The Effect of Extrinsic Staining on 3D Printed Provisional Crowns

Purpose: The aim of this study was to evaluate the color stability of 3D printed resin disks using spectral reflectance data obtained at different time periods after immersion in various staining solutions. The color stability of 3D-printed temporary crowns is clinically important, as it directly affects the esthetic outcome and patient satisfaction during the provisional phase of treatment. Materials and methods: Forty identical round disk specimens measuring 10 mm in diameter and 2 mm in thickness were fabricated using CAD/CAM 3D printing resin (shade B1). Half of the specimens (n = 20) were polished using an acrylic bur and medium pumice. The remaining specimens were unpolished (n = 20). Each group of disks was then immersed in one of the following immersion solutions: artificial saliva, black tea, carrot juice, and red wine. Color difference ΔE was evaluated using the spectrophotometer, a spectral reflectance instrument, at baseline, day 1, week 1, week 2 and week 3, against a white background. Comparisons between polished and unpolished disks at each time point were conducted using Mann–Whitney tests. Differences among the staining solutions at each time point for both polished and unpolished disks were analyzed using a one-way ANOVA with Tukey’s post hoc test. Results: Color difference ΔE was measured using the CIELAB formula. The mean ΔE values of each group were calculated. The greatest difference in color was observed in the unpolished and polished disks immersed in red wine. Polished disks showed less color difference when compared to unpolished disks. Significant differences in ΔE were detected between polished and unpolished disks immersed in red wine at week 1 (p = 0.0159), week 2 (p = 0.0079) and week 3 (p = 0.0079) and in carrot juice at week 3 (p = 0.0317). Conclusions: Immersion of 3D printed disks in different staining solutions caused detectable color difference in the tested materials, which was relative to the immersion duration and the staining solution used. The color of the 3D printed resins is influenced by the surface finishing, which may result in visually perceptible color differences. The color stability of 3D printied materials should be improved to provide long-term esthetics.