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This research presents a new solution to use bottle glass wastes together with aluminum hydroxide for porous alumina glass ceramics synthesis. The firing of the samples was conducted at three temperatures: 800, 1000 and 1200 °C. The effect of the bottle waste glass addition on the firing shrinkage, apparent density porosity, chemical stability and compression strength of the sintered samples was investigated. The dimensional stability of the samples, varying between 4.75–11.87% is positively affected by waste glass/alumina substitution ratio. Higher amounts of glass waste lead to higher apparent densities, up to 1.80 g/cm3 and lower apparent porosities, around 33.74%, depending on the heat treatment temperature. All the studied glass ceramics have very good chemical stability that increase with the glass waste/alumina ratio. The compression strength of the obtained samples, ranging between 4.72–24.20 N/mm2 is negatively affected by increasing the glass waste amount due to its brittle behavior. The obtained results suggest the viability of the proposed recycling alternative for bottle glass waste together with aluminum hydroxide as porous alumina glass ceramics.

Samples of nanocrystalline PbF2 glass ceramics were obtained by heat-treating SiO2–GeO2–PbO–PbF2–CdF2 glasses. The Ho2O3 and Tm2O3 doping effects on the structural features of PbF2 nanoparticles were studied using small-angle X-ray scattering and X-ray diffraction methods. The enlargements of the average sizes of nanoparticles and the sizes of local areas of density fluctuations have been found to be correlated with an increase in concentrations of Ho2O3 and Tm2O3 in initial glasses. A variation in the concentrations of Ho2O3 and Tm2O3 does not affect the morphology and fractal dimension of the formed PbF2 nanoparticles.

Oxide glasses have functional properties that make them attractive for various applications, from optics and laser technology to nuclear waste immobilization and biomedicine. In particular, sodium phosphate-based glasses have emerged as potential candidates for use as solid-state electrolytes. Due to the incorporation of alkali oxides into the phosphate network, these glasses exhibit unique peculiarities, among which electrical transport attracts much attention. Furthermore, the addition of oxides such as Nb2O5, V2O5, and/or Al2O3, ZnO, affects the glass structure, which in turn impacts electrical transport and manifests itself as, for example, the mixed glass-former effect, mixed transition-ion effect, and/or the mixed ion-polaron effect, depending on composition and type of charge carriers. Although glassy materials have many advantages, their low electrical conductivity often limits their application. A flexible method to improve their performance is thermally induced crystallization resulting in composite materials, so-called glass-ceramics, in which single or various crystalline phases are embedded in a glassy matrix and, as such, offer improved properties compared to analog glass. Glass-ceramics can also be prepared by unwanted spontaneous crystallization during melt cooling procedure. In this study, sodium phosphate-based glass-ceramics with different incorporated oxides (Nb2O5, V2O5, and/or Al2O3) were prepared by spontaneous crystallization during melt-quenching of target compositions from the edge of the glass-forming region. Their micro(structural) properties were investigated by PXRD and SEM-EDS, and obtained results are correlated with electrical properties studied through impedance spectroscopy (IS). The micro- and nano-scale features were under scrutiny using SEM-EDS analysis, qualitative and quantitative, utilizing Axia ChemiSEM Microscope System. Different setups in high/low vacuum are applied along with detectors such as ETD, CBS-BD mode and EDS coloring mapping for visualization of elemental distribution. The obtained results allowed us to have better insight into the crystallization processes and the resulting crystalline phases embedded in an amorphous matrix, which is also confirmed by PXRD and ultimately affects electrical transport. The analysis of the (micro)structure-property relationship contributes significantly to a better understanding of the changes that occur in these materials, which promotes their use in new technologies.

Three-dimensional (3D) particles in composite materials often have sharp corners which cause complex stress singularities. In our current research, the 3D singular stress fields in the corner front vicinity of various revolution-shaped inclusions have been investigated using a specially developed novel singular inclusion corner element SICE. Numerical eigensolutions with both singular and non-singular terms for the 3D singular stress and displacement fields in the curvilinear coordinate system are transformed into the interpolation forms of the SICE. The robustness of the element stiffness matrix is reflected in the fact that it is established based on a local coordinate system attached to the rotation axis with arbitrary inclusion orientation. The singular stresses in the vicinities of revolution-shaped inclusions of various shapes, orientations and material properties are investigated. The benchmark examples show that the proposed SICE has excellent versatility and are very useful for micro-damage analysis of particle-reinforced composites. Agency for Science, Technology and Research (A*STAR) The authors acknowledge the support of the National Natural Science Foundation of China under Grant Nos.51975411 and 51365013, the Tianjin Natural Science Foundation of China under Grant No. 18JCYBJC88500, and the Personnel Training Plan for Young and Middle-aged Innovation Talents in Universities in Tianjin, China. The support of Singapore A*STAR SERC AME Programmatic Fund for the “Structural Metal Alloys Programme” (Project WBS 4070307.051) is acknowledged. Congman Wang acknowledges the support of Tianjin Graduate Research and Innovation Project under grant No. 2020YJSB072.

The leaching of heavy metals (HMs) is the key factor affecting the resource utilization of municipal solid waste incineration (MSWI) fly ash. A novel fly ash and andesite-tailings-based (FAAT) glass ceramic is prepared with the full-component utilization of MSWI fly ash and andesite tailings. The effects of the content and distribution state of HMs on their leaching toxicity are studied by performing a sequential extraction procedure and leaching toxicity test. The results show that the MSWI fly ash content greatly impacts the HMs’ leaching toxicity in glass ceramics. Thus, the addition of MSWI fly ash must be maintained at below 20% so as to meet the class III groundwater standard. Furthermore, the different distribution states of Zn and Cr also affect their leaching toxicity. Zn suits the requirements for leaching toxicity only in a 2080c sample, while Cr fulfills the class III groundwater standard for all the glass ceramics. Since this finding is mismatched with the calculated potential ecological risk index of glass ceramics, the latter can only be used as a reference. Therefore, the results of the present study are of great significance in the vitrification application of MSWI fly ash.

Hydrofluoric acid is a common surface treatment agent for glass ceramic restorations before bonding. However, the use of hydrofluoric acid has a high safety risk, so the search for hydrofluoric acid substitutes has been a research hotspot. Tetrabutylammonium dihydrogen trifluoride is a kind of fluoride, whose chemical activity is lower than that of hydrofluoric acid, so it’s safer, and the surface morphology changes on glass ceramics caused by it are smaller and more superficial. At present, the vast majority of laboratory studies and clinical case reports indicate that the mechanical strength and bonding strength of glass ceramics treated with tetrabutylammonium dihydrogen trifluoride can meet the clinical requirements. In the future, according to the research results, the performance of porcelain surface treatment agents containing tetrabutylammonium dihydrogen trifluoride can be further improved, and more hydrofluoric acid substitutes may be developed. In this review, the research progress of tetrabutylammonium dihydrogen trifluoride as a substitute for hydrofluoric acid is reviewed in terms of the influence of the surface morphology, mechanical strength, and bonding strength of glass ceramics.

In this paper we report on the study of sintered ceramic composites based on a low melting glass in which ZnO nanocrystals and commercial YAG:Ce3+ phosphor are embedded. A low Tg is necessary to avoid high temperature sintering which can damage the optical properties of the embedded phosphor, while ZnO is introduced to increase the thermal conductivity of the system. The compositions have been optimized in terms of stability, sintering efficiency and thermal conductivity. Selected samples were optically characterized using a GaN high power multimode 450 nm Laser Diode, with a maximum output power of 1.6 W at 1.5 A.

The effects of Cr2O3 on the crystallization, structure, and properties of Ti-bearing blast furnace slag-based glass ceramics were investigated. The results show that the transition temperature and crystallization temperature decreased with introduction of Cr2O3 as a while. Specifically, the crystallization temperature first decreased, then increased with the increase Cr2O3 concentration from 0.2 wt% to 0.8 wt%, and finally decreased with further increased in Cr2O3 concentration. The crystal phases were identified as anorthite, diopside, and akermanite. As the content of Cr2O3 increased to 0.8 wt%, the dendrites gradually decreased and the granular crystals gradually increased. When the Cr2O3 concentration further increased, the number of granular crystals gradually decreased and the dendrites gradually accumulated. With the increase of Cr2O3 from 0.2 wt% to 0.8 wt%, the structure of the investigated glass gradually depolymerized, while the opposite trend was presented with further increased in Cr2O3 content. With increasing Cr2O3 content from 0.2 wt% to 2 wt%, the flexural strength values and Vickers hardness values of the glass ceramics first increased and then decreased, and the maximum values of flexural strength and Vickers hardness were obtained as 94.371MPa and 974.43MPa, respectively. The prepared Ti-bearing blast furnace slag-based glass ceramics showed good acid and alkali resistance.

