Influence of aging on mechanical and microbiological properties in CAD-CAM-milled and 3D-printed denture base resins

To evaluate the adhesion of Candida albicans and the mechanical properties of resins in denture bases fabricated using conventional, milled, and 3D printing methods at different aging times.

A total of 96 resin samples were manufactured, divided into three resin groups (n=32) (conventional thermally activated, milled and 3D printed), and subdivided into four aging times by thermocycling at temperatures 5± 1°C and 55 ± 1°C in 24 hours, 5,000, 10,000, 20,000 cycles (n= 8), evaluating the adhesion of C. albicans (ATCC90028), surface microhardness (Knoop), flexural strength and elastic modulus by three-point mechanical test. Data were evaluated by two-way ANOVA and Tukey's test for multiple comparisons (P< 0.05).

The milled resin demonstrated significantly lower colonization of C. albicans at times T0 (0.50± 1.37) (P= 0.007) and T1 (0.60±1.33) (P= 0.032) compared to other resins. The 3D-printed resin exhibited significantly lower values of surface microhardness at T1 (11.05± 0.26), T2 (10.92±0.63), and T3 (10.21± 0.45) (P< 0.001). The conventional and 3D-printed resins did not show significant differences in flexural strength over time (P> 0.05). The 3D-printed resin exhibited a significant difference in elastic modulus compared to the other resins, notably displaying the lowest value at time T3 (750.36± 29.32 MPa) (P< 0.05).

Denture base materials compatible with the CAD-CAM system are increasingly available, leading to a rise in the use of dentures fabricated with this technology. This study provided promising evidence for CAD-CAM system denture base materials.