Root Canal Irrigation — MFDS Part 1 MCQ
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Correct answer: A — Sodium hypochlorite
Sodium hypochlorite is the principal root canal irrigant because it combines broad antimicrobial activity with the clinically important ability to dissolve organic tissue and necrotic pulp remnants. Chlorhexidine is antimicrobial but does not dissolve organic tissue, so it is not the routine principal irrigant. Normal saline provides mechanical flushing but has little antimicrobial or tissue-dissolving action. Hydrogen peroxide is not recommended as the main contemporary irrigant. EDTA is a chelating agent used as an adjunct to remove the inorganic component of the smear layer; it does not replace sodium hypochlorite as the principal disinfecting irrigant. Sodium hypochlorite must be delivered cautiously to minimise the risk of extrusion into periradicular tissues.
Reference: British Endodontic Society. A Guide to Good Endodontic Practice, Chapter 5: Root canal treatment procedures. First edition, September 2022. https://www.rcseng.ac.uk/-/media/FDS/The-British-Endodontic-Society-guide-to-Good-Endodontic-Practice.pdf