Microstructural Properties of Leucite-type Glass-ceramics for Dental Use (original) (raw)
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Microstructure of lucite glass-ceramics for dental use
Materials Letters, 1996
Microstructure of lucite glass-ceramics for dental use was investigated using X-ray diffraction, FT-IR spectroscopy and laser Raman spectroscopy. Main features of the IT-IR and laser Raman spectra were similar to those of silicate glasses containing A13+, or other M3+ (M = metal), as network forming ions. Two weak IR bands at 640 and 543 cm-' were typical of all lucite-type glass-ceramics and these bands disappeared with the conversion of glass-ceramics into the glass state. The laser Raman spectrum of lucite-type glass showed a broad band with center at = 4600 cm-' due to fluorescence/luminescence spectral feature with two luminescence sharp peaks at 5037 and 5007 cm-'. The results were compared with those obtained for different silicate glasses.
Development of leucite glass-ceramics for non-metallic dental product
Journal of Chemical Engineering, 2016
The objective of this study was to determine the potential of using Malaysian silica sand as the SiO2 raw material in producing leucite (SiO2-Al2O3-K2O) glass-ceramics. The crystallization, mechanical and biological properties of the glass-ceramic was studied. A starting glass composition in the system of leucite was melted in an electric furnace, quenched in deionized water and dry milled to obtain glass powder. The glass powders were ball milled and compressed to form 13 mm x 10 mm pellet. The thermal analysis, phase composition, microstructure, flexural strength and cytotoxicity of the glass-ceramics were investigated. Thermal analysis showed that crystallization of the glass occurred at the range of 650 and 850°C. The pellets were sintered at 650, 700, 750, 800 and 850°C for 1.0 h. The effect of sintering time on crystallization was also studied through five different soaking time at 3.0, 6.0, 9.0 and 12.0 h. The crystallization depends on the temperature and time of sintering. ...
The preparation of dental glass-ceramic composites with controlled fraction of leucite crystals
Processing and Application of Ceramics, 2008
This work is dealing with synthesis of leucite powder, which can be used for the preparation of dental glassceramic composites by subsequent thermal treatment. Newly developed procedure is based on preparation of dental raw material as a mixture of two separate compounds: the crystalline leucite powder prepared at relatively low temperature and a commercial matrix powder. Hydrothermal synthesis of tetragonal leucite particles (KAlSi2O6) with the average size of about 3 ?m was developed in our laboratory. The leucite dental raw material was prepared by mixing of 20 wt.% of synthetic tetragonal leucite with commercial matrix. Dental composites were prepared from the dental raw material by uniaxial pressing and firing up to 960?C. Dilatometric measurements confirmed that the coefficient of thermal expansion increased by 32% when 20 wt.% of the tetragonal leucite was added into the basic matrix. In addition, it was showed that the synthesized leucite powder was suitable for the preparat...
The aim of this research work was to investigate the effect of using natural Malaysian silica sand as the SiO 2 raw material on the crystallization, mechanical and biological properties of leucite (KAl 2 SiO 6 ) glass-ceramics. Glass in the system of SiO 2 -Al 2 O 3 -K 2 O was prepared by melting the raw materials, quenched in deionizing water and dry milled to obtain glass powder. The powder was pressed and sintered to obtain glass-ceramics. The thermal analysis, phase composition, microstructure, flexural strength, in-vitro bioactivity and cytotoxicity of the glass-ceramics were investigated. Thermal analysis defined the crystallization of glass at the range of 650°C and 850°C. The crystallization depends on the temperature and time duration of sintering. At 700°C, leucite began to form with minor phase of sanidine. The peak intensity enhanced with increasing the temperature up to 850°C. For sintering duration between 3 to 12 hours, the peak intensities of leucite and sanidine increased but microcline was formed as a minor phase. The microstructure analysis shows dendritic leucite and prismatic sanidine. The surface developed a glassy texture with no obvious micro cracks. The leucite glass-ceramics appeared translucent. The flexural strength values (80-175MPa) were comparable with commercial product (112-140 MPa). The in-vitro bioactivity results prove that the leucite glassceramics sample can be classified as a bio-inert and non-cytotoxic material and can be used for restorative dental applications.
