Assessment of the Impact of the Addition of Nanoparticles on the Properties of Glass–Ionomer Cements

Abstract

The aim of the study was to evaluate the effects of incorporation of Al₂O₃, ZrO₂ and TiO₂ nanoparticles into glass-ionomer cements (GICs). Two different GICs were used in the study. Four groups were prepared for each material: the control group (without nanoparticles) and three groups modified by the incorporation of nanoparticles at 2, 5 or 10 wt %, respectively. Cements were mixed and placed in moulds (4 mm × 6 mm); after setting, the samples were stored in saline (one day and one week). Compressive strengths were measured and the morphology of the fractured surfaces was analyzed by scanning electron microscopy. The elements released into the storage solutions were determined by Inductively coupled plasma-optical emission spectrometry (ICP-OES). Addition of nanoparticles was found to alter the appearance of cements as examined by scanning electron microscopy. Compressive strength increased with the addition of ZrO₂ and especially TiO₂ nanoparticles, whereas the addition of Al₂O₃ nanoparticles generally weakened the cements. The ion release profile of the modified cements was the same in all cases. The addition of Al₂O₃, ZrO₂ and TiO₂ nanoparticles into GICs is beneficial, since it leads to reduction of the microscopic voids in the set cement. Of these, the use of ZrO₂ and TiO₂ nanoparticles also led to increased compressive strength. Nanoparticles did not release detectable levels of ions (Al, Zr or Ti), which makes them suitable for clinical use.