Papers by Keyword: Bioglass

Abstract: Among bioceramics materials, bioglasses which exhibits either a bioactive or resorbable behavior has been studied for many applications, such as bone substitutive and regeneration. When in contact with body fluid, the bioglasses can induce the formation of a hydroxyapatite surface layer. In this paper, we studied the bioactivity of a bioglass containing 48 wt %SiO₂, 27 wt% Na₂O, 19 wt % CaO and 6 wt %P₂O₅. After fusion and annealing, the samples were immersed in SBF for different periods, up to 14 days. The samples were characterized through XRD, DRIFT and SEM before and after bioactivity experiments. The overall results suggest the formation of a surface layer of consisting of hydroxyapatite, which was crystallized within seven days after in vitro experiments, leading to a suitable bioactivity. Moreover, the samples showed a glass network with high cohesion due to calcium addition, leading to materials with high corrosion resistance.

Abstract: The bovine bone and sintetic hydroxyapatite (HA) bioceramics are reference materials to employment as a bone substitute, however, their slow rate of degradation and its low rate of bioactivity index (Ib) are presented as limiting factors for application as bone graft. In contrast, the bioglass is a resorbable and osteoinductive material. the present work objective the development of composites of dispersed bovine bone or sintetic HA in silicate-phosphate bioglass, seeking to obtain a biomaterial with properties suitable for application as bone grafts. The composites were prepared by mixing between the powder components followed by sintering for 1h. Were used HA and bioglass (45S5) with particle size <240μm. The tested proportions of HA/45S5 were 20/80, 30/70 and 40/60 (wt%). The composites characterization was made employing scanning electron microscopy, Infra-Red Spectrometry and hydrolytic resistance test. The test results indicate the potential use of the materials developed for applications such as bone graft.

Abstract: The aim of the present study is to investigate the efficacy of nanobiphasic calcium phosphate (nanoBCP) bioceramic in the treatment of periodontal osseous defects. Alveolar bone defects were surgically created bilaterally at the buccal aspects of four second premolars in two beagle dogs. After root leveling, nanoBCP was randomly filled in one defect and nothing was put into the contralateral defect as negative controls. Bioglass was randomly filled in one of left defect as positive controls and nothing was put into the contralateral defect as negative controls. Dogs were killed at the 12th week. Histological observations were processed through a light microscopy. The results reveal that a great amount of functional periodontal fissures formed in the defects in the nanoBCP groups and bioglass groups while no new bone formed in the control groups at all. In this study, nanoBCP has proven to work well as a biocompatible and bioactive material to promote periodontal regeneration effectively.

Abstract: The main purpose of this study is to prepare and characterize hydroxyapatite (HA)–10%wt bioglass (BG) composite nanopowders and its bioactivity. Composites of hydroxyapatite with synthesized bioglass are prepared at various temperatures. Suitable calcination temperature is chosen by evaluating of the phase composition. X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Scanning electron microscopy (SEM) techniques are utilized to characterize the prepared nanopowders. The bioactivity of the prepared composite samples is evaluated in an in vitro study by immersion of samples in simulated body fluid (SBF) for predicted time. Fourier transformed infrared (FTIR) spectroscopy and inductively coupled plasma (ICP) are used for evaluation of apatite formation and the bioactivity properties. Results show that HA-BG composite nanopowders are successfully prepared without any decomposition of hydroxyapatite. The suitable temperature for calcination is 600°C and the particle size of hydroxyapatite is about 40-70 nm. The apatite phase forms after 14 days immersing of the samples in SBF. It could be concluded that this process can be used to synthesize HA-BG composite nanopowders with improved bioactivity which is much needed for hard tissue repair and biomedical applications.

Abstract: Electrophoretic deposition method has been developed for the fabrication of organic-inorganic composite films, containing bioglass and hydroxyapatite in a hyaluronic acid matrix. The film composition and deposition yield were varied by variation of the electrochemical bath composition and deposition time. The films were studied by scanning electron microscopy, thermogravimetric analysis and X-ray diffraction methods. The deposition method offers the advantages of room temperature processing and allows the fabrication of composite films for biomedical applications.

