Objective： To evaluate bone formation in human extraction sockets with absorbed surroun-ding walls augmented with Bio-Oss-and Bio-Gide-after a 6-month healing period by histologic and histomorphometric analyses. Methods: Six fresh molar tooth extraction sockets in 6 patients who required periodontally compromised moral tooth extraction were included in this study. The six fresh extraction sockets were grafted with Bio-Oss-particle covered with Bio-Gide^R. The 2.8 mm×6.0 mm cylindric bone specimens were taken from the graft sites with aid of stent 6 months after the surgery. Histologic and histomorphometric analyses were performed. Results: The histological results showed Bio-Oss-particles were easily distinguished from the newly formed bone, small amounts of new bone were formed among the Bio-Oss-particles, large amounts of connective tissue were found. Intimate contact between the newly formed bone and the small part of Bio-Oss-particles was present. All the biopsy cylinders measurement demonstrated a high inter-individual variability in the percentage of the bone, connective tissues and Bio-Oss-particles. The new bone occupied 11.54% (0-28.40%) of the total area; the connective tissues were 53.42% (34.08%-74.59%) and the Bio-Oss-particles were 35.04% (13.92%-50.87%). The percentage of the particles, which were in contact with bone tissues, amounted to 20.13% (0-48.50%). Conclusion: Sites grafted with Bio-Oss-particles covered with Bio-Gide-were comprised of connective tissues and small amounts of newly formed bone surrounding the graft particles.