Glassy Ceramics Research Articles

Orthodontic bonding in special circumstances

This clinical paper provides an in-depth exploration of advanced techniques for bonding orthodontic attachments under special circumstances. Challenges arise when bonding brackets to non-enamel surfaces, such as dental restorations, and in conditions such as amelogenesis imperfecta, which affect enamel integrity. Distinct approaches required for bonding to different restorative materials, including glassy ceramics, zirconia, resin composites and metals, are outlined. Moreover, we describe strategies to manage bonding in conditions including amelogenesis imperfecta, hypodontia and microdontia in a multidisciplinary context.

Ceramic Materials in dentistry using the SPSS Method

Dental ceramics can be used in a variety of root canal therapy, such as inlays, bone grafting, crowns, and bridges, to replace earthenware (PFM) systems with everything systems. Dental crowns, dental composite components, and dentures are all made of porcelain and glass-ceramic materials, which are together referred to as dental ceramics. Conventional dental porcelain is feldspar-based and contain sizable amounts of kaolin (Al2O32SiO22H2O), quartz, and feldspar (KAlSi3O8). Rocks containing mica and iron are known to contain feldspar, a grey crystalline mineral. Ceramics are any of the countless hard, brittle, heat, corrosion-resistant substances produced by molding and thereafter scorching an inorganic, non-metallic substance like clay to high temperatures. Common examples include earthenware, pottery, and brick. Dental ceramics that are made of Lucite feldspathic material are very attractive and frequently utilized. Inlays, on lays, partial crowns, crowns, and veneers for metals and ceramics are among their clinical indications. Ceramics are resistant to high temperatures, effective thermal insulators, and have minimal thermal expansion. For uses like as lining industrial furnaces and sealing space shuttles, it makes really good thermal barriers. Dental ceramics are explained within a framework that makes it simple to comprehend how they developed. symptoms and composition. Engineering assessments of efficacy of treatment are discussed, and research is done. Behavior of all earthenware systems clinically. The usage of dental ceramics is discussed from a practical standpoint. Emphasizing what they know but also how we know it while maximizing beauty and endurance. Reviewing the history of ceramics' use in dentistry is helpful. This account has three purposes: (1) to warn professionals Pottery and improved ceramics were created to remedy the issue; (2) to increase actual issues or restoration diversity; and (3) give a soft backdrop in nature and ceramic science. The use of ceramics has always represented the adoption of "high technology" and "Craftsmanship". Ratio studies are statistical analyses of data from appraisals and property valuations. Nearly all states utilize them to produce quantitative measure of the proportion of current market price about which individually estimated taxable property is appraised as well as to offer assessment performance indicators. Evaluation parameters: Ceramic materials in dentistry, Glass-ceramics, predominantly glassy ceramics, Substructure ceramics, Particle-filled glasses and Polycrystalline ceramics. Result: The Cronbach's Alpha Reliability result. The overall Cronbach's Alpha value for the model is .658 which indicates 66% reliability. From the literature review, the above 50% Cronbach's Alpha value model can be considered for analysis. Characteristics of sisal fiber the Cronbach's Alpha Reliability result. The overall Cronbach's Alpha value for the model is .658 which indicates 66% reliability. From the literature review, the above 50% Cronbach's Alpha value model can be considered for analysis.

Repair bond strength of different CAD-CAM ceramics after various surface treatments combined with laser irradiation.

