Fig. 3

Histological analysis. The original bony defect had been prepared as 8 mm (bar in low magnification view). The residual bony defect area at 8 weeks postoperatively in the collagen group (group C) was smaller than in the gelatin group (group G). Bone regeneration from the margin was examined with high magnification view. The view of group C at high magnification showed a regenerated bony island (*). The view of group C under high magnification also showed bone ingrowth into the defect (hematoxylin and eosin stain, bar in high magnification = 50 μm). The expression level of BMP-2 was observed in the middle of bony defect. The expression level of BMP-2 was also higher in group C than in group G