Search Results (331)

Recently, 3D-printed resins have been introduced as materials for definitive indirect restorations. Herein, a comparative assessment of the bond strengths of 3D-printed resins to a resin cement was performed. Methods: four definitive restorative materials were selected, i.e., a Feldspar ceramic (VITA Mark II, VM), a polymer-infiltrated ceramic network (VITA Enamic, VE), a nanohybrid resin composite (Grandio Bloc, GB), and one 3D-printed resin (Crown Permanent, CP). VM and VE were etched and silanized, GB was sandblasted, and CP was glass bead blasted; for one further experimental group, this was followed by sandblasting (CPs). A resin cement (RelyX Unicem) was then used for bonding, and then a notched shear bond strength test (nSBS) was performed. Failure modes were observed and classified as adhesive, cohesive, or mixed, and SEM representative images were taken. Data were statistically analyzed with one-way ANOVA, Tukey, and Chi-square tests. Significant differences were detected in nSBS among materials (p < 0.001). The highest nSBS was found in VM (30.3 ± 1.8 MPa) a, followed by CP^b, GB^bc, CP^bc, and VE^c. Failure modes were significantly different (p < 0.001), and with different prevalent failure modes. The bond strength for 3D-printed permanent resin materials was shown to be lower than that of the felspathic ceramic but comparable to that of the resin block and PICN substrates. Full article

Tissue-engineered scaffolds, particularly composite scaffolds composed of polymers combined with ceramics, bioactive glasses, or nanomaterials, play a vital role in regenerative medicine by providing structural and biological support for tissue repair. As scaffold designs grow increasingly complex, the need for non-invasive imaging modalities capable of monitoring scaffold integration, degradation, and tissue regeneration in real-time has become critical. This review summarizes current non-invasive imaging techniques used to evaluate tissue-engineered constructs, including optical methods such as near-infrared fluorescence imaging (NIR), optical coherence tomography (OCT), and photoacoustic imaging (PAI); magnetic resonance imaging (MRI); X-ray-based approaches like computed tomography (CT); and ultrasound-based modalities. It discusses the unique advantages and limitations of each modality. Finally, the review identifies major challenges—including limited imaging depth, resolution trade-offs, and regulatory hurdles—and proposes future directions to enhance translational readiness and clinical adoption of imaging-guided tissue engineering (TE). Emerging prospects such as multimodal platforms and artificial intelligence (AI) assisted image analysis hold promise for improving precision, scalability, and clinical relevance in scaffold monitoring. Full article

The aim of the present research was to synthesize protective composite layers from biodegradable cellulose and biocompatible, sol–gel-derived silica cryogel. An important task in the present work was to achieve good applicability on distinct (smooth and rough) surfaces of various materials (from metallic to ceramic). The aim was to utilize the composite layers as thermal and electric insulation coating. The investigation put some effort into the enhancement of mechanical strength and the elasticity of the thin layer as well as a reduction in its water solubility. The removal of the alkali content leads successfully to a significant reduction in water solubility (97 wt% → 1–3 wt%). Adhesion properties were measured using a specialized measurement technique developed in our laboratory. Treatments of the substrate surface, such as alkaline or acidic etching (i.e., Na₂CO₃, HF, water glass), mechanical roughening, or the application of a thin alkali-containing primer layer, strongly increase adhesion. SEM analyses revealed the interactions between the matrix and the reinforcement phase and their morphology. Full article

