Effect of Zirconia Nanoparticles Incorporation on Some Properties of One High - Impact Heat cured PMMA Resin

PURPOSE: To evaluate the effect of ZrO2 nanoparticles incorporation (in two different ratios 1% and 3%) on some properties of one high-impact heat cured PMMA resin material when it was processed by two different methods (Conventional and Microwave curing methods).
Materials & Methods:
One high-impact heat cured PMMA resin (Trevalon Hi) was used in this study to be modified with nano-ZrO2 in two different ratios (1% and 3%). Both unmodified and modified high-impact heat cured PMMA resin were subjected to three different tests (Flexural strength test, Microhardness test, and Color stability test). A total of ninety specimens were prepared, thirty specimens for each test (N=30). Within each test specimens, there were three groups (n=10), (HI) group: was prepared from high-impact heat cured PMMA resin without modification by nano-ZrO2 (as a control group). (1%n-ZrO2 HI) group: was prepared from high-impact heat cured PMMA resin modified by 1% nano- ZrO2. (3%n-ZrO2 HI) group: was prepared from high-impact heat cured PMMA resin modified by 3% nano- ZrO2.Within each group, five specimens were prepared by conventional water-bath curing method, while the other five specimens were prepared by microwave curing. The significance level was set at P ≤ 0.05. Statistical analysis was performed with IBM® SPSS® Statistics Version 20 for Windows.
Results: Modification of high-impact heat cured PMMA resin with (1% and 3%) nano-ZrO2 resulted in significant increasing in the mean values of flexural strength and VHN of all tested groups (p<0.05), while the effect on the color stability of the resin was slight.
Conclusion: Within the limitation of this study, modification of high-impact heat cured PMMA resin with zirconia nanoparticles up to 3% could improve the flexural strength and surface microhardness with slight effect on the color. Microwave curing of high-impact heat cured PMMA resin gives better results than conventional one.