scholarly journals Characterisation and Properties of Lithium Disilicate Glass Ceramics in the SiO2-Li2O-K2O-Al2O3System for Dental Applications

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Naruporn Monmaturapoj ◽  
Pornchanok Lawita ◽  
Witoon Thepsuwan
Keyword(s):  
Glass Composition ◽  
Glass Ceramics ◽  
Lithium Disilicate ◽  
Nucleating Agents ◽  
Fine Grained ◽  
Melting Glass ◽  
Heterogenous Nucleation ◽  
Dental Applications ◽  
Slight Amount ◽  
Glass Compositions

This work proposes four different glass formulas derived from the SiO2-Li2O-K2O-Al2O3system to investigate the effect of glass composition on their crystal formations and properties. Glass LD1 was SiO2-Li2O-K2O-Al2O3system with the addition of P2O5and CaF2as nucleating agents. In Glass LD2, a slight amount of MgO was mixed in order to increase the viscosity of the melting glass. Finally, the important factor of Si : Li ratio was increased in Glasses LD3 and LD4 with compositions otherwise the same as LD1 and LD2. The results found that P2O5and CaF2served as a nucleating site for lithium phosphate and fluorapatite to encourage heterogenous nucleation and produce a fine-grained interlocking microstructure of lithium disilicate glass ceramics. MgO content in this system seemed to increase the viscosity of the melting glass and thermal expansion coefficient including the chemical solubility. Increasing the Si : Li ratio in glass compositions resulted in the change of the microstructure of Li2Si2O5crystals.

scholarly journals Improved performances of lithium disilicate glass-ceramics by seeds induced crystallization

2020 ◽  
Author(s):  
Ting Zhao ◽  
Mei-Mei Lian ◽  
Yi Qin ◽  
Jian-Feng Zhu ◽  
Xin-Gang Kong ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Glass Powder ◽  
Glass Ceramics ◽  
Lithium Disilicate ◽  
Nucleating Agent ◽  
Comprehensive Properties ◽  
Aesthetic Appearance ◽  
Small Crystals ◽  
Bimodal Grain Size ◽  
Glass Compositions

Abstract Self-reinforced lithium disilicate (Li2Si2O5, LD) glass-ceramics were hot pressing sintered by introducing 5 wt% Li2Si2O5 crystal seeds into two different glass compositions of SiO2-Li2O-P2O5-ZrO2-Al2O3-K2O-La2O3 (7C LD) and SiO2-Li2O-K2O-La2O3 (4C LD). The results show that the seeds play an important role in the crystallization inducement, microstructural and properties improvement of the glass, especially for the glass powder without the nucleating agent of P2O5. The microstructure features a wider bimodal grain size distribution with large rod-like crystals epitaxially grown along the seeds and small crystals nucleated from the glass powder itself, contributes to the improvement of the performance especially the fracture toughness. The specimen of 4C LD glass with the addition of 5 wt.% Li2Si2O5 seeds exhibited the best comprehensive properties with a good flexural strength (396 ± 7 MPa), improved fracture toughness (3.31 ± 0.19 MPa·m1/2) and comparable translucency as IPS e.max. This research will provide a new idea and method for the improvement of the fracture toughness of lithium disilicate glass-ceramics without affecting its aesthetic appearance, and lay the foundation for its clinical applications.

Effect of Glass Compositions on Crystallization and Mechanical Properties of Lithium Disilicate Glass Ceramics for Dental Crown

2013 ◽  
Vol 747 ◽  
pp. 194-197
Author(s):  
Naruporn Monmaturapoj ◽  
Pornchanok Lawita ◽  
Witoon Thepsuwan
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Glass Ceramics ◽  
Lithium Disilicate ◽  
Crystal Formation ◽  
Indentation Fracture ◽  
Graphite Mold ◽  
Heat Treated ◽  
Indentation Fracture Toughness ◽  
Glass Compositions

