Evaluation of Impact Strength and Surface Hardness of Acrylic Resin Modified with Different Nano Materials: An In Vitro Study

Abstract

Aim:The fracture of the denture resulting from the accidental fall on the ground is affected by the impact strength of the acrylic resin. Many attempts have been made to improve the mechanical properties of acrylic resin by reinforcing it with different materials. The aim of this study was to evaluate the effect of addition of different nano materials on the impact strength and surface hardness of the acrylic resin. Materials and methods: Fifty samples of dimensions 65 mm × 10 mm × 3 mm were made and divided into five groups. Group I is the control group of heat-activated polymethyl methacrylate (PMMA) acrylic resin, while groups II, III, IV, and V are having 1% and 3% zirconium oxide (ZrO 2 ) and silicon dioxide (SiO 2 ) nanoparticles in heat-activated PMMA by weight, respectively. A metallic block was fabricated and invested into addition silicone impression material to form a mold. The modeling wax was melted and flown into the mold cavity to form the wax block. The samples were subsequently polymerized, retrieved, finished, and polished. Impact strength and surface hardness were measured by Izod impact testing machine and Vickers hardness tester, respectively. Results: The results showed that the control group had the highest impact strength and lowest value was observed with 1% SiO 2 . The value of Vickers hardness was maximum with 1% ZrO 2 and least with the control group. The analysis of variance (ANOVA) for both the impact strength and surface hardness indicated a p value of <0.001, which is very highly significant. Conclusion: Incorporation of ZrO 2 and SiO 2 nanoparticles into the heat-activated PMMA affects the impact strength and surface hardness.

Novel Cold Cure Acrylic Denture Base with Recycled Zirconia Nano-Fillers That Were Functionalized by HEMA Agent Incorporation: Using the Sprinkle Approach

“…Also, the increase in the percentage of modified-nano-ZrO 2 powder affects the interface region, leading to a lowering of energy dissipation per unit volume and consequently lowering the impact strength. 41 A good explanation of the effect of higher filler content on reducing strength can be explained on the basis that, after reaching a saturation point, the resin cannot incorporate any further filler particles. Any attempt to add filler particles after reaching saturation of the matrix leads to an interruption in the resin matrix continuity, thus causing a decrease in the strength of reinforced specimens.…”