scholarly journals Innovative directions of development of ceramic materials for dentistry

2021 ◽  
pp. 19-25
Author(s):  
O.V. Savvova ◽  
G.K. Voronov ◽  
O.I. Fesenko ◽  
Yu.O. Smirnova ◽  
E. Bairamov
Keyword(s):  
High Temperature ◽  
Glass Ceramic ◽  
Glass Ceramics ◽  
Lithium Disilicate ◽  
Ceramic Materials ◽  
Oxide Glass ◽  
Lithium Silicate ◽  
Silicate System ◽  
Advantages And Disadvantages ◽  
Glass Ceramic Materials

The need to improve the level of dental health of the population of Ukraine was identified. The prospects for the use of ceramic prostheses to provide quality medical care in dentistry have been established. An analytical review of various types of ceramic and glass-ceramic materials used as dental prostheses for tooth replacement: porcelain, alumina, zirconium oxide, glass-ceramics based on leucite and lithium disilicate and mica with the addition of fluorides. Peculiarities of the structure and operational properties of ceramic and glass-ceramic materials for dentistry have been identified, their advantages and disadvantages have been established. The effectiveness of the use of glass-ceramic materials based on lithium disilicate for dental prosthetics is substantiated. The basic lithium silicate system was selected and glasses for obtaining glass-ceramic crowns based on lithium disilicate by the method of high-temperature pressing and calcium phosphate-silicate system for obtaining glass-ceramic coatings were synthesized. The methodological approach to the development of glass-ceramic prostheses based on lithium disilicate is determined. The limits of the compositions of oxide components are determined and raw materials for the synthesis of the glass matrix are selected. The technological parameters of melting (T = 1350 – 1400ºС) and heat treatment with simultaneous formation of products (stage of nucleation T = 600 – 650ºС, τ = 30 – 60 min; stages of formation T = 900ºС, τ ≈ 20 min) are selected. The composition of fluoroapatite glass-ceramic coating for glazing of glass-ceramics and the mode of its firing (T = 800 – 850ºС, τ ≈ 1,0 – 1,5 min) were determined. The serviceability of the developed glass-ceramic samples DL st.glass, which were obtained by the technology of high-temperature pressing, are determined. The comparative analysis of glass-ceramic prostheses for dentistry allowed to establish that the operational properties of the developed glass-ceramic prostheses according to ISO 6872:2015 are at the level of world analogues. This will allow them to successfully compete in the Ukrainian market with well-known foreign counterparts and help ensure the social priorities of the state in the field of health care.

scholarly journals Effect of Thermocycling, Surface Treatments and Microstructure on the Optical Properties and Roughness of CAD-CAM and Heat-Pressed Glass Ceramics

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 381 ◽  
Author(s):  
Roxana-Diana Vasiliu ◽  
Sorin Daniel Porojan ◽  
Mihaela Ionela Bîrdeanu ◽  
Liliana Porojan
Keyword(s):  
Surface Roughness ◽  
Optical Properties ◽  
Glass Ceramic ◽  
Glass Ceramics ◽  
Lithium Disilicate ◽  
Ceramic Materials ◽  
Surface Treatments ◽  
Lithium Silicate ◽  
Before And After ◽  
Cad Cam

Dental ceramic restorations are widely spread nowadays due to their aesthetics and biocompatibility. In time, the colour and structure of these ceramic materials can be altered by aging processes. How does artificial aging affect the optical and surface roughness of ceramics? This study aims to assess the effect of thermocycling, surface treatments and microstructure upon translucency, opalescence and surface roughness on CAD-CAM and heat-pressed glass-ceramic. Forty-eight samples (1.5 mm thickness) were fabricated from six types of A2 MT ceramic: heat-pressed and milled glass-ceramic (feldspathic, lithium disilicate and zirconia reinforced lithium silicate). The samples were obtained respecting the manufacturer’s instructions. The resulted surfaces (n = 96) were half glazed and half polished. The samples were subjected to thermocycling (10,000 cycles) and roughness values (Ra and Rz), colour coordinates (L*, a*, b*) and microstructural analyses were assessed before and after thermocycling. Translucency (TP) and opalescence (OP) were calculated. Values were statistically analysed using ANOVA test (one way). TP and OP values were significantly different between heat-pressed and milled ceramics before and also after thermocycling (p < 0.001). Surface treatments (glazing and polishing) had a significant effect on TP and OP and surface roughness (p < 0.05). The heat-pressed and milled zirconia reinforced lithium silicate glass-ceramic experienced a loss in TP and OP. Ra and Rz increased for the glazed samples, TP and OP decreased for all the samples after thermocycling. Microstructural analyse revealed that glazed surfaces were more affected by the thermocycling and especially for the zirconia reinforced lithium silicate ceramic. Optical properties and surface roughness of the chosen ceramic materials were affected by thermocycling, surface treatments and microstructural differences. The least affected of the ceramics was the lithium disilicate ceramic heat-pressed polished and glazed.

