Impact of 3D-printed and milled zirconia microstructure on its flexural strength: a scoping review

Understanding the flexural strength (FS) of dental ceramics has been crucial for the proper indication of prostheses that will be subjected to intense occlusal loads in environments with temperature and pH variations, as well as long-term material degradation. FS appears to be directly influenced by microstructure, manufacturing methods, and post-processing; however, a gap remains in understanding how these factors interact. In SM, microdefects induced by cutting tools can compromise material integrity, thereby increasing the risk of failure under occlusal forces. Conversely, AM faces challenges such as residual porosity and variations in density after sintering, which negatively impact mechanical strength. Furthermore, sintering plays a crucial role in determining the microstructure of the material, with studies indicating that inappropriate parameters can lead to excessive grain growth, reduced strength, and loss of zirconia's toughening ability. Thus, this study aims to investigate and critically assess the microstructural and mechanical differences between milled and printed zirconia.