Objective: To determine the surface microhardness after 24 hours of maturation effect of paertial weight-based substitution of conventional GIC (glass ionomer cement) powder with Y2O3 nanoparticles. Materials and Methods: Four groups with 12 specimens per group were prepared. One control without any nanoparticle addition and GIC powder partially substituted with 1wt% Y2O3, 3 wt% Y2O3, and 5 wt% Y2O3 nanoparticles. The control and substitute groups had the same powder-liquid ratios overall. Specimens were prepared as per the manufacturer’s instriction and transported away for storage for a duration of 24 hours. Surface microhardness was carried out on all groups with the use of a Vickers microhardness tester (200 g load, 15 sec). Intergroup comparisons were done with significance set at p < 0.05. Results: An increase in microhardness dependent on concentration was observed with increasing substitutions with nanoparticles (p = 0.036). Conclusion: Regular powder of GIC partially replaced with nanoparticles of yttrium oxide produced a significant improvement of surface microhardness at 24 h. Composition with lower proportions did not produce any significance changes.
Zuha Ayad Jaber (Mon,) studied this question.