Bond Strength Assessment Between Acrylic Teeth and Acrylic Resin Repairs: Effect of Different Surface Treatments

The aim of this study was to compare the shear bond strength between acrylic resin teeth and autopolymerizing acrylic resin repairs after different surface treatments. Seventy-two upper anterior acrylic resin denture teeth (MFT, Vita, Germany) were selected. Specimens were randomly assigned into six groups (n=12): G1-C, without surface treatment (control); G2-M, methylmetacrylate monomer (Jet, Classico, Brazil) application; G3-A treatment with methylmetacrylate and metiletilcetone-based bonding agent (Vitacoll, Vita, Germany). The surface of G4-OA, G5-OAM and G6-OAA was airborne-particle abraded with aluminum oxide (Polidental, Wilson, Brazil); being repeated the treatments respectively of groups G1-C, G2-M e G3-A. All groups were then repaired with autopolymerizing acrylic resin (Jet, Classico, Brazil). Shear bond strength test was performed using an universal testing machine (Instron 4444). Two-way ANOVA and post hoc Tukey's analysis (p<0,05) were used for statistical comparison. The shear bond strengths of groups G4-OA, G5-OAM and G6-OAA were significantly higher (p<0,05) than that of groups G1-C, G2-M and G3-A. The shear bond strength of Group G3-A were significantly higher (p<0,05) than that of groups G1-C and G2-M. In conclution, chemical treatments in combination with bondig agents showed significant improvements in bond strength without aluminum oxide treatment. More significantly, surface treatment with aluminum oxide particles resulted in the highest bond strength values for acrylic resin teeth repaired with autopolymerizing acrylic resin.