ObjectivesThe aim of the present study was to assess the effect of the exposure to
food-simulating liquids prior to brushing simulation on the surface roughness of
five composite materials (Quixfil, Filtek Supreme, Esthet-X, Filtek Z250, Tetric
Ceram). Material and methodsTwenty cylinders (5 mm diameter and 4 mm height) of each composite were randomly
allocated to 4 groups (n=5), according to the food-simulating liquid in which they
were immersed for 7 days at 37ºC: artificial saliva, heptane, citric acid, and
ethanol. After this period, the top surface of composite cylinders was submitted
to 7,500 brushing cycles (200 g load). Measurements of the surface roughness (Ra,
µm) were carried out before and after the exposure to the chemicals/brushing
simulation. Changes on the morphology of composite surfaces were observed through
scanning electron microscopy (SEM). ResultsThe statistical analysis (ANOVA with cofactor / Tukey's test, α=5%) detected a
significant interaction between solutions and composite resins. Esthet-X, Filtek
Z250 and Tetric Ceram were not affected by the food-simulating
liquids/toothbrushing. Citric acid and ethanol increased the surface roughness of
Quixfil and Filtek Supreme, respectively. SEM images corroborate the surface
roughness findings, demonstrating the negative effect from chemical solutions and
mechanical abrasion. ConclusionsThe surface roughness of composite resin materials are differently affected by the
food-simulating solutions, depending on the immersion media.