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Effect of indirect restorative material and thickness on light transmission at different wavelengths
摘要： Purpose: The aim of this study was to evaluate the influence of indirect restorative material type and thickness on the transmission of different wavelengths from a broad-banded dental curing light. Methods: Four dental indirect restorative materials for computer-aided design and computer-aided manufacturing (CAD/CAM) were evaluated: [RC] resin/ceramic hybrid material (Lava Ultimate), [FC] feldspathic ceramic (VitaBlocs), and two zirconia-based ceramics ([ZK] Katana; and [ZL] Lava). Total loss of irradiance (TL) was measured for blue (WB, 425–490 nm) and violet (WV, 350–425 nm) wavelengths. Specimens of 15 mm with varying thicknesses (0.5, 1.0, 1.5, and 2.0 mm) were fabricated (n = 5). A plasma-arc dental light-curing unit was used (Arc Light-II). To assess TL as a function of wavelength, a software (Spectra Suite v5.1) connected to a spectroradiometer (USB2000) and an integrating sphere (CTSM-LSM-60-SF) was used. Data was subjected to statistical analysis (two-way ANOVA and post-hoc Tukey test, α = 0.05). Results: A 0.5 mm interposition resulted in TL from 50.5 to 67.2%, depending on material. Increased thickness resulted in higher TL for all materials. FC showed less TL compared to ZK. In general, WV showed higher TL than did WB, and WV/WB proportion decreased with increasing thickness. Conclusions: Indirect materials significantly reduced TL, and this effect is greater with increasing thickness. WV showed lower penetration compared to WB.
关键词： Ceramics,Photopolymerization,Irradiance,Composite,Zirconia
更新于2025-09-23 15:23:52
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Comparative investigation into effects of ZrO <sub/>2</sub> and Al <sub/>2</sub> O <sub/>3</sub> addition in fluorapatite laser-clad composite coatings on Ti6Al4V alloy
摘要： Composite coatings consisting of fluorapatite mixed with 20 wt% yttria (3 mol%) stabilized cubic phase zirconia (c-ZrO2, 3Y-TZP) or 20 wt% alumina (a-Al2O3) were deposited on Ti6Al4V substrates using a Nd:YAG laser cladding system. The interface morphology, phase composition, micro-hardness and biological properties of the two coatings were examined and compared. The results showed that the fluorapatite/Al2O3 specimen underwent a greater inter-diffusion at the interface between the coating layer and the transition layer than the fluorapatite/ZrO2 specimen. During the cladding process, the ZrO2 and Al2O3 components of the coating were completely decomposed or underwent phase transformation. In addition, the fluorapatite was partially decomposed. For both specimens, the coating layers contained fluorapatite, CaF2 and CaTiO3 phases. The coating layer of the fluorapatite/ZrO2 specimen additionally contained TTCP, CaO, CaZrO3 and m-ZrO2 (monoclinic phase), while that of the fluorapatite/Al2O3 specimen contained b-TCP, CaAl2O4 and u-Al2O3. The average micro-hardness of the fluorapatite/ZrO2 coating layer (1300 HV) was approximately 200 HV higher than that of the fluorapatite/Al2O3 coating layer (1100 HV). Both specimens generated dense bone-like apatite following immersion in simulated body fluid for 3 days. In other words, both specimens had a good in vitro bioactivity. However, the fluorapatite/ZrO2 specimen showed a better initial attachment and spread of osteoblast-like osteosarcoma MG63 cells than the fluorapatite/Al2O3 specimen in in vitro biocompatibility tests performed for 24 h.
关键词： Ti6Al4V,bioactivity,biocompatibility,alumina,laser cladding,Fluorapatite,zirconia
更新于2025-09-23 15:23:52
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Zirconia Nanocolloids Having a Nanospace of Poly(cyclodextrin): Preparation and Application to Liquid Crystal Devices
摘要： Poly(β-cyclodextrin) (PβCyD)-protected ZrO2 nanocolloids were prepared by using a microwave reactor equipped with ultrasonic nozzle mixing at 240 °C for 30 min in a tetraethylene glycol solution of zirconium (IV) ethoxide in the presence of poly(β-cyclodextrin). Particles in PβCyD-protected ZrO2 nanocolloids have an average diameter of 7.2 nm and mainly distribute within the range of about 3 to 10 nm. The nanocolloids were dispersed in 4'-pentylbiphenyl-4-carbonitrile (5CB) and practical liquid crystal to construct novel twisted nematic liquid crystal devices (TN-LCDs). The response time of this TN-LCDs in the presence of PβCyD-protected ZrO2 nanocolloids was faster than that in the absence. The threshold voltage of TN-LCDs by doping PβCyD-protected ZrO2 nanocolloids decreased. The decrease of threshold voltage can reduce power consumption, which may meet the demands of future power-saving LCDs.
