Flexural strength and Weibull analysis of Y-TZP fabricated by stereolithographic additive manufacturing and subtractive manufacturing

Digital light processing (DLP) is a relatively mature technology of ceramic additive manufacturing and is promising for fabricating zirconia-based dental restorations. It allows for manufacturing ceramic components with nearly unlimited geometries compared to traditional subtractive manufacturing technology. In order to explore its potential for fabricating dental prosthesis and determine its clinical indications, it is essential to investigate its microstructural characteristics and mechanical behavior. In this study, yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) fabricated by stereolithographic additive manufacturing, namely DLP acquired favorable flexural strength close to that of conventional subtractive-manufactured Y-TZP as indicated by uniaxial (three-point bending) and biaxial (ring on ring) tests, though the Weibull modulus of DLP-manufactured zirconia was lower than that of subtractive-manufactured zirconia. The strength predicting approach that uses effective area calculations was found to be applicable for both DLP-manufactured zirconia and subtractive-manufactured zirconia. Though both materials showed similar microstructures considering grain size and phase composition, significant differences in critical defects were observed.