Complications of bisphosphonate therapy have received increasing attention in the fi eld of dentistry as these drugs can potentially cause osteonecrosis of the Maxilla and Mandible (MRONJ). There have been an increasing number of reports in the literature associating osteonecrosis with patients taking bisphosphonates prior to oral surgery (12). In rare cases the necrotic bone segment is entirely separated from the uninvolved bone, which is known as simultaneous sequestrum. The purpose of this case report is to present a case of spontaneous separation of necrotic bone in the maxillary arch without surgical intervention after sinus augmentation and implant placement, in a patient with a history of treatment with oral bisphosphonates. These results and those of others suggested that already osseointegrated dental implants can also cause the osteonecrosis around the implant after bisphosphonates administration. En block sequestration of bone with or without implant might be one of the characteristics of implantrelated MRONJ.