Microtensile bond strength of high-viscosity glass ionomer cements and nanoceramic composite to normal and caries-affected dentin: An in vitro study.

BACKGROUND: Modern caries management involves the removal of the carious dentin after selective removal of soft dentin while retaining the firm dentin and restoring with an appropriate restorative. AIM: To evaluate and compare the microtensile bond strength (μTBS) of high-viscosity GC Glass Hybrid and Glass Ionomer FX Ultra cements with Ceram.x nanoceramic composite on normal dentin (ND) and artificially induced caries-affected dentin. MATERIALS AND METHODS: After collecting 90 extracted human mandibular molar teeth, the occlusal enamel was removed. Vestibulolingually teeth were sectioned into two halves, in which the distal half samples (n = 90) were subjected to pH cycling. Both mesial ND and distal artificial carious dentin (ACD) tooth halves were assigned to three groups (n = 15 each) depending on the restorative material tested. After undergoing thermomechanical cycling, dentin-restorative beams were subjected to μTBS testing, and the fracture type was analyzed under a scanning electron microscope. The bond strength data were assessed with one-way ANOVA and Tukey's multiple post hoc test by establishing α =0.05 significance. RESULTS: The mean μTBS of Ceram.x composite for both ND and ACD was significantly higher when compared to both high-viscosity glass ionomer cements (GICs) examined (P = 0.0001). The μTBS of GC Hybrid and FX Ultra Tested were not different from each other in both the substrates (P = 0.6518 in ND and P = 0.9603 in ACD). Nanocomposite exhibited more adhesive failures, whereas the tested GICs showed a cohesive mode of failures. CONCLUSION: Caries-simulated dentin has substantially lower μTBS values than ND. The μTBS values of the two tested GICs were much lower than the mean bond strength of the nanocomposite.