Table 2. Mean and Standard Deviation Surface Roughness of Untreated Enamel (Ctr) and Enamel Treated with Phosphoric Acid (Etch), Optibond Versa Primer (OV), and Tetric N Bond Universal Adhesive (TNBU)a.
| surface
roughness (μm) |
||
|---|---|---|
| sample group | mean ± SD | confidence interval (95%) |
| Ctr | 1.356 ± 0.223d | 1.214–1.498 |
| Etch | 2.062 ± 0.180a | 1.948–2.177 |
| OV | 1.821 ± 0.202b | 1.693–1.949 |
| TNBU | 1.639 ± 0.184c | 1.522–1.756 |
a
Values with different superscript lowercase letters are significantly different (p < 0.05).