The aim of this study was to evaluate the effect of different surface treatments combined with laser irradiation on the shear bond strength of different CAD-CAM ceramics to composite resin. A total of hundred forty-seven ceramic specimens with thicknesses of 2.5mm were prepared from three different CAD-CAM ceramics (an yttrium oxide partially stabilized tetragonal zirconia polycrystal (Y-TZP); a zirconia-reinforced lithium silicate glass ceramic (ZLS); and a lithium disilicate-strengthened lithium aluminosilicate glass ceramic (LD-LAS)) and subjected to seven groups of treatment (n = 7): (1) control (no treatment), (2) Er:YAG laser irradiation, (3) Nd:YAG laser irradiation, (4) etching with hydrofluoric acid (HFA), (5) Er:YAG + HFA, (6) Nd:YAG + HFA, and (7) sandblasting. After surface treatment procedures, a ceramic primer (Clearfil Ceramic Primer Plus, Kuraray, Japan) was applied to the ceramics. Bonding agent (Single Bond Universal Adhesive, 3M ESPE, USA) was then applied, and the composite resin (Estelite Sigma Quick, Kuraray, Japan) was layered on the ceramic surfaces. The shear bond strength test was performed using a universal testing machine at a load of 0.5mm/min. Data were analyzed by 2-way analysis of variance (ANOVA), and the Bonferroni correction was used for pairwise comparisons (α = 0.05). Compared to the bond strength of the control group, irradiation by Er:YAG and Nd:YAG lasers alone improved the bond strength of the composite resin to the Y-TZP (P < 0.001) but did not change the bond strength of composite resin to the ZLS and LD-LAS (P > 0.05). Compared to the bond strength of the control group, etching with HFA alone increased the bond strength of the composite resin to the ZLS and LD-LAS (P < 0.001) but did not affect the bond strength of the composite resin to the Y-TZP (P > 0.05). The highest bond strength of ZLS was obtained using HFA + Er:YAG, and the highest bond strength for LD-LAS was obtained using HFA + Nd:YAG. It was concluded that Er:YAG and Nd:YAG laser treatments presented the highest repair bond strength between the composite resin and Y-TZP ceramics. Er:YAG and Nd:YAG laser treatments in conjuction with HFA presented the highest repair bond strength between the composite resin and the glassy ceramics, ZLS, and LD + LAS.

Preparation of a Ceramifiable Phenolic Foam and Its Ceramization Behavior.

Ceramifiable phenolic foam (GC-PF) with a low ceramization temperature has been prepared by incorporation of low melting point glass frits (LMG) containing B2O3 and Na2O as main components into a phenolic resin matrix. Fourier transform infrared spectrometry, X-ray diffractometry, and scanning electron microscopy were used for assessment of the structure, phase composition, and morphology of GC-PF before and after combustion analysis, respectively. A glassy ceramic protective layer is formed when GC-PF is exposed to flame or a high temperature environment. The presence of LMG not only reduces the level of defects in the phenolic foam cell wall (gas escape pore), but also promotes the generation of a glassy ceramic protective layer that could inhibit heat feedback from the combustion zone and reduce the rate of formation of volatile fuel fragments. Thermogravimetric analysis and differential scanning calorimetry were used to establish that GC-PF exhibits excellent thermal stability. Limiting oxygen index (LOI) determination suggests that GC-PF displays good flame retardancy. The LOI of GC-PF was as high as 45.6%, and the char residue at 900 °C was six times greater than that for ordinary phenolic foam (O-PF). The area of the raw material matrix of GC-PF after combustion for 60 s was about 1.7 times larger than that for O-PF. A possible mode of formation of glassy ceramics has been proposed.

Conduction process in some promising lithium-ion doped glassy ceramics

A novel glassy ceramic, 0.3Li2O-(0.7)(0.5MoO3-0.4V2O5-0.1ZnO) has been developed using the melt quenching technique. The temperature and frequency dependency of ionic conductivity has been established, following Almond-West formalism and Jonscher's universal power law respectively. The thermally activated nature of the sample can be exposed by its DC conductivity (σdc) study. The effect of composition on hopping frequency and corresponding activation energy has been calculated. The plateau (conductivity dependent on frequency) region in the lower frequency zone is pronounced by the sub diffusive movements of conducting Li+ ions. Whereas, in the dispersive high-frequency zone, Li+ ion migration in a pseudo-three-dimensional space is the main reason for conductivity in percolating networks.

