Effect of surface characterization and colour pigment on the bond strength between maxillo-facial silicone and acrylic resin using cyanoacrylate as bonding agent: an in-vitro study

Aim: To evaluate the effect of 3 surface characterizations and incorporation of color pigment into maxillo-facial RTV silicone elastomer on the bond strength with heat-cured acrylic resin using cyanoacrylate as bonding agent. Materials and Method: Five groups of 10 specimens of heat polymerized acrylic resin were fabricated with dimensions of 75 × 10 × 3 mm. These acrylic specimens were bonded to RTV maxillo-facial silicone using cyanoacrylate as a bonding agent. In the first group, silicone without any color pigment or characterization was bonded onto cured PMMA denture base blanks using cyanoacrylate as bonding agent; this was the control group. In the second group, silicone with added color pigment but no surface characterizations was bonded onto the acrylic blanks. In the remaining 3 groups, silicone was bonded onto acrylic blanks whose surface had been roughened with an acrylic bur in the form of retentive holes of 1 x 1.5 mm, 1.5 x 1.5 mm and 2 x 1.5 mm in dimension. The ‘overlap- joint’ model was used to evaluate the bond strength and the specimens were subjected to 1800peel strength test on universal testing machine according to ASTM D-903 specifications with a cross head speed of 10 mm/min until bond failure occurred. One- way ANOVA and Scheffe multiple post hoc test were carried out to detect statistical significance (p < 0.05). Result: Maximum bond strength was seen in the samples with surface characterization with retentive holes of 2 x 1.5 mm. The control group showed the minimum bond strength. Surface characterization in the form of retentive holes increased bond strength considerably as compared to color pigment and samples without any surface characterization. Conclusion: Within the limitations of the study, it was concluded that Cyanoacrylate formed a significant strong bond between maxillofacial silicone and acrylic resin. Retentive holes made on acrylic surfaces increased the bond strength considerably than those without any surface characterization and silicones with color pigment.