Purpose: To investigate the discoloration and surface properties of four CAD/CAM composite resins following storage in various food solutions and exposure to cigarette smoke.
Materials and Methods: A total of 74 specimens (N = 370) were prepared for five materials: Brilliant Crios (BC), Cerasmart (GC), Lava Ultimate (LU), Shofu Block HC (SH), and Sonic Fill 2 (SO). Discoloration (ΔE) was investigated with a spectrophotometer. Measurements were taken before immersion in storage media (carrot juice, curry, cigarette smoke, red wine, energy drink, and distilled water), after 2 weeks of immersion, and after manual polishing of the specimens following immersion. The average surface roughness (Ra) was measured with a profilometer. Qualitative surface observation was performed with scanning electron microscopy (SEM). Data were analyzed using Kolmogorov-Smirnov test, Mann-Whitney U test, and one-way ANOVA with Tukey post hoc test.
Results: The highest influence on ΔE after immersion was observed for storage medium (ηP2 = 0.878, P < .001), followed by the interaction between storage medium and material (ηP 2 = 0.770, P < .001) and material (ηP 2 = 0.306, P < .001). For ΔE after polishing, the highest influence was indicated by the interaction between material and medium (ηP 2 = 0.554, P < .001), followed by medium (ηP2 = 0.244, P < .001) and material (ηP2 = 0.196, P < .001). Immersion in carrot juice led to the highest color change (ΔE: 8.0 to 10.4), whereas the lowest values were recorded in distilled water (ΔE: 2.0 to 2.4). Carrot juice and the energy drink caused the highest Ra values (0.120 μm to 0.355 μm). SEM pictures indicated a loss of the organic matrix after manual polishing.
Conclusion: The different materials reacted dissimilarly to the various storage media in terms of discoloration. Surface roughness increased after immersion or polishing. Neither discoloration nor surface roughness could be reset to default by manual polishing.