This work investigated the structural response and phase transformation dynamics of silica-bearing cherts subjected to high-temperature processing (up to 1400 °C) and prolonged mechanochemical activation. Through a combination of X-ray diffraction (XRD) with Rietveld refinement, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and transmission electron microscopy (HRTEM), we trace the crystallographic pathways of quartz, moganite, tridymite, and cristobalite under controlled thermal and mechanical stress regimes. The experimental results demonstrated that phase behavior is highly dependent on intrinsic properties such as initial phase composition, impurity presence, and crystallinity. Heating at 1400 °C induced irreversible conversion of quartz, moganite, and tridymite into cristobalite. Samples enriched in cristobalite and tridymite exhibited notable increases in crystallinity, whereas quartz-dominant samples showed either stability or a decline in structural order. Rietveld analyses underscored the critical influence of microstrain and crystallite size on thermal resilience and phase persistence. Thermal profiles revealed by DSC and TGA expose overlapping processes including polymorphic transitions, minor phase dehydration, and redox-driven changes, likely associated with trace components. Mechanochemical processing resulted in partial amorphization and the emergence of phases such as opal and feldspar minerals (microcline, albite, anorthite), interpreted as the product of lattice collapse and subsequent reprecipitation. Heat treatment of chert leads to a progressive rearrangement and recrystallization of its silica phases: quartz collapses around 1000 °C before recovering, tridymite emerges as an intermediate phase, and cristobalite shows the greatest crystallite size growth and least deformation at 1400 °C. These phase changes serve as markers of high-temperature exposure, guiding the identification of heat-altered lithic artefacts, reconstructing geological and diagenetic histories, and allowing engineers to adjust the thermal expansion of ceramic materials. Mechanochemical results provide new insights into the physicochemical evolution of metastable silica systems and offer valuable implications for the design and thermal conditioning of silica-based functional materials used in high-temperature ceramics, glasses, and refractory applications. From a geoarchaeological standpoint, the mechanochemically treated material could simulate natural weathering of prehistoric chert tools, providing insights into diagenetic pathways and lithic degradation processes. Full article

A novel bioactive glass–ceramic was developed using biogenic hydroxyapatite (BHA) synthesized from Rapana venosa (Black Sea) shells and monocalcium phosphate monohydrate [Ca(H₂PO₄)₂·H₂O] via solid-state synthesis. The prepared batches were obtained by combining BHA with SiO₂, B₂O₃, and Na₂O, melted at 1200 °C and melt-quenched in water to form glass–ceramic materials. Dense biogenic hydroxyapatite-based ceramics were successfully sintered at 1200 °C (2 h hold) using a 25 mass % sintering additive composed of 35 mass % B₂O₃, 45 mass % SiO₂, 10 mass % Al₂O₃, and 10 mass % Na₂O. Structural characterization was carried out using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The resulting materials consisted of a well-defined crystalline hydroxyapatite phase [Ca₁₀(PO₄)₆(OH)₂] alongside an amorphous phase. In samples with increased SiO₂ and reduced B₂O₃ content (composition 3), a finely dispersed Na₃Ca₆(PO₄)₅ crystalline phase appeared, with a reduced presence of hydroxyapatite. Bioactivity was assessed in simulated body fluid (SBF) after 10 and 20 days of immersion, confirming the material’s ability to support apatite layer formation. The main structural units SiO₄, PO₄, and BO₃ are interconnected through Si–O–Si, B–O–B, P–O–P, and mixed Si–O–Al linkages, contributing to both structural stability and bioactivity. Full article

Developing resource-efficient technologies for producing ceramic materials with specific properties and performance characteristics is one of the most important tasks in modern materials science. As natural resources face depletion, the use of anthropogenic wastes, including fly ash from coal combustion, for the development of new compositions and the production of ceramics with an improved microstructure is of particular significance. The use of PM₁₀ fly ash microspheres in ceramic production will help to reduce particulate matter emissions. In this study, fine narrow fractions of PM₁₀ microspheres were successfully separated from coal fly ash using aerodynamic and magnetic separation. Glass–ceramic materials with a homogeneous microstructure, an open porosity of 0.4–37%, a compressive strength of 5–159 MPa, and acid resistance of up to 99.9% were obtained using narrow fractions. The materials obtained are promising for application as highly porous ceramics, effective microfiltration membranes, and fine-structured technical ceramics, which can be used in installations operating in aggressive media and/or at high temperatures. The ceramic membranes were characterised by high liquid permeability values up to 1194 L·m⁻²·h⁻¹·bar⁻¹. Filtration tests showed that the retention coefficient for dispersed microsilica particles with d_av = 1.9 μm is 0.99. Full article

