Authors: Siti Mazatul Azwa Saiyed Mohd Nurddin, Malek Selamat
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. 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. Key words: Silica, glass-ceramics, leucite, sanidine, dental, bioactivity, bio-inert, cyctotoxicity.