The Effect of Adding Zirconium Oxide Nanoparticles on Fracture Strength of Heat Cured Acrylic Resin

 Zirconium oxide nanoparticles have high strength and transparency to light and have been used in dentistry in dental restorations, production of high glass fillers, and improving the material's resistance to mechanical impact. The aim of this study was to investigate the effect of zirconium oxide nanoparticles on the fracture strength of heat-cured acrylic resin.

 This laboratory experimental study was conducted in the laboratory of the Faculty of Dentistry of Khorasan Azad University and Dr. Mousavi Research Center of Isfahan University during the spring and summer of 2018, 90 samples (22 × 10 × 2.5) were made using wooden blocks to make acrylic samples. After flasking, the samples were divided into 3 equal groups. In the first group no powder of zirconium oxide was added. In the second group, 2.5% by weight of zirconium oxide and in the third group 7.5% by weight of zirconium oxide were added to the mixture. Then, the fracture strength of the samples was evaluating using a universal testing machine and 3-point bending test. The data were analyzed using ANOVA one-way and Tukey's test (α = 0.05)

 There was a significant difference (p value < 0.001) between the mean fracture strength of heat cured acrylic resin samples in the three studied groups (p value < 0.001). The lowest mean fracture strength was observed in the group with 7.5 % weight of zirconia.

 The average strength to failure of heat-cured acrylic is reduced by adding zirconia oxide.