Recent archaeological sites dating to the late 19th and early 20th centuries have rarely been studied to date. Among the 500 “glassy” beads excavated from Dohouan (Côte d’Ivoire), elemental analyses reveal that fewer than half contain abnormally high alumina contents, associated with a soda–potash–lime flux (three compositional groups). The remaining beads are typical lead-based glass. The Raman spectra of the alumina-rich beads are quite complex due to their glass–ceramic nature, combining features similar to the vitreous phase of porcelain glaze with the presence of various crystalline phases (quartz, wollastonite, calcium phosphate, calcite). Organic residues are also observed. Colors are primarily produced by transition metal ions, although some specific pigments have also been identified. These characteristics suggest that the alumina-rich beads were manufactured by pressing followed by sintering, as described in patents by Richard Prosser (1840, UK) and Jean Félix Bapterosse (1844, France). A comparison is made with beads from scrap piles at the site of the former Bapterosse factory in Briare, France. This process represents one of the earliest examples of replacing traditional glassmaking with a ceramic process to enhance productivity and reduce costs. Full article

Critical-size bone defects do not heal spontaneously and require external support, making bone regeneration a central challenge in tissue engineering. Polymeric/ceramic composite scaffolds offer a promising approach to mimic the structural and biological properties of bone. In this study, we aimed to evaluate the effect of different doping oxides in bioactive glass (BG) on the performance of polycaprolactone (PCL)-based composite scaffolds for bone tissue engineering applications. Composite scaffolds were fabricated using solvent casting, hot pressing, and salt-leaching techniques, combining PCL with 25 wt% of BG or doped BG containing 4 mol% of tantalum, zinc, magnesium, or niobium oxides, and 1 mol% of copper oxide. The scaffolds were characterized in terms of morphology, mechanical properties, and in vitro biological performance. All scaffolds exhibited a highly porous, interconnected structure. Mechanical compression tests indicated that elastic modulus increased with ceramic content, while doping had no measurable effect. Cytotoxicity assays confirmed biocompatibility across all scaffolds. Among the tested materials, the Zn-doped BG/PCL scaffold uniquely supported cell adhesion and proliferation and significantly enhanced alkaline phosphatase (ALP) activity—an early marker of osteogenic differentiation—alongside the Nb-doped scaffold. These results highlight the Zn-doped BG/PCL composite as a promising candidate for bone regeneration applications. Full article

This study aimed to comparatively evaluate the effects of various surface treatment protocols on the shear bond strength (SBS) between heat-polymerized polymethyl methacrylate (PMMA) and different CAD/CAM framework materials, including cobalt–chromium (Co–Cr) alloys, ceramic particle-reinforced polyetheretherketone (PEEK), and glass fiber-reinforced composite resin (FRC). A total of 135 disc-shaped specimens were prepared from Co–Cr, PEEK, and FRC materials. Surface treatments specific to each material, including airborne-particle abrasion, sulfuric acid etching, laser irradiation, plasma activation, and primer application, were applied. PMMA cylinders were polymerized onto the treated surfaces, and all specimens were subjected to 30,000 thermal cycles. SBS values were measured using a universal testing machine, and the failure modes were classified. The normality of data distribution was assessed using the Kolmogorov–Smirnov test, and the homogeneity of variances was evaluated using Levene’s test. Group comparisons were performed using the Kruskal–Wallis test, and Dunn’s post hoc test with Bonferroni correction was applied in cases where significant differences were detected (α = 0.05). The highest SBS values (~27–28 MPa) were obtained in the Co–Cr group and in the PEEK groups treated with sulfuric acid and primer. In contrast, the PEEK group with additional laser treatment exhibited a lower SBS value. The untreated PEEK group showed significantly lower SBS (~3.9 MPa) compared to all other groups. The Trinia groups demonstrated intermediate SBS values (16.5–17.4 MPa), which exceeded the clinically acceptable threshold of 10 MPa. SEM observations revealed material- and protocol-specific surface responses; plasma-treated specimens maintained topographic integrity, whereas laser-induced surfaces showed localized degradation, particularly following dual-step protocols. Fracture mode analysis indicated that higher SBS values were associated with cohesive or mixed failures. SEM observations suggested that plasma treatment preserved surface morphology more effectively than laser treatment. This study highlights the importance of selecting material-specific surface treatments to optimize bonding between CAD/CAM frameworks and PMMA. Sulfuric acid and primer provided strong adhesion for PEEK, while the addition of laser or plasma offered no further benefit, making such steps potentially unnecessary. Trinia frameworks also showed acceptable performance with conventional treatments. These findings reinforce that simplified conditioning protocols may be clinically sufficient, and indicate that FRC materials like Trinia should be more fully considered for their broader clinical potential in modern CAD/CAM-based prosthetic planning. Full article

