Abstract
Bisphosphonates are increasingly being used in a number of bone conditions, including osteoporosis and metastatic cancer. As a consequence, the reported cases of bisphosphonate-related osteonecrosis of the jaw (BONJ) have increased. BONJ remains rare in patients being treated for osteoporosis, but is commoner in cancer patients where the bisphosphonate doses are much higher and mode of delivery is intravenous. Recently, much more is known about classification and mode of action of the bisphosphonates. The potency of the various nitrogen-containing bisphosphonates is dependent on a number of factors including bone binding, zeta potential and inhibition of the enzyme farnesyl pyrophosphate synthase. There is current debate on why BONJ affects the jaw, particularly in relation to whether the jaw has high bone turnover or not. More is being learnt about the micro-organisms involved in the pathogenesis of BONJ and there is increasing evidence on the role of surgical treatment of this disabling condition.