Papers by Keyword: Bioceramic

Abstract: Homogenous, transparent and bubble-free glass was produced through the addition of an extra silica as a replacement for its structurally analogous AlPO₄ in an aluminophosphosilicate base glass. FT-IR, DSC, XRD and SEM coupled with EDX, were all used to characterize the obtained glass, and to establish the effect of silica as a substitution for AlPO₄ on the vibrational spectra and crystallization behavior of the obtained glass.Silica was found to lower the wavenumber of the main stretching vibrational band of aluminophosphosilicate glass, thus counterbalancing the increment in the wavenumber of the main stretching band caused by P₂O₅ in the former base glass. The obtained glass crystallized in bulk at relatively low temperatures, and the first phase to crystallize was enstatite. As temperature was increased, both enstatite and forsterite coexisted. At yet higher temperatures, forsterite was the predominantly crystallizing phase with just traces of enstatite.Thus, it is believed that glass ceramization represents a challenging and yet a promising fabrication route with many technological advantages, over other making techniques, such as sol-gel and solid-state or solid solution routes, for production of forsterite-enstatite and forsterite ceramics. The obtained glass-ceramics are possible candidates for advanced applications, utilizing properties of forsterite, such as bioactivity, dielectricity and birefringence, among many others.

Abstract: The present paper presents a non-destructive technique (NDT) using active pulse infrared thermography with a thermal excitation consisting in two photographic flash laps controlled by a signal generator. For this work we used two bioceramics samples, having the same size, 15, 30 mm diameter and 3, 75 mm thickness. A non-defect sample was used as the basis to demonstrate the temperature differences in the defected zone between the healthy and the defective one. In the second sample was created an internal defect. The main advantage of this method represents its possibility to detect the internal defects in bioceramic materials, the method being more reliable then the microscopic method. Other two advantages of this method are represented bythe rapidity of testing and the maintenance of material properties after the thermal excitation.

Abstract: In this work, a hydroxyapatite (HA) bioceramic and a silica binder were used as the raw materials for manufacturing bioceramic bone scaffold after sintering by a laser beam in a home-made 3D Printing (3DP) machine. Results indicate that the bending strength of the scaffold can be improved after heat-treatment. While simultaneously increasing surface roughness conducive to osteoprogenitor cell adhesion. The processing parameters of a 90 mm/s laser scanning speed, 12 W of laser energy and 10 kHz of scanning frequency were used to fabricate a porous scaffold model, which possesses suitable biocompatibility and mechanical properties, allowing adhesion and proliferation of bone cells. Therefore, this process has great potential for manufacturing bone scaffolds.

Abstract: In order to researching the microstructure of bioceramic coating on the surface medical titanium alloy (Ti–6Al–4V), the gradient bioceramic coatings are fabricated by wide-band laser cladding. The influence of multiple rare earths oxide La₂O₃ and CeO₂ on microstructure of bioceramic coating were studied. The experimental results demonstrated that mixed La₂O₃ and CeO₂ have an effect on forming-ability of HA\β-TCP in bioceramic coating and also refined the grain of bioceramic coatings. The largest amount of HA\β-TCP is presented among all the groups when the contents of La₂O₃ and CeO₂ are 0.6wt.%, 0.4 wt.%, respectively.

Abstract: Yttria-stabilized zirconia and alumina made significant contributions to the development of health care industry, specifically as orthopedic and dental materials. Both bioceramics are nearly inert ceramics, as they do not allow the interfacial bonding with tissue. Thus, it is necessary to provide bioactive surrounding as to elicit a specific biological response at the interface of material. This research reported the microstructure and bioactivity behavior of YSZ-Al₂O₃/10HAP with 30 wt. % and 60 wt. % of YSZ content. Powders were mixed before being compacted at 225MPa using uni-axial press machine. The composites were sintered at 1200 ̊C with heating rate of 10 ̊C/min. In-vitro bioactivity behavior of the composites were evaluated by immersing the composites into simulated body fluid. Results from x-ray diffraction pattern, confirmed the phase formation of apatite by the presence of Ca₂P₂O7, and CaO that might be useful on implant cell interaction in a body environment. The apatite formation was observed on the surfaces of the composites by SEM only after 9 days of immersion and subsequently apatite nucleation increased with prolonging immersion time. The dynamic changes in pH, between ion concentration in SBF and bioceramics surfaces correspondedwith an immersion time. Up to 30 days of immersion, the pH value of SBF stabilized approximately around pH 7.4-7.6, similar to the human blood plasma. Formation of apatite on composites surface of prepared YSZ-Al2O3/10HAP bioceramics may contribute to the improved biocompatibility and osteoconductivity.

