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Using TiO2 Nanoparticles in Dental Applications
J. Sun, B. Pinto, D. Stanley, D. Skrtic, S.S. Watson
American Dental Association Foundation, US
Keywords: TiO2 nanoparticles, EPR, methacrylate, dental materials
Summary:
TiO2 nanoparticles (NPs) are attracting progressively more attention in dental applications due to their unique photo-activities. The objectives of this study are to improve the bond strength of dental adhesives by adding a small amount of TiO2 NPs. The photo-activities of TiO2 NPs functionalized with acrylic acid and acetic acid were evaluated using electron paramagnetic resonance (EPR) and UV-vis spectroscopy, respectively, to determine the amount of the radicals generated and the energy required for their production. The beneficial effects of the radicals were assessed through the improvement of degree of vinyl conversion (DC; quantified by FTIR). Light-curable methacrylate resins were formulated into different experimental resins according to viscosity and number of hydroxyl groups on the resins. The TiO2 NPs containing (0.1wt%) nano-composites were used as dental adhesives, and their shear bond strength were evaluated. EPR and UV-vis results clearly showed that the surface functionalization improved the photo-activities of TiO2 NPs. Dramatic improvement in DC and shear bond strength can be achieved through adding a small amount of TiO2 NPs into different resin compositions. Knowledge gained from this study will help formulating nano-composites with optimized use of TiO2 photo-activities, and making stronger and more durable dental adhesives.
