing infection at the periradicular area. The most likely cause is a missed canal or incomplete debridement/obturation in a tooth with complex anatomy, so the infection hasn’t fully resolved. The next step is to obtain updated imaging, preferably a CBCT, to reassess the canal system and periapical status for hidden or accessory canals. Based on what the imaging shows, retreatment to locate and thoroughly clean and refit the canal is typically the best course; if retreatment isn’t feasible or the lesion persists at the apex, surgical endodontics (apicoectomy with retrograde filling) may be considered depending on anatomy and access. Antibiotics alone won’t resolve the drainage, and extraction is not the immediate plan unless the tooth is non-restorable.