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Alfaer, Ali Salem, Ryan Hussien Alfwais, Yousef Masoud Al Haider, et al. "Differences between ceramic and porcelain laminate veneers." International Journal Of Community Medicine And Public Health 10, no. 1 (2022): 443. http://dx.doi.org/10.18203/2394-6040.ijcmph20223571.
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In dental care, treating anterior dentition esthetically has always been difficult. Numerous restorative solutions, including resin composites, all-ceramic crowns, and ceramic veneers, become accessible with the advancement of dental materials. In such situations, practitioners and patients should pick the most appropriate option to enhance oral health and aesthetic outcomes. Any substance made of non-metallic inorganic matter and fired at an elevated temperature is referred to as ceramics (pyrochemical process). Ceramics called glass ceramics are those that commence in a glassy phase and later devitrify to a partly or wholly crystalline form. Dental ceramics that most closely optically resemble the characteristics of real teeth are primarily glassy materials, which are derived primarily from triaxial porcelain compositions of feldspar, quartz, and kaolin. Glass-ceramics possess much more toughness and strength than porcelain but are also less translucent. Tougher and more durable ceramics, primarily yttrium stabilized tetragonal zirconia polycrystals, have been developed recently (Y-TZP). Due to its limited translucency, Y-TZP presents a major drawback. A significant amount of current tooth structure must be removed in order to allow for a porcelain veneer that is wide enough to overlay an opaque zirconia base and replicate the optical characteristics of the surrounding natural teeth. Ceramic restoration effectiveness, in the end, relies on the material choice, production process, and restoration strategy.
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Kasrani, S., A. Harabi, S. E. Barama, L. Foughali, M. T. Benhassine, and D. M. Aldhayan. "Sintering and dielectric properties of a technical porcelain prepared from economical natural raw materials." Cerâmica 62, no. 364 (2016): 405–12. http://dx.doi.org/10.1590/0366-69132016623641994.
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Abstract In this study, the production of a technical porcelain, for the ceramic dielectric applications by using economical natural raw materials, was investigated. The basic porcelain composition was selected consisting of 30 wt% kaolin, 45 wt% potash-feldspar and 25 wt% quartz. The obtained phases in the sintered samples were investigated by X-ray diffraction, Fourier transform infrared spectroscopy analysis, and scanning electron microscopy images. It has been confirmed by these techniques that the main crystalline phases were quartz and mullite. Dielectric measurements of technical porcelains have been carried out at 1 kHz from room temperature to 200 °C. The dielectric constant, loss factor, dielectric loss tangent, and resistivity of the porcelain sample sintered at 1160 °C were 22-25, 0.32-1.80, 0.006-0.07, and 0.2-9 x 1013 Ω.cm, respectively. The value of dielectric constant was significantly high when compared to that of conventional porcelains which did not exceed generally 9.
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Ismailov, A. Kh, A. S. Dzhalilov, A. M. Eminov, and A. Zhalilov. "Thermodynamic analysis of formation crystalline phases during firing of phosphoritic porcelain." Glass and Ceramics 45, no. 3 (1988): 137–39. http://dx.doi.org/10.1007/bf00676754.
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Djezairi, O., A. Bouzidi, N. Bouzidi, B. Ayaden, and A. Benselhoub. "Recycling of barite ore tailings into porcelain: microstructure and dielectric properties." Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, no. 6 (December 23, 2023): 48–53. http://dx.doi.org/10.33271/nvngu/2023-6/048.
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Purpose. To study the dielectric properties of porcelain obtained from a mixture of sand, kaolin, and feldspar. The latter has been partially substituted with solid barite wastes (SBWs). Methodology. The study involves preparation of porcelain using conventional solid-state reaction methods, employing two firing temperatures (1200 and 1300 °C) and a soaking time of 3 hours. SBWs are progressively added to the mixtures at levels of 0, 10, 20 and 30 wt%, replacing feldspar content. Structural and dielectric characterizations are conducted to examine the influence of SBWs substitution on macroscopic dielectric properties. Microstructural observations reveal various crystalline phases and micropores, contributing to property effects. Following sintering at 1200 °C, primary mineralogical phases include mullite, anorthite, and quartz. At 1300 °C, the celsian phase emerges alongside anorthite and quartz phases. The technological attributes of the produced porcelain samples, encompassing dilatometric properties, apparent density, and porosity, are determined. Findings. Dielectric characterization, conducted within the frequency range of 102–105 Hz, demonstrates that the relative constant permittivity values rise from 4.3 to 7.4 for samples sintered at 1200 °C and from 5.1 to 9.9 for those fired at 1300 °C, specifically for samples containing 10 wt% SBWs. Additionally, the dielectric loss tangent decreases with increasing sintering temperature. The macroscopic permittivity of porcelains can be accurately calculated using a mixing rule, which aligns well with experimental results. Originality. The original contribution lies in the use of 10 wt% Solid Barite Wastes (SBWs) from the Boucaid mine in order to effectively create environmentally friendly porcelain insulators. The study showcases the potential of SBWs as a partial substitute, thus promoting sustainability in porcelain insulator production. Practical value. The results of this study hold practical significance for the ceramics and insulator manufacturing industries by providing insights into enhancing the dielectric properties of porcelain through the incorporation of SBWs. This approach contributes to the production of environmentally friendly insulators.
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Amr, Ali, Abdallah Abdelwahab Sabreen, Abdelwahed Khaled, Ahmed Ibrahim, and I. Ali Ahmed. "Influence of Reinforcement Oxides on Structural and Mechanical Properties of Glass-Ceramics: A Review Article." International Journal of Innovative Technology and Exploring Engineering (IJITEE) 10, no. 5 (2021): 117–27. https://doi.org/10.35940/ijitee.E8670.0310521.
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This review studied the mechanical behaviors of Glass ceramics (GC) based on the Al2O3/SiO2 system. Glass ceramics are great interest due to their wide variety of applications, which have the ability to fulfil the recent demands of advanced mechanical, optical and biomedical applications. Glass-ceramics are typically heat-stable and have greater mechanical features than glasses. In addition, mechanical properties can be customized to provide variable volume fractions of crystalline phases by regulating nucleation and growth of the crystalline phases. The distribution of these crystalline phases in the glass matrix increases the consistency of the material and, in comparison, effectively limits the growth of cracks. The crystallization process resulted in substantial improvements in micro-hardness and density values such as sodium calcium phosphate (Na4Ca(PO3)6 and calcium pyrophosphate (β-Ca2P2O7) had sufficient properties for bone grafts and dental applications. This article outlines recent developments in the field of doping Oxides as reinforced with SiO2-Al2O3-based Glass- ceramics, to enhance the mechanical properties of Glass-ceramics combination. The research focused on the mechanical and the tribological behaviour of Biomedical, Electronics applications and selection of fabrication methods.
