The effect of different irrigating solutions on bond strength of two root canal-filling systems.

The bond strength of ActiV GP root canal filling system and gutta-percha/AH plus sealer when used after final rinse with different irrigation protocols was evaluated in this study. Forty roots were randomly divided into four groups (n = 10) according to the final irrigation regimen: group 1, 5 mL 17% EDTA; group 2, 5 mL 17% EDTA followed by 5 mL 2% chlorhexidine gluconate (CHX); group 3, 5 mL MTAD; and group 4, 5 mL MTAD followed by 5 mL 2% CHX. Each group was further subdivided into two subgroups (n = 5): in subgroup a, the root canals were filled using warm gutta-percha and AH plus sealer, and in subgroup b, the root canals were filled using the ActiV GP obturation system. Two-millimeter thick horizontal sections from the coronal and midthirds of each root were sliced for the push-out bond strength measurement. EDTA/CHX/ActiV GP (2.46 +/- 1.02 MPa) yielded significantly the highest mean bond strength value. The significantly lowest bond strength was recorded for EDTA/ActiV GP (1.12 +/- 0.72 MPa). It was concluded that the bond strength of ActiV GP was improved by using 2% CHX in the final irrigation after 17% EDTA, whereas CHX did not enhance the effect of MTAD on the bond strength of the material. The bond strength of gutta-percha/AH plus was adversely affected by MTAD and MTAD/CHX.