Comparison of Physical and Mechanical Properties of Various Commercially Available Nanohybrid Composites: An In Vitro Study.

INTRODUCTION: Nanohybrid resin composites are widely used in restorative dentistry because they combine favorable esthetics and improved mechanical properties. However, commercially available nanohybrid composites differ in their filler characteristics, resin matrix composition, and manufacturing processes, which may influence their clinical performance. Therefore, this study aims to compare the tensile strength, flexural strength, compressive strength, and Barcol hardness of four commercially available nanohybrid composite resins. MATERIALS AND METHODS: This in vitro experimental study was conducted using 160 standardized specimens prepared from four types of nanohybrid composite resins: Tetric N-Ceram, Fusion Universal, NanoCom Composite, and NanoFill Composite. Each material was allocated to 40 specimens, which were further divided into four subgroups (n = 10) for tensile, flexural, compressive, and Barcol hardness testing. Bar-shaped specimens were fabricated for tensile and flexural strength evaluation, whereas cylindrical specimens were prepared for compressive strength and hardness testing. Mechanical testing was performed using a universal testing machine and Barcol hardness tester under standardized laboratory conditions. Data were analyzed using one-way analysis of variance followed by Tukey's post-hoc test, with statistical significance set at p < 0.05. RESULTS: Tetric N-Ceram demonstrated the highest mean tensile strength (22.52 ± 3.79 MPa), flexural strength (94.36 ± 21.65 MPa), compressive strength (87.82 ± 55.60 MPa), and Barcol hardness (73.60 ± 2.32). Significant intergroup differences were observed in the tensile strength (p = 0.038), flexural strength (p = 0.002), and Barcol hardness (p < 0.001), whereas the compressive strength was not significantly different among the four materials (p = 0.555). Pairwise comparisons demonstrated significantly greater tensile and flexural strengths for Tetric N-Ceram compared with several other composites, while the Barcol hardness also differed significantly between most material combinations. CONCLUSION: The mechanical performance of commercially available nanohybrid composite resins differed significantly. Tetric N-Ceram demonstrated the most favorable overall mechanical properties, particularly with respect to tensile strength, flexural strength, and surface hardness. These findings indicate that nanohybrid composites are not mechanically equivalent and should be selected based on scientific evidence rather than on material classification alone.