Evaluation of shear bond strength of the composite to biodentine with different adhesive systems

Abstract

Background. Biodentine is recommended for use as a dentine substitute under resin composite restorations and for endodontic procedures. The quality and durability of the adhesive bond between Biodentine and the resin composite is of clinical significance with regard to the longevity of the final laminate restoration. The durability of this bond may be affected by different bonding strategies. Objectives. The aim of this study was to determine the shear bond strength of resin based (composite) material to Biodentine with different bonding strategies at different time intervals. Material and Methods. Cylindrical acrylic blocks were prepared and fully-filled with Biodentine®. They were randomly divided into three experimental groups according to the bonding protocols: two-step total etch Optibond® FL (group 1), one step total-etch Adper Single Bond (group 2), one step self-etch strategy Clearfill® SE Bond (group 3) and the control group (group 4). Each group was further divided into three subgroups (n = 10: 12 min (subgroup A), 7 days (subgroup B) and 28 days (subgroup C) after Biodentine placement. Bonding system was applied appropriately for respective group and then covered with resin-based composite material placed into silicone cylindrical matrices. Shear bond strength was measured by means of a universal testing machine Zwick/Roell Z020. Results. When shear bond strengths of adhesive systems was compared, group 3 (self-etch system) and group 1 (two-step total etch system) presented significantly higher bond strength values than group 2 (one step total etch) in the subgroup A. Considering the shear bond strength over time, group 2 demonstrated significantly higher bond strength than group 1 and 3. There was no difference between group 1, 2 and 3 after 7 and 28 days. Conclusions. Shear bond strength of tested bonding protocols to Biodentine depends on the time interval and bonding strategy.