The Relationship between Polymerization Shrinkage Measured by a Modified Dilatometer and the Inorganic Filler Content of Light-Cured Composites

The objectives of this study were to introduce a modified dilatometer for measuring polymerization shrinkage in light-cured composites and to investigate the possible relationship between the inorganic filler content of light-cured composites and their polymerization shrinkage. The polymerization shrinkage of 22 commercially available light-cured composites was measured using this dilatometer, with results ranging from 1.56 to 3.41 volume percent. A negative correlation (y=-0.117x+11.670, r=-0.850, p>0.05) between the inorganic filler content and polymerization shrinkage of all resins was noted, with the exception of 5 composites containing prepolymerized resin particles. It is concluded that this dilatometer can be used for measuring polymerization shrinkage of light-cured composites and that the filler content is of great importance in the polymerization shrinkage of light-cured composites.