An Assessment of The Healing Processes of Bone Tablet (Freeze Dried Bone Graft), Study in Rats

Background :  Freeze dried bone graft provide mechanical support and osteoconduction. With the development of preparation of freeze dried bone graft (Bone tablet) for clinical use concerns have been raised as to the osteoconductive properties of such preparations. Several recent studies investigating the histologic appearance of freeze dried bone grafts have questioned their healing processes. Objective :  to assess the healing processes of bone tablet graft in rat femurs. Materials and Methods : 10 Sprague-dawley rats were performed osteotomy at Rt. femurs and left the defect heal spontaneously. Lt femurs were performed osteotomy and bone graft implantation. The rats were sacrificed at 5 weeks and 10 weeks postoperatively period. Both thighs and fractures included bone grafts were sent for histological examination. Result : At 5 weeks Rt. femurs (control side) showed periosteal reaction and area of bone healing. Lt. femurs showed fibroblast and multinucleated giant cell around bone graft. No area of bone graft incorporated with host bone was demonstrated. Normal healing of thigh muscle was demonstrated. At 10 weeks. Rt. femurs (Control side) showed new bone formation. Lt. femurs showed new bone formation and bone graft were encapsulated by dense connective tissue. Freeze dried bone graft did not incorporate with host bone. Conclusions : Bone tablet freeze dried bone graft showed foreign body reaction and were not incorporated with host bone. Minimal tissue reaction can be demonstrated. This study can not show complete healing processes of bone graft due to short postoperative period. The healing processes of this bone graft need more studies and more times for conclusions and clinical advantages.