Periapical Radiolucency Interpretation — MFDS Part 1 MCQ

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EasyRadiologyPeriapical Radiolucency InterpretationMFDS Part 1

A mature permanent tooth does not respond to cold or electric pulp sensibility testing, although adjacent control teeth respond normally. A periapical radiograph shows loss of the lamina dura at the root apex with an associated periapical radiolucency. What is the most likely diagnosis?

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Correct answer: B — Pulp necrosis with apical periodontitis

The correct answer is B. Failure to respond to sensibility testing, with normal responses from control teeth, supports pulp necrosis. Loss of the apical lamina dura and an associated periapical radiolucency indicate apical periodontitis. A conventional radiograph cannot reliably distinguish a periapical granuloma, abscess or radicular cyst, so these should not be assigned as the definitive radiographic diagnosis. Normal anatomy would not explain disruption of the lamina dura. Hypercementosis produces bulbous radiopaque root enlargement with an intact periodontal ligament outline. Internal resorption produces a centred enlargement of the pulp space, while an enamel pearl is a small radiopaque enamel deposit, usually near a molar furcation.

Reference: British Endodontic Society, Guide to Good Endodontic Practice, Chapters 1 and 6, 2022. https://www.rcseng.ac.uk/-/media/FDS/The-British-Endodontic-Society-guide-to-Good-Endodontic-Practice.pdf