BACKGROUND A 43-year-old African American male initially presented for a dental evaluation of a recurrent swelling on the buccal aspect of tooth #12. His medical history was unremarkable except for a 20-pack year history of smoking. He was eventually diagnosed as having a necrotic pulp #12, and received root canal treatment. The patient's problem was unresolved, and he was subsequently referred for a periodontal evaluation with a presumptive diagnosis of a periodontal abscess. METHODS A flap was reflected from teeth #11 through #15. A buccal furcation invasion was discovered on #12. Shortly thereafter, three distinct roots with three grade III furcation invasions were located. The tooth was deemed untreatable, and was extracted. The thin buccal plate of the extraction socket was preserved using freeze-dried bone allograft to facilitate future prosthodontic replacement. RESULTS Healing was uneventful. Periodontal open flap debridement surgery was provided for the remainder of the mouth, and the patient was placed on a 3-month recall program. CONCLUSIONS Periodontitis associated with endodontic lesions are among the most daunting diagnostic and therapeutic challenges faced by periodontists. This is particularly true for maxillary premolars with multiple roots. The tooth in this case, once periodontally involved, had a very poor prognosis. The prognosis was further compromised by the pulpal involvement. Therapy consisted of extraction of the tooth to relieve the patient's discomfort and treating the adjacent teeth with periodontal open flap debridement surgery. A review of the literature pertinent to the diagnosis and management of periodontal-endodontic lesions is also presented.