File Separation — ORE Part 1 MCQ

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HardEndodonticsFile SeparationORE Part 1

During root canal treatment of a lower molar, a file separates in the mesial canal. The fragment is lodged in the apical third. The canal has been instrumented to within 1 mm of the working length. What is the most appropriate management?

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Reveal the answer and explanation

Correct answer: E — Attempt to bypass the fragment and continue treatment to the working length

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

Bypassing the fragment (option A) is the recommended first-line approach. When a file separates in the apical third of a mandibular molar, the anatomical constraints and risks of aggressive retrieval (perforation, dentin loss, root fracture) make ultrasonic removal less attractive as an immediate intervention. Bypass attempts succeed in many cases, particularly when the canal has been instrumented near working length as here. If bypass fails, sequential alternatives remain: obturating to the coronal level of the fragment, or later surgical retrieval if needed. Immediate ultrasonic removal (B) risks iatrogenic damage; extraction (C) is premature without exploring conservative options; immediate surgical referral (D) skips the non-surgical pathway; and leaving the fragment without attempting bypass (E) abandons the opportunity for apical access and complete obturation, compromising prognosis.

Reference: Expert consensus on management of instrument separation in root canal therapy. Int J Oral Sci. 2025 Jun. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12146410/; Management of intracanal separated instruments. J Endod. 2013. https://pubmed.ncbi.nlm.nih.gov/23611371/