Comparative Evaluation of Shear Bond Strength of MTA, Biodentine, and Thera Cal-LC to Different Permanent Restorative Materials: An in Vitro Study

Abstract Aim: To evaluate and compare the shear bond strength (SBS) of three calcium silicate-based pulp capping materials—Mineral Trioxide Aggregate (MTA), Biodentine, and Thera Cal-LC—to three different restorative materials: nanocomposite, Amalgomer CR, and resin-modified glass ionomer cement (RMGIC). Materials and Methods: A total of 45 acrylic blocks were prepared with standardized central cavities (4 mm diameter × 2 mm depth). These were divided into three groups based on the liner material used: MTA, Biodentine, and Thera Cal-LC. Each group was further subdivided based on the restorative material used: nanocomposite, Amalgomer CR, or RMGIC (n = 5 per subgroup). The restorative materials were applied after complete setting of liners. All specimens were stored at 37°C and 100% humidity for 72 hours, followed by shear bond strength testing using a universal testing machine at 1 mm/min crosshead speed. Data were analyzed using SPSS 26.0, applying ANOVA and Bonferroni post hoc tests (p < 0.05). Results: Thera Cal-LC demonstrated the highest bond strengths across all restorative materials, followed by Biodentine and MTA. The nanocomposite showed significantly higher SBS values compared to RMGIC and Amalgomer CR within all groups. Among the base materials, significant differences were observed particularly in combinations with RMGIC. Conclusion: Nanocomposite restorations over TheraCal-LC provided the highest SBS, indicating superior compatibility. Amalgomer CR and RMGIC showed lower SBS values with all liners. This suggests TheraCal-LC combined with nanocomposites may offer enhanced performance in clinical scenarios requiring strong adhesion.