Post-Endodontic Flare-Up — ORE Part 1 MCQ

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ModerateEndodonticsPost-Endodontic Flare-UpORE Part 1

A patient presents 3 days after root canal treatment of an upper lateral incisor with severe pain, swelling of the periapical region, and the tooth is very tender to percussion. What is the most likely diagnosis?

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Correct answer: C — Acute apical abscess (flare-up)

Option C is correct. The triad of severe pain, swelling, and percussion tenderness at 3 days post-RCT is pathognomonic for acute apical abscess (flare-up)—an acute inflammatory response at the periapex. Option E fails because normal post-operative discomfort is mild and transient (resolves 6–48 hours). Option B (vertical fracture) is wrong because fractures develop insidiously without acute swelling post-treatment and are radiographically evident. Option D (perforation) is incorrect as perforations occur during access or instrumentation, not as a delayed complication, and would not present with acute abscess formation alone. Option A (allergic reaction) is implausible because medication allergies present with urticaria, angioedema, or systemic signs rather than localised periapical swelling and percussion tenderness.

Reference: Abbott PV. Pain and flare-up after endodontic treatment. In: Cope A, et al. (2014). Systemic antibiotics for symptomatic apical periodontitis and acute apical abscess. Cochrane Database Syst Rev. 6:CD010136. https://pubmed.ncbi.nlm.nih.gov/24824057/; SDCEP Acute Apical Abscess (MADP). https://madp.sdcep.org.uk/content/conditions-library/acute_apical_abscess.html