Papers by Keyword: Bone Tissue

Abstract: This research synthesized a composite ceramic material base CaCO₃/Al₂O₃, CERMET, with possible biomedical applications. Eggshell was used as raw material to obtain CaCO_3, and it was reinforced with silver nanoparticles to improve the structural and mechanical properties of the ceramic system. The addition of silver nanoparticles promotes the formation of two phases. The first is a continuous phase called a matrix formed of CaAl₂O₄ (calcium aluminate). The second is a dispersed phase known as reinforcement made up of silver nanoparticles. The composite ceramics were synthesized using the solid-state synthesis technique from a chemical mixture of CaCO₃ and Al₂O₃ powders in the following chemical ratio: 49.5% CaCO₃ + 50.5% Al₂O₃, with silver nanoparticles added at different percentages (1%, 5%, 10%, 15%). The powder mixture was made in a high-energy mill for homogenization. After that, the mixture was compressed into cylindrical samples for their consolidation by sintering in a high-temperature muffle with a controlled atmosphere, using heating ramps. The sintered samples were characterized by X-ray diffraction, optical microscopy, scanning electron microscopy, and microhardness, including fracture toughness studies. In addition, the Archimedes method determined the sintered samples' density. The results showed a clear relation between the mechanical properties of the CaAl₂O₄ ceramic base and the incorporated silver nanoparticles since these increased as the percentage of silver nanoparticles increased. In addition, it was observed that the porosity of the samples could be controlled, making the composite material suitable for biomedical applications.

Abstract: Today, the ability to form porous structures and coatings from titanium powder on implants parts of specified porosity, size and morphology of pores into which newly formed bone tissues and, thus, they contribute to the osseointegration and high and long-term stability of the implant functioning in the body is widely used. The ability to obtain work pieces of complex geometry by powder metallurgy methods with a minimum of mechanical rework by cutting, it also promotes the diffusion of this technology in the implants manufacturing as the titanium alloys are classified as difficult to process. The future progress in the development of new materials and types of implants is directly related to powder metallurgy - there is information about the creation of a highly solid biocompatible composite based on the intermetallic system β-Ti3Au, from which rib replacement implants are made

Abstract: The detailed study devoted to instrumental diagnostic methods of bone tissue research was performed by authors. The main idea which is the basis for this work is the analysis and study of X-ray methods for examining bone tissue, highlighting their advantages. As a result of the work, we analyzed published scientific data in Russian and foreign literary sources, which addresses many instrumental methods of bone tissue research. After experiments a detailed description of the most common research methods related to the study of bone tissue was given, its structure and other functions. Analysis of the modern scientific data has shown that there is a great need to know the instrumental methods for studying human organs and systems, and their more accurate possibilities for identifying pathological processes, which will permit the use of the research method that in any particular case will be the most informative, which would provide timely diagnosis and its accuracy.

Abstract: The detailed research and analysis of modern data on the problem of methods of histological and immunohistochemical researches of connective tissue, bone in particular, was conducted by us so as to evaluate the possibility of creating a single method of bone tissue immunohistochemical analysis.The description was given in detail to most widespread methods of preparation of connective, bone in particular, tissues for the research conduction during experiments connected with the study of bone tissue regeneration including implants with bioactive coverage. The present-day medical data reflects a variety of methods of immunohistochemistry, as well as the experience of their use in complex trauma surgery. However, there is no consensus about which method and material are most reliable when conducting this analysis.

Abstract: This paper deals with evaluation of mechanical properties of human trabeculae in the interconnection area. Local changes in the trabecular connections were evaluated using both quasi-static nanoindenation and modulus mapping technique. Connecting point of two trabeculae was revealed by precise grinding and polishing. A rectangular region in the interconnection was selected and inspected by modulus mapping procedure. Moreover several quasi-static indentation measurements using cube-corner indenter were performed along distinct lamellae. The obtained elastic properties were then compared with the values of the rod-like trabeculae. The comparison does not indicate significant differences in elastic properties between the trabecular rods and interconnections.

