Zirconia Materials Research Articles

Zirconia in fixed prosthodontics: a review ofthe literature.

The purpose of this narrative review is to organize information and knowledge about the properties of the clinical evidence of zirconia-applied dental restorations and to provide relevant information to establish application methods to obtain long-term clinical prognosis of zirconia-applied dental prostheses. From PubMed and manual searches, found "zirconia," "crown," "survival," and "success" keywords were searched. Case reports, case series, reviews, abstracts, in vitro studies, and observational studies were excluded. Additionally, implant superstructures not supported by the periodontal ligament and partially covered crowns were excluded. A total of 42 studies were identified. According to the studies in this review, the most common complication of porcelain-layered zirconia restorations is porcelain fracture, but the long-term prognosis is stable. However, complications of monolithic zirconia restorations include crown fractures and fractures of the abutment tooth and root, and long-term clinical evidence is not available yet. Additionally, bruxism can be a complication factor with both types of restorations, so it is important to carefully examine the oral habits, including bruxism, before treatment. Therefore, the success of zirconia-based restorations in clinical practice requires a careful approach in addition to accurate knowledge of the zirconia material and identification of applicable cases.

From biomass to power: High-performance reactor design for coking-resistant operation

Biomass gasification coupled with solid oxide fuel cell (SOFC) technology utilizes the gas generated from biomass gasification directly as fuel for SOFC, thereby realizing power generation from solid waste. This technology combines the carbon–neutral feature of biomass with the high efficiency and low emissions of SOFC, making it a promising route for clean energy generation. However, biomass gasification syngas possesses a complex composition, including a high concentration of inert gases, which imposes higher requirements on SOFC. This study developed a multi-channel, hierarchical structural design based on the commercial NiO-yttria-stabilized zirconia (YSZ) material system, realizing high-performance power generation using biomass gasification syngas. The results showed that the combination of a unique structural design and an enhanced interface electrochemical reaction effectively mitigates the influence from inert composition dilution. When operating in gasification syngas with nearly 60 % inert components, the power density can reach 2.07 W·cm−2 (750 °C). In addition, due to the spatial separation of the inert support region and the electrochemically active region, the effect of controlling the position of carbon deposits was achieved, demonstrating 100 h stable operation with dry biomass gasification syngas. Hence, the combination of micro-tubular SOFC with distinctive structural regulation and biomass gasification exhibits promising prospects for further development.

Zirconium hydroxide-activated carbon hybrid material for chemical warfare agents detoxification: Implication of water and temperature

In light of the recent threat from chemical warfare agents (CWAs), the scientific community has focused extensively on developing effective and safe decontamination methodology for CWAs based on environmentally benign technology and the avoidance of corrosive and toxic chemicals. Herein, we report the decomposition of CWAs sarin and sulphur mustard on the hybrid material Zirconium hydroxide-granular activated carbon i.e. Zr(OH)4@GAC which is synthesized by utilizing the reactive zirconium hydroxide and high surface area carbon. In-situ zirconium hydroxide was generated in the pores of GAC by varying the precursor concentration i.e. zirconium oxychloride followed by hydrolysis. The morphology, structural, and textural properties of the reactive hybrid material Zr(OH)4@GAC were examined using several analytical techniques including powder x-ray diffraction, TGA, FT-IR, BET, SEM, EDX, and TEM. Furthermore, the degradation capability of Zr(OH)4@GAC was evaluated in the hydrolytic abatement of CWAs sarin and sulphur mustard. Under pristine laboratory conditions, the effectiveness of reactive hybrid material Zr(OH)4@GAC has been attributed due to a combination of defects and diverse surface hydroxyl species of Zr(OH)4, as well as a high surface area carbon matrix. The impact of water content and temperature on CWAs degradation was also investigated by altering the water percentage from 2 to 8 % and the temperature 25 °C to 45 °C. The GC–MS/GC technique was used to observe the kinetics of in-situ degradation of CWAs over Zr(OH)4@GAC The results indicated that the degradation process follows a first-order reaction kinetics. It is observed that higher water content along with elevated temperature enhance CWA decomposition on Zr(OH)4@GAC; conversely, at lower temperature, it slowed down the degradation of CWAs. This significant enhancement in the decontamination capability of hybrid materials Zr(OH)4@GAC towards CWAs was attributed to the synergistic effects of GAC (adsorption capacity) coupled with the reactive functional group of Zr(OH)4.This strategy will pave the way for the development of self-detoxifying adsorbent material for environmental and defence purposes.

