Background and objectives: The literature suggests that persistent intraradicular infections are the major cause of root canal treatment failure. Secondary to this colonization of the root canal system, microorganisms are able to survive and colonize beyond the root canal causing persistent extraradicular infections. These persistent extra-radicular infections are not affected by the action of antimicrobial agents such as irrigants and medicaments used during root canal treatment. Apical surgery may be the only method for the definitive removal of an established extra-radicular infection, promoting repair in resistant cases.

Methods: This is a case report of a 42 year old patient in which an abnormaly large radiolucency associated with the upper incisors was detected. Constant purulent drainage during an endodontic approach, suggested a well established extra radicular infection. It was decided that a surgical approach for the enucleation of the lesion would be performed. Since the teeth involved presented large apical diameters, orthrogade filling with mineral trioxide agreggregate was performed with three millimetres of the roots being resected and the apical sealing controlled under surgical microscope.

Results: The treatment was successful at a ten month post-operative follow up with radiographic bone healing and the patient reporting no further symptoms.