The use of rhBMP-2/absorbable collagen sponge (ACS) combined with all of the bone substitute materials tested resulted in a greater amount of bone formation than that produced with the bone substitute materials alone or rhBMP-2/(ACS) and CL using the rabbit calvarium GBR model.

ObjectivesThis study aimed to evaluate the bone formation process in experimental defects created on rabbit calvarial, in which one of the bone defects was covered by the impermeable membrane before suturing the skin flap, while the other was closed only by the cutaneous flap. The experimental holes were filled only by the blood clot.Material and methodsSixteen New Zealand female rabbits weighing between 3.5 and 4 kg were used. Two experimental bone defects were made in the rabbit calvarial. The holes were filled only with the blood clot and one of them was covered with an impermeable polypropylene membrane. A histological analysis was made at 21 and 42 days following the surgery. Histological evaluation consisted of the following: 1. inflammatory process; 2. Bone repair; 3. Bone remodeling; 4. Presence of osteoid matrix and mineralization, and 5. Formation of hematopoietic tissue. Each characteristic was analyzed semi quantitatively.ResultsThere was a statistical difference between the test and the control group at 21 days of healing in the following items: presence of cementation line (p = 0.012), presence of osteoid tissue (p = 0.012), and trabecular bone tissue development and mineralization (p = 0.012). A greater amount of lamellar bone tissue (mature) was also observed in the test group compared to the control group.ConclusionThe semiquantitative analysis showed that at 21 days there was a superiority of the repair process in the test group; at 42 days there was no significant difference in bone formation between the two groups; and that the polypropylene membrane is feasible to be used in GBR.Clinical significanceThe impermeable polypropylene barrier is feasible for use in the guided bone regeneration technique. It can be used only on the blood clot, without the need for grafting, and can be easily removed a few days after surgery. These results are unprecedented.

Evaluate the width and height dimension in dental human sockets covered by an impermeable barrier for a guided bone regeneration technique. Sixteen tooth extractions were performed, divided into two groups: a) Study group (n = 10), with polypropylene barrier; b) Control group (n = 6), without polypropylene barrier. The alveoli of both groups were filled with only blood coat. The evaluation was clinical to measure width, and radiographic for height. Evaluations were done immediately after tooth extraction and four months later. The mean reduction in width was lower in the study group (p < 0.05, bi-flow test), while in height there was no difference between groups (p > 0.05, bi-flow test). The width loss was lower in the barrier group, but there was no difference between groups in height loss.