One of the goals of endodontic treatment is the complete debridement of the root canal system. Mechanical cleaning can greatly reduce the number of microorganisms but not completely eliminating them. Therefore, there is a need for an irrigant to enhance debridement. Sodium hypochlorite is still the most widely used irrigation solution in endodontics. However, many new irrigants have been introduced, MTAD is one of them. It is a mixture of tetracycline isomer, an acid and a detergent. MTAD is capable of removing the smear layer without causing excessive erosion and it has an antibacterial action against E. faecalis. With the more interest in resin-based obturation materials, it has been important to study the effect of the used irrigants on the adhesion of those materials to dentine. As MTAD is not a single component it is wise to study its effect on the adhesion of a self-etch resin-based sealer (Epiphany SE) to dentine.