Search Results (2,033)

Background/Objectives: This study aimed to automatically classify Zirconia-based fixed restorations and porcelain-fused-to-metal (PFM) restorations on panoramic radiographs using an artificial intelligence-based model. Unlike previous studies that mainly focused on classifying types of restorations (e.g., crowns, fillings, implants), this research concentrated on material-based differentiation, aiming to provide a more specific contribution to clinical decision support systems. Method: Panoramic radiographs obtained from the archive of Süleyman Demirel University Faculty of Dentistry were included in this study. Radiographs with poor image quality or insufficient visibility of the restoration area were excluded. A total of 593 cropped region-of-interest (ROI) images, labeled by expert prosthodontists using ImageJ software (version 1.54r; National Institutes of Health, Bethesda, MD, USA), were included in the analysis. In order to reduce class imbalance, data augmentation was applied only for images in the Zirconia-based fixed restorations class. By using various image processing techniques such as rotation, reflection and brightness change, the number of samples in the zirconia-based restorations class was increased and thus a balanced dataset was obtained with a close number of samples for both classes. For model training, the pre-trained VGG16 architecture was used with a transfer learning method, and the final layers were retrained and fine-tuned. The model was configured specifically for binary classification. The entire dataset was randomly split into 70% training, 20% validation, and 10% testing. Model performance was evaluated using accuracy, F1-score, sensitivity, and specificity. Results: The model correctly classified 90 out of 94 images in the test dataset, achieving an overall accuracy rate of 96%. For both classes, the precision, recall, and F1-score values were measured in the range of 95% to 96%. Additionally, the Area Under the Curve (AUC) of the ROC curve was calculated as 0.994, and the Average Precision (AP) score was determined to be 0.995. According to the confusion matrix results, only 4 images were misclassified, consisting of 2 false positives and 2 false negatives. Conclusions: The deep learning model demonstrated high accuracy in differentiating zirconia and metal-supported porcelain restorations on panoramic radiographs, suggesting that material-based AI classification may support clinical decision-making in restorative dentistry. Full article

Modern bioimplants increasingly depend on surface-engineered functionality to elicit adaptive biological responses. One promising strategy involves the electrodeposition of bioresponsive elements such as magnesium (Mg), which plays a critical role in osseointegration. In this study, we present a novel approach for modifying anodized zirconia nanotubes (ZrNTs) via Mg decoration using electrochemical deposition. A controlled pulsed cathodic linear sweep protocol was employed to control Mg deposition behaviour, enabling reduced clustering and improved spatial distribution. Notably, ultraviolet (UV) irradiation was found to influence Mg adsorption dynamics, revealing a distinct pattern of interaction. Comprehensive surface characterization was conducted to assess nanotube morphology, Mg adherence, and distribution. These modified surfaces were subsequently evaluated for their potential in further functionalization, targeting surface chemistries conducive to biomaterial viability. The biomineralization capacity of Mg-decorated ZrNTs was systematically investigated using electrochemical impedance spectroscopy (EIS) and Tafel analysis, demonstrating enhanced apatite formation and improved corrosion resistance. This work establishes Mg decoration of ZrNTs as a viable route for developing bioactive, corrosion-resistant implant surfaces. Full article

High-temperature particulate matter (PM) filtration remains a fundamental challenge, because most fiber filters not only face the challenge of high temperatures but also suffer from an inherent trade-off between capture efficiency, pressure drop, and service life. This paper reports a hierarchical layered zirconia (ZrO₂) ceramic fiber aerogel featuring a continuous multiscale gradient. The aerogel was prepared by gradient air-blown spinning, and the resulting structure has directional order, with the fiber diameter gradually decreasing from upstream to downstream, thus forming a pore size gradient and achieving hierarchical particle interception across multiple scales. This rational design simultaneously suppresses surface clogging and reduces flow resistance, resolving the longstanding trade-off between efficiency and permeability. Consequently, this aerogel achieves an ultra-high filtration efficiency of 99.96%, a low pressure drop of 156 Pa, and a high dust-holding capacity of 101 g m⁻². The material also exhibits outstanding mechanical toughness (80% compressive strain elasticity and 25.75% tensile fracture strain) and thermal stability up to 1000 °C. Moreover, it maintains over 99.95% filtration efficiency at high temperatures and can be fully regenerated through 800 °C heat treatment. This work establishes a structure-based design paradigm for high-temperature filtration media and provides a scalable pathway for next-generation industrial flue gas purification. Full article

