Fig. (6) Histological findings in furcation defect at 10 days for collagen scaffold-treated group. (A) The defect was fully filled with collagen hydrogel scaffold. (B) Higher magnification image of the framed area (1) in (A). Cellular ingrowth into the scaffold was marked. (C) Higher magnification image of the framed area (2) in (A). Alveolar bone was slightly formed in the defect. Col, collagen hydrogel scaffold; PB, preexisting bone; NB, new bone; R, root; arrowheads, apical notches. Staining: hematoxylin and eosin. (Scale bars represent 1 mm (A) and 100 µm (B, C)).