Knoop Hardness of Resin-modified Glass-ionomer Cements

Abstract

The null-hypothesis tested was the indifference in Knoop hardness between a newly launched nanofilled resin-modified glass-ionomer cement (RMGIC): KetacTM N100 (3M/ESPE) – G1 and two commonly used RMGIC: VitremerTM (3M/ESPE) – G2 and Vitro Fill LC® (DFL) – G3. Ten specimens of each material were inserted in PVC molds, stored in paraffin and wet polished. The Knoop hardness was determined with Knoop indentator. On each specimen three indentations were taken in upper surface and three in the lower surface. ANOVA and Tukey post hoc test were conducted (p=5%). The mean Knoop hardness number (and SD) of each group were: G1 – 39.3 (8.8); G2 – 69.9 (16.5) e G3 – 53.5 (3.1). There were significant difference among the mean of the materials’ hardness and no significant difference between the upper and lower surfaces of the same specimen. The newly launched glass-ionomer cement with nanotechnology did not achieve comparable Knoop hardness of the others RMGIC tested.