In this study, 1.5Y-2.2Ca-TZP materials were obtained by hot pressing of a mixed and milled blend of 3Y-TZP and 4.4Ca-TZP powders. The materials were sintered at temperatures between 1250 °C and 1400 °C and characterized with respect to mechanical properties, microstructure, phase composition and stability against low-temperature degradation. In the tested range, the bending strength of the TZP decreases with increasing sintering temperature from 1300 MPa to 1050 MPa while the toughness shows a rising trend from 5 MPa√m to 8 MPa√m. The grain size distribution in the microstructure is broad with average grain sizes increasing from 150 nm to 250 nm with rising sintering temperature. LTD tests revealed high aging resistance for TZP sintered at 1300 °C. The Y-Ca-co-stabilized TZP equilibrates the properties of Ca-TZP and Y-TZP. Full article

This study investigates how torch standoff distance influences the microstructure, surface topography, and progressive-load scratch response of air plasma-sprayed 8YSZ and rare-earth co-doped GdYbYSZ thermal barrier coatings on an St-52 grade carbon steel substrate. Three nozzle-to-substrate spraying distances were examined: 80, 100, and 120 mm. X-ray diffraction revealed that the 8YSZ coatings possessed a predominantly tetragonal (t′) structure, with minor monoclinic fractions detected in the coatings obtained with the 80 mm and 100 mm distance parameters. The GdYbYSZ coatings, in contrast, exhibited a single-phase cubic defect-fluorite structure; their diffraction peaks appeared at lower 2θ angles relative to undoped cubic ZrO₂, consistent with lattice expansion caused by the substitution of Zr⁴⁺ by the larger Gd³⁺ and Yb³⁺ cations. Surface topography was quantified by non-contact laser profilometry, providing areal (Sa) and profile (Ra) roughness parameters for the as-sprayed condition as well as three-dimensional scratch-damage morphology after testing. Progressive-load scratch tests were performed using a Rockwell diamond indenter over a 2 mm track with the normal load ramped from 0.03 N to 30 N. Penetration depth, residual depth, tangential force, and acoustic emission were recorded continuously to identify critical damage transitions. Across all spraying distances, 8YSZ exhibited systematically shallower scratch grooves than GdYbYSZ; end-of-track maximum groove depths remained below 37 µm for 8YSZ, whereas GdYbYSZ reached up to 72 µm under identical loading conditions. The novelty of this study lies in combining torch standoff distance as a processing variable with multi-channel progressive-load scratch diagnostics, including in situ acoustic emission, depth profiling, and friction monitoring, to comparatively assess the scratch wear performance of 8YSZ and rare-earth co-doped zirconia TBCs for the first time. Full article

This study compared three internal surface treatments of zirconia copings—silane alone (control), airborne-particle abrasion followed by silane, and high-temperature hydrofluoric acid etching followed by silane—regarding initial pull-out retention strength, retention after thermocycling, failure mode assessed by scanning electron microscopy (SEM), and surface wettability. Sixty-three monolithic zirconia copings were allocated to three groups (n = 21) according to surface treatment and cemented to titanium bases with a self-adhesive resin cement. Initial pull-out tests were performed. A subset (n = 10 per group) underwent thermocycling followed by repeat testing. Failure modes were analysed by SEM, and wettability was measured using the sessile drop method. Surface roughness and crystalline phase were additionally characterized by white-light interferometry and X-ray diffraction (XRD), respectively. High-temperature acid etching produced significantly higher initial pull-out forces than airborne-particle abrasion and silane alone, with mean values 125% higher than control and 42.6% higher than airborne-particle abrasion. After thermocycling, acid-etched specimens maintained the highest retention, whereas airborne-particle abrasion showed critical loss. SEM revealed predominantly cement remnants on zirconia in the acid-etched group, indicating a stronger zirconia–cement interface. Acid etching also yielded significantly lower contact angles, reflecting improved wettability. High-temperature hydrofluoric acid etching followed by silanization provided superior and more stable retention, more favourable failure modes, and improved wettability. Full article

