universidade de são paulo - Faculdade de Odontologia - Unesp

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forces, the development of the methods that reduce the adherence of Candida to
these surfaces, could be a significant step toward treatment and prevention of
denture stomatitis. Glow-discharge plasma, a type of cold plasma, has been often
used as a method of surface modification; however, in dentistry it has received
little attention. In this technique, gas temperature can remain as low as room
temperature 24 , preserving the integrity of polymer-based materials. This is of
particular importance for denture base acrylic resins, in which the heating may
cause dimensional changes and affect the fit of the denture bases to the supporting
tissues 23 .
In this study, the aim was to investigate whether surface modifications
with different plasma treatments could decrease the adherence of Candida
albicans to a denture base resin. One of these modifications was intended to
decrease the surface hydrophobicity. The results revealed that plasma treatments
with Ar/50 W, ArO 2 /70 W, AAt/130 W decreased the hydrophobicity of all
surfaces (rough and smooth) immediately after the plasma treatment, when
compared to the untreated specimens. This occurred most likely because the
plasma treatments generated free radicals in the material by inelastic collisions,
mainly involving energetic electrons in the discharge and species on the polymer
surfaces 15 . Chemical reactions that occur between these free radicals and species,
such as atomic hydrogen or oxygen from the polymer or atmospheric
contaminants, incorporate hydrophilic groups to the polymer surfaces 15 , and the
contact angle is reduced.