Effect of different irrigating protocols on push out bond strength of Resilon/Epiphany obturation system

Purpose: To evaluate the effect of different root canal irrigating regimens on the push-out bond strength of RealSeal root canal obturation system. Materials and methods: 16 mm ± 1 of roots of 70 freshly extracted single rooted human teeth were obtained and divided randomly into seven groups (n= 10) according to irrigation regimens throughout root canal preparation and final rinse: 1(DWeDW), 2(NaOCleNaOCl), 3(NaOCleMTAD), 4(NaOCleEDTA), 5(CHXeCHX), 6(CHXeMTAD), 7 (CHXeEDTA). All root canals of all groups were prepared using K3 root canal preparation system up to size #40/0.06 taper and filled using RealSeal Root canal obturation system. Two-millimeter thick horizontal sections from the coronal, middle and apical thirds of each root were sliced for the push-out bond strength measurement. Results: In cervical sections the highest push-out bond strength value was recorded for NaOCleMTAD (4.074 ± 2.524) followed by CHXeMTAD (3.795 ± 1.935), CHXeEDTA (2.659 ± 0.587), NaOCleEDTA (2.404 ± 1.166), CHXeCHX (1.905 ± 0.573), NaOCleNaOCl (1.690 ± 0.427) and the least value was recorded for DWeDW (0.791 ± 0.381) with statistical significant difference between groups (P 0.001). In middle sections the highest value was recorded for CHXeMTAD (3.801 ± 0.186) followed by CHXEDTA (3.222 ± 0.148), NaOCleMTAD (3.119 ± 0.306), NaOCleEDTA (2.066 ± 0.805), CHXeCHX (1.624 ± 0.724), NaOCleNaOCl (1.350 ± 0.539) while the lowest value was recorded for DWeDW (0.684 ± 0.382) with no statistical significant difference among groups (P = 0.067). In apical sections the highest value was recorded for groups NaOCleMTAD (2.654 ± 0.733), CHXeMTAD (2.020 ± 1.5522), CHXeEDTA (1.878 ± 0.808), NaOCleEDTA (1.763 ± 0.068), NaOCleNaOCl (1.260 ± 0.846), CHXeCHX (1.175 ± 0.298) and the lowest value was recorded for DWeDW(0.631 ± 0.152) with statistical significant difference between groups (P= 0.006). Conclusion: Whenever root canal obturation using RealSeal is decided, it is preferred to use NaOCl solution throughout instrumentation in association with MTAD as a final irrigant after instrumentation to obtain a the highest push-out bond strength to root canal dentin specially at the coronal sections that showed higher bond strength than middle and apical sections.