Persistent Sinus CBCT Investigation — ORE Part 1 MCQ

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ModerateRadiology & ImagingPersistent Sinus CBCT InvestigationORE Part 1

A patient has a persistently draining intraoral sinus tract on the buccal alveolar mucosa adjacent to a root-treated mandibular molar. Non-surgical endodontic retreatment was completed 6 months ago. A current periapical radiograph does not explain the persistent drainage. What is the most appropriate next investigation?

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Correct answer: D — Limited-field CBCT of the affected tooth

Explanation lettering: B = shown as A · D = shown as B · E = shown as C · A = shown as D · C = shown as E

A is correct. Persistent sinus drainage six months after retreatment is not an acceptable outcome, and the conventional radiograph has not identified the cause. UK endodontic guidance supports justified CBCT after conventional radiographs when additional information is needed for diagnosis or treatment planning. A limited-field scan is appropriate because it can provide three-dimensional assessment of local causes of failure, including complex canal anatomy, untreated anatomy, root damage or fracture. B is unlikely to add useful information when a current periapical radiograph is already non-diagnostic. C gives an unnecessarily large field and radiation burden for a local dental problem. D is not first-line without a history suggesting systemic disease or recurrent unusual infections. E inappropriately accepts persistent disease rather than investigating its cause.

Reference: British Endodontic Society, The British Endodontic Society guide to good endodontic practice, 2022, section on cone beam computed tomography. https://www.rcseng.ac.uk/-/media/FDS/The-British-Endodontic-Society-guide-to-Good-Endodontic-Practice.pdf