Natural nonorganic bone(NNB) was obtained after the fresh bone of pig was heated to 100℃. The NNB was white and in a shape as its original bone.The tensile strength of the compact bone was 200kg/cm3 and that of the cancellous bone was 25kg/cm3. The ratio of calcium to phosphorus was 10∶6. The main componentwas hydroxyapatite. The material was composed of trabeculae and intertrabecular spaces. Three experiments were performed. Experiment 1: 18 pieces of NNB in a size of 0.5×0.5×0.5cm3 were implanted intothe back muscle of 18 rabbits. At 4, 8 and 12 weeks after the operation, 6 specimens were obtained seperately and were stained by HE, and then examined under microscope. The result showed that the mesenchymal cells had no regeneration and differentiation, and the NNB and the surrounding tissues had no evidence of formation of new bone or chondrosynthesis. This NNB did not produce rejection reaction between tissues but the new blood vessels could easily grow into the space of the NNB. The fibrils had intimate contact with NNB. Experiment 2: The NNB and hydroxyapatite(HA) were mixed to make a cylindroid body with 2mm in diameter and 4mm in length and was implanted in the bilateral tibias of 40 rabbits, respectively. The roentgenography, fluroscent microscopic examination and histological observation were carried out at 2, 3, 4 and 8 weeks after the implantation. Experiment 3: In 50 rabbits, a defect of 2.5cm was made on both radius, and in one sideNNB was implanted and the other side was served as the control. Another 50 rabbitsHA was implanted in the defect in one side and the other side was served as the control. The results showed that in the NNB group at the 16th week, the bone united in 16 of the 30 cases, while in the HA group, in the 30 cases,only 2 had the bone united, while those of the controls no union had occurred.It was suggested that NNB had more formation of new bone than HA did.
It is extremely necessary to find an ideal filling material for the treatment of benign bone defect, particularly those benign osteolytic defect in children with a comparatively large cavity. From July, 1995 to December, 1996, 10 cases of benign osteolytic bone defects were treated, in which 5 cases of benign osteolytic defects, 3 cases of bone cysts, 1 case of fibrous dysplasia of bone and 1 case of non-ossifying fibroma. After through curettage of the cavity, the natural non-organic bone in cube-shaped was used to fill the prepared cavity. The results showed that the activities of the patients resumed normal in 3 to 6 months after operation. The roentgenographic examination after operation showed that the lucent spaces between NNB cubes disappeared with obvious new bone formation and the bony cavity was obliterated with newly-formed bone. There was no recurrence of the lesion during a follow-up of 7 to 24 months. It was concluded that to treat the osteolytic defect of bone with NNB was a method of choice. The new bone formation appeared early in large amount and increased rapidly.