A Comparative Study on Regeneration of Bone Defects after the Grafts of Demineralized Bone Matrix and Hydroxyapatite

Kim, Jin Yeop; Kim, Baik Yoon; Kim, Sun Hun

Abstract

Bone substitutes used in regeneration of bone defect are classified into osteoinductive materials such as demineralized bone matrix and osteoconductive such as hydroxyapatite. But the comparative studies on the bone regeneration after grafts were very rare. About 700 mm demineralized bone matrix particles made from the long bone and hydroxyapatite were allografted into the artificial defect at the medial surface of tibia of adult rabbits, and then the grafts were observed histologically from 3 days to 8 weeks. Lots of fibrin network with blood cells were formed among the demineralized bone particles and hydroxyapatite particles on the 3rd day after graft. Endochondral and intramembranous bone formation from demineralized bone matrix particles, which were resorbed by multinucleated cells, were induced on the 7th day after graft. More rapid bone formation was seen in hydroxyapatite group compared with control group. The central portions of the defect were regenerated with trabecular bone on the 2nd week after graft in the demineralized bone matrix and hydroxyapatite graft group, but they were filled with fibrous tissue in control group. The trabecular bone was being replaced by lamellar bone when the animals were grafted with demineralized bone matrix but the bone just started to be replaced with lamellar bone in hydroxyapatite graft group 4 weeks after graft. On the contrary, the defect was filled by trabecular bone only in the control group. More rapid and perfectionistic lamellar bone formation was seen in bone matrix group compared with hydroxyapatite group after 8 weeks of graft. Partial non-union of the defect is noted in control group. These results suggest that osteoinduction by demineralized bone matrix is more effective than osteocon-duction by hydroxyapatite in regeneration of bone defects.