Freeze-dried dura mater for guided tissue regeneration in post-extraction dental implants: a clinical and histologic...

Soft membranes were used in 69 patients for bone regeneration around implants (blades and screws, submerged and non-submerged) placed into extraction sockets. In about 10% of the patients a prosthetic restoration was completed immediately, while in the remaining patients the prostheses were connected after a healing period of 3 to 6 months; follow-up ranged from 6 to 30 months. In 22 patients a re-entry procedure was done to evaluate the membrane and in 4 patients a bone biopsy was taken from 3 to 6 months after the placement of the membrane. In all cases the peri-implant tissues appeared clinically healthy and it was possible to see radiographically that the newly formed bone closely adapted to the implants. In most cases it was possible at 6 months re-entry to see the membrane and detach it from the underlying tissues. There was a partial dehiscence of the membrane in only 4% of the cases. After 3 months the tissue under the membrane presented macroscopical features similar to mature bone, and bone biopsies in all cases showed a spongious lamellar bone with a high level of activity and a wide band of osteoid tissue.