Shear bond strengths of composite to acrylic resin denture teeth using a filled bonding system

Modifying acrilic resin denture teeth with composite can be a reliable clinical procedure, if these bond strengths are comparable to the bond strengths obtained using autopolimerized acrylic resin. Objectives: the purpose of this study was to compare the shear bond strengths(SBS) of composite to resin teeth using a filled bonding resin and a unfilled bonding resin with the SBS of an autopolimerized acrylic resin . Material and Methods: thirty central incisors resin denture teeth (Acrotone Gold-Wright) were embedded in a autopolimerized acrylic resin cylinder, the labial surface of each tooth was polished with wet 120-,240-, and 400-grit Sic paper. The specimens were then randomly assigned for each test group (n=10). The bonding surface of each specimen was treated with methyl methacrylate monomer for 3 min. before bonding. In group I composite cylinders (XRV Herculite-Kerr) were bonded to the treated surfaces using a filled bonding resin (Composiv-Ivoclar)-COP. In the group II the composite cylinders were bonded with an unfilled bonding resin (Panavia F Kuraray)-PAF; Finally, in the group III, autopolimerized acrylic resin cylinders (Probase Cold-Ivoclar)- PBC were bonded to the treated surfaces without a bonding agent. All the materials were applied per manufacturers` directions. After bonding, the specimens were stored in distilled water for 24 hours and thermocycled for 500 cycles at 5ºC and 55ºC. SBS´s were measured with an Instron Testing Machine with a crosshead speed of 0.5 cm/min. Data were recorded in Newton(N) and analyzed using Student`s t- test (p * 0.05). Results: of average values and SD among the groups: COP- 108.3±36.3, PAF-31.9±23.2, PBC-170.7±48.8. Conclusions: PBC had statistically higher SBS´s then COP and PAF. COP had statistically higher SBS´s then PAF. Results suggest that filled bonding agents could increase the SBS between composite resins and acrylic resin denture teeth. However, acrylic resins give significantly higher SBS to acrylic resin denture teeth than composite resins with bonding agents.