Edgar Dutra Zanotto

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• Professor of glass science and technology
• Managing Director at Federal University of São Carlos

This letter reports a novel method for synthesizing RE 3 Ga 5 O 12 , RE 3 Al 5 O 12 , and RE 3 Fe 5 O 12 single-crystal garnets, where RE refers to rare earth elements, including Sc and Y.

Biosilicate® is a strong, highly bioactive, bactericidal, machinable, (almost) fully crystalline glass–ceramic that has been successfully used in several in vivo and clinical trials. However, there is still scope to optimize its crystallization ability, resulting microstructure and properties. Here we tested 13 compounds, from which we choose six f...

Multicomponent glasses containing a diverse range of element oxides are increasingly being designed using machine learning (ML) techniques to optimize their properties. These rather complex compositions present new opportunities for both fundamental research and applied materials development. A key challenge in ML-assisted and empirical glass desig...

Objective: This study aimed to evaluate the chemical solubility (CS) and conduct a comprehensive physicochemical characterization of several experimental and commercial lithium silicate-based glass-ceramics towards an understanding of the chemical processes governing dissolution in these glass-ceramics. Methodology: Glass-ceramic (GC) samples were...

Purpose To evaluate the efficacy of two third-generation resorbable biomaterials—F18 bioglass and β-tricalcium phosphate (β-TCP)—in promoting new bone formation in post-extraction sockets in rats. β-TCP, a synthetic porous ceramic, is well-established in clinical use, while F18 bioglass, a novel silica based bioglass. Methods After extraction of t...

Transparent and hard ZnO−Al2O3−SiO2 (ZAS) glass-ceramics (GCs) are desirable for various applications. However, TiO2, an effective nucleating agent for this system, can introduce an unwanted yellow coloration. This study explores the effect of partially replacing TiO2 with ZrO2 on the crystallization pathways, color, transparency, and hardness of Z...

Aim: To evaluate the bleaching efficacy, decomposition rate, and pH of experimental gels containing 35% hydrogen peroxide (HP) and different concentrations of 45S5-bioglass (BG) or Biosilicate® (BS). Methods: Bovine enamel/dentin blocks (n=10) were allocated into the groups HP_BG or HP_BS (2.5, 5, 7.5 and 10 wt%) and HP (35% HP – positive control)....

Transparent glass‐ceramics (GCs) are promising for applications that require both optical clarity and superior mechanical strength, such as high‐performance displays and ballistic armor. However, achieving this combination typically involves a trade‐off, as crystallization processes that enhance mechanical properties often compromise transparency....

The evolution of biomaterials engineering allowed for the development of products that improve outcomes in the medical–dental field. Bioglasses have demonstrated the ability to either compose or replace different materials in dentistry. This study evaluated the cytotoxicity, biocompatibility, calcium deposition, and collagen maturation of 45S5 biog...

Crystal surfaces play a pivotal role in governing various significant processes, such as adsorption, nucleation, wetting, friction, and wear. A fundamental property that influences these processes is the surface free energy, γ. We have directly calculated γ(T) for low-index faces of Lennard-Jones (LJ), germanium, and silicon crystals along their su...

Aim This study evaluated the efficacy and cytotoxicity of 35% hydrogen peroxide (HP) gel incorporated with 10% (w/w) biosilicate (BioS) on sound enamel and early‐stage enamel erosion lesions. Methods Discs of enamel/dentin were selected, subjected to erosive cycles (0.3% citric acid, pH 2.6), and treated with ( n = 8): HP (35% HP, positive control...

A combination of density measurement, differential scanning calorimetry, refractometry, and Raman and ²⁹Si nuclear magnetic resonance (NMR) spectroscopy is employed to characterize the evolution of the structure and physical properties of lithium disilicate (Li2Si2O5) and lead metasilicate (PbSiO3) glasses during physical aging. Both glasses displa...