Charge carrier transport and electrochemical stability of Li2O doped glassy ceramics

We study electrical conductivity of new Li2O doped glassy ceramics in wide frequency and temperature regime not only for their applicability in various fields like lithium ion conductors but also for academic interest. Here, we employ “Jonscher’s power law model and Almond-West formalism” to interpret mixed conduction process in the present system. We use “Mott’s variable range hopping” model to analyse low temperature DC conductivity data. It also points that the ratio of power law pre-factor to the exponent (–log10 A/S) indicates temperature independency and strong composition dependency of present conductors. Higher lithium content in the composition may disturb “electrochemical stability” of the present system. We do believe that these glassy ceramics are suitable candidates for lithium ion battery application with lower lithium content.

Microstructures and charge carrier transport of some Li2O doped glassy ceramics

We study electrical conductivity of new Li2O doped glassy ceramics in wide frequency and temperature regime not only for their applicability in various fields like lithium ion conductors but also for academic interest. Here, we employ “Mott’s variable range hopping” model to analyse low temperature DC conductivity data. The microstructures and electrical conductivity of them have been explored and correlated. We do believe that these glassy ceramics are suitable candidates for lithium ion battery application.

Additive manufacturing of ceramics from preceramic polymers: A versatile stereolithographic approach assisted by thiol-ene click chemistry

Here we introduce a versatile stereolithographic route to produce three different kinds of Si-containing thermosets that yield high performance ceramics upon thermal treatment. Our approach is based on a fast and inexpensive thiol-ene free radical addition that can be applied for different classes of preceramic polymers with carbon-carbon double bonds. Due to the rapidity and efficiency of the thiol-ene click reactions, this additive manufacturing process can be effectively carried out using conventional light sources on benchtop printers. Through light initiated cross-linking, the liquid preceramic polymers transform into stable infusible thermosets that preserve their shape during the polymer-to-ceramic transformation. Through pyrolysis the thermosets transform into glassy ceramics with uniform shrinkage and high density. The obtained ceramic structures are nearly fully dense, have smooth surfaces, and are free from macroscopic voids and defects. A fabricated SiOC honeycomb was shown to exhibit a significantly higher compressive strength to weight ratio in comparison to other porous ceramics.

Conductivity spectra of lithium ion conducting glassy ceramics

Study of ac conductivity spectra of Li2O doped different glassy ceramics in wide frequency and temperature regime using Jonscher's power law model and Almond-West formalism reveals that Li+ migration depends upon nature of doping reagent. It also points that the ratio of power law pre-factor to the exponent (–log10 A/S) indicates temperature and composition dependency of present conductors. Motion of Li+ may predict that the process of conduction is percolation or pseudo three dimensional types. These glassy ceramics should be suitable candidates for lithium ion battery application. Improvements in the capacity of modern lithium (Li) batteries can be made by enhancing conductivities and ionic diffusivities in various anode and cathode materials. Fundamentally, such improvements can be achieved in the present electrolyte compositions. It is also interestingly noted that constantly changing nature of electrical conduction in present systems are strongly microstructure dependent.

High-temperature glassy-ceramic sealants SiO2—Al2O3—BaO—MgO and SiO2—Al2O3—ZrO2—CaO—Na2O for solid oxide electrochemical devices

Glasses of the SiO2–Al2O3–BaO–MgO and SiO2–Al2O3–ZrO2–CaO–Na2O systems were synthesized in the perspective to apply them as sealants in SOFC at operating temperatures of 700–900 °C. Thermal properties of the chosen glass compositions and their compatibility with the SOFC materials (YSZ-electrolyte and alloy-interconnector Crofer22APU, 15×25T) were investigated by means of synchronic thermal analysis and high-temperature dilatometry. The elemental analysis was performed by atomic emission spectroscopy. The average values of the temperature coefficients of the linear extension are 10.0×10−6 °C−1 for glass 45%SiO2– 15%Al2O3–25%BaO–15%MgO and 9.5×10−6 °C−1 for glass 60%SiO2–10%Al2O3–10%ZrO2–5%CaO–15%Na2O. The gluing microstructure in YSZ/glass/Crofer22APU was studied by scanning electron microscopy. The crystallization process of silicate phases was revealed to occur in the SiO2–Al2O3–BaO–MgO glass. The analysis of the crystallization products was performed by Raman spectroscopy and X-ray diffraction. Glassy ceramics was proved to possess better parameters in comparison with amorphous glass to be used as a sealant in electrochemical sensors and oxygen sensors. The SiO2–Al2O3–ZrO2–CaO–Na2O low-temperature amorphous glass can be applied in SOFC.

