effect of chemical composition on sinterability an‎d crystallization behavior of lithium metasilicate glass-ceramic

10/22/2026 12:00:00 AM

The present study aimed to investigate an‎d enhance the mechanical an‎d chemical properties of a multicomponent dental glass–ceramic system containing SiO₂, Li₂O, B₂O₃, P₂O₅, TiO₂, CaO, Al₂O₃, K₂O, ZrO₂, ZnO, BaO, an‎d SrO, with lithium metasilicate (Li₂SiO₃) as the predominant crystalline phase. To eva‎luate the effect of chemical composition on sinterability an‎d property optimization, three formulations :base body, glaze 1, an‎d glaze 2, were prepared with varying contents of Li₂O an‎d B₂O₃ (Li₂O = 39.9, 36.6, 33.9 mol%; B₂O₃ = 1.6, 4.6, 7.6 mol%). The parent glasses were melted at 1250 °C in air using an alumina crucible an‎d quenched in water to form frits. The frits were milled (< 75 µm), pressed into cylindrical pellets (Ø 1 cm) under 3 bar + 6 bar uniaxial pressure, an‎d thermally analyzed to determine the optimum sintering temperature. Glaze layers were subsequently applied onto the sintered base body by the brush-coating method. Characterization included X-ray diffraction (XRD), simultaneous thermal analysis (STA), three-point flexural strength testing, Vickers microhardness, chemical solubility, an‎d dilatometric measurements of the thermal expansion coefficient (CTE). Phase analysis confirmed lithium metasilicate (Li₂SiO₃) as the main crystalline phase in all samples, while lithium disilicate (Li₂Si₂O₅) appeared as a secondary phase in the base body an‎d glaze 2. Glaze 1 exhibited the lowest CTE (10.89 × 10⁻⁶ K⁻¹) among the studied compositions. The base body showed the highest flexural strength (132.3 ± 3.6 MPa) an‎d Vickers hardness (994.0 ± 17.2 HV), reflecting a denser structure an‎d superior sinterability compared with the glazes. Conversely, glaze 2 demonstrated the lowest chemical solubility (554 µg/cm²), indicating enhanced chemical durability due to its higher content of lithium disilicate an‎d optimized glass network. SEM observations revealed distinct morphologies: rod-like lithium metasilicate an‎d plate-like lithium disilicate in the base body, polygonal rods in glaze 1, an‎d a combination of rod-shaped Li₂SiO₃ an‎d plate-like Li₂Si₂O₅ crystals in glaze 2. Overall, the results indicate that increasing B₂O₃ an‎d reducing Li₂O content promote the formation of the more stable lithium disilicate phase, thereby improving chemical resistance an‎d optimizing the thermal compatibility of the coating with the base body.

شيشه سراميك , متاسيليكات ليتيم , دي سيليكات ليتيم , شيشه سراميك دنداني

Dental glass–ceramic , Lithium metasilicate , Lithium disilicate , dental glass ceramic

zahra barpour

seyed mohammad mirkazemi sara banijamali