Porcelain enamel is an inorganic-type coating, which is applied to metals or glass for both decorative and functional purposes. This coating is a silica-based solidified glass mass obtained by high-temperature firing (temperature can range between 450 and 1200 °C depending on the substrate). Porcelain enamel coatings differ from ceramic coatings mainly by their glass structure and dilatation coefficient, and from organic paints mainly by the inorganic nature of the matrix and the chemical bond that exists between the coating and the substrate.

A complete methodology combining experiments and modeling has been developed to investigate the constrained sintering of low-temperature cofired ceramic (LTCC) systems. The thermomechanical and sintering behavior laws, previously identified for the selected commercial LTCC material, were implemented in a finite element model. The reliability and validity range of the built model has been investigated thanks to the development of a specific distortion experience. The distortion generated during the constrained sintering of a porous LTCC layer deposited on a dense one has been monitored in situ by ombroscopy. The measured camber evolution was compared with numerical results. The camber phenomena predicted numerically and observed experimentally are very similar, characterized by the onset of distortion around 918 K and a similar evolution during heating. However, at high temperatures (around 1100 K), the simulated camber slightly differs from the experimental one. It seems to be related to the damage to the dense LTCC layer by microcracking.

This study aimed to investigate the effect of the thickness of computer aided design-computer aided manufacturing (CAD-CAM) restorative materials on the bond strength of light-polymerized resin cement. Ninety specimens were prepared from three different CAD-CAM materials (a leucite-based glass-ceramic [Empress CAD], a polymer-infiltrated ceramic network [Vita Enamic], and a zirconia-reinforced lithium silicate glass-ceramic [Vita Suprinity]) in different thicknesses (1, 2, and 3 mm). One surface of each specimen was treated by using a single-step self-etching ceramic primer (Monobond Etch & Prime). Light-polymerized resin cement was bonded to treated surfaces by exposure to a light-emitting diode curing unit from the untreated side of the samples. Shear bond strength (SBS) between the ceramic and the resin cement was measured by using a universal testing machine. The leucite-based glass-ceramic had higher SBS values than the other materials at each thickness. For each material, 1 mm-thick specimens had the highest SBS values. The difference between the SBS values of 2 mm- and 3 mm-thick polymer-infiltrated ceramic network was nonsignificant, whereas the SBS values of 2 mm-thick leucite-based glass-ceramic and the zirconia-reinforced lithium silicate glass-ceramic were significantly higher than those of the corresponding 3 mm-thick specimens. The choice of the material and its thickness may be highly important for clinical success when light-polymerized resin cements are used for cementation. 35969188

Background/Aim: The aim of this study was to evaluate the bond strength of glass ceramic inlay system using 2 antibacterial adhesive luting protocols with 2 cementation techniques to bur-cut dentin. Material and Methods: Class I inlay cavities with 6-degree occlusal divergence and size of 6-, 3and 2-mm in length, width and depth, were prepared on extracted human molars, randomly assigned to 2 main groups; each to 1 cementation technique, with or without immediate-dentin-bonding (IDB or NIDB) further divided into 3 subgroups; 2 to 2 antibacterial luting protocols, traditional (T) and experimental (E); and 1 to a control (C) group. In group IDBT, IDB-E and IDB-C dentin bonding was applied immediately after cavity preparation. In group NIDB-T, NIDB-E and NIDB-C dentin bonding was applied just before cementation of the restorations. The cavities in IDB-T and NIDB-T were treated with 2% chlorhexidine-digluconate (CHX) prior to dentin bonding application. The cavities in IDB-E and NIDB-E were treated only with dentin bonding system containing MDPB (12-methacryloyloxydodecylpyridinium bromide) active monomer featuring antibacterial effect. IDB-C and NIDB-C served as control. Dual-cure adhesive resin cement was used for the cementation of Lithium disilicatebased ceramic inlay restorations. Fourteen test specimens per group were prepared for microtensile testing and consecutively subjected to tensile load at a crosshead speed of 1 mm/min. The mode of failure was observed under SEM and evaluated for each group. The Kruskal-Wallis test was used to investigate the statistical difference between groups (a=0.05). Results: The microtensile load was 5.96 MPa (median: 5.99 MPa) for IDB-T, 7.23 MPa (median: 7.55 MPa) for IDB-E, 6.68 MPa (median: 6.56 MPa) for IDB-C, 7.24 MPa (median: 7.20 MPa) for NIDB-T, 6.98 MPa (median: 6.30 MPa) for NIDB-E, and 7.02 MPa (median: 6.99 MPa) for NIDB-C, with no statistical difference between the groups (p>0.05). SEM monitoring for mode of failure revealed either cohesive (within resin cement) or adhesivecohesive (mostly within resin cement along with partially involved areas between resin cement and ceramic restoration) character. Conclusions: Within the limitations of the current study, none of the tested antibacterial luting protocols with either cementation technique was found to be superior in terms of bond strength.

Glass ceramics from the CaO–P2O5–SiO2 system were synthesized. They were characterized by XRD, SEM and EDX methods. It was found that they contain two crystalline [Whitlockite, Ca3 (PO4)2 and Hydroxylapatite, Ca5 (PO4)3 (OH)] and one residual amorphous phase. The ceramics are composed of porous aggregates of fine particles with predominant macro- and mesopores in it. The ceramics were used as a functional filler in natural rubber based composites, as the filling is in the range of 5–50 phr. The influence of the chemical nature and structure of the ceramics and the degree of filling on the vulcanization characteristics, physicomechanical parameters, dielectric and dynamic properties, the coefficient of thermal conductivity and the volume resistivity, including external pressure or bending on the specimens were investigated. An influence of the filler and the degree of filling on all studied properties was found. All tested composites have dielectric parameters (ε′, real part of complex permittivity; ε′′, imaginary part of complex permittivity; σ, conductivity; tanδ ɛ, tangent from dielectric loss angle) suitable for use as substrates and insulating layers of flexible antennas. Particularly impressive are composites containing 30 and 50 phr fillers, which have the lowest tangent from dielectric loss angle values.

The dental ceramic materials are constantly being developed due to their continuous clinical application in the field of esthetic dentistry. Glass ceramics (GC) materials are also of special interest for dental application due to their specific properties; and thus, they can be applied as crowns, veneers and small bridges. Purpose: However, due to a variety of different GC materials, it is of keen interest to inspect their morphology and ion-diffusion, which also governs aging properties. Material and methods: In this study, two different GC materials were processed, i.e., lithium silicate (LS-10) and lithium disilicate (LS-20). The aforementioned properties can be inspected by using impedance spectroscopy (IS) and scanning electron microscopy (SEM). Results: SEM study suggested that LS-10 material is harder to mechanically process by computer-aided design/computer-aided manufacturing (CAD/CAM) technology. Furthermore, IS measurements showed that LS-20 (vs. LS-10) has more pronounced resistance properties. Conclusion: According to IS data, it was concluded that LS-20 (vs. LS-10) has more pronounced resistance properties that point out to hindered ion-diffusion and to better aging properties., Dentalni keramički materijali kontinuirano se razvijaju zbog svakodnevne primjene u području estetske dentalne medicine. Tako su za dentalnu primjenu posebno zanimljivi staklokeramički (GC) materijali zbog specifičnih svojstava zbog kojih se mogu primijeniti kao krunice, ljuskice i mali mostovi. Cilj: Kako postoje mnogo različitih GC materijala, vrlo je važno ispitati njihovu morfologiju i ion-difuzijska svojstva koja utječu na starenje. Materijal i metode: U ovom istraživanju ispitana su dva različita GC materijala – litijev silikat (LS-10) i litijev dislikat (LS-20). Gore navedena svojstva mogu se ispitati s pomoću impedancijske spektroskopije (IS) i pretražnom elektronskom mikroskopijom (SEM). Rezultati: Ispitivanja s pomoću SEM-a pokazala su da je materijal LS-10 teže mehanički obraditi tehnologijom računalno potpomognutoga dizajna/proizvodnje (CAD/CAM). Zaključak: IS mjerenja pokazala su da LS-20 (u usporedbi s LS-10) ima naglašenija otporna svojstva koja upućuju na njegovo bolje svojstvo starenja.