scholarly journals Surface Characterization and Optical Properties of Reinforced Dental Glass-Ceramics Related to Artificial Aging

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3407
Author(s):  
Liliana Porojan ◽  
Roxana-Diana Vasiliu ◽  
Mihaela-Ionela Bîrdeanu ◽  
Sorin-Daniel Porojan
Keyword(s):  
Optical Properties ◽  
Thermal Cycling ◽  
Glass Ceramic ◽  
Artificial Aging ◽  
Lithium Disilicate ◽  
Ceramic Materials ◽  
Dental Restoration ◽  
Lithium Silicate ◽  
Glass Ceramic Materials ◽  
Silicate Ceramic

The development of various dental glass-ceramic materials and the evolution of novel processing technologies lead to an essential change in the clinical and technical workflow. The long-term success of a dental restoration treatment is defined by its durability, which is directly influenced by the oral environment. This study’s purpose was to evaluate the artificial aging behavior of nanostructured, respective microstructured ceramics related to surface topography, roughness, and optical properties. Six monolithic restoration materials were selected: milled lithium disilicate glass-ceramic (LDS-M) MT (medium translucency), hot-pressed lithium disilicate glass-ceramic (LDS-P) MT and HT (high translucency), milled zirconia-reinforced lithium silicate ceramic (ZLS-M) MT and hot-pressed zirconia-reinforced lithium silicate ceramic (ZLS-P) MT and HT, resulting n = 96 surfaces. All the samples were artificially aged by thermal cycling, and all investigations were made before and after thermal cycling. In terms of optical properties, differences recorded between ZLS and LDS ceramics are not significant. Thermal cycling increases the translucency of ZLS and LDS glass-ceramic materials significantly, with the most harmful effect on the pressed and polished samples. Micro- and nano roughness are significantly influenced by in vitro aging and a negative correlation was recorded. Glazed samples are characterized by significant rougher surfaces for all types of materials. On nanolevel, ZLS materials are significantly smoothed by thermal cycling.

scholarly journals Preparation of basalt-based glass ceramics

2003 ◽  
Vol 68 (6) ◽  
pp. 505-510 ◽  
Author(s):  
Branko Matovic ◽  
Snezana Boskovic ◽  
Mihovil Logar
Keyword(s):  
Optical Microscopy ◽  
Phase Analysis ◽  
Glass Ceramic ◽  
Glassy Phase ◽  
Raw Materials ◽  
Glass Ceramics ◽  
High Strength ◽  
Ceramic Materials ◽  
X Ray ◽  
Glass Ceramic Materials

Local and conventional raw materials?massive basalt from the Vrelo locality on Kopaonik mountain?have been used as starting materials to test their suitability for the production of glass-ceramics. Crystallization phenomena of glasses of the fused basalt rocks were studied by X-ray phase analysis optical microscopy and other techniques. Various heat treatments were used and their influences, on controlling the microstructures and properties of the products were studied with the aim of developing high strength glass-ceramic materials. Diopside CaMg(SiO3)2 and hypersthene ((Mg,Fe)SiO3) were identifies as the crystalline phases. The final products contained considerable amounts of a glassy phase. The crystalline size was in range of 8?480 ?m with plate or needle shape. Microhardness, crashing strength and wears resistence of the glass-ceramics ranged from 6.5?7.5, from 2000?6300 kg/cm2 and from 0.1?0.2 g/cm, respectively.

scholarly journals Utilization of discarded foundry sand (DFS) and inorganic waste from cellulose and paper industry for the manufacture of glass-ceramic materials

Cerâmica ◽  
2020 ◽  
Vol 66 (380) ◽  
pp. 413-420
Author(s):  
L. M. S. e Silva ◽  
R. S. Magalhães ◽  
W. C. Macedo ◽  
G. T. A. Santos ◽  
A. E. S. Albas ◽  
...  
Keyword(s):  
Glass Ceramic ◽  
Raw Materials ◽  
Paper Industry ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Foundry Sand ◽  
X Ray ◽  
Glass Ceramic Materials

