Dislodgement Resistance of Biodentine When Various Chelates Used to Remove Smear-layer.

Objectives: Smear layer could affect adhesion of dental materials to dentin and should be removed with sodium hypocloride and various chelates.The aim of this study was to evaluate the effect of various calcium chelates (10% citric acid, 17% EDTA, QMix2in1) on the push-out bond strength of a novel material, Biodentine (Septodont, Saint Maur des Fossés, France) in comparison with ProRoot MTA (Dentsply Tulsa Dental, Tulsa, OK).
Methods: Single rooted teeth was horizontally sectioned into 1-mm-thick slices and the canal space of each dentin slice was then enlarged with a diamond bur to 1.4 mm in diameter. Seventy-two samples first dispersed in 5.25% NaOCl for 3min and were divided into three experimental groups (n = 24) according to the chealiting agent used for smear layer removal Group 1; 10% citric acid, Group 2; 17% EDTA, Group 3; QMix2in1 and twenty-four samples only washed with serum as control (Group 4). Each group were then divided into two subgroups (n=12) and either Biodentine or ProRoot MTA were placed. The samples were stored in an incubator for 48 hours under 100% humid conditions. The dislodgement resistance of the samples was then measured using a universal testing machine using a push-out test set-up at a cross-head speed of 1 mm min^-1. The samples were examined under a stereomicroscope to determine the nature of the bond failures and scanning electron microscopic evaluation was done to analyse the material-dentin interface.Data were analyzed using two-way ANOVA and post-hoc Tukey's test for bond strength. Statistical significance was set at P<0.05.
Results: Biodentine showed significantly higher push-out bond strength than MTA (P<0 .05). Biodentine showed statistically higher dislodgement resistance when smear layer removed with EDTA and Qmix2in1 solution (P<0.05). ProRoot MTA demonstrated better dislodgement resistance when smear layer removed (P<0.05).

Conclusions: Smear layer removal prior to Biodentine application could improve adhesion of this material to root dentin. Smear removal with EDTA and EDTA containing QMix2in1 could be better options for the practitioners to achieve this result.