IADR Abstract Archives
Nanoparticle Incorporation Into Conventional Glass-ionomer Cements
Objectives: The use of the conventional glass-ionomer cements (GICs) is limited by their relatively low mechanical properties. The present study attempts to improve these materials by incorporation of different types of nanoparticles into conventional GICs.
Methods: Two commercially available conventional GICs were used in the study: ChemFil®Rock (DENTSPLY DeTrey, Konstanz, Germany) and GC EQUIA™Fil (GC Europe N.V., Leuven, Belgium). Four groups consisting of 18 samples were prepared for each material by mixing the GICs in a capsule mixer according to the manufacturers’ instructions. The first group served as a control (without addition of nanoparticles), whereas the other three groups were modified by incorporation of aluminum oxide, zirconium oxide and titanium dioxide nanoparticles; each at 2, 5 and 10wt%. The nanoparticles were mixed into the mixed cement by spatulation on a ceramic tile to obtain the most uniform distribution possible.
The cement was placed in a cylindrical metal mold (4mmX6mm) covered on both sides with metal slides, clamped, and left in an incubator (at 37°C) for 1h to allow setting. Following setting, the samples were stored at room temperature in physiological saline for 24 hours and 1 week.
The fractured samples were mounted onto aluminum stubs covered with conductive carbon tape and the morphology of the fractured surfaces was analyzed uncoated in high vacuum by SEM (Quanta™250 SEM; FEI™Company, Oregon, USA) at 1.000× and 5.000×magnifications.
Results: The results indicate that the nanoparticles readily dispersed into the cement matrix and reduced the porosity of set cements by filling the empty spaces between the glass particles. Fewer air voids were observed in all nanoparticle containing cements and this, in turn, reduced the development of cracks within the matrix of the cements.
Conclusions: The reported changes in the microstructure provided by the addition of nanoparticles appear to be a promising strategy for improving the physical properties of GICs.
Methods: Two commercially available conventional GICs were used in the study: ChemFil®Rock (DENTSPLY DeTrey, Konstanz, Germany) and GC EQUIA™Fil (GC Europe N.V., Leuven, Belgium). Four groups consisting of 18 samples were prepared for each material by mixing the GICs in a capsule mixer according to the manufacturers’ instructions. The first group served as a control (without addition of nanoparticles), whereas the other three groups were modified by incorporation of aluminum oxide, zirconium oxide and titanium dioxide nanoparticles; each at 2, 5 and 10wt%. The nanoparticles were mixed into the mixed cement by spatulation on a ceramic tile to obtain the most uniform distribution possible.
The cement was placed in a cylindrical metal mold (4mmX6mm) covered on both sides with metal slides, clamped, and left in an incubator (at 37°C) for 1h to allow setting. Following setting, the samples were stored at room temperature in physiological saline for 24 hours and 1 week.
The fractured samples were mounted onto aluminum stubs covered with conductive carbon tape and the morphology of the fractured surfaces was analyzed uncoated in high vacuum by SEM (Quanta™250 SEM; FEI™Company, Oregon, USA) at 1.000× and 5.000×magnifications.
Results: The results indicate that the nanoparticles readily dispersed into the cement matrix and reduced the porosity of set cements by filling the empty spaces between the glass particles. Fewer air voids were observed in all nanoparticle containing cements and this, in turn, reduced the development of cracks within the matrix of the cements.
Conclusions: The reported changes in the microstructure provided by the addition of nanoparticles appear to be a promising strategy for improving the physical properties of GICs.