Objectives The degree of conversion (DC) and polymerization shrinkage of resin composites are closely related manifestations of the same process. Ideal dental composite would show an optimal degree of conversion and minimal polymerization shrinkage. These seem to be antagonistic goals, as an increase in monomer conversion leads to a high polymerization shrinkage. This paper aims to determine the effect of opaque mineral fillers and monomer ratios on the DC and the shrinkage-strain of experimental composites based on (BisGMA/TEGDMA) monomers (traditionally used monomers). A relationship between the shrinkage-strain and the degree of conversion values was also investigated. The radiopacity of these experimental composites has been investigated in a previous paper.
