[Structural changes in composite resins identified using Lugol's solution]

The authors studied the staining of specimens of composite resins, when they were immersed in Lugol solution. In this study, we related chemical and photo-activated resins, and the estructure modifications were analysed in relation to the consulted bibliography. The use of Lugol solution showed a practical way to identify the possible modifications in the polymeric structure of the composite resins.