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Rica, Radu, Ionela Teodora Dascalu, Mihaela Jana Tuculina, et al. "The Use of Colour Codes in Ceramics Build-up for Achievement Esthetic Anterior Restorations." Revista de Chimie 68, no. 5 (2017): 953–56. http://dx.doi.org/10.37358/rc.17.5.5588.
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The ability to mimic the optical characteristics of enamel and dentin, the excellent biocompatibility and the chemical durability of dental ceramics are the reason reasons why this topic is considered of great importance in dentistry. The aim of this study was to highlight the differences during the process of manufacturing anterior esthetic restorations, i.e. the proper selection of color shades of dental ceramics and their correct deposition.Techniques for performing aesthetic ceramic restorations are influenced by the experience of the dental technician and their skills in realizing the restoration, which should be as little complicated, even if the dental ceramic powders has coded shades of color. Some dental technicians prefer their own color labels in order to facilitate their work and to modify or to highlight some effects of the powders, during the dental ceramics build-up. Naturalness of eight anterior restorations was obtained by alternating the opalescent base layer of the dental ceramic and the fluorescence of crystalline layers subsequently applied over opaque. Different translucent type of ceramic layers was used in order to create the true aspect of the incisal area, with a natural halo appearance. The increasing expectations of the patients in aesthetic restoration of anterior area of dental arches demand a complex build-up of the porcelain layers and this technique requires that the dental technician to possess special skills for obtaining a successful result.
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Ali, Amr, Sabreen Abdallah Abdelwahab, Khaled Abdelwahed, Ibrahim Ahmed, and Ahmed I. Ali. "Influence of Reinforcement Oxides on Structural and Mechanical Properties of Glass-Ceramics: A Review Article." International Journal of Innovative Technology and Exploring Engineering 10, no. 5 (2021): 117–27. http://dx.doi.org/10.35940/ijitee.e8670.0310521.
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This review studied the mechanical behaviors of Glass ceramics (GC) based on the Al2O3 /SiO2 system. Glass ceramics are great interest due to their wide variety of applications, which have the ability to fulfil the recent demands of advanced mechanical, optical and biomedical applications. Glass-ceramics are typically heat-stable and have greater mechanical features than glasses. In addition, mechanical properties can be customized to provide variable volume fractions of crystalline phases by regulating nucleation and growth of the crystalline phases. The distribution of these crystalline phases in the glass matrix increases the consistency of the material and, in comparison, effectively limits the growth of cracks. The crystallization process resulted in substantial improvements in micro-hardness and density values such as sodium calcium phosphate (Na4Ca(PO3 )6 and calcium pyrophosphate (βCa2P2O7 ) had sufficient properties for bone grafts and dental applications. This article outlines recent developments in the field of doping Oxides as reinforced with SiO2 -Al2O3 -based Glassceramics, to enhance the mechanical properties of Glassceramics combination. The research focused on the mechanical and the tribological behaviour of Biomedical, Electronics applications and selection of fabrication methods
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Denry, Isabelle L. "Recent Advances in Ceramics for Dentistry." Critical Reviews in Oral Biology & Medicine 7, no. 2 (1996): 134–43. http://dx.doi.org/10.1177/10454411960070020201.
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For the last ten years, the application of high-technology processes to dental ceramics allowed for the development of new materials such as heat-pressed, injection-molded, and slip-cast ceramics and glass-ceramics. The purpose of the present paper is to review advances in new materials and processes available for making all-ceramic dental restorations. Concepts on the structure and strengthening mechanisms of dental ceramics are provided. Major developments in materials for all-ceramic restorations are addressed. These advances include improved processing techniques and greater mechanical properties. An overview of the processing techniques available for all-ceramic materials is given, including sintering, casting, machining, slip-casting, and heat-pressing. The most recent ceramic materials are reviewed with respect to their principal crystalline phases, including leucite, alumina, forsterite, zirconia, mica, hydroxyapatite, lithium disilicate, sanidine, and spinel. Finally, a summary of flexural strength data available for all-ceramic materials is included.
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Okoubulu, A. B., H. E. Mgbemere, E. O. Obidiegwu, and C. C. Nwaeju. "Effect of feldspar and silica variation on the properties of dental porcelain." Nigerian Journal of Technology 42, no. 1 (2023): 107–13. http://dx.doi.org/10.4314/njt.v42i1.13.
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Dental porcelain was produced by mixing feldspar, silica, kaolin and bone ash by varying the contents of feldspar and silica. The processing steps include milling, sieving, pressing/shaping, drying, and sintering while the characterisation techniques were Hardness, Compressive strength, X-ray diffraction, Scanning electron microscopy and Fourier Transform Infrared (FTIR). The mixture was subjected to temperatures of 1100 and 1200 oC in a sintering furnace. The chemical composition was determined using X-ray fluorescence and they confirm that SiO2 and Al2O3 are the two major constituents in feldspar and kaolin while CaO is the major constituent in bone ash. For samples sintered at 1200oC, the X-ray diffraction showed that some glass phase possibly consisting of hedenbergite, ilmenite and silica were formed while crystalline phases namely microcline and sanidine were obtained for samples sintered at 1100°C. The morphology of the grains revealed that samples sintered at 1200oC had some hexagonal silica crystals while flakes of different sizes were obtained for samples sintered at 1100oC. Hardness values between 262 and 536 BHN, compressive modulus values ranging from 219 MPa to 324 MPa and linear shrinkage values between 6.34 and 7.6% were obtained. The batches of different compositions with ranges: quartz (silica) (15-25%), feldspar (70-80%), kaolin (Edda/Bauchi) (4%) and bone ash (1%) were fired at 1100, 1200oC, and the developed properties were tested. The sample with 70 wt.% of feldspar, 25 wt.% silica, 4 wt.% of Bauchi clay, and 1 wt.% bone ash sintered at 1200oC gave the best properties and has the potential to be used in dental restoration.
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Stoian, Caius, Lavinia Cosmina Ardelean, Meda Lavinia Negrutiu, et al. "Crystalline Structure Assessment of Ceramic Veneered Co-Cr-W Dental Alloy Substructures Obtained by Selective Laser Melting—A Pilot Study." Applied Sciences 13, no. 14 (2023): 8052. http://dx.doi.org/10.3390/app13148052.
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The aim of this work is to assess the crystalline structure modification of an SLM Co-Cr-W dental alloy, veneered with two different ceramics, by means of X-ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscopy, coupled with energy-dispersive spectroscopy (SEM-EDS). Ten identical plates were fabricated using SLM and were subsequently subjected to ceramic veneering. Following the repeated firing of the ceramic layers, carried out at temperatures exceeding 900 °C, new crystalline phases and variations in the crystallite sizes in the SLM Co-Cr-W dental alloy used for the substructure were detected via XRD. The two veneering ceramics showed significant differences in their behavior, beginning with the first firing, accompanied by structural changes. AFM micrographs and histograms of the surface heights over the whole scanned area of the samples showed that the surface of the Co-Cr-W dental alloy is strongly affected by the repeated firings necessitated by the ceramic firing process, a finding in accordance with the XRD results. The SEM investigation revealed that the different firing parameters had an impact on the alloy, the ceramic microstructure, and the surface quality. The differences in the chemical composition of the ceramics, highlighted by EDS, are reflected in their behavior. The crystalline alloy structure is influenced by the repeated firings of the ceramic layers.