The aim of this study was to produce a coating for protective glass glued to touch displays with high antibacterial effectiveness. This paper presents the structural, mechanical, optical, and antibacterial properties of a TiO₂:Ag–Pt coating prepared by dual reactive DC and RF magnetron sputtering. Characterization techniques used include XRD, TEM with EDS, SEM, AFM, nanoindentation for hardness and Young’s modulus, wettability tests, and optical property analysis. The coating exhibited columnar crystals with a width of 30–50 nm. Crystals of anatase, rutile, silver, and platinum with a size of up to 3 nm were identified. The coating deposited on glass had a concentration of 5.0 ± 0.2% at. Ag and 4.4 ± 0.1% at. Pt. The value of the optical band gap energy, corresponding to the direct transition, was 3.36 eV, while Urbach’s energy was in the order of 500 meV. The hydrophilic coating had a roughness RMS = 1.8 ± 0.2 nm, hardness HV = 6.8 ± 0.5 GPa, and Young’s modulus E = 116 ± 8 GPa. A unique combination of the phase composition of the TiO₂:Ag–Pt coating, metallic Ag and Pt nanoparticles in a ceramic matrix of anatase and rutile crystallites resulted a >90% reduction of Staphylococcus aureus bacteria. This antibacterial effect was attributed to the activation of the doped semiconductor under visible light via plasmon resonance of the Ag and Pt nanoparticles, as well as a light-independent antibacterial action due to Ag⁺ ion release. In contrast, commercial antibacterial coatings typically achieve only around 60% bacterial reduction. Full article

Many studies have examined the ability of polymer-based gels or hydrogels to serve various purposes, particularly as absorbents. Several studies have reported that polyvinyl alcohol (PVA), with specific compositions and additives, is an absorbent and a decontamination material usable for heavy metals and radioactive substances. PVA has a high cost and is slowly degradable under anaerobic conditions. This study investigated the potential of natural materials, namely cassava starch, which is an environmentally friendly, non-toxic, and readily available gel-forming polymer that, notably, is inexpensive in Indonesia. The FTIR analysis showed a bond and polymer formation between cassava starch and glycerol. The cassava starch–glycerol–water mixture was applied to media such as glass, aluminum plates, and ceramics contaminated with heavy-metal stable ions which correspond to a radionuclide. The media, stored at room temperature for 24 h, becomes a film. According to the SEM and XRF results, the gel becomes a film that binds and absorbs metals when dried. The SEM results showed the presence of metals corresponding with the sources of contamination, and the XRF results showed that the quantity of metals absorbed was large. The cassava starch gel absorption results indicated the formation of an amorphous compound, as indicated by the XRF results. Based on all the analyses, the cassava starch–glycerol gel has enormous potential. It is almost equivalent to a PVA gel as an absorbent material and heavy-metal decontamination material, when used for radioactive decontamination on the material’s surface. Full article

SiC matrix composites are widely used in high-temperature structural components of aircraft engines and nuclear reactor materials because of their excellent properties such as their high modulus, high strength, corrosion resistance, and high-temperature resistance. However, the bonding of SiCf/SiC composites poses significant challenges in practical engineering applications, primarily due to residual stresses, anisotropy in composite properties, and the demanding conditions required for high-performance joints. This work reviews various bonding technologies for SiC ceramics and SiC matrix composites. These include solid-state diffusion bonding, NITE phase bonding, direct bonding without filling materials, MAX phase bonding, glass ceramic bonding, polymer precursor bonding, metal brazing bonding, and Si-C reaction bonding. Key results, such as the highest bending strength of 439 MPa achieved with Si-C reaction bonding, are compared alongside the microstructural characteristics of different joints. Additionally, critical factors for successful bonding, such as physical mismatch and metallurgical incompatibility, are discussed in detail. Future research directions are proposed, emphasizing the optimization of bonding techniques and evaluation of joint performance in harsh environments. This review provides valuable insights into advancing bonding technologies for SiC composites in aerospace and nuclear applications. Full article

