Three-dimensional printing of bone repair and replacement materials: impact on craniofacial surgery.

Solid freeform fabrication techniques such as direct write technology can be used to fabricate tissue-engineering scaffolds in 3 dimensions with high levels of reproducibility and precision. These can comprise complex structures made of osteoconductive, remodelable lattices to conduct bone ingrowth and solid barriers to prevent soft tissue invasion. As such, they act as a combination of bone graft and barrier membrane. Results from animal studies have shown that these structures fill rapidly with healing bone and can conduct bone across critical-size defects to fill large defects in rabbit skull. Results indicate that this technology can be used to produce both off-the-shelf and custom-fabricated bone graft substitutes. These may initially be used to restore alveolar ridge defects, but could also be used, in the future, to repair or replace complex craniofacial bone defects such as cleft palate defects. In the more distant future, these technologies could be combined with controlled-release bioactive substances such as growth factors and pharmaceuticals to regenerate complex structures comprising multiple tissue types.