Investigating Some of the Mechanical Properties of Glass-Ionomers Cements Modified with ZnO and TiO2 Nanoparticles

Abstract

Glass-ionomer cement (GIC) is one of the common restorative materials, but they exhibit relatively low mechanical properties. The aim of this study is the improvement of the properties of glass ionomer cement by incorporation of (1, 3 and 5wt.%) of different types of ZnO and TiO2 nanoparticles. Two conventional types of GIC Luting Cement were used (Ketac Cem radiopaque and Polyalkenoate Cement). Flexural strength and diametral tensile strength were calculated after 24 hr. and 3 weeks according to ISO4049. The results show a slight increase in flexural strength of glass ionomer cement, after adding 1 wt.% of both ZnO/NPs and TiO2/NPs, while the increase in flexural strength was significant at 3wt.% which reached 14% and 15.71% for ZnO/NPs and TiO2/NPs respectively for Ketac Cem radiopaque and reached 4.79% and 8.59% for Polyalkenoate Cement at the same ratio. Also, the flexural strength value increased after 3 weeks for all incorporation weight percentages. The modified tested cement also exhibited higher diametral tensile strength after 3 weeks, than that recorded in 24 hr for all concentrations (1, 3 and 5wt.%) of ZnO and TiO2 nanoparticles, in addition to the increase in diametral tensile strength after the incorporation of nanoparticles with glass ionomer cement. Within the limits of this study, a considerable increase in flexural strength and diametral tensile strength was observed with ZnO and TiO2 nanoparticles incorporations in 3wt% by weight. Furthermore, an increase in these properties after 3-week storage in distilled water was noticed.