The effect of plasma treatment on the bonding of soft denture liners to heat cured acrylic resin denture base material and on some surface properties of acrylic resin polymer

Abstract EN

Background : Acrylic resin polymers used in dentistry, are usually with problems in bonding, especially failure of the bond with soft denture lining materials.

The aim of this study is to investigate the effect of plasma treatment on tensile bond strength, wettability and on physical surface changes for acrylic resin polymer.

Materials and methods : heat cured acrylic resin specimens with dimensions 8 × 10 × 30 mm were prepared for tensile bond strength test, in which each two acrylic specimens were joined by a 3-mm thick soft liner (Vertex Soft, Molloplast-B).

Another heat curd acrylic resin specimens were prepared with dimensions 2×8×30 mm for wettability test and physical surface analysis.

For each test done in this study, the specimens were grouped as control, oxygen plasma treated and argon plasma treated acrylic specimens.

Results : plasma treatment increased the tensile bond strength for both Vertex and Molloplast-B soft lining materials, also induced a decrease in water contact angle values (i.e., increase in wettability) for oxygen and argon plasma treated groups compared with control group, with highly significant difference (P <0.01) among groups.

AFM images showed a collection of new distinct nanograins and numerous grooves (pitlike-structures) after oxygen and argon plasma treatment with argon plasma treatment showed more new nanograins, deepest grooves and highest protuberances which increased the surface-roughness (i.e.

nano-roughness) when compared with control and oxygen plasma treated groups.

Conclusion : plasma treatment was an effective method for increasing tensile bond strength, wettability, and induced physical topographical surface changes that increased the surface roughness(mainly after argon plasma treatment) for plasma treated heat cured acrylic resin specimens.