Effect of zirconium oxide nanoparticles addition on the optical and tensile properties of polymethyl methacrylate denture base material

Abstract

Background Polymethyl methacrylate (PMMA) is widely used for the fabrication of removable prostheses. Recently, zirconium oxide nanoparticles (nano-ZrO 2 ) have been added to improve some properties of PMMA, but their effect on the optical properties and tensile strength are neglected. Objective The aim of this study was to investigate the effect of nano-ZrO 2 addition on the translucency and tensile strength of the PMMA denture base material. Materials and methods Eighty specimens (40 dumbbell-shaped and 40 discs) were prepared out of heat-polymerized acrylic resin and divided into four groups per test (n=10). The control group for each test included unreinforced acrylic, while the test groups were reinforced with 2.5, 5, and 7.5 wt% nano-ZrO 2 . Acrylic resin was mixed according to manufacturer’s instructions, packed, and processed by conventional method. After polymerization, all specimens were finished, polished, and stored in distilled water at 37°C for 48±2 hours. Tensile strength (MPa) was evaluated using the universal testing machine while the specimens’ translucency was examined using a spectrophotometer. Statistical analysis was carried out by SPSS using the paired sample t -test ( p ≤0.05). A scanning electron microscope was used to analyze the morphological changes and topography of the fractured surfaces. Results This study showed that the mean tensile strength of the PMMA in the test groups of 2.5%NZ, 5%NZ, and 7.5%NZ was significantly higher than the control group. The tensile strength increased significantly after nano-ZrO 2 addition, and the maximum increase seen was in the 7.5%NZ group. The translucency values of the experimental groups were significantly lower than those of the control group. Within the reinforced groups, the 2.5%NZ group had significantly higher translucency values when compared to the 5%NZ and 7.5%NZ groups. Conclusion The addition of nano-ZrO 2 increased the tensile strength of the denture base acrylic. The increase was directly proportional to the nano-ZrO 2 concentration. The translucency of the PMMA was reduced as the nano-ZrO 2 increased. Clinical significance Based on the results of the current study, the tensile strength was improved with different percentages of nano-ZrO 2 additions. However, translucency was adversely affected. Therefore, it is important to determine the appropriate amount of reinforcing nano-ZrO 2 that will create a balance between achieved properties – mechanical and optical.

Tensile Strength of Denture Base Material Reinforced With Zirconia Nanoparticle and Glass Fibers

“…The results of the current study showed that the addition of NZ increased the tensile strength of PMMA/NZ composite. This outcome is in agreement with previous studies confirming the positive effect of NZ addition to PMMA denture base material where it had a direct relation with flexural, impact, and tensile strengths (11,24,26) . The increase in tensile strength could be linked to a good dispersion of the NZ fillers within the matrix, and due to their nano-size, they have the capability of filling the matrix interstitially and improving the strength thereafter.…”

“…The value of tensile strength was computed using the following formula: TS=F/A, Where, TS = Tensile strength (N/mm 2 ), F = Force at failure (N), A = Area of a cross section at failure (mm 2 ). Testing procedures were performed at 23° C and 50% relative humidity (24) .…”

Effect of hydroxyapatite filler concentration on mechanical properties of poly (methyl methacrylate) denture base

“…Several ceramic powders are used as reinforcement for PMMA, e.g. barium titanate, zirconium oxide, alumina and hydroxyapatite (HA) [2,6,7]. The biodegradation, osteoconduction, osteointegration and biocompatibility of the HA is the promise behind the used of HA reinforcement material for biomedical application.…”

Applications of nano-materials in diverse dentistry regimes

“…The enhancement in the tensile strength of the denture base acrylic was directly proportional to the nano-ZrO 2 concentration while PMMA translucency declined when nano-ZrO 2 concentration was increased. 121 Sarraf et al built a hybrid biofunctionalized coating encompassing nano-tubular rows of titanium dioxide (TiO 2 NTs) with decorated silver oxide NPs (Ag 2 O NPs) on their edges in order to improve the biological behaviors and anti-bacterial activities of Ti 6 Al 4 V implants ( Fig. 3).…”