universidade de são paulo - Faculdade de Odontologia - Unesp

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adherence observed in the present study could not be related to hydrophobic
interactions. Although ArO 2 /70W plasma treatment resulted in a more hydrophilic
surface (Table 1), after immersion of the specimens in water for 48 hours, the
contact angles were similar to those of the control specimens. A possible
explanation for this recovery could be that the decrease in the water contact angle
obtained with ArO 2 /70 W enhanced the surface energy. Under such a situation, it
has been observed the polymer surfaces submitted to plasmas tended to return to
their original hydrophobicity 15 . This was attributed to movement of polar groups
from the surface to the polymer bulk.
The results also demonstrated that the adherence of C. albicans to
ArSF 6 /70W plasma treated specimens was significantly reduced compared to
control. To the author’s knowledge to date, the potential of fluorine plasma
treatment to reduce adhesion of Candida albicans to denture base material has yet
not been addressed. Similarly to the ArO 2 /70W treatment, it was not possible to
correlate the reduction in C. albicans adhesion promoted by ArSF 6 /70W treatment
with surface hydrophobicity. After the ArSF 6 /70W plasma treatment, the sample
surfaces became hydrophobic exhibiting the highest contact angle values.
However, after water immersion for 48 hours, a decrease in the contact angle
values was observed and the values were close to those obtained in the other
groups, including control. Despite these changes, the fluorine was still present in
the surface, as demonstrated by XPS analysis. Hence, the reduction of the
adherence of C. albicans with ArSF 6 /70W plasma treatment could be attributed to
repulsive electrostatic forces between the fungal cells and specimens in which