Bond strength of different resin-based cements to 3D-printed permanent restorations

To investigate the shear bond strength of different primers with adhesive cements to 3D printed restorations.

72 3D-printed restorations (Formlabs permanent crown resin) and nano-hybrid composite (Tetric EvoCeram) resin cylinders prepared and assigned to two groups, according to G-Multi Primer (GMP) with G-Cem One (GCO) and Clearfil ceramic primer plus (CCP) with Panavia F2.0 (PF) cements and three subgroups (n=9) were created for each cement: (1) control group, (2) 5,000 thermal cycles, (3) 10,000 thermal cycles. 3D-printed restorations were embedded in Teflon molds and cemented with nano-hybrid composite resin cylinders and a shear bond strength test was performed according to group. Failure modes were observed with stereomicroscope (30x), and surface morphology was evaluated with SEM analysis (100x and 2,000x). Statistical analysis was performed using Kolmogorov-Smirnov and Shapiro Wilks tests, and for evaluating the study data, 2-way ANOVA test and post hoc Tukey HSD test were used.

The GCO groups exhibited significantly higher SBS values than the PF groups in the bonding of the tested 3D-printed restorations. There was no statistically significant difference in the bond strengths of tested GCO cement groups. A control group of PF cement showed significantly higher SBS values than the 5,000 and 10,000 cycling of PF groups. However, there was no statistically significant difference in the 5,000 and 10,000 cycling PF groups. The bonding performance was superior for the GCO group.

This study showed that exposure to gutta-percha solvents (chloroform, orange oil and Endosolv) for 5 minutes did not affect the bond strengths of both iRoot SP (bioceramic sealer) and AH Plus (resin sealer) to root dentin.