Repair of experimental mandibular defects in rats with autogenous, demineralised, frozen and fresh bone

This prospective experimental study aimed to assess the regenerative capability of demineralised bone autografts resected and replaced orthotopically, compared with traditional fresh and deep frozen mandibular autografts in rats. In 60 adult Wistar rats, a bone defect 4 × 4 mm was created at the left ascending mandibular ramus and the removed bone was used as a fresh (n=20), deep frozen (n=20), or demineralised (n=20) graft which was implanted orthotopically 2 weeks later. Ten rats in each group were killed at 2 and 6 weeks later. Outcome was measured by cellular proliferation on histological examination. The number of mesenchymal cells was significantly greater (P < 0.05) at both 2 and 6 weeks in the demineralised grafts than in the other two groups. There were no differences between the 2- and 6-week examinations of deep frozen bone, nor between the medullary and peripheral aspects. It was concluded that demineralised bony autografts cause greater osteoinduction both in the short (2 weeks) and the medium (6 weeks) term.