skip to main content

Persistent Sinus CBCT — ORE Part 1 MCQ

Instant feedback + full explanation. One question, done properly.

ModerateRadiology & ImagingPersistent Sinus CBCTORE Part 1

A patient has a chronic discharging intraoral sinus adjacent to a lower premolar that was root canal treated previously. A well-angulated periapical radiograph shows an apparently satisfactory root filling, but does not explain the persistent sinus. There is no facial swelling, fever or other evidence of spreading infection. What is the next most appropriate step?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: A — Refer for a small-volume CBCT assessment

**A is correct.** A chronic sinus from a root-treated tooth represents persistent endodontic disease, yet the apparently adequate two-dimensional radiograph does not identify its cause. Where conventional imaging is insufficient to explain clinical failure and the result will alter management, a justified small-volume CBCT assessment is appropriate before selecting retreatment, surgery or extraction. It may clarify untreated anatomy, periapical lesion extent and fracture-associated bone defects; CBCT findings must still be interpreted with the clinical examination because root-filling artefact can limit fracture detection. **B** and **C** are premature irreversible management choices without establishing the cause or prognosis. **D** is inappropriate: in the absence of spreading/systemic infection, antibiotics do not eliminate the intraradicular source and UK guidance advises against routine prescribing. **E** treats only the drainage point and has no role in resolving the dental source.

Reference: Patel S, Brown J, Semper M, Abella F, Mannocci F. European Society of Endodontology position statement: Use of cone beam computed tomography in Endodontics. International Endodontic Journal. 2019. https://pubmed.ncbi.nlm.nih.gov/31301231/