Preparation of Zinc Oxide Mesocrystal Filler and Its Properties as Dental Composite Resin

The inorganic filler is the main component of the dental restoration composite resin, which is very important for the properties and functions of composite resin. In this paper, zinc oxide (ZnO) mesocrystal microspheres were prepared from Zn(NO3)center dot 6H(2)O solution in presence of triethanolamine as the soft template by hydrothermal method, these microspheres were self-assembled by 37.5 nm ZnO crystallite and with good order. ZnO mesocrystal microspheres were modified with gamma-methacryloxypropyl trimethoxysilane (gamma-MPS) and subsequently mixed with modified SiO2 microspheres as fillers, and then added to the Bis-GMA/TEGDMA system to prepare the composite resin. Through morphology observation and performance test, it is found the filler is uniformly dispersed in composite resin. The one filled with 20wt% ZnO mesocrystals has excellent mechanical properties and wear resistance, among which the flexural strength and modulus reach 133 MPa and 9.8 GPa, respectively with the volume loss at 1.02 mm(3) after 3000 times of wearing, which was 88.7% and 90.8% lower than that of the composite resin filled with commercial ZnO microspheres and bare SiO2, respectively. Moreover, the antibacterial rate of zinc oxide composite resin against streptococcus mutans in the oral cavity reached 99.9%.