Effect of Zirconium Oxide Nano-Fillers Addition on the Flexural Strength, Fracture Toughness, and Hardness of Heat-Polymerized Acrylic Resin

Abstract

Purpose: The mechanical strength of polymethyl methacrylate (PMMA) remains far from ideal for maintaining the longevity of denture. The purpose of this study was to evaluate the effect of Zirconium oxide (ZrO2) nanofillers powder with different concentration (1.5%, 3%, 5% and 7%) on the flexural strength, fracture toughness, and hardness of heat-polymerized acrylic resin. Materials and methods: Zirconium oxide powders with different concentrations (1.5%, 3%, 5% and 7%) were incorporated into heat-cure acrylic resin (PMMA) and processed with optimal condition (2.5:1 Powder/monomer ratio, conventional packing method and water bath curing for 2 hours at 95˚C) to fabricate test specimens of PMMA of dimensions (50 × 30 × 30 mm) for the flexural strength, fracture toughness, and (50 × 30 × 30 mm) were fabricated for measuring hardness. PMMA without additives was prepared as a test control. Three types of mechanical tests; flexural strength, fracture toughness and hardness were carried out on the samples. The recorded values of flexural strength in (MPa), fracture toughness in (MPa.m 1/2 ), and hardness (VHN) were collected, tabulated and statistically analyzed. One way analysis of variance (ANOVA) and Tukey's tests were used for testing the significance between the means of tested groups which are statistically significant when the P value ≤ 0.05. Results: Addition of Zirconium oxide nanofillers to PMMA significantly increased the flexural strength, fracture toughness and hardness. Conclusion: These results indicate that Zirconium oxide nanofillers added to PMMA has a potential as a reliable denture base material with increased flexural strength, fracture toughness, and hardness. According to the results of the present study, the best mechanical properties were achieved by adding 7%wt ZrO2 concentration. M. A. Ahmed, M. I. Ebrahim 51

The effects of adding various ratios of zirconium oxide nanoparticles to poly(methyl methacrylate) on physical and mechanical properties

“…Moreover, hardness measurement has been used as an indirect method of evaluating polymerizing depth of resin-based materials (17). Moreover, hardness impacts the surface characteristics of PMMA indicating the ease of finishing a material (6).…”

“…Polymerized acrylic resin hardness is an important material property in terms of residual monomer content in the resin material (17) and resistance to wear (27). Moreover, hardness measurement has been used as an indirect method of evaluating polymerizing depth of resin-based materials (17).…”

“…Moreover, hardness impacts the surface characteristics of PMMA indicating the ease of finishing a material (6). These days, nano-ZrO 2 is used to fabricate reinforced denture base materials with high hardness (17,28).…”

“…Nanoparticle aggregates disrupt the mechanical properties and reduce the optic properties of polymer-based material. Good adhesion and dispersion homogeneity of nano-ZrO 2 with the resin matrix and the small nanoparticle size improve the transverse strength of PMMA (12,17). Therefore, organic solvents or monomer (silane coupling agent) could be used to disperse nanoparticles in the matrix (2,18).…”

Translucency Evaluation of Polymethyl Methacrylate (PMMA) Reinforced with ZrO₂-Al₂O₃-SiO₂ Filler System in Fabricating Indirect Restoration

“…According to the results of the present study, the best result was obtained when using the concentration of 7% ZrO2 nanofiller by weight. 11 An alternative way to synthesize the filler particles with a sol gel technique had improved new ideas to assist in relative conditions. 12 Based on the previous study by Rasikh in 2014, he measured the hardness of heat cured PMMA among three groups, a control with no filler and other groups with a ratio of PMMA -filler at 2:1 and 4:1 which was filled by a ceramic filler system ZrO₂-Al₂Oз-SiO₂ synthesized with a higher silica precursor using the sol gel technique, reinforcing the filler system to PMMA with different ratio of filler.…”