The aim of this study was to evaluate the efficacy of bFGF-incorporated gelatin microspheres (bFGFGMs) for regeneration of experimental mandibular defects. Biodegradable microspheres were prepared from gelatin with an isoelectric point of 4.9, and their water contents were fixed at 75, 85, 90, and 95%. The freerse-dried microspheres were impregnated with PB solution of bFGF, to obtain bFGFGMs. They were implanted in defects made in the base of mandibles of 13 adult beagle dogs. As controls, GMs without bFGF were implanted in the defects, or nothing was implanted. The animals were sacrcificed at 4 and 12 weeks after implantation, and regeneration of the bone defects was studied by histological examination and soft X-ray images.
The area of bone formation was larger in the experimental animals than in the controls, and active bone formation was observed around the bFGF-GMs. GMs with water contents of 95 and 90% were absorbed at 4 and 12 weeks after implantation, respectively. However, those with water contents of 75 and 85% remained, being surrounded by osteoid or bone tissue, at 12 weeks after implanation. It was concluded that the favorable water content of bFGFGMs for bone regeneration in the mandible is 90 to 95%.
