Extrusion 3D printing advances for craniomaxillofacial bone tissue engineering

3D printing assisted tissue engineering has been a research hotspot for decades. Due to the uniqueness and complexity of craniomaxillofacial (CMF) bone, a thorough understanding of anatomy and mechanics is imperative to restore damaged tissues. Bone grafting is the standard clinical strategy to treat CMF injuries. However, for enhanced bone regeneration, tissue-mimicking biomaterial design incorporating biological molecules, stem cells, osteoinductive cues and growth factors promoting cell-material interaction is very much pertinent. Extrusion three-dimensional (3D) printing offers a new domain for cell-free printing to cell-laden bioinks, matching the physical, chemical, mechanical and biological properties of the native tissue. Herein, a comprehensive review is presented on the most common extrusion printing techniques, focusing on the versatility of extrusion 3D printing in material design and printability to achieve advanced clinical outcomes. In addition, a concise glimpse of the advantages of medical 3D printing and the advanced strategies to enhance CMF tissue regeneration are also provided. A succinct discussion on the significance of artificial intelligence (AI) in the optimization of print fidelity to reduce the complexity of the biofabrication process is also reviewed.