Thickness | N | ΔL | Δa | Δb |
0.5 mm | 20 | 0.83 ± 0.01a | 0.30 ± 0.03a | 0.25 ± 0.03a |
1 mm | 20 | 0.82 ± 0.02b | 0.21 ± 0.02b | 0.15 ± 0.02b |
1.5 mm | 20 | 0.81 ± 0.01c | 0.18 ± 0.02c | 0.13 ± 0.02c |
2 mm | 20 | 0.80 ± 0.01d | 0.16 ± 0.02d | 0.12 ± 0.02d |