One of the most important issues in dental treatment is the failure of the filling material. This failure happens due to the marginal degradation between the dentine and the filling material because of the structural weakness of the surface of the dentine. The aim of this study is represented by the treatment of the dentine with three essential oils (oregano, rosemary, myrtus) in order to test the impact of these oils on the collagenic structure of the surface of the dentine. The results of this study showed that essential oils could improve the stability of the dentine.