In this review, we summarize the challenges of the three-dimensional (3D) printing of porous bioceramics and their translational hurdles to clinical applications. The state-of-the-art of the major 3D printing techniques (powder-based and slurry-based), their limitations and key processing parameters are discussed in detail. The significant roadblocks that prevent implementation of 3D printed bioceramics in tissue engineering strategies, and medical applications are outlined, and the future directions where new research may overcome the limitations are proposed. In recent years, there has been an increasing demand for a nanoscale control in 3D fabrication of bioceramic scaffolds via emerging techniques such as digital light processing, two-photon polymerization, or large area maskless photopolymerization. However, these techniques are still in a developmental stage and not capable of fabrication of large-sized bioceramic scaffolds; thus, there is a lack of sufficient data to evaluate their contribution. This review will also not cover polymer matrix composites reinforced with particulate bioceramics, hydrogels reinforced with particulate bioceramics, polymers coated with bioceramics and non-porous bioceramics.
Keywords: 3D printing; additive manufacturing; bioactive ceramics; bioceramics; bioprinting; bone scaffolds; bone tissue engineering; clinical translation; in-situ bioprinting.