A REVIEW OF POLYMERIZATION CONTRACTION - THE INFLUENCE OF STRESS DEVELOPMENT VERSUS STRESS RELIEF

The insertion of bonded resin composites into cavity preparations lead s to a competition between polymerization contraction forces and the s trength of bonds to tooth structure. The degree of stress development can be controlled, to some extent, by the cavity design (C-factor), th e use of bases, the size, shape, and position of of composite resins p laced in the whether the resin light- or cured. Stress relief be accom plished by maintaining the C-factor as low as possible, using chemical -curing resins, low modulus liners, and, over time, by water sorption. A thorough understanding of these principles permits clinicians to ex ercise more control over these variables, thereby improving the qualit y of their bonded restorations.