There are three basic concepts that must be taken into account when discussing bone grafts and implants. Osteoconduction is the process by which bone is formed by apposition. Osteoconductive materials have a mechanical structure over which new bone is formed by the process of apposition and remodeling. Osteoinduction is the process by which differentiation of the mesenchymal cells to osteoblasts is stimulated. Finally, osteogenesis refers to bone formation itself. The osteoconductive materials include synthetic grafts, coral, hydroxyapatite and bioactive glass. Osteoinductive materials are allografts obtained from a cadaver by freeze-drying. Finally, the osteogenic graft refers to bone homografts (53)(54)(55)(56).