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Zhang, Xin, Yi Wen Hu, Yin Wu, and Wen Jie Si. "Crystal Phase Formation and Mechanical Properties of Lithium Disilicate Glass-Ceramics for Dental Restoration." Advanced Materials Research 177 (December 2010): 447–50. http://dx.doi.org/10.4028/www.scientific.net/amr.177.447.
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The purpose of this study was to evaluate the crystal phase formation behavior and its influence on the mechanical properties of LiO2-SiO2-P2O5 glass-ceramics system. High temperature XRD was used to analyze the crystal phase formation in situ. The crystalline phases in the material both before and after heat-treatment were also analyzed. The flexural strength was measured by three-point bending test according to ISO 6872:2008(E). The SEM analysis showed that the high strength of the glass-ceramics is attributed to the continuous interlocking microstructure with fine lithium disilicate crystallines.
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Wang, Gaoqi, Yunkai Li, Shouren Wang, Xuefeng Yang, and Yujing Sun. "Two-Body and Three-Body Wear Behavior of a Dental Fluorapatite Glass-Ceramic." Coatings 9, no. 9 (2019): 580. http://dx.doi.org/10.3390/coatings9090580.
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As a veneering porcelain coating of dental prosthesis, two-body and three-body wear behavior of dental glass-ceramic with the main crystalline phase of fluorapatite has not been comprehensively studied. In this work, a self-made fluorapatite glass-ceramic was synthesized and the mechanical and tribological performances of the glass-ceramic were tested, comparing with a commercial feldspathic glass-ceramic. The friction and wear experiments were performed between disk-shaped glass-ceramics and natural teeth in two-body (dry, water, saliva) and three-body (slurry) modes, respectively. Results showed that good mechanical properties of fluorapatite glass-ceramic can be achieved by the sintering process. In both two-body and three-body modes, the fluorapatite glass-ceramic had a smaller friction coefficient and wear rate and caused less damage on antagonistic teeth than the feldspathic glass-ceramic. The greater mechanical properties give fluorapatite glass-ceramic a better wear resistance and reduce the adhesive wear.
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Lyra e Silva, João Paulo, José Ricardo Mariano, and Lucas Costa de Medeiros Dantas. "Uso de cerâmicas à base de dissilicato de lítio." Prosthesis and Esthetics in Science 10, no. 37 (2020): 27–30. http://dx.doi.org/10.24077/2020;1037-cb2730.
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Manufacturing of metal-free ceramic restorations become possible thanks to the emergence of reinforced ceramics and was consolidated with the development of adhesive materials and vitreous ceramic, allowing restorations adhesion to the dental structure. Lithium dissilicate-based ceramic offers features like, luting agent adhesion, resistance and optical effect, to be used without covering ceramics or thin restorations, maintaining their characteristics. The first ceramic systems were based on the development of infrastructure materials, replacing the metal, with increased reinforced crystalline phase which associated with the roofing porcelain can provide excellent aesthetics results without compromising the mechanical performance indispensable to restoration clinical longevity. Thus, we can perceive the importance of knowledge and planning of the steps to be followed in the process of ceramic restorations adhesion. The careful definition of protocols for the processes of moisture isolation, substrate preparation and restoration for the adhesion process are fundamental for clinical procedures to have reduced risk.
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Bai, Jia, and Duangrudee Chaysuwan. "Nucleation, Crystallization and Characterization of Mica-Based Glass-Ceramics with Fluorapatite." Advanced Materials Research 936 (June 2014): 164–69. http://dx.doi.org/10.4028/www.scientific.net/amr.936.164.
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The glass system of SiO2-Al2O3-MgO-MgF2-SrCO3-CaCO3-CaF2-P2O5 was used to prepare machinable glass-ceramics for restorative dental applications. The aim of this study was to apply various heat treatments to produce mica-based glass-ceramics. Differential Thermal Analysis (DTA) was used to determine the optimal heat treatment conditions for nucleation and growth of the crystalline phases in the quenched glass. It was found that the optimum nucleation temperatures for the first and the second crystallization temperatures (Tp1 and Tp2) were 642°C and 635°C, respectively, and the optimum nucleation times were between 2 and 4 hours. X-Ray Diffraction (XRD) showed the phases developed were anorthite, calcium-mica, fluorapatite, strontium apatite, forsterite, fluorite and stishovite phases. The microstructures of glass-ceramics were observed by Scanning electron microscope (SEM), found to exhibit plate-like mica crystals with high interlocking and randomly oriented with a higher soaking temperature and prolongation of the soaking time for crystallization.
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Kasuga, Toshihiro, Emiko Ueno, and Akiko Obata. "Preparation of Apatite-Containing Calcium Phosphate Glass-Ceramics." Key Engineering Materials 330-332 (February 2007): 157–60. http://dx.doi.org/10.4028/www.scientific.net/kem.330-332.157.
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A new type of glass-ceramic for novel dental fillers, which require excellent chemical durability, was investigated. A 40CaO-5CaF2-25TiO2-30P2O5 (in mol%) glass-ceramic was newly suggested. The glass-ceramic was prepared by a conventional two-step heating method. The resulting glass-ceramic included Nasicontype-CaTi4(PO4)6, titanium phosphates, such as (TiO)2P2O7 and Ti(PO3)3, and TiO2 (anatase) with apatite crystal, which was induced by incorporation of fluorine. In the glass-ceramic, dissolution by acid-treatment was strictly controlled. The excellent chemical durability of the glass-ceramic was suggested to originate from increase in the amount of the crystalline phases and a high content of titanium constituent in the residual glassy phase.
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Colomban, Philippe, Marino Maggetti, and Antoine d’Albis. "Non-invasive Raman identification of crystalline and glassy phases in a 1781 Sèvres Royal Factory soft paste porcelain plate." Journal of the European Ceramic Society 38, no. 15 (2018): 5228–33. http://dx.doi.org/10.1016/j.jeurceramsoc.2018.07.001.
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Srichumpong, Thapanee, Kallaya Suputtamongkol, Warat Chinpanuwat, et al. "Effect of Heat Treatment Time on Properties of Mica-Based Glass-Ceramics for Restorative Dental Materials." Key Engineering Materials 702 (July 2016): 23–27. http://dx.doi.org/10.4028/www.scientific.net/kem.702.23.
