Abstract
The purpose of this study was to measure the filler content by weight and volume of universal shade flowable resin-based composites and analyze the correlation between polymerization shrinkage and filler content. The filler content by weight of six universal shade flowalble resin-based composites (Bulk Base Hard II Medium Flow, A-Uno Flow Basic, Clearfil Majesty ES Flow Low, Gracefill Low Flow, Omnichroma Flow, Omnichroma Flow Bulk) was measured in accordance with ISO 17304. The filler content by volume of each flowable resin-based composite was determined by measuring the density of the filler using a dry density meter, and the filler content by volume of the composite was calculated from the densities obtained. The correlations between filler content by weight or volume, polymerization shrinkage and filler content by weight ratio, and polymerization shrinkage and filler content by volume were analyzed. The filler content of the universal flowable resin-based composites ranged from 59.40 to 69.81% (by weight) and from 40.61 to 54.84% (by volume), and the correlations between the values for filler content of the composites by weight and volume were weakly negative and not statistically significant. The correlations between polymerization shrinkage (3.15–4.48%) and filler content by weight or volume were also not statistically significant.