Table 3: The mean difference in roughness of composite resin before and after 2% NF gel.

Composite Resin Before NF
Mean ± SD
After NF
Mean ± SD
Difference P Value
Tetric-N-Ceram 0.226 ± 0.0496 0.2650 ± 0.0828 0.1360 Ns
Z250 0.236 ± 0.0406 0.2493 ± 0.0563 0.0203 Ns
Z350 XT 0.2127 ± 0.0422 0.2273 ± 0.0432 0.0293 Ns

*NF, Sodium Fluoride; SD, Standart Deviation Ns: no statistically different.