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The objective of this research is to focus improving the properties of machinable mica-based glass-ceramics in order for restorative dental materials. The glass-ceramics derived from the SiO2- Al2O3-MgO-MgF2-SrCO3-CaCO3-CaF2-P2O5 system were produced by a two-stage heat treatment. It was elucidated that the optimum nucleation and the crystallization temperatures were at 643°C and 892°C. The various heat treatment times in the first stage were applied as 3, 6, 12, 24, 48 and 72 h, respectively, on the optimum nucleation temperature to produce mica-based glass-ceramics. XRD results showed that specimens of variety of nucleation time had similar crystalline structures such as calcium-mica, fluorapatite, stishovite, anorthite, strontiumapatite and forsterite phases. The microstructures of glass-ceramics were observed by SEM basically as interlocked plate-like and needle-like microstructures of mica and fluorapatite, respectively, in all specimens. Furthermore, different heat treatment times influenced on the revealed crystal size of the glass-ceramics; the longer heat treatment, the smaller crystals. The resultant glass-ceramics gave the results of biaxial flexural strength (178-224 MPa) and Vickers hardness (295-393 HV) increasing with the formation of the interconnected mica phases which contributed to improve the machinability. The values of the properties were comparable to those of human enamel and suitable for some restorative dental applications.
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Goudouri, Ourania Menti, Eleni Theodosoglou, Anna Theocharidou, et al. "Magnesium Based Sol-Gel Derived Bioactive Glass Ceramics for Dental Tissue Regeneration." Key Engineering Materials 493-494 (October 2011): 884–89. http://dx.doi.org/10.4028/www.scientific.net/kem.493-494.884.
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Scaffold-based tooth engineering is currently the most popular approach towards replacing dental tissues or even engineering a bio-tooth. Although, various scaffold materials have been employed in tooth regeneration, the scaffold-based tooth design has, until now, achieved only limited success. Recently, bioactive Mg-based ceramics have attracted interest as Mg plays an important role on skeletal metabolism and affects the quality and structure of hard dental tissues. Mg has been reported to improve the mechanical properties of calcium phosphate ceramics, control biodegradation rate and stabilize the cell-material interface improving cell attachment and growth. The aim of this study was the development of an experimental Mg-based ceramic material, with enhanced bioactivity and adequate mechanical properties, in order to be potentially used in dental tissue regeneration. The Mg-based ceramic was prepared by the sol-gel method, while the stabilization was performed at 1300, 1400 and 1450oC in order a fully crystalline material to be obtained. The characterization of the materials -before and after immersion is Simulated Body Fluid (SBF)- was performed by Fourier Tranform Infrared Spectroscopy (FTIR), X-Ray Diffractometry (XRD) and Scanning Electron Microscopy associated with an EDS analyzer (SEM-EDS), while the flexural strength of uniaxially pressed pellets was measured using a universal testing machine for 3- point bending tests (Instron 3344). FTIR spectra and XRD patterns of all powder samples before immersion in SBF solution confirmed the presence of three crystalline phases; akermanite, merwinite and diopside. The onset of apatite formation on the surface of all powders was observed even after three days of immersion, while the apatite formation on the surface of the sintered pellets was slightly delayed. Flexural strength values were in the range of 30Mpa. In conclusion, Mg-based glass-ceramics attain adequate mechanical integrity and high rate of bioactivity and could be potentially used in the construction of ceramic scaffolds for dental tissue regeneration.
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da Silva Jr., Rafael Bernardino, Claudinei dos Santos, Leonardo Queiroz Bueno de Campos, Sabrina Vieira Campos, and Yan Carlos Ambrosio de Souza. "Properties of Pre-Sintered ZrO2(Y2O3) Blocks Consolidated by Cold Isostatic Pressing." Materials Science Forum 912 (January 2018): 159–64. http://dx.doi.org/10.4028/www.scientific.net/msf.912.159.
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In this work, dental ceramics based on ZrO2-Y2O3, made by cold isostatic pressing, were characterized and the properties were compared to conventional uniaxially pressed blocks. Pre-sintered ZrO2-3%mol Y2O3 blocks were sintered at 1530oC-120min. The crystalline phases were identified by X-ray diffraction (XRD) and microstructural analysis was performed using Scanning Electron Microscopy (SEM). The materials were mechanically evaluated for their hardness, fracture toughness and its bending strength. The results of mechanical tests indicate that the ceramics studied showed hardness greater than 1220HV, fracture toughness of about 8.2 MPam1/2 and bending strength higher than 1000 MPa. The results indicate excellent mechanical behaviour and negligible differences between uniaxial and isostatic products, but it is possible to see an increase of homogeneity in the final shrinkage after sintering.
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Saber-Samandari, Saeed, Saeid Baradaran, Bahman Nasiri-Tabrizi, Kadhim Alamara, and Wan Basirun. "Severe sink-in occurrence in thermally sprayed hydroxyapatite coating." Processing and Application of Ceramics 12, no. 2 (2018): 189–97. http://dx.doi.org/10.2298/pac1802189s.
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The performance of orthopaedic and dental implants counts on the ability to appraise the mechanical properties of biomaterials. In the present study, nanoindentation was used to characterize the mechanical properties of thermally sprayed hydroxyapatite-coated commercial pure titanium (HA/CP-Ti). From the XRD patterns, the as-sprayed HA coating showed an inhomogeneous mixture of polycrystalline and amorphous phases along with the formation of the decomposed constituents including tricalcium phosphate (?-TCP), tetracalcium phosphate (TTCP) and calcium oxide (CaO). The SEM micrographs of HA coating indicated some incompletely melted particles on the surface of flattened droplets, where the average pore size was around 0.8 ?m. After the loadunload indentation experiment, a clear severe sink-in deformation feature was observed around the residual indentation impression of the amorphous part. In contrast, pile-up only occurs during loading for the crystalline part of the coating. In addition, the crystalline part of the coating exhibited a Young?s modulus and hardness of around 120.46 and 7.91GPa, respectively, which were almost 8 and 259% higher than that of the bare CP-Ti substrate. This is the first report on the nanoindentation characterization of the inhomogeneous mixture of various phase structures in thermally sprayed HA coatings.
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Mukaeda, L. E., A. Robin, Claudinei dos Santos, Simone P. Taguchi, João Paulo Barros Machado, and L. A. Borges. "Effect of pH and Fluoride on Behavior of Dental ZrO2 Ceramics in Artificial Saliva." Materials Science Forum 660-661 (October 2010): 879–84. http://dx.doi.org/10.4028/www.scientific.net/msf.660-661.879.
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A considerable increase in the ceramic products demand occurred due to the evolution of dental restoration techniques and these materials must resist to the complex mouth environment. The pH of saliva can decrease significantly due to the ingestion of acidic foods and beverages and mainly due to reactions occurring during bacteria metabolism that lead to the formation of organic acids. Fluorides are also present in the mouth since fluorides are usually added in drinking water, mouth washes, tooth pastes and gels for the prevention of plaque and caries formation. The combination of low pH and presence of fluorides can lead to the formation of HF and HF2- which are detrimental to metallic and probably to ceramic devices. In this work, commercial blocks of ZrO2 ceramics (ProtMat Materiais Avançados® and Ivoclar®) were immersed in Fusayama artificial saliva of different pHs and fluoride concentrations. The properties of the as-produced ceramics (crystalline phases (XRD), microstructure (SEM), roughness (3D surface topography AFM) and mechanical resistance – Vickers hardness (Hv) and fracture toughness (KIC) were evaluated. Some of these properties were also determined after the immersion tests as well as the mass variation of the samples in order to evaluate the resistance of these ZrO2 ceramics to degradation under these conditions.
