ABSTRACT INTRODUCTION:

The objective was to compare the effects of irrigation protocols on the push-out bond strength of calcium silicate materials at two different time periods (7-days and 3-months).

Root canals (n=300) were irrigated with one of the following (n=60): group 1 (3% NaOCl–17% EDTA); group 2 (17% EDTA–3% NaOCl); group 3 (1:1 mixture of 6% NaOCl and 18% etidronic acid); group 4 (3% NaOCl–QMix 2in1); group 5 (3% NaOCl–2% chlorhexidine). Specimens were subdivided into three subgroups (n=20): A, Endosequence BC sealer [EBC]; B, MTA Plus [MTA-P]; C, Tech Biosealer Endo [TECH]. Specimens were suspended in phosphate buffered saline [PBS] for 7 days or 3 months (n=10 per sealer). Push-out bond strength was measured and data were analyzed (P=0.05).

MTA-P: showed the highest bond strength at both time periods, when NaOCl+EA was used as an irrigant. This was not significantly different from the strength produced when NaOCl–QMix was used for 7 days (P>0.05). There was no significant difference between the bond strengths of the three materials when irrigated with group 1, 2 or 5 (P>0.05), but these groups showed significantly lower bond strengths than groups 3 and 4 (P<0.05). While the bond strength of EBC and MTA-P in specimens irrigated with groups 3 and 4 improved significantly with time [P<0.05], this was not true for TECH.

Push-out bond strength of calcium silicate cements was differentially influenced by irrigation protocol and time. MTA Plus showed the highest bond strength at both time periods, when root canals were irrigated with NaOCl+EA. The bond strength of Tech Biosealer Endo did not improve with time immaterial of the irrigation protocols.