Spontaneous Bisphosphonate-related Osteonecrosis Associated with a Tooth that Had a Necrotic Pulp: A Case Report

This study reports the endodontic treatment performed in a patient who presented with spontaneous bone exposure in the mandible while using intravenous bisphosphonate medication (ZometaÒ, Novartis Pharmaceuticals Co., Basel, Switzerland). A 63-year-old female patient was referred to a private dental clinic at Fortaleza, Brazil. The patient reported that one year before, she had undergone chemotherapy for the treatment of lung cancer and associated bone metastasis. Among the medications administered was the zolendronic acid, with dosage of 4 mg every 21 days. In the oral exam, the presence of extensive bone exposure was observed in the lingual region near tooth 37. The patient reported severe pain on palpation in the region; in the pulpal sensitivity test with cold stimulus, there was an absence of pain, characteristic of pulp necrosis. Radiographically, no periapical lesion was observed. Thus, endodontic treatment was performed, and instrumentation with Reciproc R25 files in the mesial root canals and R40 in the distal canal was done, alongside with abundant 2.5% sodium hypochlorite irrigation. Interappointment medication with calcium hydroxide was maintained for 15 days. In the second session, there was the spontaneous detachment of the exposed cortical bone fragment. The root canals were filled with gutta-percha and Endosequence BC Sealer cement. After two years, complete tissue repair was observed, and the patient presented with normal periapical tissues and the tooth in masticatory function.   It may be concluded that a possible relationship between pulp and periapical infections and osteonecrosis exists in patients who use bisphosphonates.