Evaluation of microtensile bond strength of nanoclay modified adhesive systems using bulk fill resin composite

Background: Composite polymerization creates internal stresses that cause bond loss at the tooth composite interface, cuspal deflection, and enamel crack formation; that are potential restoration failure. Aims: The aim of the present study was to evaluate micro-tensile bond strength of bulk-fill resin composite to human dentine of extracted teeth using nanoclay modified adhesive system (with and without organic modifier). Materials and Methods: A total of 120 caries-free permanent human posterior teeth were used and classified three groups according to adhesive system (each with 40 teeth); including Prime&Bond universalTM, Dellite®43B and Dellite®LVF modified adhesive systems. Each group was subdivided into two equal subgroups whether thermocycling was conducted or not. Results: Result revealed that there was a significant difference in mean microtensile bond strength of the three tested materials The best results achieved by Dellite®43B followed by Dellite®LVF modified adhesive system finally conventional Prime&Bond universal adhesive system. Difference in Microtensile bond strength between thermocycled and Nonthermocycled was highly significant. Conclusion: Addition of Nanoclay (montmorillonite) with organic modifier to universal adhesive material is valuable to augment the bond strength of bulk fill resin composite to human dentition. (2) Thermocycling adversely affect the bond strength of nanoclay /adhesive system complex to tooth tissue.