The Effect of Increased Temperatures of QMix and EDTA on the Push-out Bond Strength of an Epoxy-resin Based Sealer

J Clin Diagn Res. 2015 Jul;9(7):ZC98-ZC101. doi: 10.7860/JCDR/2015/13402.6262. Epub 2015 Jul 1.


Background: Bond strength of root canal sealers is mainly influenced by the surface tension of the root canal wall. Heat, or the use of a surfactant might reduce surface tension and it is known that surface tension of an EDTA solution significantly affected from temperature rise. QMix is a novel endodontic irrigant for smear layer removal containing EDTA, chlorhexidine and a detergent. There is no data regarding the influence of the temperature of the EDTA and QMix on the push-out bond strength of root canal sealers.

Aim: To evaluate effect of temperatures of QMix and EDTA on the bond-strength of AH Plus.

Materials and methods: Sixty premolars were prepared with ProTaper F4. During preparation 3% NaOCl was performed. Specimens were divided into 4 groups as follows: 5-mL 17% EDTA at 22°C and 37°C; 5-mL QMix at 22°C and 37°C. Three specimens from each group were prepared for observation using SEM. Remaining roots were obturated and prepared for a push-out test. Data was analysed using Anova and Bonferroni tests (p<0.05).

Results: Samples irrigated with QMix had higher push-out bond strength values than those irrigated with EDTA (p=0.01), regardless of temperature. Samples irrigated with 37°C EDTA resulted in higher bond-strength values than those irrigated with 22°C EDTA (p<0.001).

Conclusion: Temperature of the final irrigant does affect the bond strength values of AH plus to root dentin irrigated with EDTA. Bond strength of AH Plus sealer to root canal dentin may improve with QMix.

Keywords: Adhesion; Root canal irrigants; Smear layer.