Study of local silica sand deposits for producing leucite glass-ceramics for dental applications
Malaysian Journal of Fundamental and Applied Sciences, 2014
The objective of this research work was to examine the potential of using local silica sand from Terengganu, as a raw material in producing leucite glass-ceramics for dental applications. The characterization of the silica sand was carried out using chemical analysis and X-ray fluorescence (XRF) analysis. The study also focused on the effect of temperature and soaking time of sintering on the formation and properties of leucite glass-ceramics for dental applications. A starting glass composition of weight %; 64.2% SiO2, 16.1% Al2O3, 13.6% K2O, 5.10% Na2O, 0.5% TiO2 and 0.5% LiO2 was melted in an electric furnace, and then quenched in cool water to produce glass frit. The glass powders were ball milled and compressed to form 13mm diameter discs. The discs were sintered at 700°C,750°C, 800°C and 850°C for 1.0, 3.0, 6.0, 9.0 and 12.0 hours. The XRD analysis results show that the glass powders produced leucite phase as the major phase at certain temperature and soaking time of sinter...
Clinical applications of glass-ceramics in dentistry
Journal of Materials Science: Materials in Medicine, 2006
Glass-ceramics featuring special properties can be used as a basis to develop biomaterials. It is generally differentiated between highly durable biomaterials for restorative dental applications and bioactive glass-ceramics for medical use, for example, bone replacements. In detail, this paper presents one biomaterial from each of these two groups of materials.
Applied Sciences, 2017
Multicomponent silicate glasses and their corresponding glass-ceramic derivatives were prepared and tested for potential applications in dentistry. The glasses were produced via a melting-quenching process, ground and sieved to obtain fine-grained powders that were pressed in the form of small cylinders and thermally treated to obtain sintered glass-ceramic samples. X-ray diffraction investigations were carried out on the materials before and after sintering to detect the presence of crystalline phases. Thermal analyses, mechanical characterizations (assessment of bending strength, Young's modulus, Vickers hardness, fracture toughness), and in vitro bioactivity tests in simulated body fluid were performed. On the basis of the acquired results, different potential applications in the dental field were discussed for the proposed glass-ceramics. The use of such materials can be suggested for either restorative dentistry or dental implantology, mainly depending on their peculiar bioactive and mechanical properties. At the end of the work, the feasibility of a novel full-ceramic bilayered implant was explored and discussed. This implant, comprising a highly bioactive layer expected to promote osteointegration and another one mimicking the features of tooth enamel, can have an interesting potential for whole tooth substitution.
Effect of Al 2 O 3 on leucite based bioactive glass ceramic composite for dental veneering
Ceramics International, 2016
A wide variety of dental ceramic composites have been introduced in the restorative dentistry in order to associate the desired aesthetics and superior mechanical performance. Mechanochemically derived leucite based bioactive glass ceramic composites have been prepared and studied by their thermal, crystal structure, microstructural, mechanical and biological behavior. In the prepared glass-ceramic composites, fine alumina has been added to improve their mechanical properties because it has biocompatibility, high hardness and good mechanical strength. Flexural strength and coefficient of thermal expansion (CTE) have been studied and the results are compared to the commercial dentine. Alumina added glass ceramic composites show high flexural strength than that of the pure leucite based glass ceramic composite. A second phase nepheline has been formed in the alumina added samples. Nepheline has high CTE. This causes a slight increase in the CTE of the whole matrix. Micrographs show the complete attachment and proliferation of the SSC-25 cells on the surface of the samples. This confirms the bioactive behavior of the prepared composites. Therefore, it is concluded that the addition of alumina to the glass ceramic composite is a successful approach to improve its mechanical and biological properties.
Preparation and Characterization of LAS Glass Based Materials for Dental Applications
Key Engineering Materials, 2016
Glass ceramic materials are widely used in dental application because of their strong similarity with natural teeth. In this study LAS glass ceramic/glass materials were prepared by glazing processing and characterized in terms of mechanical flexural strength. The selected glass ceramic support derives from an industrial process. Different glasses were applied to the glass ceramic support in order to investigate firstly their effect on the glass ceramic/glass interface and secondly how these structural changes are correlated to the flexural strength property. Different thermal cycles were applied to the glass ceramic in order to promote the increasing of mechanical flexural strength. Preliminary results clearly points out that the application of a glass on the support leads to the decrease of the flexural strength if compared to the materials without any coating applied.