Unpolished polymethyl methacrylate

Polished polymethyl methacrylate

Unpolished bis-acrylic resin

Polished polymethyl methacrylate

2.5 × 10⁻¹⁴

-

-

Unpolished bis-acrylic resin

1.2 × 10⁻¹³

p < 0.001

-

Polished bis-acrylic resin

p < 0.001

0.39

p < 0.001