Comparison of Mechanical and Surface Properties between Conventional and CAD/CAM Provisional Restorations

This study compared the flexural strength, surface hardness, and surface roughness of conventional, milled, and three-dimensional (3D)-printed provisional restorations.

Bar-shaped polymethyl methacrylate (PMMA) specimens (25 × 2 × 2 mm³) and disc-shaped specimens (9 × 2 mm²) were fabricated using three different techniques (n = 10/group): conventional (SR Ivocron C&B, Ivoclar Vivadent, Schaan, Liechtenstein), milling (Aidite Temp PMMA Blocks, Aidite, Qinhuangdao, China), and 3D printing (Asiga DentaTOOTH, Asiga, Sydney, Australia). Flexural strength was evaluated using a universal testing machine until fracture occurred. Vickers hardness and surface roughness tests were performed on the disc-shaped specimens using a micro-Vickers hardness tester and atomic force microscopy, respectively.

Data were statistically analyzed using one-way ANOVA. The post hoc Tukey's honest significant difference was conducted to compare the differences value between groups (p < 0.05).

The milled computer-aided design/computer-aided manufacturing (CAD/CAM) provisional restorative material exhibited a significantly higher flexural strength (125.16 ± 6.83 MPa) compared with both the traditional (109.74 ± 14.14 MPa) and 3D-printed (71.09 ± 9.09 MPa) materials (p < 0.05). The conventional material had a higher Vickers hardness (19.27 ± 0.41 kgf/mm²) compared with the milled (18.53 ± 0.32 kgf/mm²) and 3D-printed (17.80 ± 1.85 kgf/mm²) materials, though the difference was statistically significant only between the conventional and 3D-printed groups. The surface roughness of the milled CAD/CAM material (8.80 ± 2.70 nm) was significantly lower than that of the 3D-printed material (24.27 ± 9.82 nm) (p < 0.05).

The provisional restorations fabricated using milled PMMA technology provide adequate flexural strength, surface hardness, and low surface roughness, offering a viable alternative for creating provisional restorations.