FIG. 4.

Histological features of human DDM and DDM/rhBMP-2 implanted for socket preservation. (a) Biopsy specimens of human DDM alone in mandibles at 3.5 months after the socket preservation procedure (hematoxylin–eosin staining, scale bar = 200 μm) under gingival tissue.²⁹ DDM was surrounded by dense fibrous connective tissues (DF), which were in close contact with the particle, leaving no gaps. The FC seemed to consist of inactive flat fibroblast-like cells. Dentin matrix resorption was not observed. (b) Biopsy specimens of human DDM/rhBMP-2 (0.2 mg/mL; Cowell BMP, Busan, Korea) in the maxilla at 6 months after the socket preservation procedure (hematoxylin–eosin staining, scale bar = 200 μm) under gingival tissue.²⁹ Enlarged dentinal tubules (ED) were observed. Multiple activated cell layers encapsulated the dentin matrix surface. The resorption cavity was infiltrated with osteoclast-like cells (Ocs) that may facilitate the release of ED-BMPs present as matrix- and hydroxyapatite-binding proteins. (c) Trephine biopsy specimens of human DDM alone in the mandible at 3 months after the socket preservation procedure (hematoxylin–eosin staining, scale bar = 200 μm).³¹ Bone formation (arrows) around the DDM particles (*) surrounded by dense fibrous connective tissue. (d) Trephine biopsy specimens of human DDM DDM/rhBMP-2 (0.2 mg/mL; Cowell BMP, Busan, Korea) in the mandible at 3 months after the socket preservation procedure (hematoxylin–eosin stain, scale bar = 200 μm).³¹ Active bone formation (arrows) was observed with embedding of osteocytes and lining of osteoblasts around the DDM particles (*), which were surrounded by highly vascularized alveolar tissue. DF, dense fibrous connective tissues.