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Four formulations of triaxial porcelain composed from 34 – 49% clay, 13 – 22% potash feldspar, 10 – 30% Soda feldspar and 14 – 28% silica sand, were prepared from raw materials sourced from Malaysian deposits. Specimens were made using the dry pressing method and characterized in terms of constituent oxide composition, compressive strength and powder-XRD analyses, respectively. XRD studies revealed that the crystalline phases are mullite and quartz and their intensity is almost identical for all samples fired at 1250°C but there is a decrease in quartz content as temperature is increased. Samples with 28% sand content resulted in higher compressive strength compared to those containing 14% and 25% sand. The major factor influencing compressive strength was found to be porosity in samples as opposed to crystallinity. A body EP3 with 64.9% SiO2, 25.4% Al2O3, 3.6% K2O, 1.5% Na2O and 1.09% others exhibited best mechanical properties due to greater density and lower porosity formation.

The objective of this study was to determine the potential of using Malaysian silica sand as the SiO 2 raw material in producing leucite (SiO 2 -Al 2 O 3 -K 2 O) 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 glassceramics 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. At 700°C, leucite began to form with minor phase of sanidine. The peak intensity increased as the temperature was increased up to 850°C. For sintering time 3.0 to 12.0 h, the peak intensity of leucite and sanidine were increased but microcline was formed as a minor phase. The microstructure analysis showed that the dendritic leucite and prismatic sanidine. The leucite glass-ceramics appeared translucent. The flexural strength values (80 to 175 MPa) were comparable with commercial product (112 to 140 MPa). The in vitro bioactivity results prove that the leucite glass-ceramics sample can be classified as a bio-inert and non-cytotoxity material and can be used for restorative dental products.

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The objective of the study was to determine the degree of biocompatibility of leucite glass-ceramics that have been produced from local high grade silica sand in terms of cytotoxicity and mutagenicity assays. In the present study, the cyctotoxicity and mutagenicity were studied using the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay (MTT) and Ames Reverse Mutation. In the MTT assay, a dose response cytotoxicity of leucite sample was evaluated in L929 cells. The cells were treated with the concentrations of 6.25, 12.5, 25.0, 50.00, 100.00 and 200.00 mg/ml of the leucite sample for 24 hours. The cytotoxicity was determined by assessing the cell viability through the reduction of tetrazolium salts (MTT). The mutagenenicity of leucite sample was evaluated inS. typhiriumTA98. TA100, TA1535, TA1537 andE. coliWP2 in the Ames Reverse Mutation assay. Mutagenic effects were evaluated by comparing the mean number of revertant colonies of each extract concentraction with mean number of revertant colonies of the negative control. In results of MTT assay evaluated that the leucite did not show a cytotoxic effect at all concentrations under the condition of the study. Ames Reverse Mutation assay result proven that the leucite sample did not demonstrate a mutagenic effect under the condition of this study withSalmonella typhimuriumandEscherichia coli.