Objective: The objective of this study was to compare the efficacy of Biosilicate and Duraphat in the treatment of dentin hypersensitivity (DH). Methods and materials: This clinical trial was conducted with young adults presenting DH. A visual analogue scale (VAS) was used to assess the level of pain, using volatile and tactile tests. Forty part...

There is a lack of understanding of both the conversion of an unstable glass into a metastable supercooled liquid (MSL) upon heating and the metastability of MSLs. In this study, we investigated the time- and temperature-dependent metastability of an MSL using an advanced nano-calorimetric technique. The chosen Au-based metallic glass (AuMG) allowe...

In this article, we investigate the structural relaxation of lithium silicate glass during isothermal physical aging by monitoring the temporal evolution of its refractive index and enthalpy following relatively large (10–40 °C) up- and down-jumps in temperature. The Kohlrausch–Williams–Watts function aptly describes the up- and down-jump data when...

The precipitation of nonstoichiometric crystals (of different composition from the parent glass) motivated us to study the stoichiometric Na2O·2CaO·3SiO2 ( N2CS3) glass‐forming system comprehensively. The concentration profiles of Na and Ca in the diffusion zone around Na4+2xCa4−x[Si6O18], 0<x<1$0{\mathrm{\;}} < {\mathrm{\;}}x{\mathrm{\;}} < {\math...

After testing over 50 experimental lithium disilicate (LS2)-based glass-ceramic (GC) compositions and evaluating their glass-forming ability and the effect of various heat treatments on their crystallized fraction, crystal size, and morphology, a particularly promising formulation was selected for the optimization of the mechanical properties of ma...

Novel approaches for caries lesion removal and treatment have been proposed. This study evaluates the combined use of an experimental ultrasound, aPDT (antimicrobial photodynamic therapy) and bioactive glasses on the removal, decontamination and remineralization of dentin caries lesions. A biological model created with a duo species biofilm (Strept...

Relaxation occurs spontaneously in all glasses and is a fundamental step of important technological processes, such as annealing, crystal nucleation, and chemical strengthening by ion exchange. Despite extensive studies over the past decades, there are still conflicting results on whether the kinetics of structural relaxation depends on the analyze...

Glass hardness varies in a non-linear fashion with the chemical composition and applied load, a phenomenon known as the indentation size effect (ISE), which is challenging to predict quantitatively. Here, using a curated dataset of over 3,000 inorganic glasses from the literature comprising the composition, indentation load, and hardness, we develo...

While niobium-containing oxide glasses are used in many technological applications, especially optical glasses, the exact structural role of Nb and its impact on the structure of covalent/ionic oxide glasses remain incompletely understood. In the present study, this issue is addressed for Nb2O5-containing lithium silicate glasses using 7Li, 29Si, a...

This study investigated the influence of incorporating Biosilicate® on the physico-mechanical and biological properties of glass ionomer cement (GIC). This bioactive glass ceramic (23.75% Na2O, 23.75% CaO, 48.5% SiO2, and 4% P2O5) was incorporated by weight (5%, 10%, or 15%) into commercially available GICs (Maxxion R and Fuji IX GP). Surface chara...

Objectives To evaluate cytotoxicity, biocompatibility, calcium deposition, and collagen maturation of 45S5 bioglass experimental paste and Bio-C Temp compared to calcium hydroxide (Ca(OH)2) paste. Materials and methods 45S5 bioglass and Ca(OH)2 powder were mixed with distilled water (ratio 2:1) and Bio-C Temp is ready-for-use. Dental pulp cells we...

Objective To evaluate color change, surface roughness, microhardness, and morphology of enamel submitted to bleaching with 35% hydrogen peroxide (HP) gels associated with different concentrations of bioglass 45S5 (BG). Methods Enamel blocks (n = 10) were submitted to a positive control (PC): 35% HP bleaching; HP_BG: HP associated with a gel contain...

