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
Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3407
Author(s):  
Liliana Porojan ◽  
Roxana-Diana Vasiliu ◽  
Mihaela-Ionela Bîrdeanu ◽  
Sorin-Daniel Porojan

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.


Author(s):  
O.V. Savvova ◽  
G.K. Voronov ◽  
O.I. Fesenko ◽  
Yu.O. Smirnova ◽  
E. Bairamov

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.


2014 ◽  
Vol 2 (46) ◽  
pp. 10002-10010 ◽  
Author(s):  
Sébastien Chenu ◽  
Emmanuel Véron ◽  
Cécile Genevois ◽  
Alain Garcia ◽  
Guy Matzen ◽  
...  

Highly transparent ZnGa2O4 glass-ceramic materials, showing red long-lasting luminescence arising from the entire sample volume, are reported.


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