Toothbrush Resistance of Resin-Based Stain and Glaze Materials Applied to 3D-Printed Denture Resins

Three-dimensional (3D)-printed dentures are often fabricated from a single tooth-colored resin and externally characterized using stains and glaze coatings to enhance gingival esthetics and surface properties. However, routine toothbrushing may degrade these coatings, potentially affecting surface gloss and roughness. This study evaluated the effects of stain timing and glaze application on the gloss and surface roughness of a 3D-printed denture resin following simulated toothbrushing. Eighty disc-shaped specimens (12 mm × 3 mm) were fabricated and assigned to two staining systems (OPTIGLAZE Color and Palette 2.0), with subgroups based on stain timing (before or after post-curing) and glaze application (with or without glaze) (n = 10). Specimens underwent 20,000 cycles of simulated toothbrushing, and gloss and surface roughness were measured before and after brushing. Data were analyzed using two-way ANOVA (α = 0.05). Glaze application significantly improved gloss retention for both staining systems (p < 0.001), while stain timing had no independent effect. Glaze application with Palette 2.0 demonstrated improved gloss retention when post-cured in a post-curing unit. Toothbrushing increased surface roughness in all groups, with no significant effects of stain timing or glaze. Within the limitations of this study, glaze improves gloss stability, whereas stain timing has minimal influence and does not affect surface roughness.