[Bisphosphonates and osteonecrosis of the jaws]

The osteonecrosis of the jaws (ONJ) has been reported occasionally in cancer patients treated with radiotherapy and chemotherapy. However, bisphosphonate (BP)-associated ONJ in patients with cancer such as multiple myeloma, breast cancer and prostate cancer mainly administered with intravenous BPs has been first reported in 2003. Since then, many cases over 2,500 are accumulating worldwide. Since BPs are often used for osteoporosis, cancer-associated hypercalcemia and osteolytic bone metastasis, it is speculated that ONJ cases will increase in Japan where a small number of them were reported until now. Most of ONJ in cancer patients receiving BP administration occur after dental treatments such as tooth extraction, periodontal surgery and dental implants, and do not respond to conventional treatment modalities such as debridement, antibiotic therapy and hyperbaric oxygen therapy. No effective therapy for ONJ is established yet and empirical conservative therapy is recommended in the guidelines for prevention, diagnosis, and treatment of ONJ. Therefore, dentists and oral and maxillofacial surgeons need to recognize ONJ as a serious side effect of BPs and to make informed consent to the patients and a close consultation with medical oncologists for administration of BPs.