3D Printing of Highly Dense and Translucent Zirconia Parts for Dental Applications: Effect of Filament Overlapping

ABSTRACT A 5Y‐PSZ zirconia paste was formulated for extrusion‐based additive manufacturing via Direct Ink Writing (DIW) to produce dense ceramic components for dental applications. A colloidal approach was adopted using nanometric zirconia powder (47 vol%) with tailored dispersant, thickener, and flocculant agents. Rheological behavior was evaluated by shear viscosity, viscoelastic moduli, and three‐step thixotropy tests to ensure printability and shape stability. Specimens were printed with different filament overlap percentages (20%, 25%, and 30%) and compared with a control group obtained by uniaxial pressing. After sintering, all groups were characterized in terms of relative density, microstructure (SEM), phase composition (XRD), translucency, and biaxial flexural strength. The 30% overlap printed group achieved average densification above 99%, optical translucency comparable to the pressed controls, and flexural strength of 432 ± 37 MPa. Weibull analysis of 30% filament overlap group indicated σ ₀ = 420 MPa and m = 7.0, comparable to the pressed group (σ ₀ = 658 MPa; m = 7.3). Overall, this study establishes a robust formulation and processing route for DIW of 5Y‐PSZ with high densification, translucency, and mechanical reliability, fulfilling ISO 6872 and offering a viable alternative for dental applications. This is the first study demonstrating filament overlaps as a densification‐enhancing parameter for DIW zirconia.