Mechanical and biological properties of two types of bioactive bone cements containing MgO-CaO-SiO2-P2O5-CaF2 glass and glass?ceramic powder

Abstract

In this study two types of bioactive bone cement containing either MgO-CaO-SiO2-P2O5-CaF2 glass (type A) or glass-ceramic powder (type B) were made to evaluate the effect of the crystalline phases on their mechanical and biological properties. Type A bone cement was produced from glass powder and bisphenol-a-glycidyl methacrylate (BIS-GMA) resin, and type B from glass-ceramic powder containing apatite and wollastonite crystals and BIS-GMA resin. Glass or glass-ceramic powder (30, 50, 70, and 80 by wt %) was added to the cement. The compressive strength of type A (153-180 MPa) and B (167-194 MPa) cement were more than twice that of conventional polymethylmethacrylate (PMMA) cement (68 MPa). Histological examination of rat tibiae showed that all the bioactive cements formed direct contact with the bone. A reactive layer was seen at the bone-cement interface. In specimens with type A cement the reactive layer consisted of two layers, a radiopaque outer layer (Ca-P-rich layer) and a relatively radiolucent inner layer (low-calcium-level layer). With type B cement, although the Ca-P-rich layer was seen, the radiolucent inner layer was absent. Up to 26 weeks there was progressive bone formation around each cement (70 wt %) and no evidence of biodegradation. The mechanical and biological properties of the cements were compared with those of a previously reported bone cement containing MgO-free CaO-SiO2-P2O5-CaF2 glass powder (designated type C).

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

“…4,6 Furthermore, the filler consisted of one type of mother glass of AW-GC, resulting in high bioactivity. 11,19 The low-signal layer 4 observed in the SEM photo- graphs may be a sign of degradation, but because this layer was narrow (ca. 5-20 m), it seems unlikely that degradation had occurred.…”

“…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.…”

Demineralization–remineralization dynamics in teeth and bone

“…202 Bioactive glass, HA, and β-TCP have also been used to develop bone cements that have been reported to exhibit bone-bonding properties. 204,205 Enhanced cellular activity has been associated with increased levels of HA fillers in the composite materials. 206 Ultimate tensile strength, however, decreased with increased HA content.…”