The Investigation of Bioactivity and Mechanical Properties of Glass Ionomer Cements Prepared from Al₂O₃‐SiO₂ Glass and Poly(γ‐glutamic acid)

Abstract

The glass ionomer cement as one of the dental cements has been subjected to be widespread application in restoring tooth structure. Most of glass ionomer cements employ the poly(acrylic acid) (PAA) as the liquid phase, but the presence of PAA inhibits the apatite formation on the surface in the body environment, which is an essential requirement for exhibiting bone-bonding ability (bioactivity). In this study, poly(γ-glutamic acid) (γ-PGA), a kind of biopolymer, was utilized for cement preparation. The effort of preparation parameters including the glass powders/liquid ratio (P/L) and the concentration ofγ-PGA on diametral tensile strength were investigated. A maximum diametral tensile strength value of11.88±1.43MPa was obtained when the cement sample was prepared by P/L ratio of 1 : 1 and theγ-PGA concentration of 30% after aging for 3 days. The TF-XRD patterns, SEM images, and EDX spectra suggested that the cement induced a precipitation of calcite on the surface after 7 days of immersion in stimulated body fluid (SBF), although the apatite formation was not observed. The present results suggest that the cement has potential to show bioactivityin vivo, because calcite is also reported to be bioactive.

A Multimaterial Scaffold With Tunable Properties: Toward Bone Tissue Repair

“…The bioactivity was assessed by immersing the scaffolds in SBF solution at 37 °C for 7, 14, 21, and 28 d and testing the growth of apatite on their surface. The SBF with ion concentrations nearly equal to that of human blood plasma was prepared by dissolving NaCl, KCl, NaHCO 3 , MgCl 2 ·6H 2 O, CaCl 2 , K 2 HPO 4 ·3H 2 O, and Na 2 SO 4 (reagent grade, all from Beijing Chemical Reagent Company, China) into distilled water and buffered with trishydroxymethyl aminomethane and hydrochloric acid solution to pH 7.4 . The scaffolds (Φ15 mm × 5 mm) were immersed in the SBF for different time intervals at a concentration of 0.1 cm 2 mL −1 with a volume of 100 mL.…”

“…The SBF with ion concentrations nearly equal to that of human blood plasma was prepared by dissolving NaCl, KCl, NaHCO 3 , MgCl 2 •6H 2 O, CaCl 2 , K 2 HPO 4 •3H 2 O, and Na 2 SO 4 (reagent grade, all from Beijing Chemical Reagent Company, China) into distilled water and buffered with trishydroxymethyl aminomethane and hydrochloric acid solution to pH 7.4. [33] The scaffolds (Φ15 mm × 5 mm) were immersed in the SBF for different time intervals at a concentration of 0.1 cm 2 mL −1 with a volume of 100 mL. After the predetermined time, the scaffolds were removed, rinsed three times with deionized water, and dried at 60 °C for 12 h. The formation of apatite on the scaffold surface was investigated using SEM and XRD.…”

Kinetics of ion release from a conventional glass-ionomer cement

“…There has been some question in the literature as to whether glass-ionomers are inherently bioactive [23], and whether they need additives to become so. However, on the basis of Hench's definition, and the observations of ionexchange bonding [20,21] it seems they definitely are bioactive [5], even if this property can be improved by the use of additives or by formulating the cement from alternative acid and glass components [24].…”

Calcium aluminate cement-based compositions for biomaterial applications

“…The presence of polyacrylic acid for the Meron and Vidrion F compositions (glass ionomers) inhibits the apatite formation of the sample's surface in SBF liquid [32]. However, the mercury intrusion porosimetry results indicate the pore sizes decrease in these materials (Fig.…”