Mechanical Properties of SDR™ and Biodentine™ as Dentin Replacement Materials: An In Vitro Study

The aim of this study is to evaluate the shear bond strength of nanohybrid composite resins (NCR) and microhybrid composite resins (MCR) placed over three different dentin replacement materials: SDR-Smart Dentin Replacement™, Biodentine™, and resin-modified glass ionomer cement (RMGIC). Thirty acrylic blocks (50 mm × 20 mm × 15 mm), each with a central hole, were prepared, which were randomly distributed into three equal groups, each corresponding to one of the three dentin replacement materials-SDR, Biodentine, and RMGIC. The central holes were then filled with these materials. After setting and application of the respective adhesive system, the specimens were further divided into two subgroups each of NCR or MCR. The respective composite material was then applied to the dentin replacement materials using a cylindrical plastic matrix. Shear bond strength was tested on a universal testing machine (Instron 3366), at a crosshead speed of 1.0 mm/minute. SDR attained consistently higher shear bond strength (means: 21.18, 22.19 Mpa) values than RMGIC and Biodentine, with both types of composite resins (MCR and NCR), which were statistically significant (