Zirconia Materials Research Articles

Evaluation of Extra-High Translucent Dental Zirconia: Translucency, Crystalline Phase, Mechanical Properties, and Microstructures

Highly translucent zirconia (TZ) is frequently used in dentistry. The properties of several highly translucent zirconia materials available in the market require an in-depth understanding. In this study, we assessed the translucency, crystalline phase, mechanical properties, and microstructures of three newly developed highly translucent zirconia materials (Zpex 4. m, 4 mol% yttria-stabilized zirconia: 4YSZ; Zpex Smile.m, 5YSZ; ZR Lucent ULTRA, 6YSZ). The translucency parameter (TP) was analyzed using the CIELAB system. X-ray diffraction was conducted for the crystalline phase analysis, followed by Rietveld refinement. A biaxial flexural strength test using the Weibull analysis was performed to evaluate the mechanical properties. Scanning electron microscopy, grain size distribution, and average grain size were used to analyze the microstructures. The TP content of the ZR Lucent ULTRA was the highest among the samples investigated. The Rietveld analysis revealed that the cubic zirconia phase content of the ZR Lucent ULTRA was the highest. The biaxial flexural strength of the ZR Lucent ULTRA was the lowest (622.9 MPa). The average grain size and proportion of large grains (1.0 µm < x) were the highest in ZR Lucent ULTRA. Therefore, extra-high translucent zirconia has the potential for use in anterior monolithic restorations owing to its esthetics and strength.

Surface treatments with TiO2 nanostructures for bonding to zirconia materials as an alternative to conventional airborne-particle abrasion of the surface

Surface treatments with TiO2 nanostructures for bonding to zirconia materials as an alternative to conventional airborne-particle abrasion of the surface

An in vitro Prosthodontics Study on the Impact of Mouth rinses on the Color Stability of Monolithic and Multilayered Yttria –Stabilized Zirconia

The diverse array of restorative materials utilized in computer-aided design/computer-aided manufacturing (CAD/CAM) technology necessitates a comprehensive understanding of their aesthetic properties and color stability. This study aimed to evaluate the color stability of two different types of zirconia after immersion in Chlorhexidine and ANTIPLACA mouthwashes. We prepared 30 zirconia specimens (n = 15) as follows: Group 1 consisted of monolithic zirconia and group 2 consisted of KATANA™ YML Zirconia. Groups 1 and 2 were divided into three subgroups (n = 5). Each subgroup was immersed in one of the following three solutions: distilled water (control), CHX, or ANTIPLACA 0%Alcohol. We recorded the samples’ color values at baseline and after immersion according to the CIELab system by using a color spectrophotometer operated by an experienced operator. All data were collected and analyzed using Graph Pad Instat (Graph Pad, Inc.) software for windows. Irrespective of group totally it was found that immersion solutions significantly affected on mean values as revealed by two-way ANOVA test (p=<0.0001< 0.05) where (0% Alcohol > CHX ≥ DW). Mouthwashes staining had a marked effect on the color of the tested zirconia materials. The color change was material and staining solution-dependent, with Monolithic Zirconia showing the greatest color stability.

Osseointegration and Foreign Body Reaction of Dental Implants

The concept of titanium dental implant osseointegration is associated with mechanical stability and the formation of mineralized bone tissue at the organism-implant interface. However, a conceptual divergence exists explaining why only titanium implants have osseointegration. It is possible to explain the differences between the interaction mechanisms of cells and proteins with titanium, zirconia, stainless steel, or other material implants. Due to this lack of explanation, some researchers proposed that titanium implants have a foreign body reaction and zirconia implants have osseointegration. This work presents the differences between the organism’s responses to titanium and zirconia.

Reference CAD-CAM Samples for Dental Shade Communication for Successful Aesthetic Outcome.