Recovery of waste anode materials in solid oxide fuel cells

This study focuses on the recovery and recycling of production wastes from solid oxide cell (SOC) anode support manufacturing, specifically targeting the state-of-the-art NiO-YSZ (yttria stabilized zirconia) materials. A practical recovery strategy involving a burn-out process to remove additives is developed, followed by milling to manage grain growth and achieve desirable powder properties. The various reclaimed powders obtained after milling at different conditions are subsequently used to fabricate anode support microtubes through extrusion and tape casting coupled with isostatic pressing. Microtubular cells are also constructed on these supports. Comparative analyses of the mechanical and electrochemical performance, along with microstructural investigations, are conducted on supports and cells fabricated from both recovered and commercial powders. The findings indicate that anode supports fabricated from powders recovered through the suggested method exhibit flexural strengths and electrochemical performances comparable to those fabricated from commercial powders, thereby validating the effectiveness of the proposed recovery strategy.

Digital Workflow for Rehabilitation of Severely Discolored Teeth Due to Red Staining from Endodontic Material.

The aim of this short communication is to present a technique to rehabilitate severely discolored teeth with computer-aided designed and computer-aided manufactured (CAD-CAM) zirconia crowns. After confirming the absence of periapical lesions and sufficient crown structure, any caries or fractured restorations can be removed and replaced by an interim composite restoration. A shoulder subgingival preparation is performed and scanned with an intraoral scanner to design a CAD-CAM zirconia crown using a monolithic zirconia material. This crown is highly polished using a specific polishing kit, but not glazed. This technique is suggested to be useful in cases of dark discolored teeth due to staining endodontic materials such as resorcinol-formaldehyde resin.

Effect of the Intaglio Surface Treatment and Thickness of Different Types of Yttria-Stabilized Tetragonal Zirconia Polycrystalline Materials on the Flexural Strength: In-Vitro Study.

Surface treatment of the intaglio surface of zirconia is important for bonding. However, it could affect the strength of the materials. The purpose of this study is to compare the effect of laser, etching, and air abrasion surface treatment methods to a control group on the flexural strength of three zirconia materials with two different thicknesses. (1) Methods: A total of 120 disks were divided into three groups according to the type of zirconia and the ceramic thickness. Then, according to the surface treatment method, the groups were divided into four subdivisions. The change in the microstructure of the ceramic material was investigated through Scanning Electron Microscope (EVO LS10, Carl Zeiss SMT Ltd. Oberkochen, Germany). Phase identification was performed using an X-ray diffraction device (XRD; Ultimate IV X-ray Diffractometer, Rigaku Inc., Tokyo, Japan). The flexural strength was assessed with a biaxial flexural strength test in a universal testing machine. Data were analyzed using SPSS Software (SPSS version 26.0.Armonk, NY: IBM Corp). A three-way ANOVA and a post hoc Dunnett T3 test were employed to evaluate the effect of the yttria concentration, thickness, and surface treatment on the flexural strength of zirconia (α = 0.05). (2) Results: At 0.8 mm thickness, air abrasion significantly increased the flexural strength of 3Y-TZP (1130.6 ± 171.3 MPa) and 4Y-TZP (872 ± 108.6 MPa). However, air abrasion significantly decreased the flexural strength of 5Y-TZP materials (373 ± 46.8 MPa). Laser irradiation significantly decreased the flexural strength of 5Y-TZP (347 ± 50.3 MPa), while etching significantly decreased the flexural strength of both 3Y-TZP (530 ± 48.8) and 4Y-TZP (457.1 ± 57.3). When the thickness increased to 1 mm, air abrasion continued to significantly decrease the flexural strength of 5Y-TZP materials. (3) Conclusions: There was a negative effect of surface treatment on the flexural strength at 0.8 mm thickness rather than at 1 mm thickness. Air abrasion enhances the flexural strength of 3Y-TZP and 4Y-TZP materials but significantly reduces the flexural strength of 5Y-TZP materials. Zircos-E etching and Er:YAG surface treatment methods did not significantly reduce the flexural strength of 5Y-TZP materials at 1 mm thickness and can be recommended as an alternative surface treatment for 5Y-TZP materials.

