Table 2.
Descriptive statistics (Vickers Hardness number (VHN)) of the different groups.
| Group | Enamel | Mean (SD) (kgp/mm2) |
Minimum Value (kgp/mm2) |
Median (kgp/mm2) |
Maximum Value (kgp/mm2) |
|---|---|---|---|---|---|
| 1a | Intact | 264.74 (57.10) a | 151.70 | 263.18 | 365.00 |
| 1b | H2O2 35% | 138.96 (43.48) b | 64.20 | 136.80 | 231.20 |
| 2a | Intact | 272.21 (61.68) a,f | 112.50 | 292.05 | 335.90 |
| 2b | CH6N2O3 16% | 215.79 (53.13) c,e | 92.30 | 222.35 | 313.60 |
| 3a | Intact | 254.26 (53.95) a,e | 146.80 | 252.45 | 350.50 |
| 3b | H2O2 35% + Hydroxyapatite | 371.08 (40.70) d | 293.50 | 369.70 | 453.70 |
| 4a | Intact | 232.29 (46.04) a,e | 150.10 | 229.75 | 335.20 |
| 4b | CH6N2O3 16% + Hydroxyapatite | 308.24 (36.97) d,f | 240.30 | 303.70 | 382.10 |
SD: standard deviation. Significant difference at p < 0.05. Superscript letters (a, b, c, d, e and f) have been used to indicate statistical results: different letters among the groups indicate significant difference in micro-hardness among the groups.