ABSTRACT
PURPOSE: To investigate whether the chemical bond between acrylic teeth and heat polymerized PMMA can be altered by chemical and/or mechanical treatment. MATERIALS AND METHODS: One hundred fifty acrylic teeth were divided in groups of 10. Their ridge lap surface underwent mechanical and/or chemical treatments: 1) no treatment, 2) air-abrasion with Al2O3 particles, 3) acid etching with phosphoric acid, 4) application of composite resin bonding agent, 5) application of MMA and ethylmethylketone bonding agent, 6) PMMA monomer application. The teeth were then placed in heat polymerized acrylic resin. Each specimen was compressed with a universal testing machine. Descriptive statistics, one-way ANOVA (α=0.05) and Tukey's HSD test were used. A scanning electron microscope (SEM) was also used to study the fracture areas. RESULTS: Statistically significant differences (p⟨0.001) in the bond strength were found. The strongest bond (239.41 N), was noted in the group treated with sandblasting followed by PMMA monomer application. CONCLUSIONS: Mechanical and/or chemical preparations affect significantly the bond strength between the acrylic resin denture teeth and the PMMA denture base. Air abrasion was the most effective treatment, either alone or combined with other treatments.
