Effect of Orange Juice on the Properties of Heat-Polymerized and 3D-Printed Denture Materials

This study evaluated the color stability, surface roughness, and hardness of 3D-printed and heat-polymerized denture materials. A total of 90 samples were prepared, with equal numbers of 3D-printed and heat-polymerized disks. The initial hardness, surface roughness, and color values of the samples were measured. After 14 days of immersion in distilled water, natural orange juice, or commercial orange juice, the measurements were repeated. Based on the findings, 3D-printed samples exhibited a greater reduction in Vickers hardness (56.24 ± 15.81%) compared to heat-polymerized samples (18.93 ± 11.41%). Materials immersed in commercial orange juice exhibited a greater reduction in hardness compared to those in other solutions (43.13 ± 23.66). Surface roughness increased by 46.66 ± 26.8% in heat-polymerized samples and by 26.16 ± 20.78% in 3D-printed samples, with the highest increase observed in commercial orange juice (50.73 ± 28.8%) (<i>p</i> < 0.001). The color change (ΔE) was significantly higher in heat-polymerized samples (ΔE = 5.05 ± 0.28) than in 3D-printed samples (ΔE = 3.9 ± 0.26) (<i>p</i> < 0.001). This study demonstrates that the material type and immersion solutions play a critical role in determining the mechanical and optical properties of denture materials, with commercial orange juice having the most pronounced effect on surface roughness and hardness.