“…The second heat-treatment stage, usually at a higher temperature range than the initial, supplied the thermal energy to induce growth of lithium disilicates and to thermodynamically destabilize the lithium metasilicates [33]. According to Borom et al (1975), the growth of lithium disilicate crystals was not dependent on the crystalline nuclei of lithium metasilicates [33]. Rather, lithium metasilicates kinetically competed with lithium disilicates but slowly diminished since it was thermodynamically less stable than lithium disilicates at high temperatures [33].…”