Table 2.
Descriptive statistics of VHN for each tested material, considering both the external and the internal side of the samples.
| Group | Material Code | Side | Mean | Min | Mdn | Max |
|---|---|---|---|---|---|---|
| 1 | VIS | External (A) | 82.82 (1.62) a | 80.10 | 83.21 | 85.10 |
| 1 | VIS | Internal (B) | 67.80 (2.51) b | 64.60 | 67.65 | 72.30 |
| 2 | FUS | External (A) | 62.08 (0.92) c | 60.58 | 62.29 | 63.08 |
| 2 | FUS | Internal (B) | 53.14 (2.31) d | 50.10 | 53.12 | 57.00 |
| 3 | XTF | External (A) | 87.00 (1.97) e | 84.40 | 87.20 | 90.50 |
| 3 | XTF | Internal (B) | 82.80 (2.28) a | 78.90 | 83.00 | 86.20 |
| 4 | GRA | External (A) | 71.50 (1.70) f | 68.30 | 72.15 | 73.44 |
| 4 | GRA | Internal (B) | 65.60 (1.28) b | 63.80 | 65.70 | 67.20 |
SD: standard deviation; Min: minimum value; Mdn: median; Max: maximum value. Superscript letters (a, b, c, d, e and f) have been used to indicate statistical results: different letters indicate the presence of significant differences in micro-hardness among the groups (significance was set at P < 0.05).