Conventional and surgical retreatment of complex periradicular lesions with periodontal involvement.

A periradicular pathosis with an associated periodontal breakdown creates a complex problem during endodontic therapy. In cases in which nonsurgical retreatment does not have a successful outcome, a surgical retreatment has to be taken into consideration. With the introduction of microsurgical techniques in endodontics, surgical treatment success has improved considerably. The surgical treatment of combined lesions, however, is still considered to have a less favorable prognosis. The presented cases illustrate successful treatments in which a periodontal breakdown and an endodontic breakdown were present.