Low-density cancellous bone results in reduced trabecular support and may increase crestal cortical strain around implants. Osseodensification (OD) compacts trabecular bone and may create a peri-osteotomy densified zone, but its strain-level effects in osteoporotic-like bone are unclear. This study evaluated whether an OD-inspired peri-implant densified trabecular zone reduces crestal cortical strain compared with conventional drilling (CD) in an osteoporotic-like model. A three-dimensional finite element model of a mandibular posterior segment with a 2.0-mm cortical shell and D4 cancellous core was constructed with a 4.3 × 11.4-mm titanium implant and a cemented monolithic zirconia crown. CD used a 4.0-mm osteotomy in D4 bone. The OD model used the same osteotomy plus a concentric peri-implant densified shell with radial density gradation from D1 to D3. The implant–bone interface was defined as bonded. Static 100 N axial and 45° oblique loads were applied. Outcomes were ε_eq, ε_max, and ε_min, summarized as mean top-10 nodal values. OD reduced crestal cortical strains under both loads. Under axial loading, ε_eq, ε_max, and |ε_min| decreased by 17.7%, 19.0%, and 24.1%, respectively. Under oblique loading, the corresponding reductions were 9.8%, 8.0%, and 8.9%. Oblique loading produced higher cortical strains than axial loading in both models. OD-inspired peri-implant densification reduced crestal cortical strain in this osteoporotic-like model, whereas oblique loading remained the main driver of elevated strain. These findings support occlusal/prosthetic strategies that minimize oblique forces and warrant experimental and clinical validation. Full article

This article provides an overview of modern surface engineering technologies used in the manufacturing of dental components, with a particular focus on dental implants, abutments, and crowns. The main objective of the study is to critically evaluate selected surface treatment and coating deposition methods applied to materials such as titanium, zirconia, hydroxyapatite, and NiTi alloys, and to discuss their relevance in terms of functionality, biocompatibility, and sustainability. The analyzed technologies include anodic oxidation, alkaline oxidation, electrochemical coating deposition, and other surface modification approaches aimed at improving osseointegration, corrosion resistance, and antibacterial performance. This literature review was conducted as a narrative review supported by the PRISMA framework, using the Scopus and Web of Science databases for the period 2016–2025. The findings highlight the increasing importance of surface treatments as a key factor influencing the durability and clinical success of dental implant systems. At the same time, the results indicate that the environmental aspects and energy efficiency of manufacturing and surface treatment processes are still addressed only marginally or qualitatively in the available literature. The identified research gaps include the lack of quantitative data on the energy demand of individual technologies, the absence of standardized indicators for environmental impact assessment, and the limited number of comparative studies evaluating different surface modification techniques in the context of dental manufacturing. Overall, the results emphasize the need for a more systematic sustainability assessment of surface engineering as an integral part of modern dental manufacturing practice. Full article

This work presents the synthesis, characterization, and application of zirconium oxide (ZrO₂)-based catalysts, modified with macro (silica nanospheres, NSP-SiO₂) and mesopore templates (Pluronic 123), impregnated with tungstophosphoric acid (TPA), in the catalytic pyrolysis of tomato agro-industrial residues. The NSP-SiO₂ (SXX) and P123 (PYY) amount mainly influences the ZrO₂SXXPYY-specific surface area (S_BET) and average pore diameter (D_p). ³¹P MAS NMR and FT-IR characterization results show that TPA (H₃PW₁₂O₄₀) was partially transformed into [P₂W₂₁O₇₁]⁶⁻ and [PW₁₁O₃₉]⁷⁻ during the synthesis steps. The acidic properties of ZrO₂SXXPYY samples containing 25 and 50 wt% of TPA (ZrO₂SXXPYYT25 and ZrO₂SXXPYYT50, respectively) are dependent on both the TPA content and the support nature. Bio-oil composition and product selectivity were strongly influenced by the textural and acid-based properties of the catalysts. Notably, non-catalytic pyrolysis favored pathways leading to C2 compounds, with a high content of acetic acid and hydroxyacetone. In contrast, the use of catalysts promoted the formation of higher molecular weight oxygenated compounds (C5–C6), specifically furans, aldehydes, and ketones. Full article

