Bone in-growth induced by biphasic calcium phosphate ceramic in femoral defect of dogs.

Biphasic calcium phosphate (BCP) ceramics consisting of hydroxyapatite (HA) and tricalcium phosphate (TCP) has been used as a bone graft material during the last decade. In this paper, we report the bone in-growth induced by BCP ceramic in the experimentally created circular defects in the femur of dogs. This BCP ceramic consists of 55% hydroxyapatite (HA) and 45% b-tricalcium phosphate (TCP) prepared in situ by the microwave method. The defects were created as 4-mm holes on the lateral aspect of the femur of dogs and the holes were packed with the implant material. The defective sites were radiographed at a period of 4, 8, and 12 weeks postoperatively. The radiographical results showed that the process of ossification started after 4 weeks and the defect was completely filled with new woven bone after 12 weeks. Histological examination of the tissue showed the formation of osteoblast inducing the osteogenesis in the defect. The collageneous fibrous matrix and the complete Haversian system were observed after 12 weeks. The blood serum was collected postoperatively and biochemical assays for alkaline phosphatase activity were carried out. The measurement of alkaline phosphatase activity levels also correlated with the formation of osteoblast-like cells. This microwave-prepared BCP ceramic has proved to be a good biocompatible implant as well as osteoconductive and osteoinductive materials to fill bone defects.