Application of Additive Manufacturing in Oral and Maxillofacial Surgery.

Additive manufacturing is the process of joining materials to create objects from digital 3-dimensional (3D) model data, which is a promising technology in oral and maxillofacial surgery. The management of lost craniofacial tissues owing to congenital abnormalities, trauma, or cancer treatment poses a challenge to oral and maxillofacial surgeons. Many strategies have been proposed for the management of such defects, but autogenous bone grafts remain the gold standard for reconstructive bone surgery. Nevertheless, cell-based treatments using adipose stem cells combined with osteoconductive biomaterials or scaffolds have become a promising alternative to autogenous bone grafts. Such treatment protocols often require customized 3D scaffolds that fulfill functional and esthetic requirements, provide adequate blood supply, and meet the load-bearing requirements of the head. Currently, such customized 3D scaffolds are being manufactured using additive manufacturing technology. In this review, 2 of the current and emerging modalities for reconstruction of oral and maxillofacial bone defects are highlighted and discussed, namely human maxillary sinus floor elevation as a valid model to test bone tissue-engineering approaches enabling the application of 1-step surgical procedures and seeding of Good Manufacturing Practice-level adipose stem cells on computer-aided manufactured scaffolds to reconstruct large bone defects in a 2-step surgical procedure, in which cells are expanded ex vivo and seeded on resorbable scaffolds before implantation. Furthermore, imaging-guided tissue-engineering technologies to predetermine the surgical location and to facilitate the manufacturing of custom-made implants that meet the specific patient's demands are discussed. The potential of tissue-engineered constructs designed for the repair of large oral and maxillofacial bone defects in load-bearing situations in a 1-step surgical procedure combining these 2 innovative approaches is particularly emphasized.