Regenerative repair of the mandible using a collagen sponge containing TGF-β1

Introduction: Alveolar bone resorption and atrophy of the mandible are a major challenge for regeneration medicine. In the present investigation, a collagen sponge that contained TGF-β1 was placed at a mandibular defect and the osteogenic effects of collagen-TGF-β 1 complex were evaluated. Material and Methods: The Pm2, Pm3, and Pm4 teeth on both sides of the mandibles of 12 adult beagle dogs (9.0-12.0 kg) were extracted. After the extraction-site wounds healed, a bone defect (10.0 x 15.0 mm-wide, 10.0mm-deep or 10.0 x 10.0mm-wide, 10.0mm-deep) was created on the mandible. A collagen sponge (10.0 x 10.0 x 10.0 mm) that contained TGF-β 1 (1.0 μg, 5.0 pg, or 10.0 pg, in physiological saline) was placed at the bottom of the defect and the overlying mucous membrane was sutured with 4-0 prolene. As a control, a collagen sponge that contained physiological saline only was placed in a defect on the opposite side. Two weeks after the surgery the wounds above the bone defects on both the control and TGF-β 1 -treated sides had healed completely. Results: At four, six, or eight weeks post-operatively animals were killed. Soft X-ray and bone-salt measurement analyses confirmed clearly that there was greater calcified bone formation in the defects into which TGF-β 1 had been incorporated than with the control defects. The implanted collagen sponges were fully resorbed and the bone tissue had regenerated from the bottom of the defects on the TGF-β 1 side by four weeks. On the control side, no such regeneration was observed. Conclusions: These results indicate that TGF-β 1 released slowly from a collagen sponge was effective in promoting bone remodeling when applied to mandibular defects in adult dogs.