Objective: To analyze simplified adhesive containing pure or silanized bioglass 45S5 (with calcium) or Sr-45S5 (strontium-substituted) fillers applied on dentin and to evaluate the microtensile bond strength (µTBS), interface nanoleakage, degree of conversion of adhesive, collagen degradation and remineralization. Methods: Ambar Universal adhesi...

Until quite recently, in almost all papers on crystal nucleation in glass-forming substances it was assumed that nucleation proceeds in a completely relaxed supercooled liquid and hence at constant values of the critical parameters determining the nucleation rate for any given set of temperature, pressure, and composition. Here, we analyze the vali...

Glass hardness varies in a non-linear fashion with the chemical composition and applied load, a phenomenon known as the indentation size effect (ISE), which is challenging to predict quantitatively. Here, using a curated dataset of over approx. 3000 inorganic glasses from the literature comprising the composition, indentation load, and hardness, we...

Due to the unusual crystallization of (nominally) stoichiometric BaSi2O5 (BS2) glass, which shows unexpected and diverse crystal phases, a series of six glasses with different chemicals and melting procedures were prepared in three laboratories and characterized before and after crystallization by differential scanning calorimetry, density measurem...

A few authors have reasonably proposed that liquid–liquid phase‐separated (LLPS) glasses could show improved fracture strength, Sf, and toughness, KIc, as the second phase could provide a barrier to crack propagation via deflection, bowing, trapping, or bridging. Due to the associated tensile or compressive residual stresses, the second phase could...

This presentation briefly demonstrates the structural rearrangements that occur upon thermal treatment of LS2 glass 20 °C below its glass transition temperature.

Nucleation is one of the primary contributions to the microstructure of glass-ceramics. However, the nucleation process within glass-ceramics is not understood across all glass systems, nor is the specific role of nucleating agents. The present article proposes a comprehensive definition of a nucleating agent: “a nucleating agent is a minority comp...

Crystallization is a vital process in nature and technology; however, the detailed microscopic mechanisms of crystal nucleation and growth in most materials and the associated theoretical models are still elusive. In this work, we applied molecular dynamics (MD) simulations of spontaneous and seeded growth to infer the crystallization kinetics in s...

Bioactive glasses have been recommended for the occlusion of dentinal tubules in treating cervical dentin hypersensitivity. This study evaluates an in vivo model of dentin exposure, and tests the efficacy of bioglass treatments. Thirty male Wistar rats received gingival recession surgery on the upper left first molar. The treatments were applied ov...

Due to their unique optical and electronic functionalities, chalcogenide glasses are materials of choice for numerous microelectronic and photonic devices. However, to extend the range of compositions and applications, profound knowledge about composition-property relationships is necessary. To this end, we collected a large quantity of composition...

Structural rearrangements taking place during relaxation and crystal nucleation in lithium-disilicate (LS2) glass have been investigated by a comprehensive set of solid-state nuclear magnetic resonance (NMR) experiments, supported by molecular dynamics (MD) simulations. Samples were subjected to heat treatments at 435°C, i.e., 20 K below the labora...

Barium disilicate (BaO.2SiO2=BS2) glass is one of the few stoichiometric glasses that nucleates internally, homogeneously via thermal treatment. This system has been scarcely assessed in microstructure-property studies. Here we address fracture strength and toughness (KIC) variation as a function of crystallized volume fraction and crystal size, as...

Atomic structure dictates the performance of all materials systems; the characteristic of disordered materials is the significance of spatial and temporal fluctuations on composition-structure-property-performance relationships. Glass has a disordered atomic arrangement, which induces localized distributions in physical properties that are conventi...

Magnetic hyperthermia (MHT) is a therapy that uses the heat generated by a magnetic material for cancer treatment. Magnetite nanoparticles are the most used materials in MHT. However, magnetite has a high Curie temperature (Tc~580 °C), and its use may generate local superheating. To overcome this problem, strontium-doped lanthanum manganite could r...

