Synthesis of Silica Hybrid Nanoparticles and the Effect of Their Addition on the Hardness of the Dental Nanocomposites (original) (raw)
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Dental Composites Based on Dimethacrylate Resins Reinforced by Nanoparticulate Silica.pdf
This paper describes morphological differences and associated functional properties of dental composites based on dimethacrylate resins reinforced by nanoparticulate silica filler modified according to different silanization procedures. Surface morphology of the materials was evaluated by means of AFM, while nanohardness and elasticity modulus of the surface layer -by nanoindentation and abrasion -gravimetrically. The effects of silane treatment of nanoparticulate silica surface on possible filler loading, mechanical properties and abrasion resistance of the composites were discussed. The influence of the amount and kind of silane coupling agent on the example of 3-methacryl-oxypropyltrimethoxysilane and vinyltrimethoxysilane were presented. The modification of nanoparticulate silica with 3-methacryloxypropyl -trimethoxysilane enabled the introduction of 15% more filler than modification with vinyltrimethoxysilane. The abrasion resistance depended strongly on the composite morphology and the micromechanical parameters of the surface layer. The composite modified with vinyltrimethoxysilane, containing the highest percentage of filler particles smaller than 1 μm in diameter, exhibited the lowest abrasion (0.3 vol.%). Abrasive wear seemed to be a linear function of nanoindentation hardness with the correlation coefficient of R 2 = 0.96. The highest hardness of the surface layer of commercial composite (130 MPa) resulted in the highest abrasive wear (7.7 vol.%). The type and the quantity of silane coupling agent used for silica modification strongly influence the morphology and mechanical and tribological properties of the dental composites. The application of more than the calculated, optimal amount of silane to nanosilica modification enables higher filler loading, but the composites exhibit inferior mechanical characteristics. Nanoindentation hardness of surface layer showed to be the most useful parameter in estimation of material susceptibility to abrasion.
Dental Composites Based on Dimethacrylate Resins Reinforced by Nanoparticulate Silica
Polymers & Polymer Composites, 2016
This paper describes morphological differences and associated functional properties of dental composites based on dimethacrylate resins reinforced by nanoparticulate silica filler modified according to different silanization procedures. Surface morphology of the materials was evaluated by means of AFM, while nanohardness and elasticity modulus of the surface layer-by nanoindentation and abrasion-gravimetrically. The effects of silane treatment of nanoparticulate silica surface on possible filler loading, mechanical properties and abrasion resistance of the composites were discussed. The influence of the amount and kind of silane coupling agent on the example of 3-methacryloxypropyltrimethoxysilane and vinyltrimethoxysilane were presented. The modification of nanoparticulate silica with 3-methacryloxypropyltrimethoxysilane enabled the introduction of 15% more filler than modification with vinyltrimethoxysilane. The abrasion resistance depended strongly on the composite morphology and the micromechanical parameters of the surface layer. The composite modified with vinyltrimethoxysilane, containing the highest percentage of filler particles smaller than 1 μm in diameter, exhibited the lowest abrasion (0.3 vol.%). Abrasive wear seemed to be a linear function of nanoindentation hardness with the correlation coefficient of R 2 = 0.96. The highest hardness of the surface layer of commercial composite (130 MPa) resulted in the highest abrasive wear (7.7 vol.%). The type and the quantity of silane coupling agent used for silica modification strongly influence the morphology and mechanical and tribological properties of the dental composites. The application of more than the calculated, optimal amount of silane to nanosilica modification enables higher filler loading, but the composites exhibit inferior mechanical characteristics. Nanoindentation hardness of surface layer showed to be the most useful parameter in estimation of material susceptibility to abrasion.
Biomedical and Pharmacology Journal, 2017
The aim of this investigation was to assessand comparethe impact of incorporation of nanosilica sand (crystalline) and nano-silica (amorphous) on the properties (impact strength, transverse strength, and hardness)of heat-cure type acrylic resin denture base material, polymethylmethacrylate (PMMA). Nanoparticles(NPs) with different concentrations (3%, 5% and 7%) were incorporated by weight into PMMA and processed under optimal conditions.161 samples were prepared for this study.These samples were placed in three groups according to the tests performedandeach group consisted of seven subgroups according to the percentage of NPs added. Charpy test for impact strength, transverse strength test and hardness test (shore D) were conducted. The morphology, size distribution and crystallinity of the NPs were estimated by scanning electron microscope, atomic force microscope, and X-Ray diffraction respectively.The results show that each investigated property was enhanced after NPs filler wasincorporatedwhen compared to control group. Highly significant improvements in impact strength,transverse strength and hardness were observed with addition of NPsto PMMA at 3%, 5% and 7% by weight. However, compromised mechanical properties is still a drawback of PMMA , hence it can be easily damaged by accidents or high mastication forcesduring denture wear. One of the ways of improving the mechanical properties of PMMA based materials may be NPsincorporation which canimprove the physical and mechanical properties. Optimum nanoparticle doses can yield superior mechanical properties.
