Objective: Althogh Bisphosphonates(BPs) are very effective medication for bone metastasis due to breast or prostate cancer, osteoporosis and multiple myeloma, its adverse effects of oral ones is an important problem for both patients and dentists.The number of Osteonecrosis of the Jaw (ON J) cases has been increasing due to lately their extensive use.The purpose of this study is to review clinical data on the treatment of ONJ obtained at the Department of Oral and Maxillofacial Surgery, Tokyo Dental College, Japan for further our understanding and protocol of this disease.