Factors affecting polymerization shrinkage of composite resin restoration materials, and stress created in the cavity preparations

Abstract

I investigated the polymerization shrinkage of composite resin restoration materials and stress created in the cavity preparations by this shrinkage as a function of cavity depth, area of adhesion and pressure welding. Various cavity depths were prepared in multi-crystalline glass. There was an increase in gap formation as the cavity depth increased and as the consistency of the composite resin decreased. Gap formation was greater with light-cured than chemically-cured resins. Pressure welding was not effective in decreasing gap formation. Crack formation was influenced by depth of cavity preparation and mode of curing, but not by consistency of the composite resin or pressure welding.