International audience; High ionic conductivity, low grain boundary impedance, and stable electrochemical property have become the focus for all-solid-state lithium-sulfur batteries (ASSLSB). One of the approaches is to promote the rapid diffusion of lithium ions by regulating the chemical bond interactions within the framework. The structure control of P5+ substitution for Sn4+ on lithium-ion transport was explored for a series of Li3PS4-Li4SnS4 glass-ceramic electrolytes. Results showed that the grain boundary impedance of the glass electrolyte was reduced after heat treatments. The formation of LiSnPS microcrystals, a good superionic conductor, was detected by X-ray diffraction tests. Electrochemical experiments obtained the highest conductivity of 29.5 S cm(-1) at 100 degrees C and stable electrochemical window from -0.1 to 5 V at 25 degrees C. In addition, the cell battery was assembled with prepared electrolyte, which is promoted as a candidate solid electrolyte material with improved performance for ASSLSB.

Alluaudite-type materials are systematically attracting more attention as prospective cathode materials for sodium-ion batteries. It has been demonstrated that optimized thermal nanocrystallization of glassy analogs of various cathode materials may lead to a significant increase in their electrical conductivity. In this paper, three alluaudite-like glasses (Na2Fe3(PO4)3—FFF, Na2VFe2(PO4)3—VFF, and Na2VFeMn(PO4)3—VFM) were synthesized and subjected to an optimized thermal nanocrystallization. This procedure resulted in nanostructured samples with increased electrical conductivity at room temperature: 5×10−7 S/cm (FFF), 7×10−5 S/cm (VFM), and 6×10−4 S/cm (VFF). The nanocrystalline microstructure was also evidenced by ultra-high-frequency impedance spectroscopy (up to 10 GHz) and proposed electrical equivalent circuits. Prototype electrochemical cells were assembled and characterized with voltage cutoffs of 1.5 and 4.5 V. The electrochemical performance was, however, modest. The gravimetric capacity varied between the studied materials, but did not exceed 35 mAh/g. Capacity retention after ca. 100 cycles was satisfactory. Further optimization of the residual-glass-to-nanocrystallite volume ratio would be desirable.

In this work, more than 70 wt % of ferromanganese slag (containing 40 wt % CaO) was used to synthesize high-calcium, CaO-MgO-Al2O3-SiO2 (CMAS) glass ceramics. The effect of SiO2/CaO on the structure, crystallization behavior and microstructure of high-calcium, CMAS, slag glass ceramics was studied by IR, NMR, DSC, XRD and SEM. The results showed that in the high-calcium, CMAS glass ceramics, the main existing forms of silicon–oxygen tetrahedra (Qn) were Q0 and Q1. With the increase in the SiO2/CaO, Qn changed from Q0 and Q1 (main units) to Q1 (main units) and Q2, and then to Q1 and Q2 (main units). The polymerization degree of Qn changed from low to high, making the glass more stable, which led to the increase in crystallization temperature and the decrease in crystallization kinetic constant (k) and frequency factor (υ). At the same time, the change in the Qn structure resulted in a gradual change to the main crystal, from akermanite to diopside–wollastonite.

The dental ceramic materials are constantly being developed due to their continuous clinical appli- cation in the eld of esthetic dentistry. Glass ceramics (GC) materials are also of special interest for dental application due to their speci c properties ; and thus, they can be applied as crowns, veneers and small bridges. Purpose: However, due to a variety of different GC materials, it is of keen inter- est to inspect their morphology and ion-diffusion, which also governs aging properties. Material and methods: In this study, two different GC materials were processed, i.e., lithium silicate (LS-10) and lithium disilicate (LS-20). The aforementioned properties can be inspected by using impedance spec- troscopy (IS) and scanning electron microscopy (SEM). Results: SEM study suggested that LS-10 ma- terial is harder to mechanically process by computer-aided design/computer-aided manufacturing (CAD/CAM) technology. Furthermore, IS measurements showed that LS-20 (vs. LS-10) has more pro- nounced resistance properties. Conclusion: According to IS data, it was concluded that LS-20 (vs. LS- 10) has more pronounced resistance properties that point out to hindered ion- diffusion and to bet- ter aging properties.

This study aimed to compare the effect of acid etching, sandblasting, or silica coating on the micro-shear bond strength of dual-cured resin cements to computer-aided design and computer-aided manufacturing (CAD/CAM) glass ceramic materials. Feldspathic, lithium disilicate, and zirconia-reinforced CAD/CAM ceramics were divided into four groups: control group (C), no surface treatment; hydrofluoric (HF) group, 5% HF acid-etched; sandblasting (SB) group, abraded with 50 µm aluminum oxide (Al2O3) particles; silica-coated (CJ) group, abraded with 30 µm silica-modified Al2O3 particles. Roughness values were obtained by using a profilometer. The cements were condensed on the surface-treated specimens and a micro-shear bond test was conducted. The ceramic material (p < 0.001) and surface treatment type (p < 0.001) significantly affected the micro-shear bond strength values. HF acid etching can be recommended for the surface pretreatment of feldspathic, lithium disilicate, and zirconia-reinforced CAD/CAM ceramics. Better bond strengths can be obtained with HF acid etching than with sandblasting and silica coating.

This paper presents an alternative way to recycle cathode ray tube glass waste, together with fly ash and kaolin, into new glass ceramic materials. The samples were obtained using three firing temperatures: 700, 800, and 900 °C. The effect of the fly ash/CRT waste ratio upon the materials’ firing shrinkage, apparent density, apparent and total porosity, chemical stability, and compression strength was investigated. The firing shrinkage used as a dimensional stability parameter, a firing shrinkage range between 2.19–8.18%, was positively influenced by the waste mix amount. The apparent density of the obtained materials is positively affected by the heat treatment temperature, rising from 2.09 to 2.93 (g·cm−3), while the apparent porosity decreases with the increase of the firing temperature from 6.08 to 2.24 %. All the studied glass ceramics show very good chemical stability and complete immobilization of the Pb2+ and Ba2+ ions in the glass ceramic matrix. The compression strength of the sintered materials ranges between 1.42–11.83 (N·mm−2), being positively influenced by the kaolin amount and negatively influenced by porosity. The obtained results confirm the viability of the proposed alternative to use CRT waste and fly ash together with kaolin to obtain glass ceramic materials that can be used for outdoor paving applications.

Background: There has been an increase in demand for orthodontic treatment within the adult population, who likely receive restorative treatments using ceramic structures. The current state of the art regarding the most effective method to achieve an appropriate bond strength of brackets on ceramic surfaces isn’t consensual. This systematic review aims to compare the available surface treatments to ceramics and determine the one that allows to obtain the best bond strength. Methods: This systematic review followed the PRISMA guidelines and the PICO methodology was used, with the question “What is the most effective technique for bonding brackets on ceramic crowns or veneers?”. The research was carried out in PubMed, Web of Science, Embase and Cochrane Library databases. In vitro and ex vivo studies were included. The methodological quality was evaluated using the guidelines for reporting of preclinical studies on dental materials by Faggion Jr. Results: A total of 655 articles searched in various databases were initially scrutinized. Sevety one articles were chosen for quality analysis. The risk of bias was considered medium to high in most studies. The use of hydrofluoric acid (HF), silane and laser afforded the overall best results. HF and HF plus laser achieved significantly highest bond strength scores in felsdphatic porcelain, while laser was the best treatment in lithium disilicate ceramics. Conclusions: The most effective technique for bonding brackets on ceramic is dependent on the type of ceramic.

