Table 2: Comparison of average microcrack alteration both in the vertical and horizontal directions between groups after bracket debonding (µm).
| Crack directions | Bracket types | Median | Minimum | Maximum | Mean rank |
|---|---|---|---|---|---|
| Vertical | Metal | -11.5 | -23.6 | 3.6 | 21.4a |
| Ceramic | -8.1 | -19.9 | 5.1 | 23.8a | |
| No bracket | -9.0 | -17.2 | -4.7 | 23.7a | |
| Horizontal | Metal | -7.9 | -14.5 | -2.3 | 26.9a |
| Ceramic | -10.5 | -16.3 | 2.9 | 16.7a | |
| No bracket | -8.4 | -13.7 | -4.2 | 25.4a |
Similar superscript letter on the column indicates no statistically significant difference.