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Kheur, Mohit, Tabrez Lakha, Saleha Shaikh, et al. "A Comparative Study on Simulated Chairside Grinding and Polishing of Monolithic Zirconia." Materials 15, no. 6 (2022): 2202. http://dx.doi.org/10.3390/ma15062202.
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This study evaluated the effects of different simulated chairside grinding and polishing protocols on the physical and mechanical properties of surface roughness, hardness, and flexural strength of monolithic zirconia. Sintered monolithic zirconia specimens (15 mm × 3 mm × 3 mm) were abraded using three different burs: diamond bur, modified diamond bur (zirconia specified), and tungsten carbide bur, along with a group of unprepared specimens that served as a control group. The study was divided into two phases, Phase 1 and Phase 2. Surface roughness, surface hardness, and flexural strength were assessed before and after the grinding procedure to determine the ‘best test group’ in Phase 1. The best abrasive agent was selected for Phase 2 of the study. The specimens in Phase 2 underwent grinding with the best abrasive agent selected. Following the grinding, the specimens were then polished using commercially available diamond polishing paste, a porcelain polishing kit, and an indigenously developed low-temperature sintered zirconia slurry. The physical and mechanical properties were again assessed. Results were analyzed using one-way ANOVA test. Specimens were observed under scanning electron microscopy (SEM) and X-ray diffraction (XRD) for their microstructure and crystalline phases, respectively. Grinding with diamond burs did not weaken zirconia (p > 0.05) but produced rougher surfaces than the control group (p < 0.05). Tungsten carbide burs did not significantly roughen the zirconia surface. However, specimens ground by tungsten carbide burs had a significantly reduced mean flexural strength (p < 0.05) and SEM revealed fine surface cracks. Phase transformation was not detected by XRD. Polishing with commercially available polishing agents, however, restored the surface roughness levels to the control group. Dental monolithic zirconia ground with tungsten carbide burs had a significantly reduced flexural strength and a smooth but defective surface. However, grinding with diamond burs roughened the zirconia surface. These defects may be reduced by polishing with commercially available polishing agents. The use of tungsten carbide burs for grinding dental zirconia should not be advocated. Grinding with diamond abrasives does not weaken zirconia but requires further polishing with commercially available polishing agents.
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Pontes, F. H. D., Simone P. Taguchi, L. A. Borges, João Paulo Barros Machado, and C. Santos. "Unidirectional Infiltration Method to Produce Crown for Dental Prosthesis Application." Materials Science Forum 660-661 (October 2010): 885–90. http://dx.doi.org/10.4028/www.scientific.net/msf.660-661.885.
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Alumina ceramics have been used in dental prosthesis because it is inert, presents higher corrosion and shear resistance when compared to metals, excellent aesthetic, and mechanical resistance. In this work it was produced an infrastructure material for applications in dental crowns, obtained by glass infiltration in alumina preforms. Various oxides, among that, rare-earth oxide produced by Xenotime, were melted at 1450°C and heat treatment at 700°C to obtain the glass (RE-glass). The alumina was pre-sintered at 1100°C cut and machined to predetermine format (unidirectional indirect infiltration) and finally conducted to infiltration test. The alumina was characterized by porosity (Hg-porosity and density) and microstructure (SEM). The glass wettability in alumina was determined as function of temperature, and the contact angle presented a low value (<90º), showing that glass can be infiltrated spontaneously in alumina. The infiltration test was conducted at glass melting temperature, during 30, 60, 180, 360 minutes. After infiltration, the samples were cut in longitudinal section, ground and polished, and analyzed by XRD (crystalline phases), SEM (microstructure) and EDS (composition).The REglass presents higher infiltration height when compared to current processes (direct infiltration), and homogeneous microstructure, showing that it is a promising method used by prosthetics and dentists.
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Khomenko, E. S., and E. V. Karasik. "Sol - gel method for producing of glass binding in the Li2O - Al2O3 - SiO2 system for ceramic materials." Scientific research on refractories and technical ceramics 120 (December 30, 2020): 186–95. http://dx.doi.org/10.35857/2663-3566.120.18.
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The results of glass binding obtaining in the Li2O — Al2O3 — SiO2 system for ceramic materials are presented in the article. The lithium aluminum silicate system was chosen taking into account the low temperature expansion coefficients of crystalline phases that form in it. This will allow controlling the thermal expansion of materials into which the glass binding will be introduced. A sol - gel method based on ethyl silicate and soluble salts of the corresponding oxides is proposed as a method for producing of glass binding. This method is more rational in comparison with the traditional method of glass melting due to low energy costs. Also, the method allows to obtain a more uniform and active product.
 The effect of glass binding on the properties of ceramic materials for various purposes has been investigated. As such materials, low-temperature electrotechnical porcelain, quartz ceramics, and engobe coatings were chosen. The glass binding was introduced into the raw material charge of these materials in an amount of 5 wt. %. Further, the properties of calcined product without additives and with additives under the same conditions were compared.
 The intense fluxing effect of glass binding during the formation of electrical porcelain has been established. The glass binding reinforces the effect of natural fluxes (pegmatites) that are present in the basic composition of the mass. This contributes to the material compaction during firing. The formation of eucryptite and spodumene helps to reduce the thermal expansion of material. The introduction of glass binding into the engobe led to a less intense compaction of its structure. This was observed due to an insufficient amount of the added glass binding for this type of material. In the composition of quartz ceramics, glass binding contributed to the material sintering, but the thermal properties were deteriorated.
 Thus, the sintering results of ceramic material with the introduction of glass binding in the charge composition are positive. However, sintering significantly depends on the material type. The glass binding stimulates the formation of a melt in which solid finely dispersed components of the ceramic mass dissolve. This contributes to the formation of a dense durable ceramic.
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Silva, P. C., L. P. Moreira, M. F. R. P. Alves, L. Q. B. Campos, B. G. Simba, and C. dos Santos. "Experimental analysis and finite element modeling of the piston-on-three balls testing of Y-TZP ceramic." Cerâmica 66, no. 377 (2020): 30–42. http://dx.doi.org/10.1590/0366-69132020663772784.
