universidade de são paulo - Faculdade de Odontologia - Unesp

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values [15,35]. Similar results were also reported in other investigations in which
plasma treatments were made to modify polymeric surfaces [14,17,18,35,40].
The results also showed that, after immersion in water for 48 hours, an
alteration of the contact angles of all groups evaluated was detected. This
demonstrates that the hydrophobicity of the specimens submitted to plasma
treatments came close to that observed for the control group specimens. This
alteration occurs because the modification caused by plasma treatment increases
the surface energy [15,35]. Under this condition, it has been observed that the
polymers have a tendency to recover their hydrophobicity, which has been
attributed to the rotation of polar groups around the polymeric backbone into the
material bulk [35]. Despite the increase in the contact angle values observed in
experimental groups, they remained significantly more hydrophilic compared to
control after 48 hours of immersion in water.
In this study, when the acrylic surfaces were preconditioned with saliva,
there were no significant differences in Candida glabrata adhesion among all
groups evaluated. It has been demonstrated that the salivary coating is an
important factor in determining the wettability properties of denture materials and,
after conditioning with saliva, wettability characteristics of biomaterials can be
altered [18,41]. The surface free energy of various materials, including a
microwave-cured acrylic resin, was decreased in approximately 10% when the
specimens were coated with saliva [41]. This may help explain the absence of any
plasma effect in Candida glabrata adhesion after preconditioning with saliva.