Papers by Keyword: In Vitro Bioactivity

Abstract: Hydroxyapatite is a kind of calcium phosphate that has generated great interest as an advanced orthopedic and dental implant candidate. Although HA has excellent biocompatibility, it’s poor mechanical properties limit its use as an implant material. Therefore HA is preferred as a main component in composite materials. The aim of this study is to determine the characterization and bioactivity of HA-ZrO₂ composites with the addition of 5 and 10 wt% commercial inert glass (CIG). The highest density and Vickers microhardness were obtained in HA-ZrO₂-5 wt% CIG composite sintered at 1300 °C. The highest compression strength was measured in HA-ZrO₂-5 wt% CIG composite sintered at 1200 °C. The in vitro bioactivity tests were performed on the composites having the highest physical and mechanical properties. The apatite formation was observed on all samples subjected to bioactivity tests. As a result, the optimum mechanical properties and bioactivity were obtained on HA-ZrO₂- 5 wt% CIG composite sintered at 1200 °C.

Abstract: Abstract: In this study, in-vitro bioactivity of manganese blended hydroxyapatite (Mn-HAp) pellets is carried out using simulated body fluid (SBF) solution. The incubated Mn-HAp samples are characterized by XRD, FTIR and SEM/EDAX. Dielectric and photoluminescence properties of Mn-HAp samples are studied as a function of incubation period in SBF. XRD profiles show that hexagonal apatite structure remains intact after partial replacement of calcium ions by manganese ions and even after incubation. The change in absorption due to phosphate group, depicted in FTIR spectra, for incubated samples confirms growth of apatite on Mn-HAp surface. SEM/ EDAX studies suggest that Mn-HAp surface promotes the growth of apatite without changing its structure due to apatite nucleation and growth on the surface of Mn-HAp. The value of dielectric constant of Mn-HAp increases after incubation. Increase in period of immersion in m-SBF leads to decrease in dielectric constant of manganese exchanged hydroxyapatite. The photoluminescence (PL) study reveals that the Mn-HAp can be used stable and efficient blue luminescent material.

Abstract: Bioactive glasses based on SiO₂-CaO-P₂O₅ system have been synthesized by sol – gel process. The powder glass obtained has been characterized by X-ray diffraction, X-ray fluorescence spectroscopy (XRF), and Fourier transform-infrared spectroscopy (FTIR). In vitro study reveals formation of apatite layer at surface of powder glass, after 3 days of soaking in simulated body fluid.

Abstract: In this work we summarize the most important findings of the influence of glass composition, sample shape and fluid circulation on in vitro behavior of bioactive glasses in the system Na2O-K2O-MgO-CaO-B2O3-P2O5-SiO2. The sample shapes included plates, particulates, powdered glasses, glass fibers and sintered cones with interconnected porosity. The in vitro bioactivity was measured as the changes observed in the immersion solution, SBF, and the formation of reaction layers on the samples at 4 to 168 h immersion. A lower surface area to volume ratio gave smaller changes on the ion concentrations and pH of the immersion solution but thicker reaction layers on the glass surfaces. In particulate systems with circulating fluid the pH gradients in SBF were lower but surface layers more even than in static systems. The influence of glass composition on reaction layer formation as suggested by glass plates correlated with the in vitro behavior of glass particulates larger than 250 µm, porous cones and fibers when using similar SA/V ratio.

Abstract: The aim of this study is to investigate the crystallization behavior and in-vitro bioactivity character of glass ceramics having 3:7 weight ratio of fluorapatite (Ca10(PO4)6F2) to potassium mica (K2Mg3AlSi3O10F2) as a function of cerium oxide addition, and compare the morphology of hydroxycarbonate apatite (HCA) layer formation depending on cerium oxide addition.