3D-printed silicon nitride ceramic implants for clinical applications: the state of the art and prospects

Si₃N₄ ceramic has received great attention because of its sound biological performances, which make it an attractive ceramic implant material in healthcare, particularly in orthopedic surgery. With the advancement of 3D printing technology, Si₃N₄ ceramics can now be fabricated into customized implants with precise anatomical shapes, sizes, and microstructures, catering to the individual needs of patients. We, therefore, conducted a comprehensive review of how 3D printing enables complex-shaped Si₃N₄ ceramic implants for clinical applications. Firstly, commonly used 3D printing technologies are introduced. Then, the state of the art of the 3D-printed Si₃N₄ ceramic implants are summarized. Finally, we forward the prospects towards the 3D printing of Si₃N₄ ceramic implants, including high mechanical properties, composites, drug loading, and economics and low cost. We hope that this review will provide a thorough examination and helpful guidance to related scientists, clinicians, and dentists in this field.