Preparation, Physicochemical Characterization, and Bioactivity Evaluation of Strontium-Containing Glass Ionomer Cement

Background. Glass ionomer cements are one of the most important restorative materials in dentistry. One of the disadvantages of glass ionomer cements is their undesirable mechanical properties and bioactivity. Aim. The aim of this work was preparation and characterization of strontium-containing glass ionomer cement and evaluation of its bioactivity in the simulated body fluid. Materials and Methods. The ceramic component of glass ionomer cement was made by melting method. Scanning electron microscope (SEM) was used to study the size and the shape of glass particles. In order to determine the phase combination in the produced material, X-ray diffraction (XRD) analysis was carried out. The chemical composition of the glass was evaluated by X-ray florescence (XRF), and the surface area of the particles was determined using BET method. In order to investigate the biological properties of the glass, samples were immersed in simulated body fluid (SBF). Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) were used to recognize and confirm the apatite layer on the composite surface. Results and Conclusions. The result of X-ray diffraction (XRD) analysis confirmed the glassy structure of the produced ionomer cements. The result of XRF confirmed the presence of Sr in the chemical composition. Fourier transform infrared spectroscopy test and electron microscope confirmed the formation of apatite layer on the surface of material. The final result of this research was gaining glass ionomer cement containing Sr with improved bioactivity. 1. Introduction Due to desirable characteristics such as chemical-physical bonding to hydrophilic tissues of enamel and dentine, microleakage reduction, long-term release of fluoride, capability of absorbing fluoride and storing it, low thermal expansion coefficient, and biocompatibility with pulp and gum tissues, use of glass ionomer cements is increasing in recent years [1–3]. Despite the mentioned advantages, this kind of materials has disadvantages too that limit their use in some areas. One of their disadvantages is their brittleness that, as a result, the material has no resistive capability against chewing forces. The other main disadvantages of these materials could be regarded as long-term hardening, sensitivity to humidity (that requires water balancing maintenance during working with these materials), surface roughness, lack of adequate strength, high erosion, opaqueness, and short life. Enormous efforts have been done since the invention of glass ionomer to modify the defects, such that