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Abstract The objectives of this study were to characterize and evaluate the physical and mechanical properties of an experimental zirconia for dental application and compare the biaxial flexural strength results with the finite element simulation (FEM). Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramic samples were sintered at 1475 °C/2 h and characterized by X-ray diffraction, scanning electron microscopy, relative density, flexural strength using piston-on-three balls (P-3B) test and Young’s modulus. From the flexural strength results, numerical simulations were performed using Abaqus software. The complete model used 70216 elements, considering the components of the test. The results indicated full densification of sintered samples, ZrO2-tetragonal and ZrO2-cubic as crystalline phases, and average grain size of 0.6±0.2 μm. Mechanical characterization of sintered samples indicated Young’s modulus of 195±4 GPa, flexural strength of 1191±9 MPa and Weibull modulus m=16.3. FEM simulation indicated a flexural strength close to 1100 MPa, with a difference lower than 7% in relation to the experimental results. The results were compared associating the physical and mechanical properties of Y-TZP with its intrinsic phenomena such as tgm transformation and ferroelastic domain.
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de Assis, Luiz Cláudio Lemos, Roberto de Oliveira Magnago, Camila Aparecida Araújo da Silva, Alexandre Fernandes Habibe, Gabriel Rocha Lellis Villanova, and Claudinei dos Santos. "Reuse of ZrO2(Y2O3) Arising from Making Dental Implant - Characterization of Materials." Materials Science Forum 798-799 (June 2014): 632–37. http://dx.doi.org/10.4028/www.scientific.net/msf.798-799.632.
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The yttria stabilized zirconia, ZrO2 (Y2O3) has been widely used in dental prosthesis manufactured by CAD/CAM technique. This material is developed in the form of pre-sintered blocks, which are machined by extracting various customized prosthesis and generating a loss of about 30% of material. ZrO2(Y2O3) is notably a toughening for other ceramics, and has a high cost, so reusing discards these applications less noble, is strategically interesting. In this work the proposal is to recover discharges of ZrO2 (Y2O3) arising from prosthetic laboratories, reprocess them in order to reduce the particles size and subsequently sintering, demonstrating the potential use in applications less noble in dentistry. Discharges Residual of ZrO2-(Y2O3) were fragmented and then sieved to particle size separation. Powders of smaller than 63 μm were uniaxially pressed at different pressures. The compacts were characterized by the relative density showing green density of the order of 40%. After characterization, compacts were sintered at 1550°C-2h. The sintered material was characterized as its relative density and crystalline phases.
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Silva, C. P., C. Santos, and Cosme Roberto Moreira Silva. "Mechanical Properties of Nanostructured Zirconia." Materials Science Forum 660-661 (October 2010): 757–61. http://dx.doi.org/10.4028/www.scientific.net/msf.660-661.757.
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In this work itria stabilized ZrO2 based ceramics for dental applications has been sintered and characterized in terms of physical and mechanical properties. Nanostructured blocks were sintered at 1400 0C and microstrutured blocks sintered at 1600 0C. Both nanostructured and microstructured materials were characterized in terms of densification, crystalline phases, mechanical properties and microstructure. Fracture toughness and four point bending strength were evaluated and compared. For the nanostructured zirconia, the reduced grain size allowed the increase of its toughening capacity, generated from maximization of volumetric fraction of retained tetragonal zirconia particles. For this material higher bending flexural strength is related to induced nucleation of microcracks, increase of energy absorption during crack propagation and developed compressive surface stress. The fracture toughness obtained at nanostructured samples sintered at 1400 0C is approximately 20% higher when compared to microstrucutured samples. These results represent the toughening ability of nanostructured zirconia, originated from higher amount of retained tetragonal phase and grain boundary microcracks. The higher Weibull moduli in this case are indicative of material reliability improvement and these results are correlated to grain size and its influence at mechanical strength.
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Huang, A. W., C. Santos, R. O. Magnago, R. F. F. Silva, K. Strecker, and J. K. M. F. Daguano. "Sintering of alumina ceramics reinforced with a bioactive glass of 3CaO.P2O5-SiO2-MgO system." Cerâmica 61, no. 358 (2015): 160–67. http://dx.doi.org/10.1590/0366-69132015613581887.
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<p>Alumina-based ceramics, Al<sub>2</sub>O<sub>3</sub>, exhibit a combination of properties which favor its use as biomaterial, specifically as structural dental prosthesis. Its most important properties as biomaterial are its elevated hardness, chemical stability and biocompatibility. Usually, Al<sub>2</sub>O<sub>3</sub> is processed by solid-state sintering at a temperature of about 1600 <sup>o</sup>C, but it is very difficult to eliminate the porosity due to its diffusional characteristics. The objective of this work was the development and characterization of sintered Al<sub>2</sub>O<sub>3</sub> ceramics, densified with a transient liquid phase formed by a bioactive 3CaO.P<sub>2</sub>O<sub>5</sub>-SiO<sub>2</sub>-MgO glass. Powder mixtures of 90 wt.% Al<sub>2</sub>O<sub>3</sub> and 10 wt.% bioglass were milled, compacted and sintered at 1200 <sup>o</sup>C to 1450 <sup>o</sup>C. Comparatively, monolithic Al<sub>2</sub>O<sub>3</sub> samples were sintered at 1600 <sup>o</sup>C/120 min. The sintered specimens were characterized by relative density, crystalline phases, microstructure and mechanical properties. The results indicate that the specimen sintered at 1450 <sup>o</sup>C/120 min present the best properties. Under this sintering condition, a relative density of 95% was reached, besides hardness higher than 9 GPa and fracture toughness of 6.2 MPa.m<sup>1/2</sup>. XRD analysis indicate alumina (αAl<sub>2</sub>O<sub>3</sub>), whitlockite (3CaO.P<sub>2</sub>O<sub>5</sub>) and diopsite [3(Ca,Mg)O.P<sub>2</sub>O<sub>5</sub>], as crystalline phases. Comparatively, monolithic sintered Al<sub>2</sub>O<sub>3</sub> samples presented 92% of relative density with 17.4 GPa and 3.8 MPa.m<sup>1/2</sup> of hardness and fracture toughness respectively.</p>
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Nikoofar, Kobra, Yeganeh Shahedi, and Faezeh Jame Chenarboo. "Nano Alumina Catalytic Applications in Organic Transformations." Mini-Reviews in Organic Chemistry 16, no. 2 (2019): 102–10. http://dx.doi.org/10.2174/1570193x15666180529122805.
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Alumina (Aluminium Oxide, Al2O3), a white odorless solid powder is an inexpensive and widely used inorganic material which is insoluble in water and organic solvents. It may also be called aloxide, aloxite, or alundum. Nano forms of this inorganic metal oxide could be seen in different crystalline polymorphic phases for alumina, such as α-Al2O3, β-Al2O3, γ-Al2O3, δ-Al2O3, θ-Al2O3, η-Al2O3, κ-Al2O3, χ-Al2O3, and ρ-Al2O3. Generally, the nano size of alumina showed better activity due to its common form because of the vast surface area which led to larger surface-to-volume ratio. Alumina is a versatile substance in many compounds which possess interesting utility in biology, industry, and drugs. Nano alumina have been utilized in different branches of industry, medicine, and biology. It could play key role in abrasives, ceramics, and dental composites, electronic, absorbent, nano-carriers for delivery of anticancer, and surgical implants. Besides, it possesses particular position, as a heterogeneous Lewis acid catalyst or catalyst support in chemistry. Due to interesting properties of nano alumina in this report we focused on its catalytic activity in organic transformations. The review subdivided with centralization on reactions that progressed with sole nano alumina and the reactions which improved by nano alumina support catalysts. In is noteworthy that although many reactions have been reported by alumina catalytic role, the ones which underwent by nano-size aluminum oxides are few. This fact denote that this substance is a potent-catalyst system in future organic chemistry domain. The review describes the various organic reactions promoted by nano alumina catalysts relevant up to 2017.