Human gingival fibroblast response on zirconia and titanium implant abutment: A systematic review.

The peri-implant region, where restoration interfaces with mucosal tissue, plays an essential role in overall implant success and is just as important as osseointegration. The implant abutment materials are in intimate contact with human gingival fibroblasts (HGFs). This study compares the proliferation of HGFs between zirconia and titanium abutments used in dental implants. An electronic search was performed using PubMed, EMBASE, and Web of Science databases. English articles based on in vitro studies testing HGFs proliferation on zirconia and titanium implant abutment materials were included. A quality assessment of the selected study was performed using the web-based Science in Risk Assessment and Policy (SciRAP) tool. The HGFs proliferation and cellular morphology tests on zirconia and titanium materials from the included studies were summarized, exploring the role of material surface characteristics. The electronic search yielded 401 studies, of which 17 were selected for inclusion. Zirconia exhibited comparable or superior efficacy in promoting the proliferation of HGFs compared to titanium. Observations on cellular morphology showed similar outcomes for both materials. Establishing a definitive relationship between contact angle, surface roughness, and their influence on cellular response remains challenging due to the varied methodological approaches in the reviewed studies. Based on the findings of this systematic review, zirconia shows comparable reliability to titanium as an abutment material for HGFs proliferation, with comparable or superior HGFs proliferative outcomes.

Investigating the Impact of Various Abutment Materials on Peri-Implant Tissue Health at Tripoli-Libya

This research investigates the impact of different abutment materials, including titanium, zirconia, and hybrid materials, on peri-implant tissue health in dental implantology. A prospective cohort study design was employed, involving 150 participants who received single or multiple dental implants from Banzi & Bianco s.r.l. (B&B) a dental implant company based in Italy. Clinical parameters, such as peri-implant probing depth, bleeding on probing, and radiographic analysis, were measured at baseline and at 3-, 6-, and 12-months post-abutment placement. Statistical analyses, including ANOVA and regression, were conducted to identify significant associations between abutment materials and peri-implant tissue health parameters. The results revealed nuanced relationships among the abutment materials and their impact on peri-implant tissue health. Interestingly, the hybrid material group exhibited more favorable outcomes in maintaining optimal tissue health compared to the titanium and zirconia groups. This finding suggests that the choice of abutment material can significantly influence the long-term health of peri-implant tissues. This study contributes valuable insights for clinicians in selecting abutment materials for dental implant restorations, highlighting the importance of considering hybrid materials as a potential option for better clinical outcomes (p< 0.001).

