Comparative Evaluation of Shear Bond Strength of Computer-aided Design/Computer-aided Manufacturing Blocks to Dentin Luted with 10-Methacryloyloxydecyl Dihydrogen Phosphate-containing Resin Cement after Two Different Surface Pretreatments – An In vitro Study

Aim: To compare and evaluate the shear bond strength (SBS) of resin nanoceramic and lithium disilicate-based glass ceramic to dentin luted with 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) containing resin cement following two different surface pretreatments. Materials and Methods: Eighty all ceramic computer-aided design (CAD)/computer-aided manufacturing (CAM) milled blocks were made and divided into four groups (I, II, III, and IV) of twenty samples each. The groups were surface pretreated resin nanoceramic block (I), surface pretreated lithium disilicate-based glass ceramic (Group II), Groups III and IV are nontreated resin nanoceramic and lithium disilicate-based glass ceramic blocks. Groups I and II are further subdivided into two subgroups (a and b) exposing them to two different surface pretreatments, i.e., air abrasion and acid etching, respectively. Collected teeth samples were sectioned at coronal dentin surface using water cooled diamond saw and polished to produce uniform smooth surface. A thin layer of 10-MDP containing resin cement was applied on all samples and luted on the dentin surface. All the luted specimens were subjected to universal tester to determine SBS and failure types were evaluated with stereomicroscope. Results: Statistically significant difference was found in the SBS of all samples with different pretreatment methods ( P < 0.05). Group Ia showed highest SBS (16.10 ± 1.51) followed by Group IIb (14.25 ± 0.90), Group Ib (12.30 ± 1.17), Group IIa (11.20 ± 1.23), and least bond strength values for Group III (10.25 ± 1.25) and Group IV (10.10 ± 1.20). Conclusion: Resin nanoceramic block with air abrasion pretreatment has the highest SBS followed by lithium disilicate-based glass ceramic with acid etching pretreatment.