Supplemental Digital Content is available in the text., Study Design: This is a prospective, stratified randomized, multicenter, 4-year follow-up study. Objective: The authors aimed to evaluate the long-term clinical efficacy and safety of CaO-SiO2-P2O5-B2O3 glass ceramics (BGS-7) spacers in 1-level posterior lumbar interbody fusion (PLIF) at a 4-year follow-up. Summary of Background Data: According to 1-year follow-up results, BGS-7 spacer showed similar fusion rates and clinical outcomes compared with titanium cage. A long-term follow-up study beyond 2 years is necessary to investigate the status of intervertebral bone graft volumes. Moreover, longer follow-up is mandatory to also evaluate the safety and efficacy of BGS-7 spacers, because they remain in the intervertebral space for a long time. Materials and Methods: In this prospective, randomized, multicenter, 4-year follow-up study, we evaluated 62 of the 74 patients who underwent 1-level PLIF. During 1-level PLIF, titanium cages filled with autologous local bone were inserted into the control group patients and BGS-7 spacers were inserted to the experimental group patients. Bone fusion was evaluated by plain radiography and thin-section computed tomography. Visual Analog Scale (VAS), the Oswestry Disability Index (ODI), Short Form-36 Health Survey (SF-36), and evaluation of safety were conducted after 48 months. Results: Computed tomography scan showed a bone fusion rate of 90.6% in the BGS-7 spacer group and 93.3% in the control group, with no significant differences between groups. The BGS-7 spacer group showed a significantly larger area directly fused to the endplate than the control group (P

Objective To study the effects of bacterial invasion and artificial saliva immersion on the bond strength and nanoleakage between healthy dentin and glass ceramics-bonded specimens using three types of resin cements and provide a reference for the selection of clinical bonding materials. Methods One hundred eight dentin blocks were selected to prepare bonded specimens with Variolink N, Multilink N, RelyX Unicem and glass ceramics blocks. The adhesive specimens of each type of resin cements were divided into three groups according to the aging method: bacterial invasiveness group (the specimens were cultured under anaerobic conditions for 14 days after inoculation with Streptococcus mutans), artificial saliva immersion group (the specimens were immersed in artificial saliva for 6 months), and control group (the immediate test group). Each group comprised 12 specimens: 6 were selected to test the bonding strength, and 6 were observed by scanning field emission scanning electron microscopy (FESEM). Results The bond strength of Variolink N in the immediate test group was significantly higher than that of Multilink N and RelyX Unicem, and the difference was statistically significant (P < 0.05). However, no significant difference was found in the bacterial invasiveness group and artificial saliva immersion group (P > 0.05). In the bacterial invasion group, the difference in the nanoleakage of the three adhesives was statistically significant (P < 0.05), with a trend of Variolink N > Multilink N > RelyX Unicem, and pairwise comparison was statistically significant (P < 0.05). The nanoleakage of the three resin adhesives showed an increasing trend in the bacterial invasion group and artificial saliva group compared with that of the immediate test group. Conclusion Both artificial saliva soaking and bacterial invasion can reduce the sealing property of the adhesive interface of 3 types of resin cements to different degrees. The presence of Streptococcus mutans in the oral cavity may reduce the sealing performance of the resin dentine adhesive interface.

We report, for the first time to our knowledge, an ultrabroadband mid-infrared (MIR) emission in the range of 1800–2800 nm at room temperature from a Cr2+-doped chalcogenide glass ceramic embedded with pure hexagonal (wurtzite) β-ZnS nanorods and study the emission-dependent properties on the doping concentration of Cr2+. A new family of chalcogenide glasses based on (100 − x) Ge1.5As2S6.5 – x ZnSe (in mol.%) was prepared by melt-quenching method. The Cr2+: β-ZnS nanorods of ˜150 nm in diameter and ˜1 μm in length were grown in the Cr2+-doped glass after thermal annealing. The compositional variations of glass structures and optical properties were studied. The crystalline phase, morphology of the thermally grown nanorods, and the microscopic elemental distributions were characterized using advanced nanoscale transmission electron microscopy analyses.

Although the economic value of glass products and its importance to the Saudi National Economy is vast, not much information is available about the current state of the art of the industry. Likewise, little information is available about geography, potential sites for mining sand and the sand quality. This paper attempts to bridge this gap by presenting a feasibility study of fabricating normal glass and glass ceramics from Saudi Arabia’s domestically available raw materials. It discusses the current status of the glass industry in Saudi Arabia and the Middle East region. It also gives a brief explanation about the sand topography in Saudi Arabia. In order to determine the feasibility of fabricating glass using these raw materials, experimental data on the fabrication of normal glass and glass ceramics from indigenously available raw materials was obtained and reported as part of the findings of this paper. Firstly, normal transparent glass was able to be fabricated without any apparent large defects using sand collected from the Ar Rayis region in Saudi Arabia. Four nano-sized crystallization catalysts, namely VC, WC, TiC and Y2O3, were added to the constituents of the glass in 3 wt.%. For VC, the crystallization process was limited. The glass ceramics of WC consisted of multi-dimensional edges crystals which covered all the matrix. Gray crystalline whiskers were obtained by addition of TiC. The Y2O3- glass ceramics consisted of multi-directionally rosette crystals. Finally, the microhardness values of the added crystallization catalysts glass ceramics were obtained and found to be much higher compared to normal glass. The results show that glass of high quality can be produced specifically for the Ar Rayis region which would be of interest to researchers, the glass industry personnel and potential investors.

Objectives: The purpose of this study was to evaluate the effects of different resin-based and ceramic superstructure materials and two different abutment types on the stress distribution of the abutment screw using the three-dimensional finite element stress analysis method. Materials and Methods: A three dimensional implant, abutment (zirconia and titanium), abutment screw, crown (zirconia reinforced lithium silicate, lithium disilicate, polymer-infiltrated resin ceramic, and PEEK), and alveolar bone were designed using Rhinoceros 3D modeling software and VRMesh Studio software and combined to form 8 simulations. On the models prepared, loading was made on the lingual tubercule of the maxillary right first premolar crown at an angle of 30° with 150 N force obliquely in the buccolingual direction. The von Mises values obtained from the abutment screw were compared according to the types of abutment and crown materials. Results: The von Mises stress values in the abutment screw were higher in the models using a titanium abutment abutment (on average 1336.24 MPa), and the lower stress values were obtained in the models using a zirconia abutment (on average 964.26 MPa). When the prosthetic material used was changed, no apparent difference was observed in the stress values on the abutment screw. Conclusions: Considering that the abutment screw is the weakest link of the implant system, zirconia abutments can be used reliably in the maxillary first premolar region where aesthetic expectations are high.

The temperature of cities increases due to the UHI phenomenon and climate change. Among the mitigation strategies, high solar reflectance materials make an important contribution, in particular ceramic materials on which studies have shown that the functionalization of the ceramic engobe allows to increase solar reflectance (SR). This study attempted to improve the SR of ceramic tiles, starting from studies correlating the heat treatment temperatures of glass-ceramic frits with SR, because frit is fundamental for the preparation of an engobe, which plays, as some studies have shown, an increasingly important role in solar reflectance. Five glass-ceramic frits have been analysed: four of these are commercial frits, while one has been obtained and optimized experimentally.

Though fly ash in South Africa has mainly been utilized in the construction industry, a large portion of it is still discarded. Production of glass-ceramic composites through fly ash devitrification has gradually become one of the applications being examined internationally. This study reports the investigation of producing glass-ceramic composites from fly ash and varying quantities of beverage waste glass and magnesium oxide as main raw materials. Glasses were obtained by melting fly ash and its additives using an arc furnace. Based on their behaviour when subjected to differential thermal analysis, the glasses were then crystallised through a double-staged thermal treatment to form glass-ceramic composites. The composition and behaviour of the glass-ceramic composites were investigated using X-ray diffraction, Scanning Electron Microscopy, mechanical and chemical assessments. The crystal content in the glass-ceramic composites increased as the magnesium oxide content was increased. The desired diopside phase decreased with an increased magnesium oxide content and ultimately resulted in the formation of forsterite and anorthite as the major and second major phases respectively. The glass-ceramic composites with lesser amounts of magnesium oxide were chemically and thermally resistant and they also demonstrated high cold compressive strength.

Borate glasses containing Li2O and fixed concentration of heavy metal oxide Bi2O3 are prepared by melt quenching technique. The effect of addition of Li2O on borobismuthate glasses has been studied. Density of the glasses has been found to increase slightly with Li2O content whereas molar volume and glass transition temperature decreases. IR spectroscopy was used for structural studies of these glasses in the range from 400 to 4000 cm−1. IR analysis showed that Bi3+cations are incorporated in the glass structure as (BiO6) octahedral units and boron ions are incorporated as (BO3) and (BO4) units. As the Li2O content increases in the glass, some of the BO3 trigonal units get converted into BO4 tetrahedral units and non-bridging oxygens have been formed. The optical transmittance spectra have been recorded at room temperature. The cut-off wavelength shows a red shift, the optical band gap decreases and polarizability increases with Li2O content. The compositional dependence of different physical properties such as density, molar volume optical band gap and optical basicity has been studied and correlated with the glass structure.