Physical and microstructural properties of YSZ + Cr2O3 thermal barrier coatings developed using HVOF technique

A composite coating material of Yttria-Stabilized Zirconia (YSZ) and Chromium Oxide (Cr2O3) was developed on the surface of Al-6061 substrates. The coating consisting of equal measures of the composite material of YSZ and Cr2O3 was successfully obtained using the High-Velocity Oxy Fuel (HVOF) technique. The surface roughness and coating thickness of the composite coatings are evaluated. The surface roughness (Ra) was evaluated showing an average of 6.0848 µm using the Surface Roughness Tester (SRT). The coating thickness was evaluated showing an average of 220.8 µm using the Coating Thickness Tester (CTT). The surface roughness and the coating thickness obtained are comparable to typical physical properties of Thermal Barrier Coatings (TBC’s). The microstructural evaluation of the coated specimens was performed through the Scanning Electron Microscope (SEM), showing the clear unification of materials The determination of the elemental composition of surface coatings was performed through the EDAX tests, which clearly established the elements in the coatings. This article is indicative of the achievement of TBC’s consisting of composite materials though HVOF technique as an alternative to TBC’s obtained through surface coats and bond coats.

Evaluation of the tooth wear against different zirconia materials

Evaluation of the tooth wear against different zirconia materials

Impact of speed sintering on the mechanical and optical properties of multilayered zirconia

Speed sintering techniques have been introduced to shorten the sintering time of zirconia ceramics, yet their impact on multilayered zirconia properties remains understudied. The purpose of this in vitro study was to assess the effect of speed sintering on the optical properties and the mechanical flexural strength of multilayered zirconia materials. A total of 360 disks (Ø14 ±2 mm ×1.2 ±0.02 mm) were fabricated by following the International Organization for Standardization (ISO) 6872:2015 standard using 2 types of Vita A2 shade multilayered zirconia materials: IPS e.max ZirCAD Prime (ZP) and IPS e.max ZirCAD Prime Esthetic (ZPE). Each material comprised translucent (Tr), gradient l (Gr), and dentin (De) layers, with 60 disks per layer. Half were sintered using a standard sintering protocol and half using a speed sintering protocol. Biaxial flexural strength was accessed using a universal testing machine equipped with the Blue Hill Universal software program by following the ISO 6872:2015 standard, with 20 disks per subgroup. The spectrophotometric analysis of optical properties (contrast ratio [CR], translucency parameter [TP], and total transmittance [Tt%]) was performed using a dual-beam spectrophotometer (Ultrascan VIS) in accordance with the ISO 7491:2000 standard, with 10 disks per subgroup. The comparison of the optical properties and the mechanical flexural strength between the speed and standard protocol was analyzed using an unpaired t test (α=.05). Speed sintering reduced biaxial flexural strength in all ZP layers (P<.05) and in ZPE-Gr (P<.05). A statistically significant difference in the CR was observed in the ZP-Tr, ZP-Gr, and ZPE-Gr layers (P<.05). The TP of the ZP-Gr, ZP-De, and ZPE-Gr layers was significantly lower when using the speed sintering protocol. Tt% was significantly lower with speed sintering for both materials (P<.05). Speed sintering statistically changed both the optical (CR, TP, Tt%) and mechanical (flexural strength) properties of multilayered zirconia materials, but the differences may not be clinically relevant.

Impact of Sintering Protocol of Hydrothermally-aged High-translucent Zirconia Materials

Impact of Sintering Protocol of Hydrothermally-aged High-translucent Zirconia Materials

Effect of Cementation and Thermomechanical Aging on the Marginal Adaptation of Veneered and Monolithic Zirconia

Objective: The objective of current study was to evaluate the marginal discrepancy of a manually veneered CAD/CAM zirconia and two different monolithic CAD/CAM zirconia all-ceramic crowns; before and after cementation; before and after artificial aging by using a chewing simulator. Methods: A total of 36 specimens were divided into 3 groups (n=12) and crown restorations were fabricated by using 3 different type of zirconia materials for each group: Group MZ1: monolithic zirconia crowns (GC initial), Group MZ2: monolithic zirconia crowns (InCoris TZI), Group BZ: bilayered zirconia crowns; zirconia core (InCoris ZI) veneered with a low-fusing glass-ceramic. The specimens were duplicated using epoxy resin before and after cementation and after thermo-mechanical fatigue. The marginal adaptations of replicated specimens were evaluated at six points. The margins were evaluated under a scanning electron microscope. Statistical analysis was performed using SPSS. Tukey HSD test were used to investigate the differences between the three types of zirconia crown restorations. Statistically significant difference was determined at (p

Effect of sintering cycle on the strength and translucency of multilayered zirconia.

