Fig. (6) Histological findings in BMP/Col group. (A) Extensive alveolar bone regeneration was observed in the defect area. Coronal and apical notches are indicated by arrowheads. (B) Higher magnification of framed area (b) in (A). Cementum-like tissue was frequently evident on the BMP-applied root surface in coronal portion. (C) Higher mag-nification of framed area (c) in (A). Fiber-rich periodontal ligament tissue was re-established between cementum-like tissue and alveolar bone. (D) Higher magnification of framed area (d) in (A). Sharpey’s fibers inserting into both new alveolar bone and cementum-like tissue were seen. R, root; CT, gingival connective tissue; NB, new bone; NC, new cementum; PL, periodontal ligament. Staining: hematoxylin and eosin (A, B, C) and Masson’s trichrome (D). Scale bars: (A) = 1 mm; (B, C and D) = 50 µm.