Bioactive bone cement: Effect of silane treatment on mechanical properties and osteoconductivity

Abstract

A novel bioactive bone cement (GBC) was developed with newly designed bioactive MgO-CaO-SiO(2)-P(2)O(5)-CaF(2) glass beads as the inorganic filler and high molecular weight poly(methyl methacrylate) as the organic matrix. The purpose of this study was to examine the relationship between the amount of the silane coupling agent (gamma-methacryloxy propyl trimethoxy silane) used to treat the glass beads and the mechanical and biological properties of the resultant bone cement. Serial changes in the cement over time were also investigated. Five different kinds of cement, in which the glass beads were treated with different amounts of the coupling agent, were prepared. The quantities of the coupling agent were 0 (control), 0.1, 0.2, 0.5, and 1.0% (w/w) of the glass beads, and the cements were designated GBCs0, GBCs0.1, GBCs0.2, GBCs0.5, and GBCs1.0, respectively. After soaking in water at 75 degrees C for 5 days, GBCs0.1 and GBCs0.2 had significantly higher bending strengths than the other cements. Each GBC was packed into intramedullar canals of rat tibiae to evaluate osteoconductivity, as determined by affinity indices. Rats were killed 4 and 8 weeks after the operation. The affinity index was calculated for each GBC and equaled the length of bone in direct contact with the cement and was expressed as a percentage of the total length of the cement surface. Histologically, new bone had formed along all of the GBC surfaces within 4 weeks. At each time interval, a decreasing trend in the affinity index of GBC was found as the amount of the coupling agent increased. At 8 weeks, no significant change in the affinity index occurred when the amount of the coupling agent increased from 0 to 0.2%, whereas a significant decrease in the affinity index was observed when the amount of the coupling agent increased from 0 to 0.5 or 1.0%. The affinity indices for all the GBCs increased significantly up to 8 weeks. When both the mechanical properties and osteoconductivity were taken into consideration, GBCs0.1 and GBCs0.2 were the best cements, and they showed excellent osteoconductivity and strong enough mechanical properties for clinical use.

Developing a New Generation of Bone Cements With Nanotechnology

“…Another study showed that in the absence of -methacryloxy propyl trimethoxy silane (MPS), the glass-based cement was more brittle than PMMA cement. However, the bending strength of glass-based cements increased more than the PMMA cements after being treated with 0.1% of MPS [57]. In addition, the glass filler size and content are both important to determine the mechanical properties and osseointegration of the cements in vivo.…”

“…MPS not only helps inorganic fillers to form strong covalent bonds with an organic matrix but it also provides Si-OH groups to induce heterogeneous nucleation of the apatite on their surface [67,68]. Therefore, mechanical properties and osseointegration of bone ce- ments improve after being treated with MPS, but a slight increase in setting time has also been observed [57,69].…”

Injectable bone cements for use in vertebroplasty and kyphoplasty: State‐of‐the‐art review

“…The flexural properties of only a few IBCs have been reported 25, 96, 97. Values of these properties for cements from all classes of IBCs are needed.…”

Surface modification of bioceramics by grafting of tailored allyl phosphonic acid

“…The method has also been used for coupling hydroxyapatite in bone cements. 11,12 Deb et al 13 have reported the use of silane coupling agents to bind polyethylene to hydroxyapatite to improve mechanical properties. However, the stability of such a linkage is debatable in an aqueous environment and as a consequence the choice of silane coupling agents in this application is not ideal.…”