Achieving natural esthetics has become essential for successful dental restorations and supports the use of modern non-metal materials. However, complexity in esthetic features of natural teeth, determined by both inherent color factors and hierarchical and gradient microstructures, makes recording, determination, and reproduction difficult. This often leads to misunderstanding during manufacturing and dissatisfaction with the final outcome, even when using advanced digital tools. The aim of this study was to investigate a new, easy-to-handle digital tool for determining the color of restorative materials. An industrial-level handheld color identifier, the NCS Colourpin SE, together with the corresponding NCS color system, was tested on three materials: dental resin nanocomposite, self-glazed zirconia (SGZ), and Decore zirconia pellets. The repeatability and impacts of geometrical contributions such as surface roughness and thickness on different colors were measured. The Colourpin SE offered promising repeatability. Decore zirconia showed more than 90% repeatability for most of the colors, independent of thickness. The NCS scanner showed slightly better repeatability than earlier in clinical trials with an intraoral scanner. The shades A3.5 and A3 had lower repeatability, varying from 50 to 90%. It identified effects of material thickness and surface roughness, where the thicker samples were identified with higher blackness levels, and surface roughness seemed to be coupled with a lower blackness level in color identification codes. Small but consistent differences between materials were detected, suggesting that material and manufacturing methods affect the final shade. The NCS Colourpin SE shows potential to be developed into an affordable and easy-to-handle scanner for the identification of a patient’s tooth color, enabling synchronization with digital workflows and improving the match between restoration and the patient’s natural teeth. Nevertheless, further research and development in customized applications for color identification in esthetic dentistry is still required through multidisciplinary collaboration. Full article

This study applies grey theory alongside fuzzy models based on Taguchi design experiments to optimise the performance of coatings for multiple responses, which enhances the quality of plasma-sprayed ceramic coatings. An L18 orthogonal array experiment with eight control factors was conducted, and the impact of the control parameters on the surface properties of the coatings was critically evaluated. In addition, an analysis of variance was conducted, and the surface structure of the coatings was examined using SEM. The multi-response characteristics of surface roughness, porosity, hardness, coating thickness and wear depth values during the spraying of ceramic coatings were studied comparatively through optimisation. In addition, a confirmation experiment was conducted. The experimental results show that surface roughness was reduced by 15.96%, porosity by 65.35%, hardness by 34.60%, wear depth by 34.04%, and coating thickness by 32.01% through optimal factors by plasma spraying coatings. Overall, a 48.94% improvement in multi-properties was observed when compared to the initial settings. Based on the above results, this study employed Taguchi methods to optimize the modeling of plasma spraying using grey-based fuzzy theory, thereby significantly enhancing the multi-response quality of plasma-sprayed coatings. The expected outcomes in terms of coating surface properties have also been achieved by these results. Full article

The colour matching of ceramic restorations is sensitive to ceramic thickness, ceramic optical properties, the tooth region, the tooth/substrate basis colour, and the shade of the bonding agent. This in vitro study evaluates the influence of substrate darkening, resin cement shade and zirconia thickness on the final colour of monolithic Prettau^®2 zirconia restorations. An in vitro factorial design was used combining four resin substrates simulating increasing darkening (ND6–ND9), three shades of dual-cure resin cement (universal, transparent, white opaque) and three zirconia thicknesses (0.5, 1.0, 1.5 mm) of Prettau^®2 zirconia. Standardized photographs were taken under controlled conditions, and CIELAB coordinates (L*, a*, b*) were obtained in Adobe Photoshop. Colour differences relative to the Prettau^®2 A1 shade tab were calculated as ΔL*, Δa*, Δb* and ΔE*. An additive linear model on ΔE* and a main-effect MANOVA on ΔL*, Δa* and Δb* were fitted to assess the impact of each factor. The mean ΔE* was 6.67 ± 2.66, and all but two specimens showed a clinically perceptible colour difference (ΔE* > 2.7) from the A1 shade tab. Substrate shade accounted for 38.4% of the explained variance in ΔE*, cement for 27.6% and zirconia thickness for 6.7%. MANOVA confirmed significant multivariate effects of substrate and cement, but not of zirconia thickness. Translucent monolithic zirconia showed limited ability to reproduce the A1 reference shade over darkened substrates. Substrate shade was the main determinant of colour mismatch, followed by resin cement, whereas zirconia thickness within 0.5–1.5 mm played a minor role. White opaque cement reduced ΔE* and brought the final shade closer to A1, but residual mismatches often remained clinically relevant. These findings highlight the need to control and, when possible, modify the underlying substrate and to select high-opacity cements when shade matching is critical. Full article

