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 on Enterococcus faecalis (E. faecalis) strain. The 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 the 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 and 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 differences from each other. For N-EDTA, the MIC and MBC values were 12.5 mu g/ml (1:8), and MBIC values were 36 mu g/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 the smear layer and sealer penetration depth.

Automated summary

In terms of cell compatibility, there was no statistical difference between N-EDTA and MTAD. N-EDTA showed higher efficacy in biofilm disruption and bacterial killing compared to MTAD, while both materials showed similar performance in smear layer removal and sealer penetration depth.