Mechanical properties of glasses can be significantly increased by inducing surface crystallization of a low coefficient of thermal expansion phase. In this work, we produced surface crystallized lithia-alumina-silica glass-ceramics with different crystallized layer thicknesses and analysed the resulting residual stresses and their effect on mechan...

The state of polymerization in barium silicate glasses (xBaO·(1-x)SiO2, 0.28 ≤ x ≤ 0.45) has been studied by both experiment (Raman, static and MAS ²⁹Si NMR spectroscopy) and molecular dynamics simulations (Vashishta-Rahman and Du-Cormack potentials). No a priori assumptions were made about the number of Qⁿ species, specific mean polymerization nor...

If the entropy extrapolation of supercooled liquids (SCL) suggested by Kauzmann was correct, then they would have the same entropy as their stable crystalline phase at a certain low temperature, below the laboratory glass transition (Tg), known as the Kauzmann temperature (TK). Extrapolating even further, the liquid entropy would be null at a tempe...

Due to the difficulty in measuring the mobility of the “structural units” of supercooled liquids and glasses during crystal nucleation, the effective diffusivity (D) has been frequently estimated via viscosity (Dη) or nucleation time-lags (Dτ). However, it has been recently reported that, below the glass transition temperature (Tg), the experimenta...

Purpose/Aim Glass-ceramics destined for dental prostheses have evolved over the years allowing reaching ceramics materials with high quality, lithium disilicate is one of the most used materials due to its wide range of indications. Appropriate mechanical analyses of dental ceramics require a suitable biaxial flexural strength. The aim of this work...

The concentration profiles of Na and Ca in the diffusion zone around Na4+2xCa4-x[Si6O18], 00 < 𝑥 < 1, solid solution crystals in a pseudo-stoichiometric Na2O·2CaO·3SiO2 glass were characterized by Energy Dispersive Spectroscopy (EDS) and then theoretically described. This is a rare case of precipitation of solid-solution crystals (of different comp...

Introduction: Dentin Hypersensitivity (DH) is known to be a relatively common condition that affects a considerable portion of the population, and manifests itself in the form of acute pain, due to the exposure of dentin and open dentinal tubules, after the removal of enamel or root cement. It has a multifactorial aetiology. Aim: To compare the eff...

Hard and strong transparent glass-ceramics (TGCs) can be used as cooktop plates, telescope mirrors, armor materials, and screens for smartphones and tablets. In this work, transparent glass-ceramics from the MgO–Al2O3–SiO2 (MAS) system were obtained after a refined heat-treatment protocol. The evolution in fracture toughness, KIC (Single Edge Precr...

Crystallization of supercooled liquids and glasses is of gargantuan scientific and industrial importance. However, investigating its early stages is experimentally very challenging because of the nanometric size and very short lifetime of the critical nuclei; therefore, computer simulations can substantially assist in unveiling the nucleation mecha...

Raman and NMR spectroscopies have long been employed in pursuing quantitative relationships between polymerization of silicate glasses and melts. However, varying assumptions and ambiguities have often meant structural models vary significantly depending on the probe used. This study investigates a 40BaO·60SiO2 glass to determine its polymerization...

In this work, we significantly extend our new approach for analyzing nucleation kinetics below the glass transition, Tg, which considers the structural relaxation effect. Using a 5BaO•8SiO2 (B5S8) glass, we showed a significant stepwise change in the nucleation relaxation time, τsr, with temperature in the Tg region, in contrast with the expected m...

The effect of high pressure and/or high temperature on the structure and mechanical properties of pyrope glass (Mg3Al2Si3O12) was investigated. The local structure of the glass was characterized by the total pair distribution functions derived from synchrotron X‐ray diffraction. The short‐range order of the Si–O and Al–O pairs was not affected by d...

Dentin hypersensitivity (DH) is characterized by pain caused by an external stimulus on exposed dentin. Different therapeutic approaches have been proposed to mitigate this problem; however, none of them provide permanent pain relief. In this study, we synthesized and characterized experimental bioactive glasses containing 3.07 mol% SrO or 3.36 mol...

