Evaluation of Surface Properties and Elastic Modulus of CAD-CAM Milled, 3D Printed, and Compression Moulded Denture Base Resins: An In Vitro Study

OBJECTIVES: This study evaluated the surface roughness, surface hardness, and elastic modulus of CAD-CAM (Computer-aided design/computer-aided manufacturing) milled, three-dimensional printed and conventional compression-moulded denture base resins. MATERIALS AND METHODS: Thirty specimens (65*10*3 mm) were fabricated and divided into 3 groups (10 for each group) according to the type of denture base resin, Group I contained specimens of milled denture base resin, Group II contained specimens of 3-dimensional printed denture base resin, Group III contained specimens of polymethyl methacrylate heat cured denture base resin. The surface roughness of all specimens was evaluated using an atomic force microscope. Then by using the three-point bending test, the elastic modulus of the 30 specimens was evaluated. Finally, after fracturing the specimens from the bending test, the fractured specimens of the 3 groups were used to evaluate hardness using the Vickers hardness test. Data were analyzed using one-way ANOVA and Tukey’s pair-wise post hoc tests. RESULTS: There were significant differences between the tested groups (P< 0.05). The milled denture base resins showed the lowest surface roughness (27.46 ± 5.45 nm) when compared with printed (47 ± 7.01 nm) and conventional (39.72 ± 4.72 nm) denture base resins (P< 0.05); however, there was a significant increase in elastic modulus and hardness of milled (3240.06 ± 61.23 MPa and 29.18 ± 3.44 Vickers hardness number) and conventional (3017.16 ± 215.32 MPa and 22.44 ± 0.98 Vickers hardness number) denture base resins when compared with printed denture (576.65 ± 37.73 MPa and 2.64 ± 0.37 Vickers hardness number) base resins (P< 0.05). CONCLUSIONS: Milled denture base resins showed the lowest surface roughness, and highest hardness and elastic modulus among the three groups.