Recent Progress of 3D Printing Bioceramic Scaffolds for Bone Regeneration

The reconstruction of critical-sized bone defects remains a challenging clinical problem. At present, the implantation of autogenous and allogeneic grafts is the main clinical treatment strategy but faces some drawbacks, such as inadequate source, donor site-related complications, and immune rejection, driving researchers to develop artificial bone substitutes based on distinct materials and fabrication technologies. Among the bone substitutes, bioceramic-based substitutes exhibit a remarkable biocompatibility, which can also be designed to degrade concomitantly with the formation of new bone. In addition, three-dimensional (3D) printing technologies are frequently used for fabricating personalized 3D bioceramic scaffolds, which can achieve accurate imitation of native bone structures. Especially, bioprinting can produce organoids by integrating cells into scaffolds, which achieves the simultaneous imitation of organ structure and biological function. This review summarizes recent progresses of bioceramic-based materials, including hydroxyapatite, tricalcium phosphate, bioactive glass, calcium silicate, alumina, and zirconia. In addition, the application of 3D printing technologies and bioprinting is also elaborated in this text, offering important reference for future research of 3D-printed bioceramics.