A newly introduced sintering protocol promises to offer higher translucency while not significantly compromising the flexural strength of the material. However, the effect of the novel sintering protocol has not been thoroughly validated. The purpose of this study was to measure and compare the effect of two sintering protocols on the translucency and flexural strength of two multilayered zirconia materials. Two types of multilayered zirconia materials (ZirCAD Prime and Prime esthetic) were selected. Presintered disk specimens were obtained from Translucent, Gradient, and Dentin layers (n = 20). The disks were allocated to 2 groups: standard sintering protocol (peak temperature 1500°C) and high translucency sintering protocol (peak temperature 1600°C). After the sintering process, 10 specimens from each group were randomly selected. The optical values (L*, a*, b*) were measured and used to assess translucency using the relative translucency parameter (RTP00) and translucency differences (ΔRTP00). Then, all 20 specimens were tested for biaxial flexural strength. The outcomes were analyzed. The analysis of variance is used to analyze any significant effects on translucency and flexural strength. Then, any significant difference in the translucency and flexural strength between all pairs of materials was analyzed using Bonferroni-corrected Student's t-test (α = 0.05). The high translucency sintering protocol significantly decreased biaxial strength in the Prime translucent and dentine layer, Prime esthetic translucent, and gradient layer. RTP00 was significantly reduced in the Prime gradient and Prime esthetic gradient layer when sintered with a high translucency protocol. The lowest ΔRTP00 was observed in the Prime dentine layer, while the highest ΔRTP00 was observed in the Prime esthetic dentin layer. High translucency protocol significantly lowers the biaxial flexural strength of both multilayered materials, but the alteration in translucency is within clinically acceptable thresholds (TAT00 = 2.62).

Silica infiltration as a strategy to overcome zirconia degradation

The excellent clinical performance of yttria-partially stabilized zirconias (Y-SZs) makes them promising materials for indirect restorations. However, the Y-SZ phase stability is a concern, and infiltrating Y-SZs with a silica nanofilm may delay their degradation processes. In this study, we analyzed stabilities of silica-infiltrated zirconia surfaces after exposure to artificial aging (AA).Four zirconia materials with different translucencies (n = 40) were used, including low translucency 3 mol% Y-SZ (3Y-LT, Ceramill ZI, Amann Girrbach); high translucency 4 mol% Y-SZ (4Y-HT, Ceramill Zolid); and two high translucency 5 mol% Y-SZs (5Y-HT, Lava Esthetic, 3M and 5Y-SHT, Ceramill Zolid, FX white). Sintered specimens were exposed to 40 cycles of silica (SiO2) through room temperature atomic layer deposition (RT-ALD) using tetramethoxysilane (TMOS) and ammonium hydroxide (NH4OH). AA was applied for 15 h in an autoclave (134°C, 2 bar pressure). Stabilities of zirconia-silica surfaces were characterized in terms of hardness and Young's modulus using nanoindentation techniques and crystalline contents using x-ray diffraction (XRD) analyses. Silica deposition was also characterized by X-ray photoelectron spectroscopy (XPS).There was a significant effect of the interaction of materials and surface treatments on the hardness and Young's modulus values of zirconia-silica surfaces (p < 0.001). Silica deposition on zirconia surfaces improved the material resistance to degradation by AA.

