Effect of bioactive filler content on mechanical properties and osteoconductivity of bioactive bone cement

Abstract

Abstract:We took three types of bioactive bone cement (designated AWC, HAC, and TCPC), each with a different bioactive filler, and evaluated the influence of each filler on the mechanical properties and osteoconductivity of the cement. The cements consisted of bisphenol-a-glycidyl methacrylate-based (Bis-GMA based) monomers as an organic matrix, with a bioactive filler of apatite/wollastonite containing glass-ceramic (AW-GC) or sintered hydroxyapatite (HA) or ␤-tricalcium phosphate (␤-TCP) powder. Each filler was mixed with the monomers in proportions of 50, 70, and 80% (w/w), giving a total of nine cement subgroups. The nine subgroups were designated AWC50, AWC70, AWC80, HAC50, HAC70, HAC80, TCPC50, TCPC70, and TCPC80. The compressive and bending strengths of AWC were found to be higher than those of HAC and TCPC for all bioactive filler contents. We also evaluated the cements in vivo by packing them into the intramedullary canals of rat tibiae. To compare the osteoconductivity of the cements, an affinity index was calculated for each cement; it equaled the length of bone in direct apposition to the cement, expressed as a percentage of the total length of the cement surface. Microradiographic examination up to 26 weeks after implantation revealed that AWC showed a higher affinity index than HAC and TCPC for each filler content although the affinity indices of all nine subgroups (especially the AWC and HAC subgroups) increased with time. New bone had formed along the AWC surface within 4 weeks, even in the cement containing AW-GC filler at only 50% (w/w); observation of the cement-bone interfaces using a scanning electron microscope showed that all the cements had directly contacted the bone. At 4 weeks the AWC had bonded to the bone via a 10 m-thick reactive layer; the width of the layer, in which partly degraded AW-GC particles were seen, became slightly thicker with time. On the other hand, in the HACand TCPC-implanted tibiae, some particles on the cement surface were surrounded by new bone and partly absorbed or degraded. The results suggest that the stronger bonding between the inorganic filler and the organic matrix in the AWC cements gave them better mechanical properties. The results also indicate that the higher osteoconductivity of AWC was caused by the higher reactivity of the AW-GC powder on the cement surface.

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

“…4,6,7,[10][11][12][13]17 The length of bone in direct contact with the cement surface and the total length of the cement surface were measured with an integrated image analyzer (Tectron, Kyoto, Japan). 4,6,7,[10][11][12][13]17 When the total length of the cement surface was measured, the area outside the tibia (i.e., the area of the cortical bone defect) was excluded because the cement was in contact with soft tissue in that region, and our intention was to examine the reaction of the cement within the bone. 4,6,7,10-13,17…”

“…[4][5][6] The bioactive beads, consisting of MgO-CaO-SiO 2 -P 2 O 5 -CaF 2 glass, were newly designed, 4-6 and a novel PMMA powder was selected. 7 GBC showed excellent osteoconductivity and good mechanical properties [4][5][6] in comparison with cements consisting of the same type of PMMA and either apatite-and wollastonite-containing glassceramic (AW-GC) powder [4][5][6][7][8][9][10][11][12][13][14] or hydroxyapatite (HA) powder. 4 6,9,13,14 Moreover, GBC showed good handling properties that were comparable to those of conventional PMMA bone cement.…”

“…The quantities of the silane coupling agent used 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. The purpose of this study was to measure the mechanical properties and evaluate the osteoconductivity of the cements in terms of affinity indices with rat tibiae, 4,6,7,[10][11][12][13]16,17 to examine the bone-cement interface histologically, and to determine the optimum amount of silane coupling agent for the treatment of the beads.…”

Processing and tensile properties of hydroxyapatite-whisker-reinforced polyetheretherketone

“…Therefore, synthetic biomaterials that are biocompatible, bioactive and able to be tailored to mimic the mechanical properties of bone tissue may be advantageous for implant fixation, synthetic bone graft substitutes, tissue engineering scaffolds, and other orthopedic applications. To this end, numerous biocompatible polymers, including polyethylene [4,[17][18][19][20][21][22], polymethylmethacrylate [23][24][25][26], bisphenol-a-glycidyl methacrylate (bis-GMA) [27][28][29], poly(L-lactide) [30][31][32] and polyetheretherketone (PEEK) [33][34][35], among others, have been reinforced with bioactive hydroxyapatite (HA).…”

Whisker-reinforced bioactive composites containing calcium phosphate cement fillers: Effects of filler ratio and surface treatments on mechanical properties

“…[26][27][28][29][30][31] When bioactive fillers were added, Bis-GMA-based composites were rendered bioactive and were investigated for bone repair applications. [32][33][34][35][36][37][38] Bioactive fillers used in Bis-GMA-based composites included hydroxyapatite, bioactive glass and glassceramics, and calcium phosphates. [32][33][34][35][36][37][38] Previous studies have examined the effects of bioactive filler content 37 and bioactive filler/silica glass ratio 34 on Bis-GMA-based composite properties.…”