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

Abstract

Purpose: 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.

Methods: 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).

Results: 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).

Clinical significance: 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.