Effect of Acidulated Phosphate Fluoride Gel on Zirconia Intaglio Surface: An In-Vitro Study

Abstract Aim: To evaluate the micro-shear bond strength (µ-SBS) of resin-modified glass ionomer cement and to assess the chemical and topographical changes in the zirconia fitting surface induced by acidulated phosphate fluoride (APF) gel using scanning electron microscope (SEM) analysis and Fourier transform infrared (FTIR) spectroscopy. Materials and Methods: Thirty-two samples were prepared from two zirconia materials, UPCERA HT White and BruxZir® Solid Zirconia, milled by a computer-aided design/computer-aided manufacturing system. From each zirconia sample, six plates were prepared for FTIR and SEM testing. Following sintering, the samples were divided into control and test groups for each material. The APF gel (1.23%) was applied to the intaglio surface of each test group. To measure the µ-SBS between the zirconia materials and luting cement, 20 rectangular samples of zirconia material were prepared. Ten samples were obtained from Upcera and ten from Bruxzir, with five assigned to the control and five to APF groups. Statistical Analysis: For the µ-SBS test, independent samples t test was conducted to determine the level of significance between the tested groups. Results: FTIR spectroscopy revealed new bands for Upcera and Bruxzir zirconia owing to ion exchange between the formed sodium phosphate and the zirconia surface and the formation of zirconium phosphate by an ester reaction. SEM assessment identified lines, scratches, or surface dissociation that appeared on the intaglio–zirconia surface after conditioning. The µ-SBS test, as indicated by the independent samples t test, showed a significant increase in bond strength of 1.266 and 1.566 MPa for Upcera and Bruxzir zirconia, respectively. Conclusion: This study offers new practical, cost-effective, and accurate tests to enhance the µ-SBS of luting cement to yttria-stabilized tetragonal zirconia polycrystal ceramics.

Drying kinetics of CeO2-ZrO2 ceramic powders under microwave heating based on a thin-layer drying model

Volume change of ZrO2 during martensitic phase transformation can cause cracking of material and limit the application of ZrO2.Agglomeration of CeO2-ZrO2 ceramic powders can be effectively reduced by choosing the correct drying method. Microwave drying of CeO2-ZrO2 powder can effectively reduce the cracking of zirconia materials and improve powder uniformity. Microwave heating is used to dry CeO2-ZrO2 ceramic powders, and results demonstrate that Modified Page fits experimental data rather well. FT-IR spectra revealed a remarkable decrease in the intensity of the -OH bond's stretching vibration peak, and H-O-H bond's bending vibration. Utilizing Fick's second law, the diffusion coefficient of water molecules in CeO2-ZrO2 ceramic powders with a mass of 20 g and a moisture content of 6.6 % is calculated to be 5.820 × 10−15 m2/s under microwave power of 400 W. Experimental results prove that microwave heating has low activation energy, improves drying efficiency, and realizes fast and efficient drying.

Hydrogen embrittlement of Zircaloy-4 fabricated by ultrasonic additive manufacturing

Ultrasonic additive manufacturing (UAM) was successfully applied to the zirconium material system to create a planar geometry. Following fabrication, SS-J3 type tensile specimens of the UAM and wrought Zircaloy-4 with a nominal gage section of 5 × 1.2 × 0.75 mm were machined for hydriding studies and mechanical testing. The SS-J3 type tensile specimens were gas-charged with hydrogen using a custom system that precisely controls hydrogen gas flow rate, hydrogen partial pressure, and temperature. To avoid altering the UAM material, the maximum process temperature was limited to 550 °C. Using different initial hydrogen gas pressures and flow rates, various hydrogen contents (70–1755 wppm) were achieved for Zircaloy-4 specimens. Tensile testing shows that, regardless of hydrogen content, all UAM specimens measured yield strengths in the range of 557 ± 16 MPa and ultimate tensile strengths of 660 ± 4 MPa. However, total elongation clearly decreased as a function of increasing hydrogen content. At the lowest hydrogen content, the total plastic elongation measured 21.5 %, and this value decreased to less than 2 % when the hydrogen content was increased to 1000 wppm. Cross-sectional optical microscopy images revealed that the hydride distributions are randomly oriented. For the low hydrogen content specimen, these randomly distributed hydrides are isolated from each other. A sandwiched structure, consisting of high-density and low-density layers, was also observed for the specimens with hydrogen content between 200 and 400 wppm. As the hydrogen content increases, the hydrides diffuse into the low-density hydride layers to form a network across the whole specimen. Although the tensile properties of UAM and wrought Zircaloy-4 exhibit the same behavior with increasing hydrogen content, the distinctions in grain orientations led to differences in the hydride orientations at low and intermediate hydrogen concentrations.

