1 Allograft Safety through Terminal Sterilization—the Effect of Gamma Irradiation on the Osteoinductivity of Bone Matrix

Grafting with ground human bone matrix is performed widely in oral and maxillofacial procedures, in particular in the correction of ridge defects, sinus augmentation, extraction socket maintenance, and periodontal reconstruction. The bone scaffold formed by ground cortical bone and cancellous chips creates the favorable environment required for bone-forming cells to be able to generate new bone. The demineralization of bone matrix exposes bone morphogenetic protein (BMP) and other bone growth promoting factors. Because of this, demineralized bone matrix (DBM) not only provides a scaffold for bone formation, it also promotes differentiation of stem cells into viable bone-forming cells, a process termed as osteoinductivity. Even as the use of allograft tissue for oral surgery continues to increase, dental professionals remain concerned about the safety and efficacy of allograft implantation. Several allograft providers have begun terminal sterilization of allograft tissue by gamma irradiation, prompting a discussion about the effect of irradiation on the osteoinductive properties of bone matrix. Bone Remodeling and Healing Healthy adult human bone is made up of two components: cortical bone (also called lamellar or compact bone) and cancellous (or trabecular) bone. Cortical bone forms the dense outer layer of shaf