Microhardness and flexural strength of two 3D-printed denture base resins

Objectives: To evaluate the microhardness and flexural strength of printed and conventionally produced denture base acrylic resins. Methods: A total of 32 parallelepiped specimens (64×10×3.3 mm) were manufactured using two light-cured resins suitable for 3D printing (V-Print Dentbase and Denture 3D+) and two heat-cured resins for conventional production (Probase Hot and Villacryl Rapid) (n=8). After 24-h storage in water, Knoop microhardness (98.12 mN load for 30 s) and three-point flexural strength (1 kN load cell, at a crosshead speed of 5 mm/min and 50 mm between rods) were determined. Microhardness data were analyzed with one-way ANOVA followed by Tukey post-hoc tests. Flexural strength data were submitted to the Kruskal-Wallis test. A significance level of 5% was considered (α=0.05). Results: The resins showed statistically significant (p<0.001) differences regarding microhardness (V-Print Dentbase < Denture 3D+ < Probase Hot < Villacryl Rapid). No statistically significant (p=0.527) differences were found in flexural strength between the four resins. Conclusions: The printed resins had lower microhardness values than conventional resins, but all resins showed similar flexural strength.