Healing of autogenous intramembranous bone in the presence and absence of homologous demineralized intramembranous bone

This study was designed to examine the osteogenecity of demineralized bone matrix (DBM) prepared from intramembranous (IM) bone and to quantitatively assess the amount of new bone formed by IM autogenous bone grafts with or w ithout DBMIM. Forty-two defects were created in 42 New Zealand White rabbit s. Twenty-one defects were grafted with IM bone alone, and the other 21 def ects were grafted with composite IM-DBMIM. Eleven rabbits, 22 defects were used as controls, where 11 defects were left empty (passive control) and th e other 11 defects were filled with rabbit skin collagen (active control). Tissues were retrieved on days 1, 2, 3, 4, 5, 6, 7, and 14 for qualitative and quantitative analysis. Cells involved in the healing of composite IM an d IM-DBMIM bone grafts were identified. No cartilage cells were detected du ring the healing of either grafts. Appearance of small blood vessels into t he newly formed matrix was seen on day 5 in IM bone grafts and on day 4 in composite IM-DBMIM bone graft. Quantitative analysis was performed by means of image analysis on 100 sections of tissues retrieved after 14 days. Appr oximately 204% more new bone was formed in defects grafted with composite I M-DBMIM than in those grafted with IM bone alone (P < .0001). No bone was f ormed across the defects in either active or passive controls. In conclusio n, DBMIM significantly increases the osteogenicity of IM bone grafts.