O objetivo deste trabalho foi avaliar in vitro, através de microscopia eletrônica de varredura, a ocorrência e largura de fendas na parede axial de cavidades de classe V restauradas com resina com posta (TPH) e diferentes sistemas adesivos (One-Step, Prime&Bond 2.0 e Scotchbond Multi-Purpose). Com base nos resultados, os autores puderam concluir que nenhum dos sistemas adesivos utilizados foi capaz de prevenir completamente a ocorrência de fendas axiais, e o material que apresentou melhores resultados foi o One- Step, seguido por Prime&Bond 2.0 e Scotchbond Multi-Purpose, que apresentaram comportamentos semelhantes entre si.

The aim of this study was to evaluate marginal gaps at the axial wall in class V composite restorations, under scanning electronic microscopy. Standart class V cavity preparations were filled with a microhybrid composite resin (TPH – Dentsply) and with different adhesive systems (One-Step, Prime & Bond 2.0 and Scotchbond Multi-Purpose). The width of axial gap width were measured and Kruskal-Wallis statistically analysed. We concluded that the adhesive restorative systems were unable to prevent axial gaps formation and the dentin bonding adhesive system One Step showed the best results followed by Prime & Bond 2.0 and Scotchbond Multi-Purpose, wich showed similary results.