Combined endodontic-periodontal lesion — ORE Part 1 MCQ

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HardPeriodontologyCombined endodontic-periodontal lesionORE Part 1

A root-filled lower molar has persistent deep periodontal probing on the distal aspect, grade I mobility and a sinus tract. The periapical radiograph shows a distal vertical bone defect communicating with a periapical radiolucency, and the root filling is short. Adjacent teeth have mild periodontitis. What is the most likely diagnosis?

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Correct answer: D — Combined endodontic-periodontal lesion

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

The constellation of clinical and radiographic findings—persistent deep periodontal probing with a vertical bone defect extending to the apex, sinus tract, periapical radiolucency, and short root filling of a previously treated molar—is characteristic of a combined endodontic-periodontal lesion. Per SDCEP guidance, this diagnosis requires both periodontal signs (increased pocket depth, clinical attachment loss, sinus tract) and endodontic signs (pulpal necrosis evidenced by prior root canal therapy, periapical pathology). The distal vertical defect communicating with the periapical lesion indicates pathologic communication between the failed endodontic system and the periodontal compartment. Option A (simple gingivitis) ignores the periapical pathology and bone loss severity. Option C (reversible pulpitis) is inconsistent with a tooth already root-filled and with persistent periapical radiolucency. Options D and E are unrelated to periodontal or endodontic pathology.

Reference: SDCEP. Combined endo-perio lesions. In: Prevention and Treatment of Periodontal Diseases. https://www.periodontalcare.sdcep.org.uk/guidance/managing-disease/other-periodontal-conditions/combined-endo-perio-lesions/