Periapical Scar — ORE Part 1 MCQ

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HardRadiology & ImagingPeriapical ScarORE Part 1

A periapical radiograph of a previously root-treated lower premolar shows a well-defined radiolucency at the apex that has not changed in size over 12 months of monitoring. The tooth is asymptomatic and functional. What is the most appropriate diagnosis?

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Correct answer: A — Periapical scar (fibrous healing)

A stable, asymptomatic periapical radiolucency 12 months post-RCT indicates successful treatment and healing via fibrous tissue formation (periapical scar). At 12 months, approximately 70% of periapical lesions show radiographic improvement, and stability indicates positive outcome per ESE guidelines and Periapical/Endodontic Status Scale criteria. Persistent infection (B) is excluded by lack of symptoms and progression. Cysts (C) and granulomas (D) represent histological diagnoses of active inflammatory lesions incompatible with stability and asymptomatic status. Failed treatment (E) is contradicted by functional status and absence of deterioration. The discriminating feature is the 12-month timepoint of radiographic stability, which is the evidence-based threshold for confirming successful endodontic healing.

Reference: Ørstavik D, Pitt Ford TR. Apical periodontitis: microbial infection and host responses. In: Ørstavik D, Pitt Ford TR, eds. Essential Endodontology. 2nd ed. Oxford: Blackwell Science; 1998. Also: European Society of Endodontology (ESE) consensus on assessment of endodontic treatment success based on 12-month clinical and radiological criteria (2006, cited in subsequent protocols). https://pubmed.ncbi.nlm.nih.gov/2047106/