The study aims to produce CAD-CAM reference samples for shade communication milled from the material of the restoration zirconia (ZrO2) and zirconia-reinforced lithium silicate (ZLS) and evaluate the color difference with the corresponding conventional Vita Classical (VC) shade tab. Furthermore, it aims to verify the color consistency of the materials. Five-five samples were milled out of ZrO2 and ZLS in five different colors and their color parameters were compared with the corresponding VC tabs both visually and digitally. For digital evaluation, images were taken of the samples and VC tabs and analyzed in Adobe Photoshop to extract L*a*b values. Color difference (ΔE00) was calculated using the CIEDE 2000 formula. Multilevel mixed-effects linear regression model was used to derive estimates of the mean ∆E00. Color difference was significantly higher than 1.8 ΔE00 in the case of all the ZrO2, ZLS A3, B2 and C2 samples. Color difference was also found during the visual comparison. Comparing the same color samples the ΔE exceeded 0.8 in some cases but stayed under 1.8 ΔE00 in every case and showed no color difference visually. Comparing CAD-CAM samples and VC shade tabs visible and measurable color differences (ΔE00>AT50:50%) were found in the case of all ZrO2 and three out of five evaluated shades of ZLS samples. The color consistency of the blocks was acceptable. Better shade communication thus more reliable shade reproduction is achieved when reference photos are sent with a color sample made from the restoration's material.

Fracture Resistance of Different Monolithic Zirconia Crowns with Horizontal and Vertical Finishing Lines: A Comparative in Vitro Study

Objective: The primary objective was to examine how different preparation techniques and zirconia materials affected fracture strength. Materials and methods: 48 sound human maxillary first premolars of similar shape and size were used, categorized into two main groups of 24 teeth, as per the preparation technique: Group A: chamfer preparation design. Group B: vertical preparation design. Then, based on the type of material, each main group was subcategorized into three subgroups of eight teeth: IPS emax Zircad LT, IPS emax MT and IPS emax Prime (IvoclarVivadent). All the samples, prepared by the same operator, with the assistance of a dental surveyor. Intra-oral scanning was performed on the prepared teeth. The SironaInLab CAD 20.0 software was used to design crowns and were subsequently generated using a 5-axis milling machine. Self-adhesive resin cement was used to bond crowns to their respective teeth. To assess the crown's fracture strength, a computer-controlled universal testing system was used, which records the fracture strength automatically in each sample in Newton (N) during a single load-to-failure test. Burke's classification was employed to assess the fracture mode by analyzing each sample under a 40x digital microscope. The collected data were evaluated using statistical analysis using the independent t-test and ANOVA, with a 0.05 significance level. Results: Vertical preparation technique had higher fracture strength than the chamfer preparation technique with a statistically significant difference (p < 0.05). While comparable fracture resistance was identified across various monolithic zirconia crowns. All samples demonstrated a severe fracture of the crown and/or tooth (Code V). Conclusion: The vertical preparation design illustrated significantly better fracture strength than the chamfer preparation design, Materials comparisons showed comparable fracture resistance.

FABRICATION OF ALL PORCELAIN CANTILEVER BRIDGE RESTORATION IN CASES OF GINGIVA RECESSION USING ZIRCONIUM DIOXIDE MATERIAL WITH ADDITIONAL RETENSION

Background: Aesthetic and functional dental restoration is a hope for people who have lost teeth, especially in the anterior region. Missing tooth 13 with more than 2 mm gingival recession can be made into a cantilever bridge restoration with the addition of porcelain gingiva. Gingival recession is when the tooth root surface is exposed due to periodontal tissue loss. Zirconia is a dental restoration material often used because of its biocompatibility, strength, and aesthetics. Purpose: To determine the procedure for making all porcelain cantilever bridge restorations in cases of gingival recession using zirconia material. Case analysis: The dental laboratory received a dental cast model of a 39-year-old female patient missing tooth 13 and had gingival recession on tooth 14 of more than 2 mm. Order in the form of restoration of all porcelain cantilever bridges from zirconia. Result: The cantilever bridge coping was made from zirconium dioxide and then layered with feldspathic porcelain to achieve optimal strength and aesthetics. A rest is made on tooth 12 to provide additional retention. Conclusion: The procedure for making all porcelain cantilever bridge restorations includes making diagnostic wax-up, scanning, coping design, milling, sintering, fitting, sandblasting, layering, anatomy, and glazing. Things that must be considered are the design, thickness of the coping, and connectors to achieve a restoration that is strong, resistant to fracture, and has good aesthetics. Porcelain gingiva was added in the cervical area of tooth 14 restorations to cover the recession

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