Addition of glass fibers and titanium dioxide nanoparticles to the acrylic resin denture base material: comparative study with the conventional and high impact types.

PURPOSE The aim of this study was to clarify the effect of addition of glass fibers and titanium dioxide nanoparticles to the conventional acrylic resin. The tested parameters were monomer release, deflection at fracture, flexural strength, flexural modulus, and toughness. The modified acrylic resin groups were compared to the conventional unmodified and high impact types. The correlation between the tested material properties was also evaluated. MATERIALS AND METHODS The materials used were conventional unmodified and high impact acrylic resins. The conventional acrylic resin was modified using 5% glass fibers and 5% titanium dioxide nanoparticles. Specimens were prepared according to the manufacturer's instructions and American Dental Association Specification No. 12. Monomer release was measured using isocratic high-performance liquid chromatography. Deflection at fracture, flexural strength, and flexural modulus were measured using three point-bending test with a universal testing machine. The toughness was related to the total area under the load-deflection curve up to the breaking point. The correlation between the tested properties was clarified. RESULTS All materials released monomer with varying values. The tested materials exhibited comparable values of deflection at fracture. Specimens modified with glass-fibers showed improved flexural strength and toughness similar to that of the high impact acrylic resin. Specimens modified with titanium dioxide nanoparticles exhibited reduction in the flexural properties and toughness. No significant changes were observed in the flexural modulus. There were positive correlations between the flexural strength, flexural modulus and toughness. On the contrary, there was negative correlation between deflection at fracture and flexural modulus. CONCLUSIONS The most commercially successful method for reinforcement to date is the rubber toughening. The conventional acrylic resin denture base material could be reinforced by glass fibers while titanium dioxide nanoparticles could not. The tested materials released comparable amounts of monomer.