Table 2. Surface microhardness values (VHN) (median and 25%–75% values) of the tested groups.
| Groups | Distilled water | Coffee | ||||||
|---|---|---|---|---|---|---|---|---|
| Baseline | 1 week | 6 weeks | p | Baseline | 1 week | 6 weeks | p | |
| Control | 53.40 (51.56–58.78) | 55.03 (40.01–57.29) | 52.86 (46.44–56.50) | 0.185 | 53.37 (51.97–55.13) | 53.68 (48.62–58.88) | 53.53 (46.11–54.66) | 0.335 |
| Modeling Liquid | 55.19 (52.81–57.85) | 58.86 (56.52–62.33) | 55.28 (51.87–57.85) | 0.250 | 53.58 (52.77–55.60) | 53.33 (50.45–56.34) | 52.53 (50.19–54.05) | 0.859 |
| Universal adhesive | 52.15 (43.68–53.08) | 51.02 (48.48–53.88) | 49.27 (40.56–51.15) | 0.546 | 48.89 (40.25–49.54) | 47.82 (45.24–57.50) | 46.05 (45.37–49.99) | 0.670 |
| Primer | 49.36 (45.81–53.26)* | 50.76 (47.89–51.98)* | 45.73 (42.80–49.33)* | 0.496 | 45.27 (45.27–47.83)* | 45.68 (45.28–46.01)* | 43.84 (45.40–48.76)* | 0.129 |
| p | 0.023 | 0.003 | 0.003 | 0.007 | 0.025 | 0.045 | ||
*Represents a significant difference among the groups in a column (p < 0.05).