Investigations on structural, morphological and UV light detection characteristics in p- ZrO2/ n-Si Heterostructure based devices

The development of hetero-structured based UV photodiode is a rapidly growing interest in the area of optoelectronic applications. In recent years, one of the next generation semiconductor material zirconium dioxide (ZrO2), has attracted much attention for UV photodiode applications. The curent research work focuses on the fabrication of ultraviolet (UV) photodetectors using ZrO2 nanocrystals with different molar concentrations. Using the co-precipitation method, ZrO2 nanocrystals were formed onto n-Si substrate. The prepared ZrO2 nanocrystals were characterized by XRD, UV–visible spectroscopy, FeSEM, HRTEM, PL spectroscopic analysis. The structural analysis of ZrO2 nanoparticles shows the cubic space groups with ((Fm-3m, Z = 4) and (Im-3m, Z = 1) respectively. The morphological analysis reveals the irregular shape and highly agglomerated. The TEM and HR-TEM images, and SAED pattern of ZrO2 NPs were obtained at higher mole concentration. The optical energy band gap of ZrO2 nanocrystals were determined in between 3.12 and 2.86 eV. The PL emission spectrum of ZrO2 nanoparticles shows highly intensive emission bands between 360 nm and 520 nm. The optimum ZrO2 (0.3 M) nanocrystal layers were formed onto n-Si substrate which was stacked between top and bottom Ag electrodes. The current-voltage measurements (I–V) plots and ln J-V plots characteristics of the fabricated Ag/p-ZrO2/n-Si/Ag devices were investigated under dark and UV illumination. The p-ZrO2/n-Si junction diodes exhibit the ideal rectifying function at higher molar concentration of ZrO2 diode, and the reverse saturation with maximum photo sensitivity was investigated.

The impact of aging and thickness on flexural strength of various zirconia ceramics

BackgroundEffects of the aging process on the flexural strength of Y-TZP and different Y-PSZ ceramics of different thicknesses were investigated.Methods300 disc-shaped samples (12 mm diameter, 0.8 and 1.5 mm thicknesses) were made from 5 different zirconia materials 3Y-TZP LA, 4Y-PSZ, 5Y-PSZ, 3 + 5Y-PSZ and 4 + 5Y-PSZ. Experimental groups were artificially aged in an autoclave at 134 °C, 2 bar pressure for 1 and 5 h; control groups were not subjected to any treatment. Microstructural analysis was conducted using Scanning Electron Microscopy, and X-Ray Diffraction analysis determined the crystalline phase content. The impact of aging on flexural strength was investigated with the use of the biaxial flexural strength test. Data were analyzed using three-way ANOVA tests with a significance level of p < 0.05, applying Bonferroni correction for multiple comparisons.ResultsStatistically significant differences in flexural strength were observed among the materials and the material thicknesses (p < 0.05), while there were no significant differences among the aging times (p > 0.05). The highest mean flexural strength values were recorded in the case of the 3 Y-TZP-1.5 mm–5 h group (744.1 ± 61.2 MPa), which was attributed to phase-transformation toughening. The lowest values were observed in the case of the 5 Y-PSZ-1.5 mm–5 h (338.3 ± 34.8 MPa) group.ConclusionsBoth material type and thickness significantly affect the flexural strength of zirconia ceramics, whereas aging time does not; thus, material selection and thickness are crucial considerations for clinicians.