The surface free energy of solids, γ, plays a crucial role in all physical and chemical processes involving material surfaces. For the first time, we obtained γ directly from molecular dynamics simulations using a crystal cleavage method. The approach was successfully realized in a Lennard-Jones system by inserting two movable external walls, each...

This study aimed to evaluate the effect of grinding on some surface properties of two lithium disilicate-based glass-ceramics, one experimental new product denominated LaMaV Press (UFSCar-Brazil) and another commercial known as IPS e-max Press (Ivoclar), in the context of simulated clinical adjustment. Discs (N = 24, 12 mm in diameter) were separat...

A well-designed study of the relationship between crystal nucleation and relaxation in supercooled liquids could clarify some critical issues in condensed matter science. In this article, we dwell on the kinetic spinodal temperature, TKS – where the times of first critical nucleus formation and structural relaxation curves cross over – and the Kauz...

In this article the doping of chromium in a lead metasilicate glass is explored using Raman, UV–Vis, and Cr K-edge XANES spectroscopy. Our results indicate that the Cr ions are predominantly present as CrO4²⁻ complexes, with a minor amounts of Cr(III). The solubility of Cr is limited to ∼1 mol % Cr2O3. This boundary was inferred from the intensity...

Biosilicate® glass-ceramic (BioS) offers an attractive choice for the manufacturing of scaffolds because of their high bioactivity, non-toxicity, bactericidal activity and biodegradability. Despite these positive properties, Biosilicate® scaffolds that have been developed so far show low fracture strength, limiting their clinical application. For t...

The study comparing the bone regenerative capacity in an experimental model of cranial bone defects in rats, into 3 groups: G1: bone defects irradiated with photobiomodulation; G2: Biosilicate + photobiomodulation and G3: Biosilicate and Spongin + photobiomodulation. Histocompatibility and bone responses were performed after 15 and 45 days of impla...

Objectives This study aimed to optimize the crystallization process and the microstructure of a new bioactive glass-ceramic (GC) previously developed by our research group to obtain machinable glass-ceramics. Methods Differential scanning calorimetry (DSC) analyses were conducted to explore the characteristic temperatures and construct a semi-quan...

In this work, we performed a thorough study of crystal nucleation rates in supercooled liquid (SCL) nickel by comparing molecular dynamics (MD) simulation results, theoretical calculations, and experimental data. Our aim was to assess the validity of the most used theoretical framework, the Classical Nucleation Theory (CNT), in describing homogeneo...

Nucleation is a crucial phase transformation process across all materials science. In the context of crystal nucleation, accurate knowledge of the nucleation rate is essential for the design of next-generation glass-ceramic and other composite materials; however, the quantitative prediction of crystal nucleation rate versus temperature remains elus...

Due to their unique optical and electronic functionalities, chalcogenide glasses are materials of choice for numerous microelectronic and photonic devices. However, to extend the range of compositions and applications, profound knowledge about composition-property relationships is necessary. To this end, we collected a large quantity of composition...

Structural relaxation and crystallization are crucial phenomena in physics, chemistry, and materials science. A thorough study of their relationship could clarify some critical open questions. In this article, we focus on thermodynamic and kinetic properties: the Kauzmann temperature, TK (where the excess entropy tends to zero), the kinetic spinoda...

Objectives: To evaluate obliterating capability and biological performance of desensitizing agents. Methods: 50 dentin blocks were distributed according to the desensitizing agent used (n=10): Control (Artificial saliva); Ultra EZ (Ultradent); Desensibilize Nano P (FGM); T5-OH Bioactive Glass (Experimental solution); F18 Bioactive Glass (Experim...

We collected a plethora of new data to test the hypothesis that the failure of the Classical Nucleation Theory (CNT) below the glass transition range is just an experimental artifact. Since reaching the steady‐state nucleation regime takes a significant time for treatments below the glass transition temperature, data collected in this temperature r...