Table 1.
Two-way mixed ANOVA analysis of the two main factors of HAP concentration and applications on the tooth-whitening effect of nano-HAP toothpaste
| Factor | Sum of squares | DF | Mean square | F |
|---|---|---|---|---|
| ΔE | ||||
| HAP concentration | 38.71 | 2.00 | 19.35 | 37.96* |
| Applications | 4.86 | 1.37 | 3.56 | 34.74* |
| Interaction | 0.28 | 2.73 | 0.10 | 1.01 |
| ΔL | ||||
| HAP concentration | 27.68 | 2.00 | 13.84 | 20.60* |
| Applications | 0.21 | 1.43 | 0.15 | 1.07 |
| Interaction | 0.35 | 2.86 | 0.12 | 0.87 |
| Δa | ||||
| HAP concentration | 260.24 | 2.00 | 130.12 | 4.22* |
| Applications | 37.36 | 1.39 | 26.96 | 5.39* |
| Interaction | 37.92 | 2.77 | 13.68 | 2.74 |
| Δb | ||||
| HAP concentration | 879.38 | 2 | 439.69 | 14.41* |
| Applications | 12.64 | 1.05 | 11.99 | 1.77 |
| Interaction | 54.32 | 2.11 | 25.75 | 3.80* |
* P < 0.05