GBR in human extraction sockets and ridge defects prior to implant placement: clinical results and histologic evidence of osteoblastic and osteoclastic activities in DFDBA.

This study evaluated new bone formation in 3 types of osseous defects following treatment with demineralized freeze-dried bone allografts (DFDBA) and cell-occlusive membranes. For 8 patients electing to receive implant treatment, a distinction was made among 3 clinical situations: (1) existing alveolar ridge defects; (2) extraction sockets with lost buccal plate; and (3) extraction sockets with an intact alveolus. Implants were placed a mean of 6 months after the regenerative procedure. Clinical examination of bone width and height at the time of implant placement showed sufficient augmentation or preservation, and implants were inserted without incident. Histologic examination of hard tissue biopsies obtained from the implant sites revealed no discernible differences among the 3 types of defects. Specifically, all sites demonstrated DFDBA particles surrounded by woven or lamellar bone. No fibrous encapsulation of DFDBA or inflammatory reaction was observed. Osteoblasts were found lining marrow spaces. Howeship's lacunae, with and without resident osteoclasts, were clearly seen in several DFDBA particles; this finding supports the belief that DFDBA undergoes osteoclasis in vivo. These results demonstrate that commercially available DFDBA has osteoconductive properties that lead to appositional new bone growth in both self-contained and non-self contained osseous defects.

Histologic evaluation of human extraction sockets treated with demineralized freeze-dried bone allograft (DFDBA) and cell occlusive membrane.

This study evaluated new bone formation in human extraction sockets treated with demineralized freeze-dried bone allografts (DFDBA) and celloc occlusive membranes. Hard tissue biopsies of 7 sites in 6 patients were obtained 14 weeks to 13 months following extraction and grafting. Histologic analysis revealed that individual particles of DFDBA were discernible up to 13 months in situ. In all samples, all particles of DFDBA were well incorporated within new bone, which exhibited osteocyte-containing lacunae. Distinct cement lines clearly demarcated the DFDBA particles from the surrounding, intimately-apposed woven and lamellar bone. The marrow demonstrated a mild degree of fibrosis without signs of inflammatory reaction. There was also a notable lack of fibrous encapsulation of the allograft, and little osteoclasis was observed. Our findings demonstrate that commercially available DFDBA has the potential to function physically as a nidus for appositional new bone growth in alveolar sockets following tooth extraction. Further investigations of the biological activity of DFDBA in situ are warranted.