The oral environment is one of the most complex systems of the human body. It is populated by a variety of microorganisms, with some of the species still not classified. Tissue adhesives, such as cyanoacrylates, have been used in dentistry and in medicine because of their adhesiveness potential to the human tissue, even in the presence of moisture, their biological compatibility, surface isolation, hemostatic properties and bacteriostatic features. Based on these observations, the authors investigated the use of a tissue adhesive (Histoacryl; Laboratório Braun, RJ, Brazil) with the purpose of sealing the remaining dentin, especially in endodontically treated molars and premolars. The results strongly suggest that Histoacryl controls micro-leakage of oral fluids at the filling/tooth interface.