Abstract: The pursuit for an ideal bone substitute remains the main focus of many tissue engineering researchers. Among the myriad types of grafts available, synthetic bone grafts are of special importance, because it is available in large amounts, reduce the surgical trauma and eliminate the risk of diseases’ transmission. In this context, bioactive glasses have received attention mostly due to its described biocompatibility and rapid rate of surface reactivity when compared with other materials, allowing for faster interactions with the local tissue. The addition of niobium to this material has been shown as increasing the chemical resistance of the compound and providing greater stability. However, alterations on the chemical composition of biomaterials may impact on its biocompatibility. Therefore, the aim of this study was to evaluate the in vitro biocompatibility of bioglass-Niobium (BgNb) granules, in comparison with standard commercial bioglass (Biogran®) throughout an interesting multiparametrical approach, employing Phenol 2% and dense polystyrene beads as positive and negative controls, respectively. Extracts from each material were prepared by 24 hours incubation in culture medium (DMEM). Human primary osteoblasts were then exposed for 24 hours to each extract and cell viability was evaluated by three parameters: mitochondrial activity (XTT method), membrane integrity (neutral red dye uptake) and cell density (crystal violet dye exclusion test). BgNb extracts were highly compatible, since the levels of viable cells were similar to the control group (unexposed cells), on all parameters studied. The mean cell density on the Biogran® group was slightly lower than BgNb, even though this material was also non-cytotoxic. The excellent in vitro response for BgNb granules indicates the suitability of this material to future studies on its biological and physical properties when applied in vivo.

Abstract: The research of obtained bioglasses in the form of silver-containing powders were presented in this paper. The research conducted in order to determine antimicrobial activity under in vitro conditions of bioglasses. The results confirmed that these bioglasses Z-5, Z-8 and B-I inhibit the growth of most micro-organisms during the tested period and could be used in surgical treatment of the most advanced parodontium illnesses.

Abstract: It has been reported that there is a slight equilibrium between calcite and apatite precipitation from SBF solution during typical bioactivity assays, once it is supersaturating in both ionic precursors. In order to better understand this mechanism, we have proposed here to evaluate the role of three different aqueous medium (water, SBF and McCoy), under equilibrium (agitation) and out of equilibrium (no agitation).

Abstract: Bioglass Ceramics having molar composition 40SiO2-(44-X)CaO-10MgO-6P2O5-XCaF2 (where X = 0 to 8%) were prepared by conventional melting process in an electric globar furnace at 1400±10°C. Controlled crystallizations were carried out to convert the bioglasses to their corresponding ceramics. Nucleation and crystallization regimes were carried out by differential thermal analysis. The crystalline phases termed hydroxy fluoroapatite, akermanite and wollastonite were identified by using x-ray diffraction analysis. The investigation of bioactivity for the prepared glass and glass ceramics was done by infrared absorption and infrared reflection spectra after immersion in simulated body fluid (SBF) for different periods at 37.8°C. Scanning electron microscope (SEM) analysis was carried out to investigate the surface texture. Micrographs show the formation of HCA layer on the surface of the bioglass ceramics samples after 7 days of SBF treatment. The surfaces of the samples were completely covered with irregular and needle-like aggregates of Ca–P layer. The released ions were estimated by atomic absorption spectroscopy. The chemical durability of these materials was determined by pH measurement methods and it was found that pH of the solution increases up from 1 to 7 days. Further, pH decreases with increasing time period, from 15 to 30 days in SBF solution.

Abstract: The design of bioceramic scaffolds, i.e. artificial structures employed as temporary templates for cell proliferation, is a crucial issue in bone tissue reconstruction and regeneration. An ideal scaffold should be highly porous and bioactive. Additionally, a resistant and permeable surface is required in order to have manageable samples. The production of scaffolds by means of the widely used replication method can lead to samples with weak and brittle surfaces and poor mechanical properties, therefore alternative preparation procedures are necessary. In this work a new protocol to realize bioceramic scaffolds is presented. The obtained samples have an original structure, characterized by an external resistant surface together with a highly porous internal network. The external surface, which behaves as a load-bearing structure for the entire scaffold, guarantees high permeability and manageability. Here the proposed protocol is briefly discussed, together with an overview on the structure of the realized samples. Finally, some preliminary data regarding the scaffolds in-vitro bioactivity are reported.