Additively-Manufactured Spodumene-Doped Glass-Ceramics For Dental Restorations

Lithium disilicate glass-ceramics (LDGCs) are widely employed in dental aesthetic restorations; however, their application is constrained by insufficient fracture toughness and the inefficiencies inherent in conventional milling processes. This study investigated the additive manufacturing of LDGCs doped with β-spodumene to address these limitations. Lithium disilicate glass-ceramics with 0, 2.5, 5, 10, and 20 wt% β-spodumene were prepared via additive manufacturing followed by controlled multi-step heat treatments. The thermal behavior, porosity, density, phase composition, microstructure, mechanical properties, and molding accuracy were systematically evaluated. The results indicate that as the doping level of β-spodumene increased, the apparent and internal porosity, crystallinity, flexural strength, fracture toughness and elastic modulus initially improved and then decreased, with the most significant enhancement observed at 2.5 wt%. The size of lithium disilicate crystals decreased as the doping of β-spodumene increased. Notably, the 2.5 wt% doped composites exhibits higher fracture toughness than current commercial glass-ceramics. Fracture analysis shows that the doping of β-spodumene increases the transgranular and intergranular fractures inside the glass-ceramics, thus increasing the toughness of the composite material through the second phase toughening mechanism. Additionally, these β-spodumene-doped LDGCs exhibit excellent molding accuracy. These findings suggest that β-spodumene-doped LDGCs possess good mechanical properties and machinability, showing promising potential for dental restorative applications.