关键词： Twisted Nematic Liquid Crystal Devices,Zirconia Nanocolloids,Poly(cyclodextrin),Nanospace,4'-Pentylbiphenyl-4-Carbonitrile
更新于2025-09-23 15:22:29
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Rheological and Curing Behavior of Acrylate-Based Suspensions for the DLP 3D Printing of Complex Zirconia Parts
摘要： The present study demonstrates the possibility of fabricating zirconia parts with a complex shape and internal architecture using a low-cost stereolithography-based technique. One of the critical steps in ceramics stereolithography is the preparation of a photo-curable slurry with properties that fulfil specific requirements, such as having a low viscosity, high solids loading and appropriate curing characteristics. Slurries with different acrylic monomers and ceramic fillers were studied concerning their rheological and curing behavior. New formulations based on mono- and tri-functional acrylic monomers revealed the following excellent rheological properties: The viscosity of the mono-/tri-acrylate-based slurry with 75 wt.% of zirconia was 1.6 Pa·s at 30 s?1. Zirconia stabilized with 3 mol.% yttria was found to be more favorable than zirconia with 8 mol.% yttria for slurry preparation, because of its lower surface area and higher tapped density. It was shown that the cure depth of the suspensions was suitable for printing objects with a 50 μm layer thickness, good interlayers connection and surface finishing.
关键词： ceramic,digital light processing,additive manufacturing,zirconia,stereolithography
更新于2025-09-23 15:22:29
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Formation of zirconia precursor nanoplates mediated by ionic liquid and transformation to monoclinic ZrO <sub/>2</sub> nanostructures
摘要： The [Zr(OH)5]– imidazolium complex was used to synthesize a zirconia precursor with plate-like nanostructure hydrolyzed under strong acid conditions, which was characterized by means of powder X-ray diffraction, thermogravimetric-differential scanning calorimetry, Fourier transform infrared spectroscopy, Raman spectroscopy, elemental analysis, inductively coupled plasma and electronic differential system. The zirconia precursor can be transformed to monoclinic ZrO2 by annealing at a temperature above 400 °C. With the increasing of the curing temperature, it tended to give rise to porous ZrO2 nanostructures.
关键词： Zirconia precursor,Zirconium oxide,Anion exchange reaction,Nanoplate,Ionic liquid
更新于2025-09-23 15:22:29
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Epitaxial Yttria-Stabilized Zirconia on Muscovite for Flexible Transparent Ionic Conductors
摘要： The advantages of ionic conductors have attracted great interests worldwide since they can fit the requirements which standard electrical conductors struggle to meet. Yttria-stabilized zirconia (YSZ) is the most common ionic conductors for various practical applications. In this study, in order to bring ionic conductors into the field of soft technology, transparent YSZ films with superior mechanical flexibility were epitaxially grown on muscovite substrate by pulsed laser deposition. The epitaxial relation between YSZ and muscovite has been well established, indicating a high crystallinity thin film. The heterostructure of YSZ/muscovite exhibits excellent ionic conductivity with great mechanical flexibility. The smallest bending radius of this heterostructure can be achieved is ~ 10 mm with excellent mechanical cyclabilty (>800 cycles) and stability (>105 s), serving as a new platform to fabricate highly flexible ionic conductors.
关键词： epitaxial growth,muscovite,transparent,ionic conductors,flexible,yttria-stabilized zirconia
更新于2025-09-23 15:21:21
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Soluble and insoluble polymer-inorganic systems based on poly(methyl methacrylate), modified with ZrO2-LnO1.5 (Ln = Eu, Tb) nanoparticles: Comparison of their photoluminescence
摘要： The study of the lanthanide ion luminescence as a function of their environment in polymer-inorganic composites is necessary for better understanding of the electron energy transfer processes in a condensed state. From a practical point of view, these materials are promising for optics and medicine. The nanoparticles of ZrO2-LnO1.5 (Ln = Eu, Tb) solid solutions were synthesized by hydrothermal method. The surface functionalization of the obtained nanoparticles by vinyl groups was carried out using 3-(trimethoxysilyl)propyl methacrylate. Soluble and cross-linked composites based on poly(methyl methacrylate) with ZrO2-LnO1.5 nanoparticles were synthesized using radical polymerization in solution and bulk. Molecular weight, thermal stability, and microhardness of the obtained composite materials were determined. The influence of both the polymerization conditions and the forming composite structure on the lanthanide ion photoluminescence in ZrO2 nanoparticles covalently bonded to the polymer matrix was studied. The combination of ZrO2-EuO1.5 and ZrO2-TbO1.5 nanoparticles in the poly(methyl methacrylate) resulted in the production of composites with photoluminescence spectra overlapping the red and green regions of the visible range. It was shown that the structure of the composite affects the absorbing capacity of luminescent centers and allows shifting the excitation spectrum in the longer wavelength region.
