Autogenous bone grafts are considered to be the gold standard in maxillo-facial surgery. However, drawbacks of donor site morbidity and unpredictable rates of resorbtion often limit their use. In vivo tests have shown that 45S5 bioactive glass particles placed in critical size bone defects lead to regeneration of new bone that has the structural characteristics and architecture of mature trabecular bone. In vitro tests using primary osteoblast cultures have shown that the bioactive glass particles release ionic dissolution products that provide genetic stimuli that control osteoblast cell cycles and lead to rapid growth of mineralized bone nodules. These in vitro and in vivo results led to approval of use of bioactive glass particles and monolithic bioactive glass implants for use in maxillo-facial reconstructions after removal of bone cysts and trauma, as described by several case histories.