Evaluation of Healing Following Tooth Extraction With Ridge Preservation Using Cortical Versus Cancellous Freeze-Dried Bone Allograft

Background: The objective of this study is to compare histologic and clinical healing following tooth extraction and ridge preservation with either cortical or cancellous freeze-dried bone allograft (FDBA) in non-molar extraction sockets. Methods: Forty patients requiring implant placement were enrolled, with 20 patients randomly assigned to each group (cortical versus cancellous FDBA). All of the allograft materials were obtained from the same donor to control for variability between donors and processing. Patients returned after 17 to 21 weeks (average: 18.2 weeks), and a 2-mm-diameter core biopsy was obtained before implant placement. Histomorphometric analysis was performed to determine percentage of new bone formation, residual graft material, and non-mineralized connective tissue (CT)/other material. Clinical measurements of ridge dimensions were taken at the time of tooth extraction and again at implant placement. Results: There was no significant difference in new bone formation between the cortical and cancellous FDBA groups (P = 0.857). A significantly greater percentage of residual graft material was detected in the cortical FDBA group compared with the cancellous FDBA group (P = 0.019). A significantly greater percentage of non-mineralized CT/other material was found in the cancellous FDBA group compared with the cortical FDBA group (P = 0.040). The only significant clinical difference between groups was a greater loss of lingual ridge height in the cancellous group. Conclusions: This is the first reported study to compare the histologic changes following tooth extraction with ridge preservation in humans using cortical versus cancellous FDBA. There were no differences in the percentage of new bone formation between the groups.