Digital dentistry is increasingly replacing conventional methods of manually producing dental restorations. With regards to computer-aided manufacturing (CAM), milling is state of the art. Additive manufacturing (AM), as a complementary approach, has also found its way into dental practices and laboratories. Vat photo-polymerization is gaining increasing attention, because it enables the production of full ceramic restorations with high precision. One of the two predominantly used ceramic materials for these applications is lithium disilicate, Li2Si2O5. This glass ceramic exhibits a substantial fracture toughness, although possesses much lower bending strength, than the other predominantly used ceramic material, zirconia. Additionally, it shows a much more natural optical appearance, due to its inherent translucency, and therefore is considered for anterior tooth restorations. In this work, an optimized formulation for photo-reactive lithium disilicate suspensions, to be processed by vat photo-polymerization, is presented. Following the fundamental theoretical considerations regarding this processing technique, a variety of solvents was used to adjust the main properties of the suspension. It is shown that this solvent approach is a useful tool to effectively optimize a suspension with regards to refractive index, rheology, and debinding behavior. Additionally, by examining the effect of the absorber, the exposure time could be reduced by a factor of ten.

This paper aims at exploring the possibility of using a great percentage of recycled materials into vitreous china (VC), thus, contributing to urban waste decrease while lowering the industry’s buying costs, previously optimized, for the sanitaryware production. The recycled blend was introduced in the ceramic slip, Sanitser VC, and used in three sanitaryware production plants. This slip let to improve the environmental performances of the overall ceramic production through energy-saving and a decrease in greenhouse gas emissions. In fact, the firing temperature is 80-100 °C lower than traditional production. Therefore, the objective of this paper was to evaluate the firing behavior, technological properties, and microstructure of a typical industrial vitreous china body in comparison with Sanitser VC. The analytical results confirmed the force of this idea and highlighted the advantages of the choice made.

Thermal insulation materials are widely used in engineering practice to reduce the depth of seasonal freezing. The effective thermal conductivity of the material is the main criterion for predicting the freezing depth of the structure base and determining the required thickness of the thermal insulation layer. However, the effective thermal conductivity of granular thermal insulation materials can significantly depend on the seasonal temperature, hydrological conditions of the soil and the degree of water content of the material. In this regard, calculating the effective thermal conductivity of granular thermal insulation materials in natural conditions is an urgent scientific and practical task. Granular foam-glass ceramic with a bulk density of 250 kg/m3 was used in the study. To solve the problem, we employed an experimental set to simulate the natural conditions of heat transfer in a horizontal layer, which makes it possible to change the magnitude and direction of the temperature gradient. It was established that the magnitude and direction of the temperature gradient have no significant influence on the layer of granules with a size of 5���10 mm. A predictive calculation of the temperature fields of the roadbed using experimental values depending on the water content degree was carried out. It was found that the depth of freezing of the roadbed covered with a 20 cm layer of foam-glass ceramic with effective thermal conductivity of 0.075, 0.111 and 0.138 W/(m����C), respectively, is 12, 3.8 and 3 times lower than without the thermal insulation layer. A graphical interpretation of the temperature field in the form of -2��C isotherms shows that there is a dangerous zone of intense frost heaving with a depth of 58 cm forming at the roadbed without thermal insulation. Complete absence of zones of intense frost heaving in the roadbed covered with granular foam-glass ceramic was confirmed.

International audience; Tb3+ doped transparent germanate glass ceramics embedded with LaF3 nanocrystals were successfully prepared via melt-quenching and subsequent thermal treatment. The luminescent properties of the as-prepared glass and the glass ceramics were investigated in detail. The X-ray diffraction results prove that the crystalline phase precipitated in the glass matrix was pure LaF3 crystal and the crystal size was between 16 nm and 21 nm. Under the excitation of 377 nm ultraviolet light and X-ray, Tb3+ glass ceramics embedded with LaF3 nanocrystals show much intense green emission than Tb3+ doped germanate glass, and the green emission intensity increases with the increment of thermal treatment temperature and time. The maximum integrated X-ray excited luminescence intensity of the glass ceramics is about 40.3% of that of Bi4Ge3O12 crystal which is the commercial scintillating crystal. Our research shows that Tb3+ doped germanate glass ceramics embedded with LaF3 nanocrystals have potential application prospects in X-ray detection. © 2021, Science Press. All right reserved.

In integrated optics, optical waveguides are fundamental elements for the development of integrated devices, including light sources, modulators, detectors, optical pathways, receivers and switches. For the fabrication of optical integrated waveguide components, grating couplers or other complex integrated structures realized on planar optical waveguides, materials with high photorefractivity are surely of great interest since they allow applying photorefractive direct-laser-writing techniques which are of lower cost and less time-consuming than conventional photolithography and etching processes. This chapter provides an overview of classes of photorefractive materials such as photorefractive glasses, glass-ceramics, crystals and polymers, which are promising candidates for integrated optics. Different aspects, including material preparation, photorefractivity investigation and the fabrication of photorefractive direct-laser-written micro/nano-optical structures such as channel waveguides and gratings in each type of photorefractive materials, are also discussed.

Porous glass ceramic materials are widely used in the construction industry. Foam glass ceramics are obtained from industrial wastes, rocks of various chemical and mineralogical composition and other raw materials. Samples of foam glass ceramic materials obtained by burning the mechanically activated charge were studied. Siliceous rocks from six deposits were ground together with thermonatrite (Na2CO3·H2O). The resulting charge was burned at a temperature of 850 °C. The following properties were determined experimentally: bulk density, compressive strength, water absorption, sorption humidity, thermal conductivity, application limit temperature, thermal and chemical stability of samples. In order to obtain glass ceramic materials with a uniform porous structure, the total amount of cristobalite and the amorphous phase in the composition of siliceous rock has to be more than 44.5 %. The amount of quartz, calcite and muscovite in the rock should not exceed 12 %. The bulk density of the samples decreases with an increase of heilandite share in the charge composition. The maximum compressive strength of the developed materials is 6 MPa with a bulk density of samples equal to 290 kg/m3. The water absorption of samples decreases to 2.5 % (by volume) with an increase of diatomite share in the charge composition for more than 39.5 %. The minimum thermal conductivity of glass ceramics (0.0583 W/m °С) was revealed at a sample density of 180 kg/m3. Insufficiently high values of thermal stability index (167–183 °C) are associated with the presence of both amorphous phase and crystalline minerals in the material, which have different thermal expansion coefficients. The application limit temperature of the material reaches 850 °C. The developed materials demonstrated high chemical stability after boiling in water, an aqueous HCl solution, as well as in an alkaline solution. Regarding a number of indicators, porous glass ceramic materials based on siliceous rocks are superior to foam glass and can be used as thermal insulation of pipelines, industrial plants (melting furnaces, boiler equipment), etc.

Indialite/cordierite (Mg₂2Al₄Si₅O₁₈) glass-ceramics with a low dielectric constant of 4.7 and a high Qf of >200 × 10³ GHz are predicted for use as micro/millimeter-wave materials in the fifth generation (5G) mobile communication systems. The glass-ceramics have a serious cracking problem caused by the anisotropic crystal growth during the surface crystallization. In this paper, the cracking was prevented by adding TiO₂ which acts as a seed. The glass-ceramics produced without cracking were composed of spherical crystals of approximately 10 μm diameter, formed by volume crystallization. Precipitated phases of the glass-ceramics crystallized at 1200–1350 °C/10 h and 20 h were indialite, cordierite, Al₂TiO₅ and rutile. The glass-ceramics crystallized for 10 h were analyzed by the Rietveld method. Indialite precipitated as an intermediate metastable compound at the lower temperature of 1200 °C and transformed to cordierite at the crystallization temperature. The reaction between cordierite and TiO₂ produced the new Al₂TiO₅ phase. The amounts of Al₂TiO₅ and rutile affected the microwave dielectric properties. In particular, the amount of rutile affected the TCf. In the cases of 10 wt % added TiO₂, and the crystallized at 1250 °C for 10/20 h the TCf values were improved to -2/-8 ppm/°C.