Abstract: A bone tissue is modeled at the nanolevel as a composite with a quasiperiodic structure, consisting of the hydroxyapatite crystals, which are embedded into the collagen fibrils. The aim of the research is to analyze the influence of the bone nanostructure on its mechanical and strength properties. Such studies are important for the creating artificial bone-substitute materials. The influence analysis of the morphological characteristics (hydroxyapatite crystals disorientation, sizes and orientation of mineral bridges, shape of hydroxyapatite crystals, mineralization) on the local stress-strain state and mechanical properties of the representative volume element of bone is carried out by means of the direct finite element simulation and homogenization. The comparison of the obtained results with experimental data demonstrates a good agreement.

Abstract: The main subject of this study was to establish a meaningful significance of the acoustic emission technology to be incorporated in the pedicle screw fixation procedure. Its purpose was to find a replacement technique using the acoustic emission technology instead of keep using the conventional way which only depends on the surgeons expertise. The experiment of pedicle screw fixation method work was carried out on a goats vertebrae as a lab scale material instead of the human cervical vertebrae. While the experimental work was done, the acoustic emission signatures were then acquired using the Physical Acoustics acoustic emission data acquisition system. Once completed, the acoustic emission signatures were then analysed using Matlab software together with the AEWin software package. From the results obtained, the numbers of data counts are generally bigger for the pedicle screw fixation procedure at early stage of bone penetration compared to the latter. It is significant to the different structure of bones as hard bone technically takes more time to be penetrated compared to the soft ones. This technique undoubtedly has high potential to be studied further so that it can be commercialized into the medical field.

Abstract: This paper is focused on computational modeling of an interaction of dental implant with mandible bone. It describes creation of computational model including model of geometry, materials, loads and constraints. There is a comparative stress-strain analysis of the levels of cancellous bone model. Computations are performed with the use of finite element method. Results show differences between the model which includes trabecular architecture of cancellous bone tissue and the model with non-trabecular cancellous bone tissue. For better description of the processes in bone tissue and at the interface between bone tissue and implant, it is necessary to create the computational model on the highest possible level, i.e. with the trabecular bone tissue.

Abstract: A novel composites material consisting of calcium silicate deposited in bacterial cellulose membrane was synthesized by immersing BC membrane in the calcium and silicate solutions by turns with different cycle times and characterized. The results indicated that the CaSiO3 particles were homogeneously dispersed on the surface of nanofibers with the effect of BC template when two cycles of soaking proceed, during which the fabrication of most CaSiO3 particles took place. The FT-IR reveals the strong interaction between the two parts of the BC/CaSiO3 composite. The XRD pattern demonstrated a crystal structure disruption of the cellulose aroused by CaSiO3 particle. BC/ CaSiO3 is considered to have a potential application in bone tissue field.

Abstract: Fluid flow through a bone scaffold structure is an important factor in its ability to build up a living tissue. Permeability is often used as a measure of a structure’s ability to allow for flow of nutrients and waste products related to the growth of new tissue. These structures also need to meet conflicting mechanical strength requirements to allow for load bearing. In this work, the effect of different bone structure morphologies on permeability were examined both numerically and experimentally. Cubic and hexagonal based three dimensional scaffold structures were produced via stereolithography and 3D printing techniques. In particular, porosity percentage, pore size, and pore geometry were examined. Porosity content was varied from 30% to 70% and pore size from 0.34 mm to 3 mm. An adapted Kozeny-Carmen numerical method was applied for calculation of permeability through these structures and an experimental validation of these results was performed via a standard permeability experimental testing set-up. From the results it was determined that increased permeability was provided with the cubic rather than hexagonal structure as well as by utilizing the larger pore size and higher levels of porosity. Stereolithography was found to be the better processing technique, not only for improved micrometer scale dimensional accuracy reasons, but also due to the increase wettability found on the produced surfaces. The appropriate model constants determined in this work will allow for analysis of new alternate structure designs on the permeability of rapid prototyped synthetic bone structures.