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Avita, Ursula Hycynth D.-Almeida, A. S. Chaitra, Mohamed Aslam Jithin, and Singh. Nishtha. "METAL FREE CERAMICS: A REVIEW." March 16, 2018. https://doi.org/10.5281/zenodo.1237488.
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For the last ten years, the application of high-technology processes to dental ceramics allowed for the development of new materials such as heat-pressed, injection-molded, and slip-cast ceramics and glass-ceramics. To select the most appropriate type of all-ceramic system for clinical use, the clinician must be familiar with the differences between systems. High-strength all-ceramic systems for fixed partial dentures (FPDs) are available for replacing a missing tooth. New core/framework materials have been developed and have evolved in the last decade. With the advancement of CAD/CAM technology, various fabrication techniques have been developed for fabricating improved, consistent, and predictable restorations in terms of strength, marginal fit, and esthetics and for managing core/framework materials that could not otherwise be managed. Concepts on the structure and strengthening mechanisms of dental ceramics are provided. The purpose of the present paper is to review advances in new materials and processes available for making all-ceramic dental restorations.
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"Achieving the Desired Esthetic with Current CAD-CAM Ceramics." Journal of Oral & Dental Health 1, no. 2 (2017). http://dx.doi.org/10.33140/jodh/01/02/00001.
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The demand for tooth-colored restorations has grown considerably during the last decades. Restoration of anterior teeth is a difficult task, even for an experienced operator. Color is the most important determinant of esthetics. The esthetic appearance of a restoration should match the surrounding dental tissue. This requires that the optical properties of the restorative material be similar to that of the natural teeth. Thus, for an acceptable esthetic result, favorable shade matching of the all-ceramic restoration should be achieved by controlling light absorption, reflection and transmission of the ceramic material. There are many different ceramic systems that can be used to achieve highly esthetic results. These ceramic systems include In-Ceram, Hi-Ceram, IPS-Empress, Optec, and CAD-CAM ceramics. All ceramic systems have different composition, microstructure, crystalline content and phases. Direct transmission, translucency, opacity and opalescence, all influence the optical properties of the ceramic restoration. Other factors include the thickness of porcelain, number of porcelain firing, glazing, porcelain powder/liquid ratio, surface texture and even the resin shade. This article focuses on controlling these variables to achieve the best possible esthetic result with an all ceramic system with the emphasis on CAD-CAM systems.
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Denry, Isabelle. "From Feldspar Glass to Zirconia: State of the Art of Ceramics for Dental Applications." MRS Proceedings 1097 (2008). http://dx.doi.org/10.1557/proc-1097-gg06-05.
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AbstractThe evolution of dental ceramics over the past four decades has been remarkable in light of the increase in the diversity of materials and fabrication techniques that have become available. As a consequence, the applications and indications for all-ceramic materials continue to expand. The purpose of the present article is to review the evolution of dental ceramics from the various aspects of crystalline phases, glassy matrix, flaws and in vivo performance.
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"Ceramic Materials in dentistry using the SPSS Method." 4 9, no. 4 (2024): 18–27. http://dx.doi.org/10.46632/jemm/9/4/3.
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Dental ceramics can be used in a variety of root canal therapy, such as inlays, bone grafting, crowns, and bridges, to replace earthenware (PFM) systems with everything systems. Dental crowns, dental composite components, and dentures are all made of porcelain and glass-ceramic materials, which are together referred to as dental ceramics. Conventional dental porcelain is feldspar-based and contain sizable amounts of kaolin (Al2O32SiO22H2O), quartz, and feldspar (KAlSi3O8). Rocks containing mica and iron are known to contain feldspar, a grey crystalline mineral. Ceramics are any of the countless hard, brittle, heat, corrosion-resistant substances produced by molding and thereafter scorching an inorganic, non-metallic substance like clay to high temperatures. Common examples include earthenware, pottery, and brick. Dental ceramics that are made of Lucite feldspathic material are very attractive and frequently utilized. Inlays, on lays, partial crowns, crowns, and veneers for metals and ceramics are among their clinical indications. Ceramics are resistant to high temperatures, effective thermal insulators, and have minimal thermal expansion. For uses like as lining industrial furnaces and sealing space shuttles, it makes really good thermal barriers. Dental ceramics are explained within a framework that makes it simple to comprehend how they developed. symptoms and composition. Engineering assessments of efficacy of treatment are discussed, and research is done. Behavior of all earthenware systems clinically. The usage of dental ceramics is discussed from a practical standpoint. Emphasizing what they know but also how we know it while maximizing beauty and endurance. Reviewing the history of ceramics' use in dentistry is helpful. This account has three purposes: (1) to warn professionals Pottery and improved ceramics were created to remedy the issue; (2) to increase actual issues or restoration diversity; and (3) give a soft backdrop in nature and ceramic science. The use of ceramics has always represented the adoption of "high technology" and "Craftsmanship". Ratio studies are statistical analyses of data from appraisals and property valuations. Nearly all states utilize them to produce quantitative measure of the proportion of current market price about which individually estimated taxable property is appraised as well as to offer assessment performance indicators. Evaluation parameters: Ceramic materials in dentistry, Glass-ceramics, predominantly glassy ceramics, Substructure ceramics, Particle-filled glasses and Polycrystalline ceramics. Result: The Cronbach's Alpha Reliability result. The overall Cronbach's Alpha value for the model is .658 which indicates 66% reliability. From the literature review, the above 50% Cronbach's Alpha value model can be considered for analysis. Characteristics of sisal fiber the Cronbach's Alpha Reliability result. The overall Cronbach's Alpha value for the model is .658 which indicates 66% reliability. From the literature review, the above 50% Cronbach's Alpha value model can be considered for analysis.
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Zhang, Qianqian, Shanshan Gao, Chunxu Liu, Yuqing Lu, Xin Chen, and Haiyang Yu. "Evaluation of Wear Resistance of Dental Chairside CAD/CAM Glass Ceramics Reinforced by Different Crystalline Phases." Journal of Tribology 141, no. 3 (2018). http://dx.doi.org/10.1115/1.4041536.
