A method of improving marginal adaptation by elimination of singular stress point in composite restorations during resin photo-polymerization

摘要

Objectiues. To reduce the effect of stresses due to volumetric shrinkage the authors proposernan incremental technique for placing composite restorations.rnMethods. The goal of the method is to reduce the volume of the resin that is polymerizedrnand eliminate a stress singular point in the resin that is positioned at the geometric centerrnof the cavity. This is achieved by a two step type incremental technique. In the first steprnthe resin is placed in the cylindrical cavity with a metal pin embedded in the middle of therncomposite restoration. After polymerization, the metal pin is removed and the cylindricalrnhole is filled with the second layer of composite. Finally, the second layer in the center ofrnthe composite restoration is polymerized.rnResults. This study confirmed that the proposed incremental type placement techniquernreduces marginal debonding.rnSignificance. The main hypothesis is that the elimination of a stress singular point at therncenter of the restoration results in the reduction of stresses at tooth-composite interfacernand therefore improve the marginal adaptation (reduces length of the contraction gap atrntooth-composite interface).