Papers by Keyword: Bone Regeneration

Abstract: We evaluated the bone healing effect of grafting with synthetic β-tricalcium phosphate (β-TCP; Cerasorb®), bovine-derived hydroxyapatite (HA; Bio-Oss®), and a mixture of β-TCP and HA in rats. Each material was grafted in prepared 8-mm frontal bone defects in 15 rats. The control group underwent surgery without any grafting materials and was examined after 4 weeks, whereas the experimental groups received grafting materials and were examined after 1, 2, and 4 weeks. After implantation, the rats were sacrificed for histomorphometric studies using light microscopy, and the data were analyzed using analysis of variance. Considerable inflammation and fibrosis were observed after 1 and 2 weeks in all experimental groups, whereas the inflammation was reduced and fibrosis was stabilized after 4 weeks. New bone formation was observed at the defect margin. Statistically, there was no difference in new bone formation among the three experimental groups. In conclusion, there was no difference in new bone formation using Bio-Oss®, Cerasorb®, and a mixture of Bio-Oss® and Cerasorb®.

Abstract: Bone regeneration by calcium phosphates has been known to be intricately dependent on material properties or implanted milieu of host animals, such as site and species. Critical sized calvarial defects of mouse were recently used as the model for investigating bone regeneration ability and the mechanisms. The purpose of the present study is to investigate whether the critical sized mouse calvarial defects can be utilized to examine bone regeneration with synthetic octacalcium phosphate (OCP). OCP , prepared by wet synthesis methods, was sieved 0.3 ~ 0.5 mm in diameter and used for the animal experiment. At 14 days after surgery, histological examination showed that implantation of OCP grafted defects significantly enhanced bone formation compared with the control defect. OCP tended to convert to hydroxyapatite with time. The tartrate-resistant acid phosphatase (TRAP) positive osteoclastic cells were observed around the OCP particles. The results suggest that the mouse critical sized calvarial bone defects are useful model to investigate the bone formation by the OCP implantation.

Abstract: Bone mechanical function is given as a result of the material and structural parameters of bone tissue. We previously reported that the material parameter of regenerated bone can be evaluated dominantly using two indices of the density and the preferred orientation degree of biological apatite (BAp). In addition, bone morphology remarkably changes during bone regeneration, which may lead to a dynamic change in the mechanical function of whole bone. In this study, therefore, material and structural parameters of regenerated bone are analyzed separately. A 5-mm-long defect was introduced in rabbit ulna and spontaneously regenerated, and then a three-point bending test was conducted at the regenerated portion. The important parameter which dominantly controls the whole bone mechanical function shifts from a structural to material parameter during bone regeneration. Moreover, it was statistically demonstrated that the increase in the material parameter is strongly determined by recovery of the orientation degree of the BAp c-axis.

Abstract: The purpose of this study was to evaluate the osteogenesis of tetracycline blended chitosan membranes on the calvarial critical size defect in Sprague Dawley. An 8 mm surgical defect was created with a trephine bur in the area of the midsagittal suture. Forty rats were divided into four groups: negative control group, positive control group and two experimental groups. Three types of membranes were made and a comparative study was done. One type of non-woven membrane was made by chitosan for positive control. The other two types of non-woven membranes were made by immersing non-woven chitosan into either the tetracycline solution or the chitosan-tetracycline solution. Histologic analysis was done at 2 weeks and 8 weeks of healing periods. We concluded that that the use of tetracycline blended chitosan membrane on the calvarial defects in rats has a significant effect on the regeneration of bone tissue in itself. In addition it implicates that tetracycline blended chitosan membrane may be useful for guided tissue regeneration.

Abstract: To develop a suitable scaffold optimizing bone regeneration, we developed bovine bone ash derived fully connected porous HA ceramic scaffolds adopting a foaming method. They revealed excellent biocompatibility. The attached cells on the scaffolds proliferated in multi-layers with osteoblastic differentiation. The bone defects grafted with bovine bone ash derived fully interconnected porous HA ceramics having average 500 μm sized spherical pores and average 150 μm sized interconnecting interpores with average 80% porosity were favorably healed without any pathologic changes within 3 weeks. New bone ingrowth with excellent osteoconduction through the spherical pores along the inner surface was noted from 1 week after implantation. Each spherical pore was filled with hematopoietic marrow and newly formed bone which with time was well integrated with the porous HA ceramic scaffold with time. These findings suggest that the bovine bone ash-derived fully interconnected porous HA ceramic formed by foaming method can be a promising bone substitute and a scaffold for bone tissue engineering.

Abstract: Poly-L-lactic acid (PLLA) is a desirable and very attractive polymer for fabricating porous scaffolds. As of now, a solvent casting method with organic solvents has been used in scaffold fabrication process. However, residual organic solvents in the scaffolds have the problems of decreasing the effect of osteogenic induction due to the hindrance of bioceramic by polymer solution and it’s harmfulness in vivo. To avoid these disadvantages of scaffolds by organic solvent casting method, we developed a new method fabricating polymer (PLLA)/ceramic (β -TCP) composite scaffolds by baking method without using solvent, and then we tested properties of scaffolds on animals. As the result, non-toxicity has been proved through animal experiment and newly fabricated polymer/ceramic composites by a novel sintering method were induced rapid bone regeneration through enhancing the interaction of cells and a bone induction factor without any host immune response.

Abstract: Since preferential orientation of c-axis of biological apatite (BAp) crystallites depends strongly on the shape of hard tissue, closely relating to the in vivo stress distribution, it is a useful parameter to judge the bone quality. In this study, preferential alignment of BAp crystallites in original and regenerated hard tissues were analyzed by the micro-beam X-ray diffractometer (μ-XRD) with a beam spot of 50 or 100 μm in diameter. Regenerating processes of bone defects introduced artificially in the rabbit ulna or skull were healed by inserting a biodegradable gelatin hydrogel incorporating basic fibroblast growth factor-2 (FGF-2). Recovery of BAp orientation alignment depends strongly on the regenerated portion and period, which is insufficient to recover the original level, while bone mineral density (BMD) is almost improved to the original level. This means that BMD recovers prior to improvement of the BAp orientation and the related mechanical function in the regenerated tissues. Thus, reloading on the regenerated portion caused by BMD restoration is suggested to accelerate to produce the appropriate BAp preferential alignment due to the remodeling process. The BAp orientation was finally concluded to be one of the most important indices to check the regenerative degree and process in the regenerated bone under the tissue engineering technique.

Abstract: The purpose of this study was to evaluate histologically the effect of LiF-maleic acid added calcium aluminate (LM-CA) bone cement and calcium aluminate-polymethylmethacrylate (CA-PMMA) composite bone cement on bone regeneration in rat calvarial defect. After calvarial defects in 8 mm in diameter were created, three groups of 10 animals, a total of 30, each either received LM-CA bone cement, CA-PMMA composite bone cement or a sham-surgery control. Histologic analysis was done at 2 weeks and 8 weeks of healing periods. We concluded that LM-CA bone cement can be used as a bioactive bone graft material due to ability of bonding to the existing bone and CA-PMMA can be used as a graft material for augmentation of bone-volume due to dimensional stability.