INTEGRATION OF ENDOCHONDRAL BONE-GRAFTS IN THE PRESENCE OF DEMINERALIZED BONE-MATRIX

The use of endochondral bone grafts (EC) and demineralized bone matrix (DBM), which contains a potent osteoinductive matrix, may promote the repair of nonregenerative defects. The purpose of the current work is to assess qualitatively and quantitatively the effect of DBM on the h ealing of EC bone grafts and to compare it to the healing of EC bone g rafts alone. Twenty-four defects in rabbit skulls were filled with EC bone grafts alone, DBM alone, or combined EC and DBM. Histologic and i mmunohistologic changes were examined in 2 weeks. The amount of new bo ne formation was quantified by image analysis. Healing of all the grou ps was characterized by the presence of a cartilage intermediate stage . In the EC bone grafts alone, healing was localized to the host bone/ graft interface. In the composite group, amalgamation of the new bone, DBM, and bone graft progressed throughout the whole width and depth o f the defect, uniting the graft to the recipient bed. The amount of ne w bone formed was significantly greater (47%) in the composite group t han the EC group. In conclusion, DBM powder augments the bone-inductio n capacity of the recipient bed as well as the bone graft. The composi te EC bone grafts and added DBM possess properties required for an eff ective graft material and merit further clinical evaluation.