Comparative evaluation of effect of Nisin incorporated ethylenediamine tetraacetic acid and MTAD on endodontic biofilm eradication, smear layer removal and depth of sealer penetration.

Objectives: To comparatively evaluate the Nisin incorporated ethylenediamine tetraacetic acid (N-EDTA) and MTAD on cytotoxicity, endodontic biofilm eradication potential, smear layer removal ability and sealer penetration depth. Materials: and methods N-EDTA was prepared and characterized using High performance liquid chromatography(HPLC). Minimum Inhibitory, Minimum Bactericidal and Minimum Biofilm Inhibitory Concentration(MBC,MIC and MBIC) were determined. Cytocompatibility of N- EDTA and MTAD was evaluated using 3,(4,5-dimethylthiazol-2- yl)-2,5-diphenyltetrazolium bromide(MTT) based colorimetric assay. Dentin specimens ( n  = 88 for antibacterial analysis, n=170 for sealer penetration depth) were prepared and subjected to the classical irrigating strategy and obturation respectively. The scanning electron microscopic evaluation(SEM) was done for evaluation of biofilm disruption and smear layer removal. Confocal laser scanning microscopy(CLSM) evaluation was done for determining percentage of bacterial viability and sealer penetration depth. Statistical analysis of One-way ANOVA and Tukey’s HSD post hoc tests for bacterial viability, Kruskal-Wallis test and Mann Whitney test for smear layer removal and depth of penetration were done with the significance level set at p<0.05. Results: MTAD and N- EDTA showed cytocompatibility without any statistical difference each other. For N-EDTA, the MIC and MBC values were 12.5μg/ml (1:8) and MBIC values were 36 μg/ml. Biofilm disruption and killed bacterial percentage of N-EDTA was statistically higher than MTAD, whereas both the materials showed similar efficacy in the removal of smear layer and sealer penetration depth. Conclusion: N-EDTA had negligible cytotoxicity with similar smear layer removal ability, sealer penetration and better antibiofilm potential than MTAD Clinical relevance N-EDTA can serve as a viable alternative endodontic irrigant.