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The mechanical properties of crystalline phase of glass ceramics are critical. This study aimed to evaluate wear resistance of different crystalline-reinforced dental chairside computer-aided design/computer-aided manufacturing (CAD/CAM) glass ceramics. Materials of feldspar (Vita Mark II, VM), leucite (IPS Empress CAD, EC), lithium disilicate (IPS e.max CAD, EX), lithium disilicate enriched with zirconia (Vita Suprinity, VS), and enamel were embedded, grounded, and polished, respectively. Samples were indented with a Vickers hardness tester to test the fracture resistance (KIC). Two-body wear tests were performed in a reciprocal ball-on-flat configuration under artificial saliva. The parameters of load force (50 N), reciprocating amplitude (500 μm), frequency (2 Hz), and the test cycle (10,000 cycles) were selected. Specimen microstructure, indentation morphology, and wear scars were observed by scanning electron microscope (SEM), optical microscopy, and three-dimensional profile microscopy. EX, VS, and EC demonstrated significantly higher KIC values than the enamel, while ceramic materials showed smaller wear depth results. Cracks, massive delamination, and shallow plow were seen on the enamel worn scar. Long deep plow, delamination, and brittle cracks are more common for VM and EC, and short shallow plow and smooth subsurface are the characteristics of EX and VS. Greater fracture toughness values indicated higher wear resistances of the materials for the test glass ceramics. The CAD/CAM glass ceramics performed greater wear resistance than enamel. Feldspar- and leucite-reinforced glass ceramics illustrated better wear resistance similar to enamel than lithium disilicate glass ceramics, providing amicable matching with the opposite teeth.
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Bordina, Galina Evgenievna, Nadezhda Petrovna Lopina, Alexey Alekseevich Andreev, and Vasiliy Alexandrovich Osokin. "On the issue of the manufacture of ceramic structures in orthopedic dentistry." Russian Journal of Dentistry, May 7, 2024. http://dx.doi.org/10.17816/dent629888.
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The article presents a review of ceramic materials used in modern orthopedic dentistry. Currently, the main types of orthopedic structures containing dental porcelain are metal-ceramic, metal-free ceramic crowns, as well as prostheses made using pressed ceramic technology, in particular veneers. All types of prostheses produced using dental porcelain have a common manufacturing technology, which consists in the sequential application of ceramic layers with their subsequent firing. Moreover, for each group of teeth, there are additional masses for firing, for example, masses of the cutting edge, masses simulating various effects (for example, blue, yellow and other shades, imitation of tooth growth lines). These masses are created in order to give future crowns the most natural and aesthetic appearance. All structural components (layers) of ceramics used in the manufacture of ceramic prostheses have a similar chemical composition. The raw material is feldspar glass with inclusions of crystalline quartz. Depending on the conditions of the reactions, the composition of mixtures can be varied and compounds with desired properties can be obtained using the phase analysis method, which will expand the range of domestic ceramic materials produced, which are currently quite scarce. This is especially relevant in modern conditions of import substitution.
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Costa, Benilde F. O., Luísa Durães, Eunice A. B. da Silva, et al. "Synthesis, Structural, and Mechanical Properties of Alumina–Yttria‐Stabilized Zirconia Nanocomposites for Prospective Dental Ceramics." Advanced Engineering Materials, January 2, 2025. https://doi.org/10.1002/adem.202401843.
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Yttria‐tetragonal‐stabilized zirconia (YSZ) and alumina are common ceramics used in dental aesthetics/prosthetics. Their combination leads to composites with improved mechanical strength and toughness. In this work, different amounts of alumina are added to YSZ by mechanosynthesis to study the influence on the microstructural, mechanical, and aging properties of the blended nanocomposites. Moreover, a comparison with the properties of nanocomposites prepared by sol–gel method is also performed. For both cases, ≈3 mol% of yttria in zirconia proves to be an adequate amount to stabilize the tetragonal and cubic phases of zirconia at environmental temperature, with only low amounts of the monoclinic phase present. Vickers microhardness (HV) and scratching tests show that the nanocomposites with 3 mol% of alumina exhibit better mechanical properties, considering the aimed potential application as dental ceramics, even when the materials are subjected to low‐temperature degradation in artificial saliva. In fact, they can preserve their good toughness and HV, as well as the constituent crystalline phases under these accelerated degradation conditions.
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Marzouk, M. A., H. A. Elbatal, F. H. Elbatal, et al. "Preparation and Characterization of Nano Glass–ceramics from CeO2-doped Li2O-SiO2 System for Dental Applications." Silicon, December 27, 2023. http://dx.doi.org/10.1007/s12633-023-02819-3.
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AbstractGlasses based on the basic composition of lithium disilicate (Li2O.2SiO2) together with derived samples containing increasing CeO2 replacing Li2O (0.1, 0.2, 0.5, 1 Mol %) were prepared by melting – annealing method, samples from the prepared parent glasses were thermally heat treated through two-step regime (450° C /10 h – followed by 650° C / 6 h) to convert them to their glass – ceramics derivatives. The main purpose of this study is to find out the main properties of the prepared glass – ceramics to be applied as dental candidates. The optical, FTIR, and thermal expansion properties of the parent glasses were examined to identify the main structural groups which are defined as tetrahedral stronger SiO2 building groups. The detailed separated crystalline phases within the prepared glass–ceramics were identified together with their textural features. The Vickers microhardness data for both the parent glasses and their glass -ceramics derivatives were evaluated. SEM and EDAX measurements indicate the ability of the prepared samples to form hydroxyapatite upon immersion in SBF solution.
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A., Srion, Thepsuwan W., and Monmaturapoj N. "Preparation and Fabrication of Lithium Disilicate Glass Ceramic as Dental Crowns via Hot Pressing Method." International Journal of Chemical, Materials and Biomolecular Sciences 8.0, no. 12 (2015). https://doi.org/10.5281/zenodo.1337643.
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Two Lithium Disilicate (LD) glass ceramics based on SiO2-Li2O-K2O-Al2O3 system were prepared through a glass melting method. The glass rods were then fabricated into dental crowns via a hot pressing at 900˚C and 850˚C in order to study the effect of the pressing temperatures on the phase formation and microstructure of the glasses. Different samples of as cast glass and heat treated samples (600˚C and 700˚C) were used to press for investigating the effect of an initial microstructure on the hot pressing technique. Xray diffraction (XRD) and scanning electron microscopy (SEM) were performed to determine the phase formation and microstructure of the samples, respectively. XRD results show that the main crystalline structure was Li2Si2O5 by having Li3PO4, Li0.6Al0.6Si2O6, Li2SiO3, Ca5 (PO4)3F and SiO2 as minor phases. Glass compositions with different heat treatment temperatures exhibited a difference phase formations but have less effect during pressing. SEM micrographs showed the microstructure of Li2Si2O5 as lath-like shape in all glasses. With increasing the initial heat treatment temperature, the longer the lath-like crystals of lithium disilicate were increased especially when using glass heat treatment at 700˚C followed by pressing at 900˚C. This could be suggested that LD1 heat treatment at 700˚C which pressing at 900˚C presented the best formation by the hot pressing and compiled microstructure.