ABSTRACT
G.B.R is a procedure which is used for treatment of the osseous defects. In this procedure new bone forms in the defect. The aim of this study was to compare the bone formation with madrepora and membrane, madrepora alone and membrane alone. This study was done on 5 white Newzl and rabbits. Three defects were created in parietal bone. The first defect was filled with madrepora particles [250-500 micron] and covered with a piece of membrane. The second defect was filled only with madrepora and the third defect was left empty and covered with membrane. After 8, 9, 11, 14, and 15 weeks animals were sacrificed. Statistical analyses were done by Kruskal - wallis and Mann -whitney U tests. Histologically the defect which contained madrepora and membrane was filled with trabecules after 15 weeks. In the second defect the trabecules were seen only in the periphery. The defect was filled with connective tissue in the third defect. Madrepora's pieces have biocompability with rabbit tissues and the process of repair in the osseous defect was accelerated