Journal of Prosthodontics, 2010
Purpose: Mechanical properties of dental composite resins need to be improved in order to enhance their performance for applications in direct restorations. Application of nanoparticles in this field is a recent development. The aim of this study was to investigate the mechanical properties of experimental composites containing various mass fractions of silica nanoparticles.Materials and Methods: Experimental composites were composed of a visible-light-curing monomer mixture (70 wt% Bis-GMA and 30 wt% TEGDMA) and silica nanoparticles of a size ranging from 20 nm to 50 nm modified with γ-methacryloxy propyl trimethoxy silane (γ-MPS) as reinforcing filler. The composites were classified into four groups according to their filler mass fractions ranging from 20% to 50%. Following the same preparation procedure, a conventional composite was also fabricated consisting of a mass percentage of 60% silica fillers having particle sizes ranging from 10 μm to 40 μm in the same organic matrix, which served as control. Ten specimens were prepared of each experimental group and also of the control. Fracture toughness was measured using single-edge notched bend (SENB) specimens. Specimen fracture surfaces were mounted on aluminum stubs with carbon cement, sputter-coated with gold and examined under scanning electron microscopy (SEM). Flexural strength was evaluated through a standard three-point bending test and Vickers microhardness test was performed to investigate the hardness of the samples.Results: Filler mass fraction had a significant effect on composite properties. Fracture toughness, flexural strength, and hardness of composites at filler mass fraction of 40% of silica nanoparticles were (mean ± SD) 1.43 ± 0.08 MPa.m1/2, 149.74 ± 8.14 MPa, and 62.12 ± 3.07 VHN, respectively; relevant values for composites at 50% mass fraction of silica nanoparticles were 1.38 ± 0.07 MPa.m1/2, 122.83 ± 6.13 MPa, and 70.69 ± 3.67 VHN, respectively, all of which were significantly higher than 1.07 ± 0.06 MPa.m1/2, 104.61 ± 8.73 MPa, and 52.14 ± 4.02 VHN of the control, respectively (Tukey's multiple comparison test; family confidence coefficient = 0.95). Measured values for composites at 20% mass fraction of silica nanoparticles were 0.94 ± 0.06 MPa.m1/2, 103.41 ± 7.62 MPa, and 42.87 ± 2.61 VHN, respectively; relevant values for composites at 30% mass fraction of silica nanoparticles were 1.16 ± 0.07 MPa.m1/2, 127.91 ± 7.05 MPa, and 51.78 ± 3.41 VHN, respectively.Conclusions: Reinforcement of dental composite resins with silica nanoparticles resulted in a significant increase in the evaluated mechanical properties in comparison with the conventional composite. The filler mass fraction played a critical role in determining the composite's mechanical properties.
d e n t a l m a t e r i a l s 2 5 ( 2 0 0 9 ) 1315-1324 a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . i n t l . e l s e v i e r h e a l t h . c o m / j o u r n a l s / d e m a Silane coupling agents DMA ␥-MPS 3-Point bending Sorption Degree of conversion Thermogravimetric analysis a b s t r a c t Objectives. The purpose of this study was to evaluate the effect of the amount of 3-methacryloxypropyl-trimethoxysilane (␥-MPS) coupling agent on some physical-mechanical properties of an experimental resin composite for understanding the optimum amount of silanization. Methods. Silica nanoparticles (Aerosil OX 50) used as filler were silanized with 5 different amounts of ␥-MPS 1.0, 2.5, 5.0, 7.5 and 10 wt% relative to silica. The silanizated silica nanoparticles were identified by FT-IR spectroscopy and thermogravimetric analysis (TGA). Then the silanized nanoparticles (60 wt%) were mixed with a Bis-GMA/TEGDMA (50/50 wt/wt) matrix. Degree of conversion of light cured composites was determined by FT-IR analysis. The static flexural strength and flexural modulus were measured using a three-point bending set up. The dynamic thermomechanical properties were determined by DMA analyzer. Sorption, solubility and volumetric change were determined after storage of composites in water or ethanol/water solution. Thermogravimetric analysis was performed in air and in nitrogen atmosphere from 50 to 800 • C.
Preparation and characterization of a nanostructured dental composite
Physica Status Solidi (a), 2008
One of the major objectives of dental medicine that should be mentioned is the use of increasingly powerful materials of coronary restoration, as regards to their biomechanical, biofunctional and bio-prophylactic characteristics. Nanotechnologies often provide the techniques used in the field of filler particles. Solutions to obtain a first generation of composite material with nanoparticles with dimensions between 5–75 nm have been successfully tested. It has been important to also obtain conglomerates with dimensions between 0.2–0.6 mm, that should be present. The present paper describes the preparation through sol–gel methods and aims to characterize ceramic nanoparticles used as filling inorganic materials for dental composites for esthetical restorations. We have obtained nanometric powders of silica and zirconia/silica. Thermal treatments were conducted at temperatures between 700 °C and 1200 °C for 2 hours. The powders had been analyzed as regards to their mineralogical composition, granulometric distribution and microstructure. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis of nanosilica fillers for experimental dental nanocomposites and their characterisations
2011
The aim of this study was to synthesise nanosilica fillers for use in the fabrication of experimental dental nanocomposites and to evaluate their properties, including surface and mechanical properties. Monodispersed, spherical silica nanoparticles were synthesised via a sol-gel process, and a size range of 10-20 nm was obtained. Surface treatment of the nanosilica was carried out with the silane coupling agent γ-methacryloxypropyltrimethoxysilane (MPS) to reduce agglomeration of nanosilica. Experimental dental nanocomposites with two different filler contents, 30 and 35 wt%, were fabricated and polymerised with a light curing unit for 40 s. The surface morphology, surface roughness, flexural strength and elastic modulus were evaluated and compared. A nanocomposite with 35% filler content showed higher filler compaction, lower surface roughness and higher elastic modulus than a nanocomposite filled with 30% filler. However, the nanocomposite filled with 30% filler content showed higher flexural strength. Based on the results obtained, the synthesised nanosilica is a promising material for the fabrication of dental nanocomposites for tooth-filling applications.