Fig. 1

Schematic drawings of the bone regeneration process after grafting. As degrading graft by macrophages, degraded fragments may influence the macrophage. Some fragments stimulate macrophages to produce bone morphogenic protein-2 (BMP-2). It activates both osteoblast and osteoclast. Runx2, runt-related transcription factor-2; RANKL, receptor activator of nuclear factor kappa-B ligand