Surface Conditioning Protocol for the Adhesion of Resin-based Materials to Glassy Matrix Ceramics: How to Condition and Why?

Question: What is the best surface conditioning protocol for durable adhesion of resin-based materials to glassy matrix ceramics? Answer: Glassy matrix ceramics, also known as silicabased ceramics, are typically reinforced with feldspar, leucite, fluormica glass or lithium disilicate. Glass ceramics are acid sensitive when etched with hydrofluoric acid gel and they respond well to adhesive bonding techniques where silanization and adhesive resin applications are performed. In such ceramics, more pronounced surface roughness can be obtained with the increase in the amount of glassy phase present in the microstructure, which can improve the potential adhesion of resin-based luting cements to these ceramics. Proper conditioning of glass ceramics together with the subsequent application of the adhesive procedures not only enables fabrication of minimally invasive restorations, but also reinforces the vitreous matrix, increasing its strength after adhesive cemention. Since the type of ceramic matrix, etching method, silanization, and adhesive resin application are important parameters in durable adhesion to glass ceramics, the surface conditioning sequence presented in the Table (below) is recommended.

Synthesis and characterization of poly(tetramethyldisiloxane-ethynylenephenyleneethynylene) resins

Poly(tetramethyldisiloxaneethynylenephenyleneethynylene) resins were synthesized by polycondensation reactions of the bismagnesium derivative of p- or m-diethynylbenzene with 1,3-dichlorotetramethyldisiloxane. The molecular weights of the resins were determined by gel permeation chromatography. The structures of the resins were verified by 1H, 13C, and 29Si NMR as well as FT-IR spectroscopy. The thermal behavior of the resins was traced by differential scanning calorimetry (DSC). The resins can be thermally crosslinked through the acetylene groups to produce highly crosslinked resins which were thermally stable up to 539 °C in both nitrogen and air. Hard, black, and glassy ceramics were obtained after the sinter of the crosslinked resins at 1,450 °C. The polymers have a potential application as matrix materials for advanced composites and ceramic precursors.

Fractography of Dental Restorations

The dental community is using a variety of ceramic restorative materials such as porcelains (leucite or alumina based), glass-ceramics (leucite, mica, lithium disilicates), alumina-glass infiltrated, and CAD-CAM ceramics including pure alumina and zirconia (3Y-TZP) core materials. Polycrystalline ceramics such as alumina and zirconia serve as substructure materials (i.e., framework or core) upon which glassy ceramics are veneered for an improved appearance. Under masticatory loads, sudden fracture of the full-thickness restoration or of the veneering ceramic (chips) may occur. Stereomicroscope and scanning electron microscope analyses were used to perform qualitative (descriptive) fractography on clinically failed dental ceramic restorations. The most common features visible on the fracture surfaces of the glassy veneering ceramic of recovered broken parts were hackle, wake hackle, twist hackle, arrest lines, and compression curls. The observed features are indicators of the local direction of crack propagation and were used to trace the crack’s progression back to its initial starting zone (the origin). This paper presents the applicability of fractographic failure analyses for understanding fracture processes in brittle dental restorative materials and it draws conclusions as to possible design or processing inadequacies in failed restorations.

Ion transport and diffusion in nanocrystalline and glassy ceramics

In the present paper we review experimental studies on ion transport and diffusion in nanocrystalline and glassy ceramics of LiNbO3 and LiAlSi2O6 and report on new ones on LiBO2 using the measurement of dc conductivities and 7Li nuclear magnetic resonance spin-lattice relaxation rates. Nanocrystalline ceramics, with an average particle size of 50 nm and less, often show an enhanced diffusivity compared to their microcrystalline (μm-sized) counterparts. This increase is due to the large fraction of atoms or ions located in the interfacial regions. A key for understanding the structure-mobility relations in nanocrystalline ceramics is to clarify the microscopic structure of the grain boundaries and also the morphology of the grain boundary network. In this context it is useful to study not only the ion transport properties of the nano- and microcrystalline materials but also those of the corresponding glassy forms. Such comparative studies gave strong evidence that in some cases the interfacial regions are of amorphous structure. For example, this was recently shown for nanocrystalline lithium niobate which was prepared by high-energy ball milling.

