Papers by Keyword: Implant

Abstract: Cobalt exists widely in nature and is one of the essential functional elements in human body, performing in organic or inorganic forms. The lackness of adequate bone integration is a main issue to limit the biomedical substitute materials using widely in clinic. However, introducing cobalt element onto the surface of the materials can significantly change the biological behavior of the implants, which is a good way to solve the above problem. In this paper, the effects of doped cobalt ions on the biological properties of different materials were reviewed, and the development trend of cobalt ion doped biomedical device was prospected.

Abstract: TiNb coatings were obtained by the electro-explosive doping on the surface of a titanium dental implant (VT6 alloy). The elemental and phase composition was determined by the methods of scanning and transmission electron microscopy and by X-ray structural analysis. The morphology and defective substructure of the coating were studied. Hardness and Young's modulus, friction coefficient and wear resistance of the formed coating were determined. It has been established that the electro-explosive coating is multi-element and multi-phase and possesses submicro-and nanocrystalline structure, high strength and tribological properties. It was found, that the formation of TiNb coating is accompanied by a multiple (more than 2 times) decrease in the wear parameter, i.e. wear resistance increase of the surface layer, an increase in the friction coefficient by 1.5 times, significant increase in hardness (1.5 times) and Young's modulus (1.3 times).

Abstract: This paper addresses to a research of a dynamic answer obtained through numerical simulations of a human ankle joint implant with finite element method. The research background consists of an inverse dynamic analysis based on Newton-Euler formalism completed with Lagrange’s multipliers method. Thus, a parameterized virtual model of a human ankle joint was elaborated and simulated together with the implant, in dynamic conditions similar with real ones in reality. A results numerical processing was obtained with the aid of MSC Nastran and important results were obtained for orthopedic implants design.

Abstract: Synthetic polymers are widely used in biomedical applications due to their advantages compared to other materials including low cost and ease of processability, good corrosion resistance and high properties to weight ratio. Among several polymeric biomaterials, polyethylene is a biocompatible polymer which has a long history of being utilized in many biomedical applications ranging from simple components to advanced implants. Although dense polyethylene is known to be a bioinert material which does not interact with host tissue, polyethylene in its appropriate porous form has been shown to be able to integrate well with surrounding host tissues and could widen its uses as bioactive implants. Porous polyethylene structure which was fabricated by three dimensional printing (3DP) is demonstrated. Its manufacturing technique, properties and clinical applications as tissue integrated implants which permitted soft or hard tissue ingrowth in tissue regeneration and replacement is discussed.

Abstract: In the past, Electro Discharge Machining (EDM) process was well known in cutting extremely hard materials and fabricating complex shapes. Recently, EDM process has been hybridized to not only shape, but also coats the surface of workpiece material. In this study, the deposition of hard carbide and calcium-based oxides on the Zr-based bulk metallic glass (BMG) using hydroxyapatite mixed electro discharge coating (HAm-EDC) have been investigated. The aim is to enhance the biocompatibility and cell adhesion of the BMG as a potential implant. The chemical composition, morphology and thickness of the coated surface were characterized through Optical Microscope, Scanning Electron Microscopy (SEM), X-ray Spectroscopy (EDS) and X-ray Diffraction (XRD). Major hydroxyapatite elemental composition (Ca, P, O), carbides (ZrC, TiC) and oxides (ZrO, CaZrO₃) were formed on the treated BMG surface. A coating of about 23 µm thick was achieved. The addition of hydroxyapatite powder in the dielectric fluid enhances the Zr-based BMG surface quality by reducing the surface cracks and the crater size.

Abstract: A mathematical model for analysis of features of the drug release , previously introduced into a polymer implant, into a biological tissue is proposed. A carbon nanolayer obtained as a result of plasma-immersion ion implantation was created to improve biocompatibility with biological tissue on the surface of the implant. The medicine can go through micro-ruptures in this layer. Calculations show that the carbon layer allows a uniform release of the drug.

