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| Bracket types | n | Direction of microcrack | |
|---|---|---|---|
| Vertical | Horizontal | ||
| Metal | 15 | -0.10 ± 0.07 | -0.08 ± 0.04 |
| Ceramic | 15 | -0.10 ± 0.07 | -0.11 ± 0.05 |
| No bracket | 15 | -0.11 ± 0.04 | -0.09 ± 0.03 |
| p-value | 0.792 | 0.215 | |
