Oral Health and Dental Management

Abstract

Flexural strength and fracture surface characterization of glass-ionomer cements stored in water

In order to evaluate the effect of water on the microstructural and mechanical properties of glassionomer
cements, the flexure strengths of six commercial ionomer cement materials stored in water
at 37ºC for 1 h and 1 week were determined and their fracture surfaces were characterized using
electron microscopy techniques. The flexural strength value of the conventional glass-ionomer material
stored in water for 1 h was found to be less than those of the resin-modified glass-ionomers and
was higher than those of the glass-ionomer for molar filling materials. It was found that the coated
glass-ionomer materials display higher flexural strengths than in the uncoated condition. SEM and
energy dispersive analysis (EDS) investigations conducted on the fracture surfaces of the flexural
specimens revealed crack formations and cavities and porosities resulting from the loss of ionomer
particles. The 1 h specimens displayed cracks deeper and more pronounced than those occurred in
the 1-week specimens.