1304 ガラス構造のセラミックスのクラック発生に及ぼす電子線照射の影響(J14-1 知的材料・構造システム(1) セラミックスのき裂治癒、強靭化,ジョイントセッション,21世紀地球環境革命の機械工学:人・マイクロナノ・エネルギー・環境)

Effects of electron beam irradiation on the fracture resistance of glassy ceramics were studied. EB-irradiation could not change the resistance to crack propagation, which was estimated by fracture toughness evaluated by means of standard indentation fracture method. On the other hand, EB irradiation increased the plastic deformation energy to generate the crack. In addition, if EB-irradiation formed dangling bonds in glassy network structure, they probably relax the residual stress and should prevent the crack generation. As the results of electron spin resonance spectra, the EB irradiation generates dangling bonds in these glasses, partial relaxation of residual strain mainly occurs around dangling bonds in the network structure. The increasing the generation energy of crack was therefore mainly due to the relaxation of the strong bonded metal -oxygen atomic pairs in network structure, as well as annihilation of crack origin.

Synthesis of glassy boron ceramics

For the first time, dense glassy boron ceramics was produced at pressures from 2 to 8 GPa and temperatures from 750 to 1050 K by sintering amorphous boron powder. Physical and mechanical properties of the glassy boron ceramics are presented and discussed

Scaling Exponents for Fracture Surfaces in Homogeneous Glass and Glassy Ceramics

We investigate the scaling properties of postmortem fracture surfaces in silica glass and glassy ceramics. In both cases, the 2D height-height correlation function is found to obey Family-Viseck scaling properties, but with two sets of critical exponents, in particular, a roughness exponent zeta approximately 0.75 in homogeneous glass and zeta approximately 0.4 in glassy ceramics. The ranges of length scales over which these two scalings are observed are shown to be below and above the size of the process zone, respectively. A model derived from linear elastic fracture mechanics in the quasistatic approximation succeeds to reproduce the scaling exponents observed in glassy ceramics. The critical exponents observed in homogeneous glass are conjectured to reflect the damage screening occurring for length scales below the size of the process zone.

Precipitation of semiconducting carbon nanoparticles in ion irradiated gels

Sol–gel materials are converted into glassy ceramics when subjected to ion irradiation or heat treatments. In addition, a demixing occurs in the obtained glasses when their structure is metastable. In the present work, we have irradiated silicon-based gels with 120MeV and 2GeV Au ions at different fluences from 8×109 to 2×1013ions/cm2. Ion irradiation leads to formation of carbon nanoclusters, which have semiconducting properties. Photoluminescence and optical absorption spectroscopies are used to identify the semiconducting properties of carbon clusters. High resolution transmission electron microscopy (HRTEM) and energy filtered imaging of C atoms show that C particles with a size of ∼4nm are produced and they are aligned along ion tracks. Elastic recoil detection analysis has been performed to determine the kinetics of the H evolution and to evaluate the track radius, which matches with the radius obtained from HRTEM. The obtained aligned carbon clusters (wires) would find useful applications as field emitters or nanocontacts.

Electron beam irradiation induced smart properties of misting free and reinforcement of transparent glassy ceramics

Electron beam irradiation induced smart properties of misting free and reinforcement of transparent glassy ceramics

Small-angle neutron scattering characterization of processing/microstructure relationships in the sintering of crystalline and glassy ceramics

Small-angle neutron scattering measurements were used to examine the pore microstructure evolution of glassy silica and polycrystalline alpha-alumina as a function of sintering. It was shown that the two major sintering mechanisms, viscous flow and surface and volume diffusion, lead to very different microstructure evolution signatures in terms of the average pore size as a function of density. However, with respect to topology, the evolution of the porosity per unit surface area as a function of density is remarkably similar in the two systems.