Diet-Induced Chromogenic Challenge Model for Additively Manufactured Tooth-Colored Dental Resin Materials

This study aimed to evaluate the color stability of glaze-coated 3D-printed resin materials stored in different nutritionally beneficial smoothies that are commonly consumed.

Disc-shaped (27 × 1 mm) specimens were fabricated from tooth-colored 3D-printed dental resins with different indications: Arma Resin (Group A), VarseoSmile Crown Plus (Group B), Flexcera Smile Ultra+ (Group E), Formlabs Permanent Crown (Group F) (n = 10 per group). After post-processing and cleaning, all specimens received a standardized nano-filled, light-polymerized glaze coating. Water contact angle and roughness values were measured. The specimens were immersed in artificial saliva as control (AS) and three smoothies (green [G], orange [O], and purple [P]) for 30 days. pH and °Brix levels of beverages were recorded. Reflectance spectra were recorded using UV-Vis-NIR spectrophotometer and converted to color coordinates. Color differences ( ${∆E}_{\mathrm{ab}}^{*}$ and $\Delta E_{00}$ ) were calculated. Surface roughness and contact angle data were analyzed using two-way ANOVA, while color change data were analyzed using Welch's ANOVA and Games-Howell post hoc test (α = 0.05).

Surface roughness was significantly affected by material type, while storage media had no significant effect. Contact angle values were significantly influenced by both material type and storage media. Significant differences in ${∆E}_{\mathrm{ab}}^{*}$ and $\Delta E_{00}$ were observed only between the orange smoothie subgroups and their corresponding artificial saliva controls in Groups B, E, and F. No significant differences were observed for Group A in orange smoothie or for the green and purple smoothie subgroups compared with their corresponding artificial saliva controls.

Orange smoothie caused significantly greater color changes than artificial saliva in Groups B, E, and F, but not in Group A. This finding suggests that the discoloration susceptibility of specimens is strongly influenced by material composition and specific smoothie ingredients.