Papers by Keyword: Ion Release

Abstract: The effect addition of Na₂O on the solubility properties of phosphate glass of the composition, 45P₂O₅-18CaO-xNa₂O-(34-x)K₂O-6Al₂O_3, where x = 0,5,10,15 and 20 wt. %. has been studied. Glass transition temperature (Tg) of glass samples, weight loss and pH of the immersion solution were measured. The Tg value of the phosphate glass also decreased with the incorporation of Na₂O up to 10 wt. % and increased with the incorporation of 15 and 20 wt. %. These results indicates that the solubility and Tg value of phosphate glass were highly influence by the glass composition. The substitution of Na₂O to the phosphate glass system with the present of K₂O has decrease the solubility of phosphate glass. The released of phosphate and calcium ion seem to decrease with the increasing of Na₂O content in the glass composition.

Abstract: The aim of this study was to investigate the metal ion release and cytotoxicity of MU orthodontic miniscrews as well as two other brands of orthodontic miniscrews over time. Twenty-four orthodontic miniscrews were tested, divided into three groups of eight. Each sample extraction was performed following the ISO 10993-12:2012 method. Solutions were collected after 1, 7, and 30 days (T1, T2, and T3). The supernatants extracted from these three groups were added and exposed to mouse L929 fibroblastic cell line using an MTT cytotoxicity test. They were also tested for ion release by inductively coupled plasma-mass spectrometry (ICP-MS). Element analysis by energy-dispersive X-ray spectroscopy (EDS) was used to analyze the surfaces of the miniscrews. The quantification of three elements, namely, titanium (Ti), aluminum (Al), and vanadium (V) were assessed. The results indicated that there were no statistical differences between the self-made orthodontic miniscrews and those from two commercial groups (p<0.05). Throughout the testing period, the quantity of ions increased from T1 to T3. After 24 h, vanadium was the first to appear on the surface in small quantities in other two commercial groups. The self-made orthodontic miniscrews exhibited no toxic effects on living cells.

Abstract: Total hip prosthese are widely used in total hip arthroplasty, offering many benefit to patients with different articular diseases like osteoarthritis or after different accidents. Many total hip prosthesis are now available to the orthopaedic surgeons to replace the hip articulation, with different design and with components made by different type of biomaterials: metallic (cobalt-chrome and titanium alloys, zirconium-niobium alloy named oxinium), ceramic (alumina, zirconia), polymers (ultra high weight molecular polyethylene-UHMWPE). Even total hip arthroplasty has a high success rate, implant loosening may occur, with different symptoms that could be attributed to metal allergy. Because the stem components of the total hip prosthesis are made by metallic biomaterials, many papers describe the adverse effects related to the release of metal ions (like cytotoxicity, carcinogenicity and metal allergy). There are different types of metal corrosion: intergranular, pitting, crevice, fatigue, stress, fretting, and galvanic. On the other hand, in many cases (like metal-on-metal prosthesis) appear corrosion and wear between two metallic components. This processes are favourable for the aparition of hypersensitivity-related tissue reactions. Especially some metallic ions (nickel, cobalt, and chromium) presents in stainless steels and cobalt-chromium alloys are most known to be released from prostheses components and give metal allergy. Of course, during the time was developped some solutions in order to improve the performance of the hip prostheses components made by metallic components like coating with thin layers using different biomaterials like porous titanium or hydroxiapatite. The aims of this review article were to explore mainly the relationship between corrosion products and implant-related hypersensitivity, the importance of surface treatment for metallic components, try define the effect of metal ion concentrations, and differentiate between allergy and infection in total hip replacement. The long-term performance of the coated components will be also analyzed and synthetic described based on clinical results. Also, some relevant aspects from our clinical experience and retrieved prosthesis analysis using stereomicroscopy and scanning electron microscopy will be shown in order to support the conclusions.

Abstract: The influence of bone union activation realized with the use of the low-intensity pulsed ultrasound (LIPUS) on degradation of titanium alloys was presented in the work. Ti6Al4V ELI and Ti6Al7Nb alloy samples of modified surface layer were used in the study. The preliminary surface treatments were: grinding, vibration machining, mechanical polishing, sandblasting and electrochemical polishing. The final procedures of the surface modification were anodization and steam sterilization. The scope of the work included the study of pitting corrosion resistance and concentration of metal ions released to the Ringer’s solution. The study was performed for the undeformed and deformed samples subjected to the influence of ultrasound. The reference samples were the samples kept in the solution and not having the impact of ultrasound. On the basis of the study it was found that the conditions for bone union stimulation by low intensity pulsed ultrasound do not initiate pitting corrosion of the titanium alloy samples, although they increase the mass of ions released from the surface to the solution.

