Comparative Assessment of Micro-Tensile Bond Strength on Dentin of Bioactive Bulk Fill Restorative Material Versus Two Bulk Fill Dental Composites Using Different Bonding Strategies. An In Vitro Study

Objective: To a comparative assessment of micro-tensile bond strength (µTBS) on the dentin of bioactive bulk fill restorative material versus two bulk fill dental composite employing various bonding strategies. Materials and methods: 24 extracted human molars were utilized to gain 72 specimens after occlusal dentin exposed and were divided into 3 main groups concerning the restorative material (n=24) as follows: Group I: Activa BioActive Restorative Bulk-fill material applied with selective etching for enamel, Group II: Tetric N-Ceram Bulk-fill resin composite applied with total-etch adhesive system (Tetric N-bond adhesive), and Group III: bulk-fill X-tra fil composite applied with self-etch adhesive (Prim & Bond Universal adhesive). Every main group has been split into 3 equivalent subgroups (n=8) based on the storage periods (24-h, 3, and 6-months) in distilled water. The specimens were sectioned into smaller pieces to create many 1x1x8mm beam-shaped sticks. The µTBS was evaluated through a universal testing device after storage periods. Results: Tetric N-Ceram composite displayed the statistically significantly highest µTBS. This was followed by X-tra fil composite, however, the Activa displayed the significantly lowest µTBS regardless of the storage times. According to storage time, the results displayed a significant decrease in the µTBS of each restoration with time. Conclusions: The self-adhesive approach of Activa proved the lowest bond strength while the total-etch adhesive approach proved the highest bond strength. The dentin bond strength of all bonding approaches is adversely affected by water storage.