Relationship between polymerization shrinkage of matrix-monomers and marginal leakage of composite resins.

The intimate marginal adaptation of composite resins is considered to be the most important requisite, and this is strongly influenced by polymerization shrinkage, thermal expansion or mechanical properties of the resins. The highly loaded composite resins, developed recently have yielded good results on thermal expansion and mechanical properties. Consequently, little attention has been paid to the importance of the polymerization shrinkage. Asmussen1) reported the relationship of wall-to-wall polymerization shrinkage of composites to their various components and the effects of diluent monomer on the contraction in composites based on Bis-GMA. Brauer et al2) studied the marginal adaptation of Bis-GMA-based composites containing various diluents. Davidson et al3) demonstrated the influence of contraction stresses, developed during the polymerization of composites, on adhesion to dentin. The purpose of the present investigation was to clarify the relationship between polymerization shrinkage of the matrix-monomers of the composite resins and marginal leakage.