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Published on: May 26, 2023
Impact of Chelators on FAC Following Interaction With NaOCl: A Focused Evidence Synthesis Based on a Systematic
Hinrich Meijer1, Louise Franchina1, Poonam Nagarani1
1School of Medicine and Dentistry, Griffith University, Gold Coast, Australia.
Summary
Endodontic chelators significantly reduce free available chlorine (FAC) in sodium hypochlorite (NaOCl) irrigants. Careful selection and use of chelators are crucial for maintaining NaOCl efficacy in root canal treatment.
Area of Science:
- Endodontics
- Dental Materials Science
- Chemistry
Background:
- Sodium hypochlorite (NaOCl) is a vital irrigant in endodontics for its antimicrobial and tissue-dissolving properties.
- Endodontic chelators are used to remove the smear layer, but their interaction with NaOCl is not fully understood.
- Free available chlorine (FAC) concentration dictates NaOCl's effectiveness.
Purpose of the Study:
- To systematically review the effects of various endodontic chelators on FAC levels in NaOCl.
- To analyze how factors like chelator concentration, contact time, temperature, and pH influence FAC degradation.
- To assess the risk of bias in relevant in vitro studies.
Main Methods:
- Systematic review adhering to PRISMA guidelines.
- Inclusion of 12 in vitro studies evaluating 17 different chelators.
- Assessment of risk of bias using the Quality Assessment Tool for In Vitro Studies (QUIN).
- Measurement of FAC using iodometric titration.
Main Results:
- Certain chelators (Na2EDTA, malic acid, citric acid, ATMA, SmearOFF) caused rapid FAC loss (>70% within 1 min).
- Other chelators (Na2EDTA, HEDP-based, aminopolycarboxylates) showed minimal FAC reduction (0%-25%).
- FAC degradation was influenced by chelator type, pH, temperature, and exposure time.
Conclusions:
- Chelator-NaOCl interactions can significantly reduce FAC, potentially compromising antimicrobial and tissue-dissolving efficacy.
- Clinicians must consider chelator choice, contact time, and irrigant replenishment to optimize endodontic treatment outcomes.
- Tailoring irrigation protocols is essential for maximizing the clinical effectiveness of NaOCl.
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