T h e best method of reconstruction for full-thickness defects of the mandible is still debated in the surgical literature. Procedures in vogue include solid free grafts from ribs, bone-soft tissue pedicle flaps, particulate bone in trays, and other prosthetic materials. In the midst of this debate, Dr. Philip Boyne, a pioneer in the development and use of the innovative tray-cancellous bone combination has interjected an unusual observation. In an article in this issue ("Restoration of Resected Mandibles in Children Without the Use of Bone Grafts"), Boyne describes spontaneous regeneration of bone in large osseous defects in the mandibles of children 5 to 14 years of age. The probable absence of periosteum in these defects and the observation that young people can regenerate bone from seemingly pluripotential cells should create both excitement and a flurry of productive clinical and research activity. Other fields of inquiry might include the potential use of fetal tissues for bone induction in adults-an area currently being explored by scientists interested in the regeneration and replacement of cells in the brain and spinal cord.