Hardness and inorganic filler content evaluation of low viscosity composites

Abstract

The purpose of this study was to evaluate hardness and inorga- nic filler content of low viscosity composites. Twenty cylindrical specimens, 5 mm in diameter and 2 mm-thick were made with the composite resins: Natural Flow (DFL), Flow It (Jeneric/Pentron), Flow It LF (Jeneric/Pentron) and Revolution (Kerr). Vickers hard- ness was measured with a Wolpert equipment with a load of 50g du- ring 30 seconds; right immediately and seven days after the confection of the specimens. Twelve indenta- tions were made in each specimen. Folowing this, it was calculated the inorganic filler content in mass and volume in analytic scale. The results were submitted to ANOVA and Fischer’s test (p<0,05) and showed that the immediate hard- ness of Flow It (44.52) and Flow It LF (40.64) were statistically superior to Revolution (29.56) and Natural Flow (27.89). (p<0,05). After seven days, the Vickers hard- ness of Flow It (49.64) and Flow It LF (46.30) were statistically superior to Revolution (35.90) and Natural Flow (28.61) (p<0,05). For the filler content, Natural Flow (51.60%) and Revolution (53.80%) showed lower mass values follo- wed by Flow it (74.61%) and Flow It LF (65.01%). In volume, Flow It (68.12%) and Flow It LF (57.74%) showed higher percentual values in relation to Natural Flow (40%) and Revolution (46.80%). Thus, Flow It and Flow It LF showed higher inorganic filler content in mass and volume, besides the su- perior values of Vickers hardness, immediately and seven days after cure. Key words: composite resin, hardness, inorganic particle.