Als F��gungen f��r die Festoxidbrennstoffzelle werden Materialien verwendet, die gasdicht, mechanisch stabil und isolierend sind. In dieser Arbeit wird gezeigt, dass Glaskeramiken als F��gematerial eingesetzt werden k��nnen. Es werden l��semittelbasierte und wasserbasierte Suspensionen aus Erdalkali-Silikatglas hergestellt, rheologisch charakterisiert, Schichten mit dem Siebdruckverfahren aufgebracht und anschlie��end zwischen Stahl- und Keramiksubstraten verl��tet.

International audience; Lanthanide-doped up-conversion (UC) materials with color tunable property show promising application in many fields, such as biological imaging, optical multiplexing, and information security. Although great efforts have been devoted to regulate UC emission color via modifying chemical composition, crystal structure, or external stimuli condition, it is remain a daunting challenge to develop a general strategy that probably suitable for various lanthanide-doped nano-systems. Herein, we verify the cross-relaxation possibility between sensitizer Yb3+ and activator Er3+ as well as Er3+- Er3+ pairs can be well modified by engineering the crystal lattice distortion of matrix, leading to the evident UC emission color variations. Specifically, with incorporating Al3+ or Ca2+ ions into the Yb/Er co-doped BaF2 nanocrystals (NCs) contained glass ceramics (GCs), the contraction of the crystal lattice lead to the change of UC emission color from green to red. On the contrary, the high laser excitation power results in the lattice expansion of the Al3+-doped BaF2:Yb/Er GCs at different Yb3+ concentration as well as Al3+ doped CaF2 GCs, which leads to the greatly increased green-to-red ratio. These multi-color UC GCs show potential application in anti-counterfeiting filed. Our results open up a general avenue for the control of UC emission color via engineering crystal lattice distortion.

The results of studies of the structure, phase composition, and mechanical and chemical properties of aluminosilicate, magnesia-quartz, and glass-ceramic proppants (RosProp, BorProp, ForeRCP, Wauli, etc.) are reported. It is shown that glass-ceramic proppants outperform ceramic analogs because a highly efficient method of dispersing a melt jet into droplets is used to spherize the particles and because of the structural features manifested in the formation of a homogeneous dense material represented by microcrystals with pyroxene composition.

In this study, two different dental ceramics, based on zirconia-reinforced lithium-silicate (LS1) glass-ceramics (Celtra Duo, Dentsply Sirona, Bensheim, Germany) and lithium disilicate (LS2) ceramics (IPS e.max CAD, Ivoclar, Vivadent, Schaan, Liechtenstein) were examined. They were tested prior to and after the crystallization by sintering in the dental furnace. Additionally, the impact of ageing on ceramic degradability was investigated by immersing it in 4% acetic acid at 80 &deg, C for 16 h. The degradability of the materials was monitored by Impedance Spectroscopy (IS), X-Ray Powder Diffraction (XRPD), and Field Emission Scanning Electron Microscope (FE-SEM) techniques. It was detected that LS2 (vs. LS1) samples had a lower conductivity, which can be explained by reduced portions of structural defects. XRPD analyses also showed that the ageing increased the portion of defects in ceramics, which facilitated the ion diffusion and degradation of samples. To summarize, this study suggests that the non-destructive IS technique can be employed to probe the ageing properties of the investigated LS1 and LS2 ceramics materials.

Made available in DSpace on 2020-12-12T01:31:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-10-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) This study evaluated the effect of different firing processes (without firing, additional crystallization and glaze firing) and thermal-cycling (with or without) on the fatigue behavior of simplified zirconia-lithium silicate (ZLS) glass ceramic restorations cemented to a dentin-like material. Materials and Methods. One hundred twenty-nine (129) discs (diameter = 12 mm and thickness = 1.2 mm) of ZLS (Celtra Duo, Dentsply Sirona) and fiber-reinforced epoxy resin (diameter = 12 mm and thickness = 2.3 mm) were produced and tested under fatigue according to 2 study factors: a firing protocol with 3 levels (without firing, additional crystallization and glaze firing) and thermocycling of 2 levels (absence/presence), composing 6 study groups. Ceramic and epoxy resin discs had their surfaces treated and adhesive cementation was performed (Multilink N, Ivoclar). Half of the samples were immediately tested; the other half were subjected to thermal-cycling (10,000 cycles in water; 5-55 °C). The staircase method determined the fatigue failure load (100,000 cycles at a frequency of 20 Hz). The fatigue data (in N) were submitted to 2-way ANOVA and Bonferroni test (p < 0.05). Fractographic analyses were also carried out. Thermocycling decreased the fatigue failure load (FFL) of all groups when compared to those without aging. Bonferroni's test indicated that the groups with crystallization/glazing process behaved better in terms of FFL than those without firing in the same storage condition. All the samples had radial cracks and all fractures originated from defects on the cementation surface of the ceramic discs. Crystallization and glaze firing had a positive effect on the fatigue failure load of adhesively cemented ZLS glass ceramic compared to the group without crystallization firing, in both storage conditions (with or without thermocycling). Restorative Dentistry Division of Prosthodontics São Paulo State University (UNESP) Institute of Science and Technology Oral Science Division of Prosthodontics Faculty of Odontology Federal University of Santa Maria Restorative Dentistry Division of Prosthodontics São Paulo State University (UNESP) Institute of Science and Technology CAPES: 001

