Synthetic bone grafts replace bones lost to disease or injury. In a major change, a completely new type of synthetic graft can now stimulate the body to regrow lost bone. After studying the mechanism of bone regeneration, the inventor used a special form of calcium almost identical to natural bone to develop a synthetic graft that causes the body to start growing new bone. Over the course of a year, natural bone replaces the synthetic graft. In a world first, 3D printing technology is used to form these synthetic bones with 0.1 millimeter accuracy, ensuring an exact match.