Papers by Keyword: Bone Graft Substitute

Abstract: Mechanical and biological functions of b-tricalcium phosphate (b-TCP) ceramics is of importance with respect to medical application such as bone graft substitute. The degrees of crystallynity and morphology of as-prepared b-TCP powders are concerned with the above functions. Mechanochemical synthesis is a process of producing a fine particle of b-TCP through an intermediate phases (precursor) of calcium phosphate. The b-TCP precursor synthesized by mechanochemical reaction, followed by heat-treatment, was analysed by using transmission electron microscopy, X-ray diffraction and Fourier transformation infrared spectroscopy. The hydrate layer and carbonate ions involved in the precursor were found to affect the degrees of crystallinity and morphology of as-prepared b-TCP particles at a certain temperature, 700 °C. The specific characteristics of crystallinity and morophology of as-prepared b-TCP particle is expected to be favorble to forming and sintering of b-TCP ceramics.

Abstract: Calcium sulfate/hydroxyl apatite whiskers composite is possible to be used as bone graft substitute, for its biocompatibility, controllable degradation, and suitable mechanical properties. In this study, calcium sulfate/hydroxyl apatite whisker composites were fabricated and characterized. The characteristics of the composites were assessed by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and immersing testing techniques. The composites prepared in this article have been confirmed to be ideally used as biodegradable implants.

Abstract: A new porous unsintered CaP-compound material for bone graft substitutes is described. A modified sol-gel freeze casting process enables preparation of sophisticated shaped bodies. By adapted chill molds and the variation of the freeze process the porosity of the material can be engineered, i.e. the pore size distribution as well as the preferred direction of the oblong pores. Thereby controlled osteoconduction can be achieved. The mechanical properties of the CaP compounds are improved by embedding supporting structures. Due to its huge inner surface the material can serve as a scaffold supplied with agents.

Abstract: A new method of design and manufacturing of bone graft substitutes is introduced. For the first time it is possible to prepare bone graft substitutes with a directed and controlled pore structure. Furthermore, the formation of sophisticated geometries is feasible. First in vitro investigations with cell cultures show a vital cell growing on the synthetic bone graft material. Numerous applications are possible.

Abstract: The objective of this study was to evaluate the biocompatibility and effects of the particulated and surface modified Ostrich eggshell (OES) as bone graft substitutes in healing of calvarial defects in rats. Additionally we compared the bone forming ability of the surface modified OES to that of BioCoral (Inoteb, France), which has the same chemical compositions as OES, calcium carbonate (CaCO3). Surface modified OES particles were fabricated by alkaline etching (microroughened-OES) and biomimetic calcium phosphate coating (CaP coated-OES). 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was performed to evaluate cell viability at 1, 4, and 7days using ROS 17/2.8 cells, a rat osteosarcoma cell line. To evaluate the bone forming ability, surface modified OES and BioCoral were filled in the calvarial defects of fourteen adult male Sprague-Dawley rats. After 4 weeks of healing, animals were sacrificed and evaluated histologically and histomorphometrically. The MTT assay indicated the increases in viable cell numbers of all groups according to the time, and significantly increased cell numbers were observed on CaP coated-OES and BioCoral at 7 day (P<0.01). The histomorphometric results showed that significantly increased amount of new bone formation in the microroughened-OES, CaP coated-OES, and BioCoral grafted defects compared with unfilled defects (P<0.0001). The degree of ossification was most prominent in CaP coated-OES grafted defects. The results of this study suggest that surface modified OES particles are biocompatible and yield favorable bone formation in rat calvarial defects. In conclusion, surface modified OES grafts may be considered as effective osteoconductive grafting materials, but further studies are needed to produce more optimal surface modification and confirm long-term results.

Abstract: The purpose of our study is to compare the biodegradation and osteoconduction between CaO-SiO2-B2O3 glass-ceramics(CS10B) and hydroxyapatite(HA), tricalcium phosphate(TCP). Porous CS10B implants were prepared by polymer sponge method. Single-level posterolateral spinal fusions were performed on thirty rabbits. The animals were divided into three groups by implant material: HA, TCP and CS10B. Radiographs checked every two weeks. All animals were sacrificed 12 weeks after surgery. The proportion of the area occupied by ceramics in final radiography on the initial radiography was calculated. Uniaxial tensile strength was measured on 7 cases in each group. The proportion of the area of HA(88.7%±16.1) was significantly higher than those of the others(p<0.05), and the proportion of the area of CS10B(28.2%±9.3) was significantly lower than those of HA and TCP(37%±9.6)(p<0.05). The mean values of tensile strength of the HA(191.4±33.5 N) and CS10B(182.7±19.9 N) were significantly higher(p<0.05) than those of the TCP(141.1±28.2 N). CS10B showed the tensile strength of fusion masses similar to those of the HA, however, more rapid biodegradation than HA and TCP. These findings suggest that CS10B grafts have the possibility as a bone graft substitute.

Abstract: With the bone impaction grafting technique, a 50/50 volume mix of morselized cancellous bone (MCB) with TCP-HA granules was used to reconstruct a critical sized acetabular defect in the goat. The biological activity of the MCB/TCP-HA mix was assessed after 15 weeks. Defects filled with 100% MCB, currently the gold standard for this technique, were used as controls. In the 100% MCB defects, a new trabecular bone structure was found in which scarce incorporated remnants of the original graft material were present. In the MCB/TCP-HA defects, MCB was also resorbed or incorporated into new bone. Deep in the MCB-TCP-HA defects, large TCP-HA granules were generally totally osseous-integrated with new bone. Superficially, more fragmented TCP-HA granules of various sizes were present in the medullar tissue or in the interface with the cement layer. Here, the crushed TCP-HA granules were generally surrounded by osteoclasts and giant cells. The soft tissue interface between the reconstruction and cement did not differ between both groups. In conclusion, from a biological point of view, this short-term follow-up study suggests that TCP-HA granules can be safely used in a mix with MCB as bone graft extender in acetabular revision surgery with the bone impaction grafting technique.