β-spodumene-doped lithium disilicate glass-ceramics via additive manufacturing for dental applications

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. LDGCs doped with 0, 2.5, 5, 10, and 20 wt% β-spodumene were prepared via additive manufacturing followed by heat treatments, and their thermal behavior, density, phase composition, microstructure, mechanical properties, and molding accuracy were evaluated. The results indicate that as the doping level of β-spodumene increased, the porosity, crystallinity, strength, and toughness 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 demonstrated a toughness of 3.4±0.2 MPa m^1/2, attributed to the secondary phase toughening mechanism of β-spodumene. 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.