Developing a more complete understanding of stresses produced in dental composites during polymerization

The polymerization of dental composites is accompanied by significant shrinkage and the production of internal stress. This stress has been implicated as a causative factor for marginal discrepancies seen in composite restorations. This paper provides an overview of the origins of these stresses in polymerizing dental composites, a brief description of the methods for measuring them, a discussion of what little is known of the relationship between contraction stress and outcomes, an identification of the materials and placement factors that affect contraction stress, and a description of several strategies proposed to reduce the stresses. The phenomenon of contraction stress development in dental composite restoratives is highly complex, and despite many investigations, remains as a significant clinical concern. (C) 2004 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.