Effects of storage and toothbrush simulation on color, gloss, and roughness of CAD/CAM, hand-cast, thermoforming, and 3D-printed splint materials.

OBJECTIVES: The aim was to investigate color, gloss, or roughness of splint materials after storage in liquids and toothbrush simulation. MATERIALS AND METHODS: A total of 58 x 8 (n = 10 per material and group) specimens were fabricated (hand-cast, thermoforming, CAD/CAM-milled, 3D-printed materials); stored in air, water, coffee, red wine, and cleaning tablets; and investigated after fabrication, 24 h, two-, and four-week storage or toothbrushing. Color values (L*, a*, b*; ISO 11664-4:2008; CM-3500d, Konica-Minolta), gloss (ISO 2813:2014), and roughness values were determined (3D laser-scanning-microscope, KJ 3D, Keyence) before and after simulation or storage. STATISTICS: Levene-test, one-way ANOVA, Bonferroni post hoc test, between-subjects effects, Pearson correlation (alpha = 0.05). RESULTS: Color, gloss, and roughness altered due to contact with staining solutions/toothbrush simulation. Highest impact on color, gloss, and roughness presented the material followed by storage time (DeltaE material (eta2 = 0.239/p < 0.001), storage time (eta2 = 0.179/p < 0.001); gloss (eta2 = 0.751/p < 0.001) (eta2 = 0.401/p < 0.001); Ra/Rz (eta2 >/= 0.801/p < 0.001) (eta2 >/= 0.416/p < 0.001)). Correlations were found between Rz and Ra (Pearson 0.887/p </= 0.001) or Rz and DeltaE (0.517/p </= 0.001) or Ra and DeltaE (0.460/p </= 0.001). CONCLUSIONS: Storage and toothbrushing were accompanied by a change in color, gloss, and roughness. Almost all materials showed visible discoloration after 4 weeks of storage. Gloss values decreased as storage time increased. The initial roughness and polishability were better with harder materials. CLINICAL RELEVANCE: Milled and 3D printed splints show good color, gloss, and roughness resistance after 4-week storage or toothbrush application.