Abstract: The work is devoted to the discussion of hypotheses that are put forward to explain the processes occurring during ion-plasma treatment of polyurethane. A carbonized layer forms on the surface of the polymer as a result of ion-plasma treatment. However this layer is not even. Wavy relief, the geometric features of which depend on the fluence (the number of ions entering the unit surface of the sample) and the energy of ions, is formed. It is shown that a simple explanation related to material heating and subsequent shrinkage does not allow explaining the cause of the phenomenon. The second hypothesis can be the pressure of the ion flow on the surface of the sample. It causes deformation and subsequent changes in the stress-strain state after the irradiation is stopped. Calculations show that this mechanism cannot explain the formation of the folded relief of the layer. A hypothesis, based on information about a significant material change, is expressed in the article. Polymer chains under ion-plasma treatment are broken into atoms. After striking ions move deep into the material causing the polymer to swell in the near-surface layer. This swelling can cause material to move close to the sample boundary and leads to the formation of a wavy surface.

Abstract: Calvarial bone defects are due to cranial bone removal at the end of the surgery (decompressive craniectomy), either because of bone involvement of the tumor or as a method to relieve intracranial pressure caused by important cerebral edema secondary to large tumors or traumas. With the progress of biomedical technology, new materials are available for use by surgeons. The titanium mesh implant is a plating platform with a matrix design and MRI compatibility that can be easily shaped, cut, and bent by the surgeon according to the bone defect. It is locked in place by several screws tapped into the bone. Although may different type of materials are currently available there is no consensus for the best method to be used. The aim of this study was to report our experience with titanium mesh implants for cranial repair and reconstruction of bone anatomy.Twenty four patients with decompressive craniectomies that required reconstruction of the calvarial bone defect for which a titanium mesh cranioplasty was used, operated in our Neurosurgery Department between January 2013 and April 2016 where included in this retrospective study. Of the 24 patients, only one had a localized infection complication for which the patient was re-operated and the implant removed with no other complications. No other neurological, infectious and functional complications were observed during or after surgery. All other patients had excellent anatomic and functional results with a positive feedback for the aesthetic aspects of the implant. The use of these bio-compatible materials is a viable, safe and reliable solution for the management of cranial bone defects offering the surgeon a large array of options for the benefit of the patient. It has a proven cost-effectiveness when compared to other customized prosthetics with the same outcomes. The MRI compatibility was proven very useful, especially for neoplasm patients who required frequent cranial imaging follow-ups, and reduced operating time was particularly beneficial to elderly patients.

Abstract: Hip fractures/arthrosis were, still are and will be a challenge for the orthopedic surgeon. In this paper we conducted a case study on a rod used for hip replacement due to coxartrosis. The implant was used for hip replacement for NC patient aged 82 years. After twelve months the patient returns for the ablation of osteosynthesis material. Clinical and strengthen the fracture hip is found radiologic hypertrophic and degradation plaque. It was used a rod implant, on which were made following investigations in order to establish the causes that led to the fracture, namely: determining the chemical composition through spectral analysis, analysis macrostructural in stereo, microstructural analysis optical microscope metallographic respectively analysis fractogr aphic electron microscope streak. Complex analysis of the fracture surfaces of the hip prosthesis has led to the ultimate conclusion that the material has been made the hip prosthesis is inadequate chemical purity satisfactory embedding, which has led to breakage within an area of non-homogeneous structure.

Abstract: This paper will report the fabrication process and microstructure analysis of fibrous composite incorporating ultra-high molecular weight polyethylene (UHMWPE) fabric, electrospun polycaprolactone (PCL), and bioglass particles. Briefly, electrospinning was performed to form PCL fibre lamination in the surface of UHMWPE fabric. This UHMWPE/PCL material was then bioglass-coated. Sequentially, microstructure of the UHMWPE fabric, UHMWPE/PCL, and UHMWPE/PCL/bioglass was imaged and analysed. The composite showed aligned ultrafine PCL fibres and distribution of bioglass particles in the layer of electrospun PCL. The results of this study provide groundwork for more advanced investigation, as well as development of implant prototype.