Bone Regeneration of Mandibular Defects with Osteopromotive Membranes and Recombinant Human Bone Morphogenetic Protein-7 on Rabbits

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Bone Regeneration of Mandibular Defects with Osteopromotive Membranes and Recombinant Human Bone Morphogenetic Protein-7 on Rabbits

Smajilagic A, Redzic A, Filipovic S, Hadjihasanovic B.

Objectives: This study evaluates whether recombinant human Bone Morphogenetic Protein-7 in collagen as a carrier
(rhBMP-7/ACS) might be an alternative for conventional bone grafting reconstructive surgery, to promote bone regeneration
in conjunction with expanded polytetrafluoroethylene (e-PTFE) “osteopromotive” membranes.
Material and Methods: This study was carried out in the University Clinic Center Sarajevo, Bosnia and Herzegovina, from
2003 to 2005. A standardized critical-size mandibular defect was created surgically on 14 New Zealand Rabbits. 7 animals
(control) were treated with a bicortical iliac crest autologue grafts. In the other 7 (test), the defect was covered with membrane
and filled with rhBMP-7/ACS alone. A local flap of masseter muscle was previously placed in the all test defects. The healing
period was 2 months. Alkaline phosphate activity was evaluated at day 0,5,14,21,and 30.3-D. CT scans were obtained at day
30 and analyzed for bone mineral density (BMD). At day 60 the animals were sacrificed for clinical evaluation of bone
reconstruction and histological evaluation of representative bone biopsies.
Results: There was a remarkable difference in the ALP activity between the Test and Control group. Significantly higher
values of ALP activity was detected at day 21 on the test group compared at day 30 on the Control group. There was no
remarkable difference in BMD between groups, with values over 213 mg/cm3 defined as calcified bone. The clinical
evaluation of the gross specimens at sacrifice showed complete bone reconstruction in 5 of 7 test animals. Only 2 of 7 control
animals reestablished bone continuity. The histological analysis supported these findings.
Conclusions: It was concluded that the rhBMP-7/ACS and membrane was strongly osteoinductive. Although e-PTFE
membrane prevented the degradation of the collagen carrier, thus strongly reducing the availability of rhBMP, the local
muscle flap placed in the defect supplemented the environment with membranous non-occlusive macrophages and plasma
cells necessary for the collagen degradation.

         

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