A study from Amigues et al. found that bisphosphonate-associated osteonecrosis of the jaw is rare in patients with osteoporosis and may occur more often in patients treated with injectable zoledronic acid than in those treated with the oral bisphosphonates.
Osteonecrosis of the jaw (ONJ) is a condition in which an area of jawbone is not covered by the gums that has lasted for more than eight weeks. ONJ occurs when a facial bone begins to starve from a permanent or temporary lack of blood. As the name indicates—with osteo meaning bone and necrosis meaning death—the bone begins to die, causing pain and deterioration.