Abstract: Objective To evaluate the bond strength of GuttaFlow sealers to root canal walls after final rinse with two novel fi nal irrigation regimens, QMiX and 17%EDTA + 0.2%Cetrimide (CTR). Methods Thirty single-canal teeth were prepared chemomechanically using 5.25% sodium hypochlorite (NaOCl) as root canal irrigants. The teeth were then randomly distributed into three groups (n = 10) according to the final irrigation protocol: QMiX group, 17% EDTA followed by CTR group and control group (normal saline, NS). After the filling with GuttaFlow using a lentulo spiral, the roots were transversally sectioned to obtain 2 mm thick dentinal slices. Then a push-out bond strength test was carried out, and failure mode was determined at × 24 magnification. Results The push-out bond strength was significantly higher in QMiX group than that of EDTA+CTR group and NS group (P＜0.05), and no significant difference was observed between EDTA+CTR and NS groups (P＞0.05). The failure patterns were mainly mixed. Conclusion The QMiX, as the final irrigant, can improve the bond strength of silicone-based sealer GuttaFlow.

Key words: root canal irrigants, final irrigation, root canal sealer；bond strength, QMiX, CTR, GuttaFlow