Fig. 2

Histological observation of the SDF1 and BMP7 coated roots after being implanted orthotopically in canine alveolar bone socket for 6 months. a The gross histological morphology of one root of Group A. At 6 months after replantation, the interstitial space between alveolar bone and the replanted root were already filled with a high content of newly formed PDL-like connective tissue. The newly formed bundles of dense collagen fibers interposed between the cementum on the root surface and the adjacent alveolar bone. b, d, e are high-magnification images of the lined rectangular areas in a, while c is high-magnification image of the lined rectangular area in b. b, c, e from the localized area, it can be seen that bundles of collagen fibers inserted perpendicularly into the surrounding alveolar bone indicated by black arrow heads. c Growth and progression of alveolar bone towards the neo-connective tissue could be ascertained, as layered structure indicated by white arrow heads in the interface was observed. d The neo-collagen fibers were observed interpenetrating into the cementum as indicated by white arrows. Angiogenesis was also enhanced as rich capillary vessel structures were distributed in the neo-connective tissue (b–e). Bon alveolar bone, Cem cementum, Den dentin, PDL periodontal ligament, CV capillary vessel, RC root canal. Bar scales 250 μm for a–e