3, 30, 42, 43 and 44 For the find more specimens treated with the photopolymerized coatings, significant differences between smooth and rough surfaces were not detected. It has been reported that the more hydrophobic the surface, the greater is the C.

albicans cell adherence by area unit. 27 Thus, a commonly used method to reduce the attachment of microorganisms is surface modification with hydrophilic polymers 7, 21 and 24 as attempted in the present study. For instance, coating surfaces with a 2-methacryloyloxyethyl phosphorylcholine (MPC) co-polymer decreased both water contact angles and the adhesion of C. albicans. 6 Accordingly, Yoshijima et al. 28 also observed that hydrophilic coatings of denture acrylic surfaces reduced the adhesion of the hydrophobic C. albicans hyphae. More recently,

it has been also found that coating a denture base material with silica nanoparticles was effective in increasing surface hydrophilicity and decreasing C. albicans adherence. 29 Hence, in the present study, the surface free energy of the specimens was calculated. The total surface free energy is the sum of components arising from dispersive and polar contributions where the polar component describes the hydrophilic character and the dispersive component is associated with the hydrophobic character of the surface. While the dispersive component (or Lifshitz–van der Waals) is influenced by the particle size or specific surface area, the polar component is the result of different forces/interactions such as polar, hydrogen, inductive and acid–base Docetaxel order interactions.45 Thus, while the dispersive component is affected by the surface roughness

(or specific surface area), the polar component is dependent on the surface activity, which is related to the surface functional groups such as hydroxyl, carbonyl, and carboxyl.45 Generally, in this study, the coatings application decreased the water contact SPTLC1 angle (data not shown) and increased the polar surface free energy component which may have arisen from a change in the surface polar group concentration in the coated specimens. Only minor significant differences were observed for the dispersive component. Therefore, although the dispersive (or non-polar) component of the surface free energy is numerically higher than the polar component, the polar component is the main factor in determining modifications of the total surface free energy. Thus, the values of the surface energy followed the same trend as the polar component. Compared to the control, mean surface free energy values of the rough surfaces coated with S30, S35 and HP30 were significantly higher which indicates increased wettability. These results were expected because it is known that the contact angles are decreased (more hydrophilic) by surface roughness for hydrophilic surfaces.46 The effect of saliva on the hydrophobicity of the surfaces was also evaluated.