Lithium metasilicate glass‑ceramic fabrication using spark plasma sintering

Abstract

Background: The digital dentistry, requires materials with wo opposite properties of machining
ability and also enough hardness. The main objective of this experimental study was to investigate
the fabrication feasibility of the lithium metasilicate glass‑ceramic in partially crystalized stated using
the spark plasma sintering (SPS) method.
Materials and Methods: In this study, SPS for the first time was used to fabricate primary lithium
metasilicate glass‑ceramic (LMGC) blocks. The raw materials were mixed and melted and then
quenched in water and the resulted frits were grinded. The resulting powder was sintered by SPS
at 660, 680, and 700°C.
Results: Scanning Electron Microscope (SEM), X‑ray diffraction (XRD), and Vicker’s microhardness
assay were used to evaluate the properties of samples. Statistical comparison of the obtained data
was performed by ANOVA, followed by the post hoc test of Duncan. Microstructural studies by SEM
and XRD showed that all samples were composed of lithium metasilicate phase in a glassy matrix.
With increasing the sintering temperature, the number and size of lithium metasilicate particles
increased and higher mechanical properties have been achieved. However, the sintered sample at
700°C has less processing ability than the samples sintered at 660 and 680°C.
Conclusion: The optimum sintering temperature for glass frit consolidation was determined by
SPS at 680°C.
Key Words: Biocompatible materials, ceramics, crystallization