Comparative evaluation of free available chlorine in sodium hypochlorite solutions admixed with novel chelating agents

Aim: This study evaluated the effects of ethylenediaminetetraacetic acid (EDTA), etidronic acid (HEBP), peracetic acid (PAA), phytic acid (IP6), and glycolic acid (AHA) on the free available chlorine (FAC) content of sodium hypochlorite (NaOCl) solution when mixed in varying proportions. Methods: Twenty-five milliliter aliquots of 5.25% NaOCl were admixed in ratios of 90:10, 80:20, and 50:50 with secondary irrigation solutions: (a) 17% EDTA, (b) 9% HEBP, (c) 1% PAA, (d) 1% IP6, and (e) 10% AHA. Iodometric titration was done to evaluate the change in FAC. Statistical differences between means were determined using a post hoc Tukey’s analysis test after an analysis of variance. Results: On titration, the mean FAC value of NaOCl at baseline was 2.02 g%. On mixing NaOCl with EDTA and HEBP, the FAC decreased in all three proportions. On mixing NaOCl and PAA, the FAC increased on increasing dilution in all three proportions. On mixing NaOCl and IP6, the FAC decreased only in 80:20 dilutions. On mixing NaOCl and AHA, the FAC increased on increasing dilution in all three proportions. Conclusion: The FAC on the combination of NaOCl with AHA, PAA, and IP6 remained unaltered or decreased marginally, suggesting that the antimicrobial properties of NaOCl might be preserved.