This study comparatively evaluated the influence of processing routes on the optical stability of three dental resin composites: a light-cured direct composite—G-ænial A’CHORD (LCC), a CAD-CAM milled composite—BreCAM.HIPC (MC), and a 3D-printed composite—Saremco Print Crowntec (PC). Specimens were analyzed before (T0) and after hydrothermal aging for 5000 (T1), 10,000 (T2), and 30,000 cycles (T3). Optical stability was assessed through the change in color (ΔE00) and translucency parameter (TP) after aging and immersion in beverages. Surface topography was evaluated using atomic force microscopy (AFM), while Raman spectroscopy was employed to detect aging-induced molecular changes. After aging and staining, all composites exceeded the acceptability threshold for color change. ΔE00 values of 6.8 ± 1.1 (PC), 4.6 ± 0.9 (MC), and 2.1 ± 0.9 (LCC), obtained after initial aging, further increased following prolonged immersion in coffee. After 1 day of immersion in Coca-Cola, MC exhibited the highest ΔE00 values, which slightly exceeded the clinically acceptable threshold. Prolonged immersion (7 days) significantly increased staining for all materials. TP values significantly differed among materials, with the highest values detected for LCC (20.6 ± 3.6) and PC (19.1 ± 1.5) and the lowest values detected for MC (4.9 ± 0.8). Overall, the results demonstrated that ΔE00 was strongly influenced by the processing route and surface topography, whereas changes in translucency parameter (TP) were predominantly governed by the intrinsic properties of the resin composites.
Živković et al. (Thu,) studied this question.