To produce strong and wear-resistant tools for the rock drilling industry, the most commonly used metal matrix composites contain the reinforcing phase of cemented carbide. There are numerous research reports on attempts to improve the performance of WC-Co composites. The paper is a continuation of previously reported research on the SPS-processed WC–6 wt.%Co metal matrix composites with yttria-stabilized zirconia (YSZ) addition in amounts of 4 wt.% and 10 wt.%. The sintered specimens were polished and underwent the microindentation tests with a Vickers shape diamond tip. The following parameters were measured: stiffness S, the Poisson number ν, indentation creep C_IT, relaxation R_IT, indentation hardness H_IT, indentation Vickers hardness HV_IT, Martens hardness HM, reduced modulus E*, and indentation elastic modulus E_IT. The tests revealed hardness values of 16.2–17.0 GPa and indentation elastic moduli in the range of 607–670 GPa. Moreover, respective plastic and elastic parts of the indentation work W_plast and W_elast were determined. It was found that YSZ addition slightly reduced hardness and modulus, but all the three wear parameters, H/E, H³/E², and 1/(E²H), increased after addition of zirconia. Specifically, for 10 wt.% ZrO₂ H/E increased by 5%, H³/E² by 7%, while 1/(E²H) by 27% compared to 94WC–6Co composition. Full article

Background: The microtensile bond strength (μTBS) test is the gold standard for evaluating adhesive performance in restorative dentistry. However, the conventional non-trimming technique—referred to in this study as the monoblock sectioning technique (MST)—is difficult to apply to hard and brittle CAD/CAM materials such as zirconia and ceramics, thereby limiting test reproducibility. This study compared a newly developed defined-area bonding (DAB) method with MST to determine whether DAB could serve as a reliable specimen preparation technique for μTBS testing. Methods: CAD/CAM resin blocks and resin core materials were bonded using either ESTECEM II or Panavia V5. MST specimens were obtained by bonding the blocks first and subsequently sectioning them into individual beams. In contrast, DAB specimens were produced by pre-shaping the sticks and bonding them within a defined 1 mm² area. μTBS, failure modes, and fracture/interface morphology (SEM) were evaluated. Results: MST produced significantly higher μTBS values than DAB (p < 0.001), with central MST beams showing the highest bond strengths. DAB values were statistically equivalent to MST peripheral values for both cements. More than 80% of failures were cohesive within resin cement across all groups. SEM revealed uniform cement layer thickness (50–60 μm) and similar peripheral-like fracture patterns in DAB specimens. Conclusions: Although MST yielded higher μTBS overall, the DAB method produced bond strengths equivalent to the MST peripheral region and demonstrated consistent fracture characteristics. Because DAB requires minimal cutting, it offers a promising, reproducible approach for μTBS testing of high-hardness materials that are otherwise difficult to section. Full article

This paper investigates a ceramic material based on ferrite-doped zirconia intended for use as a solar absorber in systems designed for the conversion of solar energy into thermal energy. The experimental study details the synthesis procedure of the ferrite-doped zirconia ceramic and its structural, morphological, optical, and magnetic characterization using X-Ray diffraction (XRD), scanning electron microscopy (SEM), UV–Vis spectroscopy, electron paramagnetic resonance (EPR), and optical band gap energy determination. XRD analysis confirms the presence of the crystalline ferrite phase, which is responsible for the enhanced solar absorption properties. UV–Vis investigations reveal intense absorption bands across the ultraviolet, visible, and near-infrared regions, indicating high solar radiation absorptivity. These properties recommend the investigated ceramic as a promising solar receiver material for solar thermal power plants comparable to conventional materials such as carbides and nitrides. Full article