Relaxation of polymerization contraction stresses by flow in dental composites

The hardening stresses in wall-to-wall bonded composites were measured and related to calculated values obtained from freely shrinking materials. Since the ultimate tensile strength of the materials contracting under restricted conditions was not lower than that of composites which were not hindered during the polymerization shrinkage, the conclusion was drawn that the contraction was compensated for by flow instead of internal disruptions.