Mechanical Properties of Direct Composite Resins and CAD/CAM Composite Blocks

The widespread application of CAD/CAM technology in contemporary dentistry led to the development of promising restorative materials, such as resin composite blocks (RCBs). Thus, the present study aims to evaluate the mechanical properties of RCBs, comparing this material to the direct composite resin from the same manufacturer. Samples retrieved from three CAD/CAM resin composite blocks (Tetric CAD (TC), Ivoclar Vivadent, Grandio blocs (GB), VOCO GmbH and Brilliant Crios (BC), Coltene/Whaledent) and four direct composite resins (Tetric EvoCeram (TEC), Ivoclar Vivadent, GrandioSO (GS), VOCO GmbH, Brilliant EverGlow Translucent (BET) and Universal Shade (BEU), Coltene/Whaledent) were submitted to three-point bending flexural test and Vickers microhardness test. The resulting data of the flexural strength were analyzed using one-way ANOVA considering Bonferroni correction for post hoc tests (alpha = 0.05). The flexural modulus and Vickers microhardness results were analyzed using Welch's ANOVA considering Games-Howell correction for post hoc tests (alpha = 0.05). Regarding results, flexural strength and flexural modulus values ranged from 81.1 MPa (BEU) to 246.5 MPa (GB) and 10.6 GPa (BEU) to 20.3 GPa (GB), respectively. GS (121.2) and GB (136.2) groups were associated with the highest microhardness values. According to the post hoc tests, statistically significant differences in flexure strength were found in RCBs (BC, GB, and TC) compared to all direct composite resins. Flexural modulus and Vickers microhardness of RCBs (BC, GB, TC) were also significantly different from the direct composite resin (BET, BED, and TEC), except when comparing GS and GB for microhardness. In conclusion, differences between RCBs and direct composite resins were observed regarding flexural strength, flexural modulus, and microhardness, revealing that RCBs have enhanced mechanical properties compared to direct composite resins.