Do Polishing Methods and Colorant Beverages Affect the Color Stainability of 3D-printed Permanent Restorations?

Aim: This in vitro study evaluated the effect of polishing methods on the color stainability of 3D-printed permanent restorations while immersed in colorant beverages (distilled water, tea, coffee, and red wine) for 30 days. Materials and Methods: A total of 120-disc-shaped samples (10 mm × 1.5 mm) were fabricated using a stereolithography printer (Formlabs 3B, Formlabs, Massachusetts) with a three-dimensional (3D)-printable permanent resin (Permanent Crown, Formlabs, Massachusetts). The samples were polished with mechanical polishing, Optiglaze (GC Dental Products Corp, Aichi, Japan), or Vita Akzent LC (VITA Zahnfabrik, Bad Säckingen, Germany) ( n = 40). Initial color measurements were performed using a spectrophotometer (VITA Easyshade V; Vita Zahnfabrik). Then the samples were divided into four different subgroups depending on beverages immersed in distilled water, coffee, tea, and red wine ( n = 10). After immersion in beverages for 30 days, color measurements were repeated. Color changes were calculated using the CIEDE2000 color change (Δ E 00 ) formula. Δ E 00 was evaluated according to 50:50% color perceptibility (PT 00 = 0.81) and acceptability (AT 00 = 1.81) thresholds. A two-way analysis of variance (ANOVA), Tukey HSD test with Bonferroni adjustment, and paired-sample t-tests were used for statistical evaluation. Results: The highest ΔE 00 was noted in mechanical polishing groups ( p < .001). Red wine caused the most significant discoloration in the mechanical polishing group ( p < .05). ΔE 00 of mechanical polish groups showed a significantly higher color change than the perceptibility and acceptability thresholds ( p < .001). Optiglaze can reduce 3D-printed permanent restoration discoloration caused by all beverages, Vita Akzent LC can reduce discoloration caused by tea and red wine. Conclusion: Glaze materials can reduce the restoration discoloration caused by colorant beverages.