effect of various types of glass ionomers on the microhardness of cem cement

Objective: this study aimed to compare the effects of different types of glass ionomer cement (gics), including conventional gic, resin-modified gic (rmgic), and syringe-applied rmgic (ionoseal), on the microhardness of calcium-enriched mixture (cem) cement.methods: forty cem cement samples were prepared. the study included eight groups (n=5), based on the type of gic applied over cem (conventional gic, rmgic, ionoseal, or no coating) and the timing of gic placement (immediate or after a 5-minute moisture application using a wet cotton pellet). samples were incubated at 37°c for 7 days, then subjected to vickers testing to assess the microhardness of cem cement. two-way anova was used for the data analysis (α=0.05).results: there was no significant difference in cem cement microhardness among the immediate restoration groups (p=0.4). after exposure to wet cotton pellet, all gic groups exhibited significantly higher microhardness than the control group (p<0.05). furthermore, samples coated with conventional gic showed significantly greater microhardness than those coated with rmgic and ionoseal (p<0.05). delayed restoration significantly increased microhardness in the conventional gic group (p = 0.001), while no significant changes were detected in the rmgic or ionoseal groups (p>0.05).conclusions: in the case of immediate restoration, all types of gic support cem cement setting without compromising its microhardness. for delayed restorations, conventional gic offers superior results in enhancing cem cement microhardness. if rmgic or ionoseal is used for coating, placing a wet cotton pellet on cem for 5 minutes is not recommended, as it does not improve cem cement microhardness.