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES This dissertation is divided in three parts, which investigated the effects of thermal treatments on the mechanical behavior of bilayer ceramic systems as well as identify the main influencing factors. The first part gathered the scientific literature available to evaluate the effect of thermal treatments (glaze, cooling protocol, number of firings, annealing) on the flexural strength and load to fracture of porcelain-veneered zirconia (PVZ) samples. Three databases were used for performing the search (PubMed/Medline, Scopus, and Web of Science). From 393 relevant studies, 21 were selected for full-text analysis, from which 7 failed to meet the inclusion criteria. The 14 remaining papers were included for the systematic review: 8 for meta-analysis and 6 restricted to descriptive analyses. The results showed that delaying furnace opening at a temperature below the porcelain’s glass transition temperature is advised for PVZ restorations, in order to improve their fracture resistance. Moreover, there is a lack of information about the effect of glaze firings on the studied outcomes. The second part evaluated the effect of dwell time (conventional or extended) and cooling protocol (fast or slow) of glaze firings on the flexural strength, resistance to crack propagation, and optical properties stability of a porcelain-veneered zirconia system. Bilayer disc-shaped samples were prepared using a zirconia framework veneered with porcelain, and divided according to the thermal treatment to be performed after sintering: glaze firing (1 min of dwell time) followed by slow cooling (furnace opening at 200ºC) or fast cooling (furnace opening at 600ºC), extended glaze firing (15 min of dwell time) followed by slow cooling or fast cooling, or no thermal treatment (control). Porcelain roughness (Ra and Rz) and translucency (TP00) were measured before and after firings, as well as the color difference (ΔE00) after the treatments. Crystalline phase was analyzed with X-Ray diffraction. Flexural strength was measured with the piston-on-three-ball test. Additional samples were prepared and subjected to Vickers indentations on the porcelain for crack length analysis. The extended glaze firing was observed to improve the flexural strength and the resistance to crack propagation. No clinically significant difference was observed regarding the optical properties stability. The third part studied the stress development in bilayer systems with zirconia or lithium disilicate (PVLD) frameworks. The effects of cooling rate and thickness ratio were evaluated using a Viscoelastic Finite Element Method. Bilayer crown models were generated using a finite element software (ABAQUS). The physical properties (coefficient of thermal contraction, thermal conductivity, specific heat, density and elastic modulus) of each material studied were experimentally measured as a function of the temperature. Two cooling protocols were simulated (Fast: ~300ºC/min, Slow: ~30ºC/min) from 70ºC above the softening temperature of the porcelains using a heat transfer, followed by the residual stress analysis. PVLD showed lower values of residual stresses than PVZ. The maximum tensile stresses in porcelain over zirconia framework were observed in the cusp area, whereas those in porcelain over lithium silicate were located in the central fossa. Therefore, slow cooling is preferable for both PVZ and PVLD, as well as using a thinner porcelain layer over zirconia when possible. No presente trabalho, dividido em três partes, foram investigados os efeitos de tratamentos térmicos sobre o comportamento mecânico de sistemas cerâmicos bicamadas e os fatores que levam a esse efeito. A primeira delas reuniu a literatura científica disponível para avaliar o efeito de tratamentos térmicos (glaze, protocolos de resfriamento, número de queimas, annealing) na resistência à flexão e carga para fratura de espécimes de zircônia recoberta por porcelana (PVZ). Três bases de dados foram utilizadas para pesquisa (PubMed/Medline, Scopus e Web of Science). Foram encontrados 393 estudos relevantes, dos quais 21 foram selecionados para leitura completa e 7 não atenderam aos critérios de inclusão. Dos 14 restantes, 8 foram incluídos em metanálises e 6 foram submetidos à análise descritiva. Os resultados mostraram que realizar a abertura do forno em temperaturas abaixo da temperatura de transição vítrea da porcelana é sugerido para melhorar a resistência à fratura do material. Ainda, observou-se que não há evidências claras sobre o efeito da queima de glaze nos desfechos observados. A segunda parte investigou o efeito de protocolos de queima de glaze na resistência à flexão e à propagação de trinca e na estabilidade das propriedades ópticas do sistema zircônia recoberta por porcelana. Para isso, foram confeccionados espécimes em formato de disco com duas camadas (infraestrutura de zircônia e cobertura de cerâmica feldspática), que foram divididos em cinco grupos, de acordo com o tratamento térmico a ser realizado após a sinterização da cerâmica de cobertura: Queima convencional de glaze (tempo de manutenção de 1 min) seguida de resfriamento lento (forno fechado até atingir 200ºC) ou rápido (abertura imediata do forno), queima estendida (tempo de manutenção de 15 min) seguida de resfriamento lento ou rápido, ou nenhum tratamento térmico após a sinterização (controle). Os espécimes foram submetidos à análise de rugosidade (Ra e Rz) e a leituras das coordenadas CIE L*a*b*, para cálculos de alteração de cor e translucidez, antes e após os tratamentos térmicos, e ao ensaio de resistência à flexão biaxial (piston-on-three-ball). Espécimes extra foram confeccionados para realização de indentações Vickers na porcelana e análise da propagação das trincas. Foi observado que a queima estendida de glaze levou a maiores valores de resistência a flexão e maior resistência a propagação de trincas. Nenhuma diferença clinicamente significativa foi observada na estabilidade das propriedades ópticas. Por fim, a terceira parte avaliou o desenvolvimento de tensões em restaurações bicamadas com infraestruturas de zircônia (PVZ) ou dissilicato de lítio (PVLD). Foram observados os efeitos da relação entre as espessuras das camadas e dos protocolos de resfriamento nas tensões transitórias e residuais, através de uma análise visco-elástica de elementos finitos. Um software de elementos finitos (ABAQUS) foi utilizado para criar modelos bicamadas. As propriedades físicas (coeficiente de contração térmica, condutividade térmica, calor específico, densidade e módulo de elasticidade) de cada material foram medidas experimentalmente em função da temperatura e foram inseridas no modelo. Resfriamentos lento (~30°C/min) e rápido (~300°C/min) foram simulados a partir de 70ºC acima da temperatura de amolecimento das porcelanas utilizando uma análise de transferência de calor seguido de análise de tensões residuais. Os resultados mostraram que a infraestrutura de dissilicato de lítio levou a menores valores de tensão residual, especialmente, quando resfriamento lento foi aplicado. Enquanto a localização das tensões máximas de tensão se encontram na cúspide nas PVZs, as PVLDs mostraram as tensões máximas na fossa central. Assim, protocolos de resfriamento lento são preferíveis para ambos os sistemas, bem como o uso de uma fina camada de porcelana sobre zircônia, quando possível.

Purpose: To evaluate the influence of different ceramic surface conditioning methods on the fatigue failure load of adhesively cemented simplified lithium-disilicate glass-ceramic restorations. Materials and Methods: Ceramic (IPS e.max CAD, Ivoclar Vivadent) (Ø = 10 mm; thickness = 1.2 mm) and epoxy resin (Ø = 10 mm; thickness = 2.3 mm) disks were produced. The ceramic bonding surfaces were treated as follows: no etching and MPS-silane primer application only (MN); etching with 10% hydrofluoric acid (HF) for 20 s followed by primer application (HF + MN); HF + universal multimode adhesive application (HF + SU); etching with a one-step etching primer (ME&P); HF + primer + conventional adhesive (HF + MN + PAB). The epoxy resin disks were etched with 10% HF for 20 s followed by a coat of bonding agent (Multilink Primer A+B). Pairs of ceramic/epoxy resin disks were cemented with composite cement (Multilink N, Ivoclar Vivadent). The mean fatigue failure load was determined by the staircase method (100,000 cycles at 20 Hz frequency; initial load = 1435 N; step size = 72 N). Results: ME&P had the highest fatigue failure load, followed by HF etched groups, while the non-etched condition (MN group) had the lowest. All samples presented radial cracks originating from defects at the conditioned ceramic surface (interface). Conclusion: The simultaneous physicochemical conditioning with one-step self-etching ceramic primer promoted the best fatigue behavior results of the glass-ceramic restorations. It might indicate that this one-step conditioning reduces the number of flaws at the ceramic surface due to the slighter surface alterations than those produced by hydrofluoric acid etching, improving the fatigue behavior.

Purpose: To evaluate the influence of different ceramic surface conditioning methods on the fatigue failure load of adhesively cemented simplified lithium-disilicate glass-ceramic restorations. Materials and Methods: Ceramic (IPS e.max CAD, Ivoclar Vivadent) (Ø = 10 mm; thickness = 1.2 mm) and epoxy resin (Ø = 10 mm; thickness = 2.3 mm) disks were produced. The ceramic bonding surfaces were treated as follows: no etching and MPS-silane primer application only (MN); etching with 10% hydrofluoric acid (HF) for 20 s followed by primer application (HF + MN); HF + universal multimode adhesive application (HF + SU); etching with a one-step etching primer (ME&P); HF + primer + conventional adhesive (HF + MN + PAB). The epoxy resin disks were etched with 10% HF for 20 s followed by a coat of bonding agent (Multilink Primer A+B). Pairs of ceramic/epoxy resin disks were cemented with composite cement (Multilink N, Ivoclar Vivadent). The mean fatigue failure load was determined by the staircase method (100,000 cycles at 20 Hz frequency; initial load = 1435 N; step size = 72 N). Results: ME&P had the highest fatigue failure load, followed by HF etched groups, while the non-etched condition (MN group) had the lowest. All samples presented radial cracks originating from defects at the conditioned ceramic surface (interface). Conclusion: The simultaneous physicochemical conditioning with one-step self-etching ceramic primer promoted the best fatigue behavior results of the glass-ceramic restorations. It might indicate that this one-step conditioning reduces the number of flaws at the ceramic surface due to the slighter surface alterations than those produced by hydrofluoric acid etching, improving the fatigue behavior.

Made available in DSpace on 2019-10-06T15:35:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-09-10 Tellurite-based (TeO2) glass systems are known to have relatively high chemical and thermal stability, high transmittance in the infrared region as well as low light dispersion. Parallel to the investigations of the optical properties of the TeO2-based glasses, there is a growing interest in the manufacture of transparent oxides containing specific nanocrystals in the glass-matrix, thus promoting the formation of glass-ceramic materials. These new class of materials are very interesting for new optical-glasses applications. This work aims the investigation of the synthesis process and formation of ferroelectric nanocrystals in tellurite glasses-matrix, obtained by the conventional quenching method. Departamento de Física e Química UNESP Grupo de Ferroelétricos e Materiais Multifuncionais Instituto de Física Universidade Federal de Uberlândia Instituto Federal Goiano Laboratório de Novos Materiais Isolantes e Semicondutores Instituto de Física Universidade Federal de Uberlândia Departamento de Física e Química UNESP

Aim: The study aimed to measure light scattering of a broad spectrum light curing unit (LCU) as influenced by ceramic type, shade and thickness as well as exposure distance and LCU’s position. Methodology: A broad spectrum LED LCU (ASCENT OL5) was mounted above a spectrometer (MARC Resin Calibrator, Blue, Light Analytics) at exposure distances of 1.0, 1.5 or 2.5 mm. The position of the center of the head was aligned with the spectrophotometer’s sensor and then moved in 1 mm increments in the X-Y plane, while concomitantly recording the irradiance. The process was repeated with lithium disilicate and leucite glass ceramic slabs of similar thicknesses. The loss in irradiance related to the value measured at center position was analyzed by means of linear regressions and multiple ANOVA analysis. Results: The regressions showed a good fit (90% - 99%). Moving away from the center showed decreased irradiance. Values of slope obtained were divided by their respective intercept to eliminate the influence of the irradiance measured at the center. Two three-way ANOVA’s were performed. One examined the influence of ceramic slab, direction and translucency/shade. It shows only the direction of measurement exhibited significant influence (p < 0.0001) on the mean normalized slope values. The other one examined the influence of ceramic slab, direction and slab thickness. It shows the mean normalized slope values are significantly influenced by the direction of measurement and the slab thickness (p < 0.0001). Values of the slopes indicated the ceramic scattering effect of the light. Thicker samples showed more scattering. Conclusion: The ceramic types, translucency/ shade had no significant effect on the light scattering. The thicker the ceramic the less irradiance changes were found indicating that the ceramics were scattering the light and thus slightly alleviating the effect of the inhomogeneous beam profile.

