Effect of brushing and staining cycling on roughness, gloss, and color of resin-based composites

OBJECTIVES To evaluate the effect of brushing and staining media cycling on surface properties (roughness and gloss) and color parameters of a nano-hybrid resin-based composite (RBC). MATERIALS AND METHODS Forty-eight cylindrical-shaped specimens (10x2 mm) were prepared with a nano-hybrid RBC (Clearfil Majesty ES-2 Classic, A3) and randomly divided in 4 groups according to the experimental staining procedure:- G1, static immersion in a staining (coffee) solution (44 degrees C +/- 1 degrees C);- G2, cycling (32 cycles- 45 min) between coffee (44 degrees C +/- 1 degrees C) and distilled water (37 degrees C +/- 1 degrees C) with an experimental staining machine; G3, staining cycles as in G2 + brushing with a low abrasive toothpaste (RDA = 30) (Elmex Sensitive Professional) after every coffee cycle; G4, same experimental design as in G3 but a very strong abrasive toothpaste (RDA = 90) (La- cult Active) was used. Roughness (Ra), gloss (GU) and color parameters (L*, a*, b*) and color difference (Delta E) were evaluated at baseline (T0), after staining procedures (T1) and repolishing (T2) using a profilometer, a gloss- meter and a spectrophotometer. RESULTS For Ra at T1 and T2 G4 was significantly higher than other all groups (p <0.001); G1 and G2 as well as G2 and G3 were significantly different (p <0.001) at T2. For GU, at T1 G1 was significantly higher than other groups (p <0.001); G4 was significantly lower than other groups atT1 and T2 (p <0.001). L*, a*, and b* parameters showed significant differences (p <0.001) at T1 and T2. G1 and G3 showed respectively highest and lowest Delta E. Repolishing procedure partially recovered surface and color properties. CONCLUSIONS The investigated procedure in duced significant differences in roughness, gloss and color parameters. The use of a very strong abrasive toothpaste (RDA = 90) induced higher roughness and color change and lower gloss than a low abrasive one (RDA= 30). CLINICAL SIGNIFICANCE Clinicians should be aware that staining liquids and toothpastes may influence surface and color stability of resin-based composites.