关键词： hydrothermal synthesis,poly(methyl methacrylate),rare-earth ions,solid solutions,zirconia,hybrid nanomaterials
更新于2025-09-23 15:21:21
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Micro and Nanoscale Laser Processing of Hard Brittle Materials || Surface nanostructuring of hard brittle materials
摘要： In the recent developments of laser processing technology, there has been exponentially growing interest in surface structuring. A wide variety of shapes and sizes can be achieved for the structures depending on the laser parameters applied. In this chapter, we will be focusing on nanoscale surface structuring. Laser surface nanostructuring is such an attractive process, from a technological point of view, as it is so simple. Nanostructures can be generated on a large surface area using a single-step process; this is impossible on hard brittle materials by any other methods. However, as is the case with many simple technologies, the fundamental science behind it is highly complex. Surface structure generation is attributed to a complex combination of inter- and intrapulse physical processes. This chapter will attempt to clarify the scientific processes of the nanostructure formation mechanism, to describe recent trends in nanostructuring technology, and to present innovative applications of nanostructured surfaces with particular focus on the surface nanostructuring of silicon and zirconia.
关键词： zirconia,surface nanostructuring,LIPSS,silicon,laser processing
更新于2025-09-23 15:21:01
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Synthesis of high-purity zircon, zirconia, and silica nanopowders from local zircon sand
摘要： High-purity zircon (ZrSiO4) nanopowder was successfully produced from Indonesian natural zircon sand using a low-cost purification approach via magnetic separation, immersion in HCl, and reaction with NaOH, followed by a top-down nanosizing process using wet ball-milling for 10 hours and annealing at 200 °C for 2 hours. Furthermore, polymorph zirconia (ZrO2 – amorphous, tetragonal, and monoclinic) and silica (SiO2 – amorphous and cristobalite) nanopowders were also successfully derived from the purified zircon powder using a bottom-up method via alkali fusion and co-precipitation processes followed by calcination. The crystallite size of the powders was estimated from X-ray diffraction (XRD) data analysis to give 40, 31, 61, and 149 nm, respectively, for the zircon, tetragonal- and monoclinic-zirconia, and cristobalite. Microstructural characteristics of the zircon, silica, and zirconia nanopowders were revealed in transmission electron microscopy (TEM) images which confirmed that the average sizes of the particles were in a good agreement with the XRD estimated values.
关键词： zircon,tetragonal zirconia,amorphous silica,nanopowder,cristobalite,monoclinic zirconia
更新于2025-09-23 15:19:57
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Artificial tailored catalytic activity for identification of 6 kinds of volatile organic compounds via the light-regulated electrochemical reaction
摘要： Light-regulated electrochemical reaction is confirmed to be useful to improve the classification efficiency. However, the use of different photoactive sensing materials results in time-consuming for exploring well-designed materials, besides, the light-regulated electrochemical reaction only improved the classification feature while didn't bring essential difference in the distinguish capability yet. Herein, a zirconia-based electrochemical sensor array comprised of 3 types of ZnO/In2O3 composite sensing materials is fabricated. After illumination, significantly enhancement is witnessed for the response magnitude and detection limit. Additionally, the response signal of the sensor array to part of the examined volatile organic compounds (VOCs) is selectively enhanced and 3 more disparate response patterns are generated. Through inputting all the response patterns into principle component analysis (PCA) software, 6 kinds of concerned VOCs have been fully classified. Conclusively, with utilizing sensing materials with similar composition, the fabrication process of the sensor array can be simplified. Particularly, after exposure to illumination the sensor array consisting of limited photoactive sensing materials (e.g. 3 kinds of materials) can identify even more number of gases (e.g. 6 types of VOCs). We anticipate these promising results shed light on the bright future of designing compact sensing devices for progressively smarter monitoring of concerned gas species.
关键词： Principle component analysis,Light-regulated electrochemical reaction,Volatile organic compounds,Response patterns,Artificial tailored catalytic activity,Zirconia-based sensor array
更新于2025-09-19 17:15:36