Staining- and aging-dependent changes in color and translucency of 3D-printed resin-modified ceramics

Purpose: To evaluate staining- and aging-dependent changes in the color and translucency of 3D-printed resin-modified ceramics (RMC). Methods: Specimens (n= 5 per condition and material) were fabricated from test materials: Permanent Crown Resin (PCR), Crowntec (CT), Vita Enamic (VE) and Tetric CAD (TC). Specimens were stained in wine, coffee, tea, and water (control) and exposed to artificial accelerated aging (AAA). Color measurements were obtained using a spectrophotometer at baseline (TO) and at 3.5 (T1) and 7 (T2) days after immersion. For AAA, measurements were obtained at baseline (TO) and after exposure to controlled irradiance of 150 kJ/m(2) (T1) and 300 kJ/m(2) (T2). Mean and standard deviations were calculated on CIEDE2000 color differences (Delta E-00), translucency parameter (TP00) and treatment-dependent changes in the translucency parameter (Delta TP00). Differences between materials and test conditions were tested by one-way ANOVA (alpha= 0.05). Results were additionally interpreted using visual color difference thresholds in dentistry Delta E-00= 0.8 for the 50:50 perceptibility threshold (PT) and Delta E-00= 1.8 for the 50:50 acceptability threshold (AT). Delta TP00 values were interpreted using 50:50 TPT00= 0.6 and 50:50% TAT(00)= 2.6. Results: Statistically significant differences were found among the materials when exposed to the different test conditions. At the T0-T1 time interval, the highest color difference was found with wine (0.1-2.2) on all materials except CT, which showed the highest Delta E-00 with AAA (2.5). The second highest color differences were obtained upon exposure to AAA (0.2-2.5) and tea (0.5-1.1). The TP00 at baseline ranged from 5.1 to 9.8. Significant differences in Delta TP00 were found among the tested materials and staining/aging conditions, but no significant differences were found among the staining/aging intervals (T0-T1, T0-T2 and T1-T2).