Endodontic Retreatment Through the Crown: Periapical Lesion Due to a Missed Canal

Key points: Previously treated tooth presenting with an asymptomatic periapical lesion caused by an untreated (missed) canal. Retreatment was performed through the existing crown, avoiding the need for prosthetic replacement at the outset. Clinical Presentation A patient presented with a previously endodontically treated tooth that was incidentally found to harbour a periapical lesion on routine radiographic examination. The patient was entirely asymptomatic — no pain, no swelling, no sinus tract — which is consistent with a chronic, low-grade periapical infection sustained by an untreated canal that had been missed during the original treatment. The existing prosthetic crown appeared clinically acceptable, making retreatment through the crown the preferred conservative approach. Pre-op radiograph — periapical lesion associated with a missed canal Pre-op…