Periradicular surgery has become an established treatment option in endodontic surgery. The major objective of this surgery is to obtain periradicular tissue regeneration, including the formation of a new attachment apparatus, by exclusion of any potentially noxious agent within the physical confines of the affected root. However, in a substantial number of cases, the endodontic lesion has a concomitant marginal periodontal lesion that may complicate the healing success. In periodontology, the guided tissue regeneration (GTR) principle using a barrier membrane has been extensively studied and successfully used, and thus may become an adjunct in endodontic surgery. This article presents a classification system of endodontic and periodontal lesions with respect to the application of the membrane technique and reviews the pertinent literature based upon this classification system.