Table 4. Mean values (SDs) of ∆E* of red group in each concentration over aging period.
| ∆ E | 12 h | 24 h | 48 h | 72 h |
|---|---|---|---|---|
| Group | ||||
| Abbreviation: SD, standard deviation. Note: Tukey test with a level of significance of 0.05. Groups with the same superscript uppercase letter per column or lowercase letter per row are not significantly different ( p > 0.05). a Values of ∆ E * > 1.0a. | ||||
| Red - control | 0.57 (0.3) Aa | 0.92 (0.3) Aa | 1.17 a (0.1) Ba | 1.20 a (0.4) Ba |
| Red - 0.5% ZnO | 0.42 (0.4) Ab | 0.48 (0.2) Ab | 0.66 (0.3) Bb | 0.74 (0.3) Bb |
| Red - 1.0% ZnO | 0.30 (0.3) Ab | 0.38 (0.4) Ab | 0.73 (0.3) Bb | 0.86 (0.3) Bb |
| Red - 1.5% ZnO | 0.30 (0.3) Ab | 0.49 (0.4) Ab | 0.68 (0.4) Bb | 0.80 (0.3) Bb |
| Red - 2.0% ZnO | 0.60 (0.3) Aa | 0.64 (0.6) Aa | 0.87 (0.4) Ba | 0.88 (0.3) Ba |