Bone graft in the shape of human mandibular condyle reconstruction via seeding marrow-derived osteoblasts into porous coral in a nude mice model

Purpose: The purpose of this study was to develop a tissue-engineered bone graft model in the shape of a human mandibular condyle. Materials and Methods: Natural coral with a pore size of 150 to 220 mum and porosity of about 36% was molded into the shape of a human mandibular condyle. Culture-expanded rabbit marrow mesenchymal stem cells were induced by recombinant human bone morphogenetic protein-2 (rhBMP2) to improve osteoblastic phenotype. Then marrow-derived osteoblasts were seeded into natural coral at a density of 2 X 10(8)/mL and incubated in vitro for 3 days before implantation. The cell-coral complexes were implanted subcutaneously into the backs of nude mice and incubated in vivo for 2 months before harvesting. Implantation of coral alone acted as control. The specimens were processed for gross inspection, radiographic examination, and histologic and scanning electronic microscopic observation. Results: The results showed that new bone grafts in the shape of a human mandibular condyle were successfully developed 2 months after implantation and maintained the initial shape of the natural coral scaffold. New bone could be observed histologically on the surface and in the pores of natural coral in all specimens in the cell-seeding group (6 of 6), whereas in the control group there was no evidence of osteogenesis process (0 of 4). Conclusion: This study suggests the feasibility of using porous coral as scaffold material transplanted with marrow-derived osteoblasts to restore bone graft in the shape of human mandibular condyle and shows the potential of using this method for the reconstruction of bone defects. (C) 2002 American Association of Oral and Maxillofacial Surgeons.