The aim of this study was to investigate the possibility of Ag nanoparticle crystallization in B₂O₃–Bi₂O₃ glass using a heat treatment method and to investigate the possible influence of the obtained nanoparticles on the emission intensity of Eu³⁺ ions. Borate–bismuth glasses with different B₂O₃:Bi₂O₃ molar ratios of 50:50, 60:40 and 70:50 with Ag and Eu³⁺ ions were successfully synthesized. The structure of the glasses was studied using XRD and FTIR methods. The XRD results exhibited a characteristic amorphous halo, confirming the absence of long-range order in the samples. The glass transition temperatures of various compositions, required to select the annealing temperature, were measured using DTA analysis. The strong maximum in the UV–Vis spectrum of the sample with the highest Bi₂O₃ content clearly indicated the presence of Ag nanoparticles in the glass. Moreover, a color change was observed for this sample, from slightly yellow to red. The presence of Ag nanoparticles was further confirmed via TEM and XPS studies. However, with a high content of Ag nanoparticles in the matrix, their positive effect on luminescence intensity was not observed. The obtained results show that B₂O₃–Bi₂O₃ glass and glass ceramics, with Ag nanoparticles and rare-earth (Re) ions, could be considered as a new phosphor for light-emitting diodes (LEDs). Full article

Archaeology is a well-established discipline that sheds light on human history and uncovers the mysteries of materials, their origins, production methods, and areas of use. It provides significant insights into various topics such as the production history of glass and other materials, trade routes, manufacturing processes, degradation mechanisms, regional usages, and coloring com-positions. Glass, an ancient yet contemporary material, can transmit, absorb, and reflect light. Appreciating glass art requires recognizing its rich history, offering artists technical and aesthetic possibilities in modern life and architecture. This study examines the influence of archaeological research and the artistic character of ancient glass on contemporary glass art. Archaeological findings from Turkey and around the world have been reviewed, with a particular focus on the Phrygian Valley, located in and around Eskişehir, an important region for the Phrygian civilization. Artifacts unearthed through excavations and sur-face surveys conducted in the Phrygian Valley, and preserved in the Eskişehir Eti Archaeology Museum, have been analyzed. The museum houses approximately 22.500 artifacts, including sculptures, steles, ceramics, glass vessels, metal objects, jewelry, and coins. Inspired by these artifacts and Phrygian culture, original glass designs have been created using techniques such as stained glass, lampworking, and glass painting. The aim of the study is to interpret Phrygian art and culture through innovative designs. Full article

Background: The main objective of this study was to carry out an online questionnaire in order to assess dentists’ knowledge and perception of dental materials submitted to high temperatures, helping to clarify and raise awareness of possible gaps in the area of forensic dentistry, especially in human identification. Results: Out of a total of 272 respondents, there was a greater influx of responses from countries such as Portugal and Brazil, the majority being female (66.3%), with an average age of 39 years. Most dentists consider complete clinical records to be extremely important. In addition, professionals with less experience provide fewer models in releasing their clinical records. In the case of dental materials, dentists consider composite resin and glass ionomers to be more susceptible to changes in shape and colour, while amalgam is considered the most stable, followed by ceramic and metal-ceramic crowns. On the other hand, dentin is considered more susceptible to colour changes than enamel. Enamel is seen by most professionals as resistant, undergoing few changes in shape at high temperatures. Conclusions: The opinion of the surveyed dentists on this subject is broadly in line with the existing literature. The only observed differences were related to exposure time and enamel resistance, since they assume that enamel is more resistant, and dentin is more vulnerable. Full article