This work proposes three different glass formula derived from the SiO2-Li2O-K2O-Al2O3 system to investigate the effect of glass compositions on their crystal formation and mechanical properties. Glass LD_1 was SiO2-Li2O-K2O-Al2O3 system with adding P2O5 and CaF2 as nucleating agents. In Glass LD_2, a few amount of MgO was mixed to improve the viscosity of the glass. Finally, an important factor of Si:Li ratio was increased in Glass LD_3. Glass batches were melted at 1500°C and cast into a graphite mold which was annealed at 400-500°C before heat treatment at 700, 750, 800 and 850°C. XRD results can be indexed Li2Si2O5, Li2SiO3, Ca5(PO4)3F and SiO2 as an early crystallization when heat treated at 700°C. After heat treatment at 750-850°C, the intensity of SiO2 disappeared and the peaks associated to Li3PO4 appeared; meanwhile, Li2Si2O5 increased in intensity. Adding MgO resulted in decreasing the viscosity of the glass with no significant effects on the formation of lithium disilicate. By increasing Si:Li ratio, the peak of SiO2 more obviously observed. SEM results revealed the development of microstructure from plate-like to interlocking rod-shaped crystals in all glasses. The highest indentation fracture toughness and biaxial flexural strength found in all glass ceramics heat treatment at 800°C because the finest microstructure observed at this temperature, except LD_3 heat treated at 850°C, which obtained the finest microstructure. LD_1 heat treated at 850°C presented the best chemical solubility 59 μg/cm2.

scholarly journals Improved performances of lithium disilicate glass-ceramics by seed induced crystallization

2021 ◽  
Author(s):  
Ting Zhao ◽  
Mei-Mei Lian ◽  
Yi Qin ◽  
Jian-Feng Zhu ◽  
Xin-Gang Kong ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Glass Powder ◽  
Glass Ceramics ◽  
Lithium Disilicate ◽  
Nucleating Agent ◽  
Comprehensive Properties ◽  
Aesthetic Appearance ◽  
Small Crystals ◽  
Bimodal Grain Size ◽  
Glass Compositions

AbstractSelf-reinforced lithium disilicate (Li2Si2O5, LD) glass-ceramics were hot pressing sintered by introducing 5 wt% Li2Si2O5 crystal seeds into two different glass compositions of SiO2-Li2O-P2O5-ZrO2-Al2O3-K2O-La2O3 (7C LD) and SiO2-Li2O-K2O-La2O3 (4C LD). The results show that the seeds play an important role in the crystallization inducement, and microstructural and property improvement of the glass, especially for the glass powder without the nucleating agent of P2O5. The microstructure features a wider bimodal grain size distribution with large rod-like crystals epitaxially grown along the seeds and small crystals nucleated from the glass powder itself, contributing to the improvement of the performance especially the fracture toughness. The specimen of 4C LD glass with the addition of 5 wt% Li2Si2O5 seeds exhibited the best comprehensive properties with a good flexural strength (396±7 MPa), improved fracture toughness (3.31±0.19 MPa·m1/2), and comparable translucency as IPS e.max. This research provides a new idea and method for the improvement of the fracture toughness of lithium disilicate glass-ceramics without affecting its aesthetic appearance, and lays the foundation for its clinical applications.

Lithium Disilicate based Glass-Ceramics for Dental Applications

2013 ◽  
Vol 72 (1) ◽  
pp. 56-60 ◽  
Author(s):  
Anuraag Gaddam ◽  
Mudit Goyal ◽  
Sudhanshu Jain ◽  
Parag Bhargava
Keyword(s):  
Glass Ceramics ◽  
Lithium Disilicate ◽  
Dental Applications

Ceramics and Glass-Ceramics Dental Materials: Chemical Solubility, Cytotoxicity and Mechanical Properties

2018 ◽  
Vol 912 ◽  
pp. 170-174
Author(s):  
Roberto de Oliveira Magnago ◽  
Carlos Eduardo de Lima Abreu ◽  
Ronaldo Reis Silva ◽  
Manuel Fellipe Rodrigues Pais Alves ◽  
Caio Marcelo Felbinger Azevedo Cossu ◽  
...  
Keyword(s):  
Relative Density ◽  
Dental Materials ◽  
Glass Ceramics ◽  
Lithium Disilicate ◽  
Zirconia Ceramic ◽  
Dental Ceramics ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Dental Applications ◽  
Density Results

In this work three dental ceramics were characterized according to ISO 6872: yttria-stabilized zirconia (ZrO2-Y2O3), lithium disilicate (Li2Si2O5) and the spinel-zirconia composite (MgAl2O4-ZrO2). The zirconia ceramic and the zirconia-spinel composite were sintered at 1600°C-2h, while the lithium disilicate was thermally treated at 820°C-20min. These materials were characterized by relative density, X-ray diffraction, scanning electron microscopy, hardness, fracture toughness, chemical solubility and cytotoxicity. The XRD results showed for the stabilized zirconia only the tetragonal phase of ZrO2, and to the composite only the phase MgAl2O4, Li2Si2O5 was the only phase to lithium disilicate. Relative density results showed that the zirconia and the lithium disilicate showed high densification (> 99.5%) and the composite had a relative density of 75% (10% composite doped with ZrO2) and 90% (50% doped with ZrO2). Hardness and toughness showed 450HV and 3.2MPa.m1/2 to ZrO2-MgAl2O4 composites, 525HV and 1.8MPam1/2 to lithium disilicate and 1280HV and 8.0MPa.m1/2 to zirconia. The materials evaluated showed chemical solubility <30μg/cm2 and the results of cytotoxicity tests indicated cell viability of the samples near 100% for all the materials, showing good chemical stability and potential for dental applications.