Abstract: In the past two decade, the Chinese government has paid a huge effort to solve the problem of drinking water in remote rural. As an alterative success case, rainwater harvesting and utility has been the most efficient way to supplying fresh water in rural areas of the Loess Plateau, a typical water resources serious shortage area in China. Focused on improving the quality of the rural village cistern water, study about the characteristics of ion release from building materials during runoff process with five representative materials used for rainwater collection: concrete, red brick, grey tile, red tile and soil was conducted. The ion releasing process and following effect on cistern water quality index, such as hardness, pH, conductivity, has been analyzed. Results revealed that the most release strength of different materials was arriving at 30s following startup. Furthermore, the test of effects of rain acidity on ion release procession showed that the total ion release increased with storm water pH declining, however, the release strength was irrelevance with runoff’s pH. Based on research results, a detailed suggestion was provided to renovate intake construction of cistern for improving the drinking water quality in remote rural areas of Weibei Semi-arid District.

Abstract: Bioactive glasses not only can bond to hard tissues of the body, are also able to release ions that have stimulatory effects on cells and so are regarded as promising candidate materials for gene activating purposes in tissue engineering applications. In this research the effect of co-substitution of Magnesium and Zinc for Calcium on bioactivity of binary sol-gel derived glass 70S30C (70 mol. % SiO₂, 30 mol. % CaO) was investigated. Calcium phosphates forming ability tests and investigation of glass degradation products in simulated body fluid (SBF) were performed as follows.After sol-gel synthesis of glass powders of comparable and under 38 μm particle size distributions, their state of being amorphous was investigated using X-ray diffraction. Then for in vitro investigation of bioactivity, ion release, pH change and Calcium phosphate formation during immersion of glass powders in SBF at 37 ͦ C up to 2 weeks were studied. Infrared spectroscopy was performed on the reacted glass powders.Results indicate that substitution of Zinc for Calcium suppresses crystalline apatite formation more effectively than substitution of Magnesium for Calcium and help us design modified compositions of magnesium and zinc containing bioactive glasses that can find applications in bone and also cartillage tissue engineering.

Abstract: Bulk nanocrystalline 304 stainless steel (nanocrystalline 304ss) discs had been successfully prepared by the commercial microcrystalline 304 stainless steel (microcrystalline 304ss) plate using severe rolling technique. Micro-hardness was measured to reveal the different mechanical behavior after the severe plastic deformation. The electrochemical corrosion resistance and ion release behavior after immersion of the samples were investigated in Hank’s solution for its potential use as implant and orthodontic appliance in body. Furthermore, murine fibroblast cells were indirectly employed to detect cytotoxicity by co-incubation with the extraction from the given materials. Haemocompatibility, consisting of hemolysis test and adhesion of the platelets, was also measured with fresh human whole blood and platelet-rich plasma respectively. Polarization resistance trials indicate that nanocrystalline 304ss is more corrosion resistant in the Hank’s solution, with lower current density and superficial corrosion morphologies. The release values of the biotoxic ions after immersion do not exceed the set limit and turn to be well below the critical value necessary to induce allergy and below daily dietary intake level. Cellular interaction is observed via the proliferated feature of the cell line. Hemolysis and platelet adhesion results elucidates that nanocrystalline 304ss is biological and hematologic compatible.

Abstract: SrO-containing calcium phosphate invert glasses, (60-x)CaO∙xSrO∙30P2O5∙7Na2O∙3TiO2 (mol%, x = 0 ~ 60), which are expected to inhibit bone resorption by osteoclast and enhance bone formation, were prepared and estimated in their ion release behavior in Tris buffer solution. The glasses gradually released ions and the dissolved amounts of ions were the smallest when the glass contained 20 mol% of SrO. Laser Raman spectra showed that the peaks of phosphate groups and TiOy polyhedral groups red-shifted with increasing the SrO content in the glasses. The red-shift is suggested to be due to decrease in bonding strength between cations and phosphate groups or TiOy polyhedral groups in the glasses. In the case of the glasses containing SrO over 20 mol%, no Raman peaks of TiOy polyhedral shifted. TiOy (y = 4 or 6) polyhedral in the glasses can coordinate with cation up to 18 mol% since they contain 3 mol% of TiO2. Sr2+ ions are supposed to preferentially coordinate with TiOy polyhedral, the formation of this structure would induce the decrease in the ion amounts released from the glasses containing 0 ~ 20 mol% of SrO.

Abstract: The paper reports the behavior of TiNbZrTa in biological solution which simulates the body conditions (SBF-simulated body fluids) with different pH values. It has determinate the ion release quantities in time in SBF and the passive layer transformation on the implant surface. The used techniques were ICP-MS, FT-IR and contact angle measurement.

Abstract: A series of ceramic-polymer scaffolds were studied for bone tissue engineering applications. These applications require bone reactivity as well as suitable scaffold properties and structure. Bioactive glass (BAG) and sol-gel derived silicas were chosen for ceramic components of the scaffolds, and crosslinked poly(ε-caprolactone/D,L-lactide) copolymers with monomer ratios 90/10 and 70/30 were used as polymer matrices. Scaffolds were prepared by photo-curing crosslinkable oligomers in the presence of the ceramic component and porosity producing salt. Scaffolds with 60-80 vol-% continuous phase macroporosity were obtained by using calcium chloride hexahydrate (CaCl2⋅6H2O), and were further tested in simulated body fluid (SBF). The ceramics remained highly reactive during scaffold preparation resulting in in vitro calcium phosphate formation.