Purpose The aim of this study was to evaluate the potential of an autologous bone marrow graft in preserving the alveolar ridges following tooth extraction. Materials Thirteen patients requiring extractions of 30 upper anterior teeth were enrolled in this study. They were randomized into two groups: seven patients with 15 teeth to be extracted in the test group and six patients with 15 teeth to be extracted in the control group. Hematologists collected 5 ml of bone marrow from the iliac crest of the patients in the test group immediately before the extractions. Following tooth extraction and elevation of a buccal full-thickness flap, titanium screws were positioned throughout the buccal to the lingual plate and were used as reference points for measurement purposes. The sockets were grafted with an autologous bone marrow in the test sites and nothing was grafted in the control sites. After 6 months, the sites were re-opened and bone loss measurements for thickness and height were taken. Additionally, before implant placement, bone cores were harvested and prepared for histologic and histomorphometric evaluation. Results The test group showed better results (P < 0.05) in preserving alveolar ridges for thickness, with 1.14 +/- 0.87 mm (median 1) of bone loss, compared with the control group, which had 2.46 +/- 0.4 mm (median 2.5) of bone loss. The height of bone loss on the buccal plate was also greater in the control group than in the test group (P < 0.05), 1.17 +/- 0.26 mm (median 1) and 0.62+0.51 (median 0.5), respectively. In five locations in the control group, expansion or bone grafting complementary procedures were required to install implants while these procedures were not required for any of the locations in the test group. The histomorphometric analysis showed similar amounts of mineralized bone in both the control and the test groups, 42.87 +/- 11.33% (median 43.75%) and 45.47 +/- 7.21% (median 45%), respectively. Conclusion These findings suggest that the autologous bone marrow graft can contribute to alveolar bone repair after tooth extraction. To cite this article:Pelegrine AA, da Costa CES, Correa MEP, Marques JFC Jr. Clinical and histomorphometric evaluation of extraction sockets treated with an autologous bone marrow graft.Clin. Oral Impl. Res. 21, 2010; 535-542.doi: 10.1111/j.1600-0501.2009.01891.x.215535542IMPLAC LaboratoryKIM Laboratory