Abstract Recycling has been pointed out as an alternative to the disposal of waste materials in industrial landfills. In the present study, the transformation of residues (discarded foundry sand - DFS, grits, and lime mud) in glass-ceramic materials is shown. The glasses were obtained by the melting/cooling method. The precursor materials, glasses, and glass-ceramics were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), and differential scanning calorimetry/thermal gravimetric analysis (DSC/TGA). The glassy materials were milled, pelleted, and thermally treated at the crystallization temperatures given by DSC data to obtain the glass-ceramics (885, 961, and 1090 ºC). The main formed phases were cristobalite, α-wollastonite (parawollastonite), and β-wollastonite (pseudowollastonite). The glass-ceramics showed very low water absorption and apparent porosity (0.26 to 0.88 wt% and 0.66 to 1.77 vol%, respectively). The results confirmed that the studied residues can be used as raw materials for the manufacture of vitreous and glass-ceramic materials.

Technological Aspects of the Production of Optically Transparent Glass Ceramic Materials Based on Lithium-Silicate Glasses

2018 ◽  
Vol 75 (3-4) ◽  
pp. 127-132
Author(s):  
O. V. Savvova ◽  
L. L. Bragina ◽  
D. V. Petrov ◽  
V. L. Topchii ◽  
S. A. Ryabinin
Keyword(s):  
Glass Ceramic ◽  
Ceramic Materials ◽  
Silicate Glasses ◽  
Lithium Silicate ◽  
Transparent Glass ◽  
Glass Ceramic Materials ◽  
Optically Transparent ◽  
Transparent Glass Ceramic

Crystallization and Mechanical Properties of Glass-Ceramic from Silicon Slag

2014 ◽  
Vol 953-954 ◽  
pp. 1643-1648
Author(s):  
Hang Li ◽  
Li Qiang Liu ◽  
Min Jing ◽  
Zhi Gang Wang ◽  
Zheng Wang ◽  
...  
Keyword(s):  
Glass Ceramic ◽  
Mechanical Performance ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
Talcum Powder ◽  
X Ray ◽  
Glass Ceramic Materials ◽  
Spherical Grains

The glass-ceramic materials were produced from silicon slag with the addition of talcum powder and TiO2 by melting them in an electrically heated furnace and subsequent heat treatment at various temperatures and time. The microstructure and crystallization behaviors of glass–ceramics have been investigated by differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). With the increase of silicon slag content, the sequent precipitate phase is: krinovite Na (Mg1.9Fe0.1)Cr (SiO)3O, pseudobrookite Fe2TiO5 and anorthite Ca (Al2Si2O8), enstatite ferroan MgFeSi2O6, and albite Na (AlSi3O8). The shape of crystals was spherical grains. The glass–ceramic sample obtained from 70% silicon slag had the excellent mechanical performance including flexural strength of 200.45 MPa and Vickers micro hardness of 909.72 MPa.

scholarly journals Glass-Ceramic Materials on the Lithium Disilicate Basis: Achievements and Development Prospects

2018 ◽  
Vol 12 (3) ◽  
pp. 391-399 ◽  
Author(s):  
Оksana Savvova ◽  
◽  
Gennadii Voronov ◽  
Vitalii Topchyi ◽  
Yuliya Smyrnova ◽  
...  
Keyword(s):  
Glass Ceramic ◽  
Lithium Disilicate ◽  
Ceramic Materials ◽  
Glass Ceramic Materials ◽  
Development Prospects

scholarly journals Preparation and properties of Li2O-BaO-Al2O3-SiO2 glass-ceramic materials

2014 ◽  
Vol 8 (4) ◽  
pp. 203-210 ◽  
Author(s):  
Gamal Khater ◽  
Maher Idris
Keyword(s):  
Solid Solution ◽  
Water Absorption ◽  
Glass Ceramic ◽  
Density Measurement ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
Glass Ceramic Materials

The crystallization of some glasses, based on celsian-spodumene glass-ceramics, was investigated by different techniques including differential thermal analysis, optical microscope, X-ray diffraction, indentation, microhardness, bending strengths, water absorption and density measurement. The batches were melted and then cast into glasses, which were subjected to heat treatment to induce controlled crystallization. The resulting crystalline materials were mainly composed of ?-eucryptite solid solution, ?-spodumene solid solution, hexacelsian and monoclinic celsian, exhibiting fine grains and uniform texture. It has been found that an increasing content of celsian phase in the glasses results in increased bulk crystallization. The obtained glass-ceramic materials are characterized by high values of hardness ranging between 953 and 1013 kg/mm2, zero water absorption and bending strengths values ranging between 88 and 126MPa, which makes them suitable for many applications under aggressive mechanical conditions.

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