The nucleation and crystallization of fine grained leucite glass-ceramics for dental applications

2006 ◽  
Vol 22 (10) ◽  
pp. 925-933 ◽  
Author(s):  
Michael J. Cattell ◽  
Thomas C. Chadwick ◽  
Jonathan C. Knowles ◽  
Richard L. Clarke ◽  
Dayananda Y.D. Samarawickrama
Keyword(s):  
Glass Ceramics ◽  
Fine Grained ◽  
Dental Applications

scholarly journals Obsidian pyroclasts in the Yellowstone-Snake River Plain ignimbrites are dominantly juvenile in origin

2021 ◽  
Vol 83 (4) ◽  
Author(s):  
L. R. Monnereau ◽  
B. S. Ellis ◽  
D. Szymanowski ◽  
O. Bachmann ◽  
M. Guillong
Keyword(s):  
Glass Composition ◽  
Snake River Plain ◽  
Explosive Eruptions ◽  
Snake River ◽  
Pyroclastic Deposits ◽  
Volcanic Conduit ◽  
Trace Elemental ◽  
Multiple Cycles ◽  
River Plain ◽  
Glass Compositions

AbstractDense, glassy pyroclasts found in products of explosive eruptions are commonly employed to investigate volcanic conduit processes through measurement of their volatile inventories. This approach rests upon the tacit assumption that the obsidian clasts are juvenile, that is, genetically related to the erupting magma. Pyroclastic deposits within the Yellowstone-Snake River Plain province almost without exception contain dense, glassy clasts, previously interpreted as hyaloclastite, while other lithologies, including crystallised rhyolite, are extremely rare. We investigate the origin of these dense, glassy clasts from a coupled geochemical and textural perspective combining literature data and case studies from Cougar Point Tuff XIII, Wolverine Creek Tuff, and Mesa Falls Tuff spanning 10 My of silicic volcanism. These results indicate that the trace elemental compositions of the dense glasses mostly overlap with the vesiculated component of each deposit, while being distinct from nearby units, thus indicating that dense glasses are juvenile. Textural complexity of the dense clasts varies across our examples. Cougar Point Tuff XIII contains a remarkable diversity of clast appearances with the same glass composition including obsidian-within-obsidian clasts. Mesa Falls Tuff contains clasts with the same glass compositions but with stark variations in phenocryst content (0 to 45%). Cumulatively, our results support a model where most dense, glassy clasts reflect conduit material that passed through multiple cycles of fracturing and sintering with concurrent mixing of glass and various crystal components. This is in contrast to previous interpretations of these clasts as entrained hyaloclastite and relaxes the requirement for water-magma interaction within the eruptive centres of the Yellowstone-Snake River Plain province.

Effect of surface treatments on titanium alloy bonding to lithium disilicate glass-ceramics

2016 ◽  
Vol 116 (5) ◽  
pp. 797-802 ◽  
Author(s):  
Nuno Guilherme ◽  
Chandur Wadhwani ◽  
Cheng Zheng ◽  
Kwok-Hung Chung
Keyword(s):  
Titanium Alloy ◽  
Glass Ceramics ◽  
Lithium Disilicate ◽  
Surface Treatments ◽  
Effect Of Surface

Crystal Phase Formation and Mechanical Properties of Lithium Disilicate Glass-Ceramics for Dental Restoration

2010 ◽  
Vol 177 ◽  
pp. 447-450 ◽  
Author(s):  
Xin Zhang ◽  
Yi Wen Hu ◽  
Yin Wu ◽  
Wen Jie Si
Keyword(s):  
Mechanical Properties ◽  
Phase Formation ◽  
Glass Ceramics ◽  
High Strength ◽  
Lithium Disilicate ◽  
Sem Analysis ◽  
Dental Restoration ◽  
Bending Test ◽  
Crystal Phase ◽  
High Temperature Xrd

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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