EDTA Function — NDEB AFK MCQ
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Correct answer: D — To remove the inorganic component of the smear layer
17% EDTA (ethylenediaminetetraacetic acid) is a chelating agent that removes the inorganic component (calcium ions from hydroxyapatite) of the smear layer from the root canal walls. It is used as a final irrigant after NaOCl to remove the smear layer and open dentinal tubule orifices, improving sealer adaptation and penetration. EDTA has minimal antimicrobial activity. A typical protocol is alternating NaOCl and EDTA, with a final flush of NaOCl after EDTA (EDTA inactivates NaOCl if mixed).
Reference: Torabinejad – Endodontics: Principles and Practice, 6th ed., 2021