CC BY-NC-ND, Novel Er3+ doped glass ceramics containing Ba4Lu3F17 nanocrystals were successfully prepared by heat treatment of melt-quenched glasses. Highly efficient upconversion luminescence was detected under near-infrared excitation and it was at least two orders of magnitude higher than that in the precursor glass. The activator content in the crystalline phase was estimated using polycrystalline Ba4Lu3F17 with different Er3+ content as the reference and it was found to be higher than in similar glass ceramics. The structure and thermal analysis of the glass ceramics revealed the formation of cubic and rhombohedrally distorted cubic modifications of Ba4Lu3F17. Phase transition between the two modifications was studied using site selective spectroscopy of Er3+ as a structural probe. Unusually efficient incorporation of Er3+ ions in the Ba4Lu3F17 nanocrystals combined with the low phonon energy of the fluoride crystals make this material a desirable host for upconversion luminescence. ----/ / /---- This is the preprint version of the following article: G. Krieke, A. Sarakovskis, M. Springis, Cubic and rhombohedral Ba4Lu3F17:Er3+ in transparent glass ceramics: Crystallization and upconversion luminescence 200 (2018), which has been published in final form at https://www.sciencedirect.com/science/article/abs/pii/S0022231317322056. This article may be used for non-commercial purposes in accordance with Elsevier Terms and Conditions for Sharing and Self-Archiving. CC BY-NC-ND, National Research Program IMIS2; University of Latvia Foundation; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART². The authors wish to express gratitude to R. Ignatans for Rietveld refinement. This work was supported by National Research Program IMIS2 and Arnis Riekstins "MikroTik" donation. Donations are administered by the University of Latvia Foundation.

Er3+-doped and Er3+-Yb3+-co-doped transparent oxyfluoride glass-ceramics (GCs) containing LaF3 nano-crystals (NCs) have been prepared by the melting-quenching method and adequate thermal treatments. A detailed structural characterization, performed by X-ray diffraction (XRD) and high resolution transmission electron microscopy (HR-TEM), confirms the precipitation of LaF3 NCs with a size in the 10–15 nm range. The crystal growth is fast in the very beginning, from a few min up to 3–5 h of treatment at 620 °C and then it slows down, up to 20 h. A SiO2 enriched viscous barrier is formed around the NCs, thus preventing further crystal growth. The incorporation of Er3+ and Yb3+ ions into the NCs is proved by HR-TEM and energy dispersive X-ray spectroscopy (EDXS) analysis. Photoluminescence measurements have been performed upon visible and near infrared excitation. The energy transfer between Yb3+ and Er3+ ions is evidenced by the enhancement of the near infrared and Up-Conversion (UC) emissions of Er3+ ions in the co-doped samples under 980 nm excitation. A moderate back transfer from Er3+ to Yb3+ ions has been also observed under near infrared excitation of Er3+ ions at 800 nm. Upconverted green ((2H11/2,4S3/2) → 4I15/2) and red (4F9/2 → 4I15/2) emissions were observed in all samples and attributed to a two photon process. The strong enhancement of the UC emission for the co-doped glass-ceramics samples further confirms the incorporation of the rare-earth ions in the LaF3 NCs with a lower maximum phonon energy environment which reduces multi-phonon relaxation rates. Different red-to-green emission ratios are obtained depending on the heat treatment conditions for the glass-ceramic samples., This work has been supported by the Spanish Government MINECO (Project MAT2013-48246-C2-1-P and MAT2013-48246-C2-2-P) and the Basque Country University (Project PPG17/07).

Made available in DSpace on 2018-12-11T17:15:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01 This study aimed to evaluate the effect of etching time and hydrofluoric acid (HF) concentration on the fatigue failure load and surface characteristics of zirconia-reinforced lithium silicate glass (ZLS) ceramic cemented to a dentin-like, fiber reinforced epoxy resin. Ceramic (Suprinity, VITA) (1.0 mm thick) and epoxy resin (2.5 mm thick) discs (10 mm diameter) were produced. The bonding surface of the ceramic samples was nonetched (control group), or etched for 30, 60 or 90 s by 5% or 10% HF. The epoxy resin discs were etched by 10% HF for 30 s followed by the application of an adhesive material (Single Bond Universal, 3M ESPE). Pairs of ceramic/epoxy resin discs were cemented with a dual cure resin cement. The fatigue failure load was determined by the staircase method (500,000 cycles at 20 Hz; initial load = 925 N; step size = 45 N). In 10% HF the etching time was shown to influence the fatigue failure load, which increased as the etching time increased (30 s < 60 s < 90 s), and in 5% HF the fatigue failure load was not shown to be affected by the etching time; the lowest fatigue failure loads were produced in the control group without ceramic etching followed by 10% HF acid etching for 30 s. Topography analysis showed variations based on the etching protocols. All fractures (radial cracks) were shown to originate from defects at the ceramic surface on the cementing interface. For fatigue loading improvements of ZLS ceramic, 10% HF acid etching for 90 s and silanization of the ceramic surface is recommended. PhD Post-Graduate Program in Restorative Dentistry (Prosthodontics Units) Univ. Estadual Paulista (UNESP) Institute of Science and Technology at Sao Jose dos Campos PhD Post-Graduate Program in Oral Science (Prosthodontic Units) Faculty of Odontology Federal University of Santa Maria, R. Floriano Peixoto, 1184 MSciD Graduate Program School of Dentistry Meridional Faculty - IMED PhD Post-Graduate Program in Restorative Dentistry (Prosthodontics Units) Univ. Estadual Paulista (UNESP) Institute of Science and Technology at Sao Jose dos Campos

In this study, novel transparent Er3+ doped glass ceramics were prepared from melt-quenched oxyfluoride glasses with general composition of Na2O-NaF-BaF2-YbF3-Al2O3-SiO2. The crystallization of fluorite (BaF2, BaF2-YbF3, NaF-BaF2-YbF3 and Na0.5-xYb0.5+xF2+2x) and distorted fluorite (rhombohedral Ba4Yb3F17 and tetragonal NaF-BaF2-YbF3) phases was analysed in glass ceramics with different BaF2 and YbF3 ratio. The phase composition and microstructure were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Intense red upconversion luminescence (UCL) was detected under near-infrared excitation resulting from three photon upconversion followed by cross-relaxation between Er3+ and Yb3+ ions. The local environment of Er3+ ions in fluorite and distorted phases was analysed using site-selective spectroscopy. The Er3+ ions were found to act as nucleation centres in the glass ceramics containing BaF2. The phase transition from metastable fluorite to rhombohedrally and tetragonally distorted fluorite phases was detected using Er3+ ions as a probe. ----- / / / ----- This is the peer reviewed version of the following article: G. Krieke, A. Sarakovskis, M. Springis; Ordering of fluorite-type phases in erbium-doped oxyfluoride glass ceramics; Journal of the European Ceramic Society, 2018 38 (1), which has been published in final form at https://www.sciencedirect.com/science/article/abs/pii/S0955221917305769. This article may be used for non-commercial purposes in accordance with Elsevier Terms and Conditions for Sharing and Self-Archiving., This work was supported by National Research Program IMIS2 and Arnis Riekstins "MikroTik" donation. Donations are administered by the University of Latvia Foundation; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART²