Papers by Keyword: Bone

Abstract: Bone hemostatic biomaterials were prepared with different compositions of rice starch (RS) powder and glycerin-base soap. The glycerin soap was composed of liquid glycerol:KOH:stearic acid by aqueous solution method. RS powders (10, 20, 40, and 60 wt %) was added to the purified glycerin soap. The physical properties and degradation of the obtained samples were evaluated. The samples were characterized by scanning electron microscopy (SEM), degree of swelling (DS), moisture content and degradation. An addition of RS powder increased absorbability property, the smoothness, whiteness and could be smear easily on the surface. The results of optimized condition have shown the samples of 20 wt% RS powder had the highest DS of 0.91 ± 0.25 for 90 minutes, the moisture content of 0.43 ± 0.21 % and the degradability of 69.95± 1.50 % for 48 hours. Our results concluded that the samples were sufficient physical properties for use as substitute, and more degradable than bone wax.

Abstract: Stable osseointegration between implant threads and the surrounding marginal bone provides the mechanical base of an implant for daily chewing activity. The contact area of implant-bone interfaces and the concentrated stresses on the marginal bones are principal concerns of implant designers. In this work we numerically analyze by the finite element method the distribution of the equivalent stress and their level in the bone the most fragile element of the dental prosthesis. Each set of the model contained a crown, framework, abutment, implant and bone, subjected to variable dynamic loading according to time.

Abstract: Bone drilling is often used in trauma care, orthopedic and other type of surgical procedures. The elevated temperatures caused by friction may lead to temperature induced bone necrosis. This paper presents an analysis of the effect vibration assisted drilling has on the drilling temperature of the compact bone.The experimental setup was developed and two-type experiments have been conducted. The main aim was to analyze the low frequency vibrations assisted drilling effect on the drilling temperature of poly-methyl methacrylate (PMMA) and bone samples. The temperatures at the exit hole were measured using the thermal camera. The rotational speed of the drill, applied force, parameters of the drill and the samples were considered as constant, whereas the amplitude and frequency of vibrations were varied during the experiments. The obtained experimental data showed the decrease in the drilling temperatures of the vibrated bone samples, as compared to the conventional drilling. It should be noted that further investigation and research related to the vibration assisted drilling should be carried out using different type of bone samples and experimental conditions.

Abstract: The colonization of biomaterials with bacteria represents the main cause of implant-associated infections. Both an antibiotic prophylaxis and a faster osteointegration can be obtained by incorporation of bactericidal active metals in degradable CaP coatings. At present there is no reliable method on the basis of thermal spraying to get thin homogeneous layers containing silver, copper and bismuth in bacteriostatic / bactericidal concentrations. The aim of the study was the development and optimization of high-velocity suspension flame spraying (HVSFS) process for producing thin resorbable bioactive ceramics coatings on the basis of degradable calcium phosphates. In these layers the bacteriostatic / bactericidal effective metal copper should be integrated. Cells were grown on the materials for 3, 7, 14, and 21 days. Live/dead assay was used to measure cell viability. The in vitro cytotoxicity was determined by the microculture tetrazolium (WST) assay. Cell morphology, cell attachment, and cell spreading were investigated using laser scanning microscopy and raster scanning electron microscopy. All substrates supported sufficient cellular growth for 21 days and showed no cytotoxicity. On each material an identical cell colonisation of well communicating, polygonal, vital cells was verified

Abstract: Collagen is one of the most used biomaterials for bone defects repair, proving good results in tissue reconstruction research, and also its features recommend it as a very attractive drug delivery scaffold for local treatment of the affected osseous tissue. The inflammatory response is a common reaction that occurs in bone disease, the topical administration of anti-inflammatory drugs (NSAIDs) representing a reliable strategy to overcome this issue. The purpose of this paper was the physical-chemical and biopharmaceutical evaluation of some spongious matrices consisting of collagen as release support and niflumic acid as drug NSAID model, usable in bone tissue regeneration. Type I fibrillar collagen gel (2.4% w/w, 3.5 pH) was extracted from calf hide by the technology currently used in Collagen Department of Division Leather and Footwear Research Institute. The collagen sponges were obtained by freeze-drying of gels adjusted at 1% and 7.3 pH, with different dextran (0; 10 and 20%) and MgO (0; 30 and 60%) concentrations (reported to dry collagen), with 0.5% and without niflumic acid (NA) (reported to gel) and the same amount of glutaraldehyde (0.5% reported to collagen dry substance). The sponges were evaluated through water absorption, FT-IR spectroscopy and optical microscopy. In vitro NA release from the designed sponges was carried out using a sandwich device adapted to a dissolution equipment. Power law kinetic model was applied to explain drug release from the tested formulations. The NA release from collagen sponges showed a non-Fickian transport mechanism. The addition in different concentrations of dextran and MgO leads to more compact structures and improves stability of collagenic matrices. Our results showed that the designed support could be adequate for treating the inflammation associated with a bone defect in orthopedic surgery.

Abstract: Scaffolds with mechanical properties that mimic the tissue to be restored are critical to maintain the morphology and function of a scaffold after implantation and during tissue regeneration. Silk fibroin (SF), a protein from the Bombyx mori silk worm cocoon, is currently employed in the biomedical field and tissue engineering. The objective of this study was to construct three-dimensional porous silk fibroin/alpha tricalcium phosphate scaffolds for bone tissue engineering application. The scaffolds were fabricated using a solvent casting and salt leaching technique. The hybrid strain of degummed Thai silk fibroin, Nangnoi Srisaket 1 x Mor, was dissolved in hexafluoroisopropanol at 16% (w/v). Alpha tricalcium phosphate (α-TCP) was incorporated to produce 4, 8, 12, and 16 wt% solution and sucrose (particle size 250-450 μm; sucrose/silk fibroin = 8.5/1 w/w) was used as a porogen. The microstructure and pore size, calcium and phosphorus contents, and compressive modulus were evaluated. The scanning electron microscope images revealed the microstructure of scaffolds to be square shaped with continuous interconnected pores. The average pore size of the scaffolds was 265.70 + 67.45 μm. The scaffolds containing 8% (w/w) α-TCP exhibited the highest compressive modulus (64.84 + 16.65 kPa) and the highest calcium content. The results suggested that the scaffolds containing α-TCP may be a potential candidate for application in bone tissue engineering applications.

Abstract: Different graft materials and techniques are suggested based on the number of bony walls that remain after the tooth is removed. If the implant can’t be inserted within the bone contours, bone augmentation must be performed, and the graft must be stabilized with a membrane or a thin bone block graft. In the present study, two cases are presented both with small bone defects on the buccal plate. Bone augmentation with autogenous bone graft was performed in one case, respectively titanium implants with zirconia necks were used in the second case. It was demonstrated that titanium implants with zirconia necks are a good choice in some cases where small parts of the buccal plate are missing.

Abstract: The goal of this study was to create a Gephi network visualisation of the guided bone regeneration induced by tissue-engineered grafts using a histological score. Bioengineered bone grafts were obtained using CD 1 mice mesenchymal stem cells seeded on red deer antler scaffolds. Both basal and complex osteogenic media were used as osteogenic inducers of mesenchymal stem cells in the bioengineering process.Bone defects (5 mm in diameter) in the cranial bone of CD1 mice were surgically induced. Bone reconstruction was not performed in surgically induced bone defects in the control group, consisting of 30 subjects. In the study group, consisting of 60 subjects, bone reconstruction was performed using tissue engineered bone grafts. Subjects were sacrificed 2 and 4 months after surgery. Bone regeneration was assessed using a histological record.Comparative analysis of the bone regeneration process between the groups was performed using SPSS (Statistical Package for the Social Sciences) , network analysis and the visual results were performed using Gephi software.The created Gephi network indicates a more advanced bone regeneration stage for subjects in the study group sacrificed after 4 months.The Gephi networks reveal the time evolution of the bone regeneration process, the nodes size and edges complexity increasing from subjects sacrificed at 2 months to those sacrificed at 4 months.At each stage, two and four months after surgery, bone regeneration was more advanced in the study group than in the control group and it was different for the two osteogenic media. We conclude that bone regeneration in critical size defects, as in our research, cannot be obtained without bone reconstruction.

Abstract: Transient or metastable phases offer an intermediate phase with additional flexibility for creating the end product. The processing pathway remains unknown when the final product is viewed. Biological processes frequently employ the amorphous phase as the transition phase. This is shown in mineralized tissues: invertebrates, pathological calcified deposits and murine fetal teeth. After a fast transition from an amorphous calcium phosphate to crystalline material, smaller changes occur over time. For an appreciation of the transition state, crystallinity is defined and measurement methods outlined. Biotechnology using transition material states offers fast, low temperature access to nanosized high temperature phases. Alfa tricalcium phosphate and apatite is made by a phase transition, but peroxyapatite requires long-range diffusion within the same structure. Tetracalcium phosphate is also possible, but this requires multiple transition states and phase decomposition. The pathway via the amorphous state offers an alternative route to biologically important materials.

Abstract: Bisphosphonates currently represent the main therapy in the fight against osteoporosis. This is a serious condition, with an increasing incidence, presently affecting about 12 million people in the U.S. mostly women aged over 50 years. Thus, approximately 40% -50% of them suffer an osteoporotic fracture. Bisphosphonates mechanism of action consists in reducing osteoclast-mediated bone resorption, modifying bone turn over, leading to an increase in bone density. This dramatically reduces the risk of fracture. Although bisphosphonates shows a good safety profile, lately emerged some alarm signals that link their long management to some unusual side effects. Bisphosphonates is an effective therapy to combat osteoporosis, their causal relationship with FAF production not being shown. In the absence of other evidence, it is unclear whether BF therapy is directly involved in producing FAF or only a component of a combination of factors, in reality being just an indicator of a severe degree of osteoporosis. In the same time, we must not forget that the FAF are very rare compared to the number of patients in therapy with BF and the number of typical femur fractures, and the risk / benefit ratio it is definitely in favor of the benefit.