Analysis of flexural strength and Weibull modulus of printed and milled zirconia: A systematic review

STATEMENT OF PROBLEM: Additive manufacturing (AM) has been used for zirconia dental prostheses, but studies that evaluated mechanical properties in comparison with subtractive manufacturing (SM), such as flexural strength (FS) and Weibull modulus (m), are lacking. PURPOSE: The purpose of this systematic review was to evaluate studies comparing the FS and m of zirconia produced by AM and SM. MATERIAL AND METHODS: Searches were conducted in the PubMed, Science Direct, Embase, Web of Science, and Scopus databases, with the keywords zirconium, "zirconium oxide," "3D printing," "additive manufacturing," "additive manufacture," flexural, "flexural strength" from 2019 to 2024, enriched with manual searches. RESULTS: Few AM technologies are currently available to print dental zirconia, with the most used being stereolithography (SLA), digital light processing (DLP), and lithography-based ceramic manufacturing (LCM) systems. In general, specimens obtained by milling were found to have a higher FS and m than printed specimens. CONCLUSIONS: Printed zirconia has great potential for use in oral rehabilitation because, although its flexural strength and Weibull modulus are lower than those of subtractively manufactured zirconia, they still should provide adequate clinical performance.