Sintering Behavior of a Six-Oxide Silicate Bioactive Glass for Scaffold Manufacturing

Abstract

The intrinsic brittleness of bioactive glasses (BGs) is one of the main barriers to the widespread use of three-dimensional porous BG-derived bone grafts (scaffolds) in clinical practice. Among all the available strategies for improving the mechanical properties of BG-based scaffolds, strut densification upon sintering treatments at high temperatures represents a relatively easy approach, but its implementation might lead to undesired and poorly predictable decrease in porosity, mass transport properties and bioactivity resulting from densification and devitrification phenomena occurring in the material upon heating. The aim of the present work was to investigate the sinter-crystallization of a highly bioactive SiO2-P2O5-CaO–MgO–Na2O–K2O glass (47.5B composition) in reference to its suitability for the fabrication of bonelike foams. The thermal behavior of 47.5B glass particles was investigated upon sintering at different temperatures in the range of 600–850 °C by means of combined thermal analyses (differential thermal analysis (DTA) and hot-stage microscopy (HSM)). Then, XRD measurements were carried out to identify crystalline phases developed upon sintering. Finally, porous scaffolds were produced by a foam replica method in order to evaluate the effect of the sintering temperature on the mechanical properties under compression loading conditions. Assessing a relationship between mechanical properties and sintering temperature, or in other words between scaffold performance and fabrication process, is a key step towards the rationale design of optimized scaffolds for tissue repair.

Foam-Replicated Diopside/Fluorapatite/Wollastonite-Based Glass–Ceramic Scaffolds

“…Porous scaffolds based on 1d glass were produced by the foam replica method according to a processing schedule that was previously applied on a broad range of glass compositions [24]. Briefly, a polyurethane (PU) sponge panel (45 ppi) was cut into 10 mm × 10 mm × 10 mm cuboids using a scalpel, and the small foam blocks were then soaked in a glass-containing suspension to carry out the replication process.…”

Preparation and Biocompatibility of Poly Methyl Methacrylate (PMMA)-Mesoporous Bioactive Glass (MBG) Composite Scaffolds

“…The higher content of Ce 4+ as was revealed by UV-Vis analysis can lead to aggregation effect and consequently to distortion of the glass matrix. The data from the literature reported that the compressive strength of bioactive glass scaffolds ranges from 0.2 to 150 MPa depending on the scaffold’s composition, microstructure, and preparation method [ 35 , 36 ]. It is known that while the compressive strength of human cortical bone ranges between 90 and 209 MPa, the strength of cancellous bone is between 1.5 and 45 MPa [ 37 ].…”

Cortical bone screws constructive characteristics – A comparative study

“…The structural analysis of skeletal body elements and of biomechanical systems consisting of a bone element coupled to a prosthesis, an implant or a fracture synthesis device, can be performed both numerically and experimentally [18]. There are many examples of clinical problems, which have moved from a qualitative assessment to a quantitative evaluation thanks to the respective modelling or to the application of classical experimental methods of structural analysis to the evaluation of the efficacy of procedures or surgical techniques or to the evaluation of the mechanical characteristics of the materials used at different scales of investigation [76][77][78][79][80][81][82][83][84][85][86][87][88][89][90][91][92]. Moreover, the structural analysis of medical devices and biological tissues is strictly connected with the in-vivo behavior of their interaction [93,94].…”