Abstract: The calcium phosphate microporous bioceramics, and hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) biphasic compositions, in the granular form of microporous biomaterials, are research themes and present potential biomedical applications in rebuilding and repairing maxillofacial bone and tooth structure and in orthopedic applications. This is associated with microstructural characteristics of biocompatibility and bioactivity and osteoconductivity properties that these biomaterials offer when applied in vivo or in simulated environment. Another differential point of these biomaterials is the solubilization capacity that they present when applied in the biological environment. These compositions of calcium phosphates (hydroxyapatite matrix and/or β-tricalcium phosphate) allow for the gradual release of calcium and phosphate ions for the biological environment, which are absorbed and promote the formation of new bone tissue. These materials are also promising in applications in the field of traumatology as in the repair of traumatized bone tissue and drugs controlled release and bone structure treatments. The favorable results of these biomaterials as bone reconstruction matrix and drugs controlled release are associated with crystallographic characteristics, morphology, surface and solubility that these biomaterials present when in contact with body fluids. This work aimed to describe three types of calcium phosphate microporous granulated biomaterials. The biomaterials used were provided by the Biomaterials Group from Universidade do Estado de Santa Catarina - UDESC and are: hydroxyapatite, β-tricalcium phosphate and biphasic composition 60% hydroxyapatite/40% β-tricalcium phosphate. The Scanning Electron Microscopy technique (SEM) was used for carrying out the morphological characterization and microstructure studies of granulated biomaterials. The X-Ray Diffractometry (XRD) served for characterization of crystalline phases. Arthur Method was used for determining open porosity and hydrostatic density of biomaterials. The BET technique served to support determination of the surface area of microporous granulated biomaterials. The results are encouraging and show that these biomaterials present promising morphological characteristics and microporous microstructure as wettability and capillarity. These characteristics may contribute to biomaterial osteointegration by new tissue, bone formation and mineralization process.

Abstract: This work reports the influence of chemical composition and sintering schedule on the properties of sintered bodies of hydroxyapatite (HA) bioceramic. The method of preparing sintered bodies by solid state reaction and uniaxial pressing. The raw material used calcium carbonate (CaCO₃) and ammonium dihydrogen phosphate (NH₄H₂PO₄) powder as precursors. These powders were mixed at CaCO₃: NH₄H₂PO₄ mass ratio of 1:0.697, 1:0.692, 1:0.689, 1:0.685 and 1:0.68, respectively. The compositions in the temperatures range of 800-1300 °C for 3 hour. The sintered bodies were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). Properties including phase, microstructures, porosity and bending strength of the samples. The results show that green bodies can be sintered at 1150 °C for 3 hours. This temperature found that crystals growth, highest of HA phase content in sintered bodies, good density and high efficiency strength properties.

Abstract: Anodic spark deposition (ASD) is a novel technique to deposit bioceramic films on the surface of titanium (Ti) and its alloys, and the films prepared with nano/micro scale pores are characterized by high-quality performance for dental implant. Among the process parameters, electrolyte provides a leading role owing to its vital influence not only on the films chemistry but also on the electrical conductivity of the circuit, which affects the film properties. In this study, titania porous films were synthesized by ASD and the effect of electrolytic temperature on microstructure and chemical composition of the films was studied. The results show that the electrolytic temperature could significantly influence the surface topography, thickness and chemical composition of the oxidation films produced by ASD and, therefore, determined the layered hydroapatite (HA) deposition as the other process parameters were fixed.

Abstract: A kind of drug releasing 3D porous material was designed and fabricated, which could used for bone repairing. The β-tricalcium phosphate (β-TCP) material were fabricated through the rapid prototyping (RP) combining with the freeze-drying, where the scaffold-mould was fabricated by RP. The material was fabricated with ball-milled slurry which solid content was 40%, the pre-freezing temperature was-10°C, and then the material was freeze-dried under vacuum environment at-30°C without sintering. The test results showed that the material had good structure pores with the mean size of 150μm through controlling the pre-freezing temperature, and the compressive strength of the samples was 0.216Mpa.

Abstract: In order to induce bone regeneration several natural and synthetic materials have been proposed. However, single-phase scaffolds present some insurmountable disadvantages such as poor mechanical strength or brittleness and too low or too high degradation rate. In order to overcome these drawbacks, composite systems can be an interesting and promising option. In the present work a novel hybrid porous scaffold for bone tissue engineering is proposed. Chitosan/Forsterite (Ch/FS) composite scaffolds were prepared by freeze-drying method using a chitosan/forsterite ratio of 90/10. The FS nanopowder (Mg₂SiO₄) is synthesized using a simple solgel based method. The FS composition was checked by XRD analysis. The macrostructure of the Ch/FS scaffolds were analyzed by SEM, the FS distribution within the chitosan matrix observed by EDS, the mechanical strength measured by compression test in PBS and the biocompatibility of the composite on human osteosarcoma cell line (MG-63) verified by MTT assay after 48 hours. The porosity appears interconnected and with a pore size ranging from 1 to 100 μm. The FS is overall distributed within the chitosan matrix. The compression strength of composite scaffolds increased with respect to the pure chitosan scaffolds of more than two times (from 0.8 to 1.9 KPa) and the composites did not show any toxicity effect on human osteosarcoma cells.