Surface Roughness and Color Stability of 3D-Printed Dental Resin Materials Under the Influence of Different Beverages

Aim: This study aimed to evaluate the effects of the material type and immersion solution on the color stability (ΔE) and surface roughness change (ΔRa) of provisional dental materials fabricated using subtractive milling or additive 3D printing techniques. Materials and Methods: Three provisional restorative materials were evaluated: one CAD/CAM-milled material (Vita CAD-Temp) and two 3D-printed materials (NextDent C&B MFH and Freeprint Crown [Detax]). The specimens were subjected to thermocycling and subsequently immersed for two weeks in coffee, hibiscus tea, Coca-Cola, or distilled water. Color change was evaluated using independent specimens (n = 10 per material × solution combination; N = 120), and ΔE was calculated from paired baseline and post-immersion CIELAB measurements. Surface roughness change was evaluated using a separate specimen set (n = 5 per material × solution combination; N = 60) and calculated as ΔRa = Ra_post-immersion−Ra_baseline. Factorial analyses were performed to assess the effects of the material, immersion solution, and their interaction, including multiplicity-adjusted post hoc comparisons where appropriate. Results: Color change was significantly affected by material type (p < 0.001), immersion solution (p < 0.001), and the material × solution interaction (p < 0.001). The interaction effect demonstrated that material performance depended strongly on the immersion solution. The highest mean ΔE was observed for NextDent exposed to hibiscus tea (8.96 ± 0.75), followed by Detax exposed to coffee (7.38 ± 1.69), whereas the lowest values were observed for milled material in distilled water (1.41 ± 0.45) and NextDent in cola (1.52 ± 1.00). For surface roughness, the immersion solution had a significant effect on ΔRa (p < 0.001), whereas the overall material effect (p = 0.136) and material × solution interaction (p = 0.706) were not statistically significant. Cola produced the greatest overall increase in surface roughness. Conclusions: The color stability of the tested provisional materials was dependent on the material type and immersion solution, with a pronounced interaction observed between these factors. The milled material generally demonstrated relatively low color changes across the tested conditions, while the responses of the 3D-printed materials varied substantially according to the immersion solution. In contrast, the change in surface roughness was influenced primarily by the immersion solution rather than material type. These findings indicate that the behaviors of provisional restorative materials should be interpreted according to the specific material–environment combination rather than the fabrication method alone.