Bioactive Bone Cement Composed of Crystallized Glass Beads and PMMA: Evaluation of Degradation by an In Vivo Aging Test

Abstract

A new bioactive bone cement (cGBC) consisting of crystallized MgO-CaO-SiO2-P2O5 glass beads and high-molecular-weight polymethyl methacrylate (hPMMA) has been developed to overcome the degradation seen with a previously reported cement (GBC) consisting of MgO-CaO-SiO2-P2O5-CaF2 glass beads and hPMMA. The purpose of the present study was to evaluate the degradation of cGBC using an in vivo aging test, and to compare the degradation of cGBC with that of GBC. Hardened rectangular specimens (20x4x3mm) were prepared from both cements. Their initial bending strengths were measured using the three-point bending method. GBC and cGBC specimens were then implanted into the dorsal subcutaneous tissue of rats, removed after 6 or 12 months, and tested for bending strength. The initial bending strengths (MPa) of GBC and cGBC were 141.9±1.8 and 144.4±2.4, respectively, while at 6 months they were 109.1±2.6 and 114.1±4.9, and at 12 months they were 109.1±3.2 and 113.1±3.3, respectively. Although the difference in initial bending strengths was not significant, the bending strength of cGBC was significantly higher than that of GBC at 6 and 12 months, indicating that cGBC is more resistant to cement degradation. The bending strengths of both GBC and cGBC decreased significantly from 0 to 6 months but did not change significantly thereafter. Thus, degradation of cGBC and GBC does not appear to continue after 6 months. We believe that cGBC and GBC are strong enough for use under weight-bearing conditions and that their mechanical strength (especially that of cGBC) is retained in vivo.

Calcium sulfate bone cements with nanoscaled silk fibroin as inducer

“…Polymethylmethacrylate (PMMA) is another widely used bone substitute. Several great challenges remain to endow PMMA with bioactivity and binding capacity with adjacent bone tissues . Comparing to HA materials, calcium sulfate (CS)‐based bone cements have not only good biocompatibility and osteoconductive, but also self‐setting capacity as well as biodegradability .…”

Hydroxyapatite Formation on Alumina Surface Modified by Aluminoxane

“…Alumina is a type of bioceramics that has excellent mechanical properties. Therefore, it has been used both as a pure phase and also associated with other materials such as polymethyl metacrylate in hip joint prostheses, dental implants, for instance [1][2][3]. However, the usage of alumina as bioceramics is restricted, due to its bioinert behavior.…”