Aims: To compare and evaluate the bonding ability of bulk-fill resin composite (RC) to four different liners: Biodentine (BD), TheraCal (TLC) - a novel resin-modified calcium silicate cement, resin-modified glass ionomer cement (RMGIC) and conventional glass ionomer cement (GIC) using a universal silane-containing adhesive and characterizing their failure modes.
Materials and Methods: Forty extracted intact human premolars with occlusal cavity (4-mm diameter and 2-mm height) were mounted in acrylic blocks and divided into four groups of (n=10 samples) each based on the liner used as group I; (BD), group II; (TLC), group III; (RMGIC) and Group IV; (GIC). Bulk-fill composite buildup of 3 mm diameter and 5 mm height was then bonded to each sample using universal adhesive. Shear bond strength (SBS) analysis was performed using materials testing machine at a cross-head speed of 0.5 mm/min.
Statistical Analysis: Statistical analysis was performed with one-way analysis of variance (ANOVA) and Tukey's post hoc test for numerical data while chi square test for categorical one.
Results: One-way analysis with ANOVA revealed significant difference in bond strength values between the different groups (p<0.001). The observed modes of failure were predominantly cohesive in Biodentine, TheraCal and GIC groups while RMGIC showed majority of mixed and minority adhesive failures.
Conclusions: Biodentine demonstrated lower bond strength values when immediately bonded to bulk-fill resin composite compared with RMGIC, TheraCal and GIC groups