Mechanical and surface properties of resin-based materials for permanent use fabricated by subtractive, additive, and...

This in vitro study evaluated the flexural strength, elastic modulus, microhardness, and surface roughness of restorative materials fabricated using subtractive (SM, CAD/CAM milled control), additive (AM-DLP and AM-LCD), and hybrid (HM-LCD) manufacturing approaches. Grandio Disc was used as the reference baseline for the SM group, whereas VarseoSmile TriniQ was used for the AM and HM groups. Additive manufacturing groups included both DLP and LCD technologies to evaluate the influence of printing system. Standardized bar-shaped specimens (25 × 2 × 2 mm) were prepared according to ISO 4049:2019 for flexural testing, while disk-shaped specimens (15 mm in diameter × 1 mm in thickness) were used for Vickers microhardness measurements. Flexural strength, elastic modulus, and microhardness were measured, and surface roughness (Ra, Rz) was assessed. Manufacturing method significantly affected flexural strength, elastic modulus, and microhardness (p < 0.001), with the SM CAD/CAM control group exhibiting the highest values, followed by AM-LCD and AM-DLP, while the HM-LCD group showed the lowest values. Microhardness was highest in SM, with AM and HM groups showing similar values. Surface roughness (Ra) was higher in the additive groups (AM-DLP: 0.36 ± 0.07 μm; AM-LCD: 0.36 ± 0.01 μm) compared with the SM (0.27 ± 0.04 μm) and HM-LCD (0.29 ± 0.04 μm) groups. For Rz, the additive manufacturing groups showed higher values than the HM-LCD group (p < 0.05), whereas no significant differences were observed between the SM group and either the additive or hybrid groups. Both manufacturing method and material-related factors influenced the mechanical and surface properties of resin-based restorative materials. The SM group served as a clinically relevant reference baseline, while the inclusion of two different printing technologies allowed a comprehensive comparison of vat-photopolymerization systems.