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Endodontic Smear Layer — NDEB AFK MCQ

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HardEndodonticsEndodontic Smear LayerNDEB AFK

The smear layer created during endodontic instrumentation differs from the restorative smear layer in that it may contain which additional component?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: B — Bacterial biofilm remnants and pulp tissue fragments

The endodontic smear layer (2-5 μm thick) is created by rotary or hand instrumentation of the root canal walls and contains ground-up dentin, predentin, pulp tissue remnants, odontoblastic processes, and importantly, bacteria and their by-products. This bacterial contamination distinguishes it from the restorative smear layer (which contains no bacteria in uninfected dentin). Removal of the endodontic smear layer with NaOCl and EDTA improves disinfection, sealer penetration, and obturation quality.

Reference: Torabinejad – Endodontics: Principles and Practice, 6th ed., 2021