Bisphosphonates are a class of drugs used in metabolic and oncologic diseases which involve the skeletal system. Their mechanism of action is based on the ability to inhibit bone resorption by osteclasts. Bisphosphonates are generally well tolerated. However, in the past few years it has emerged that bisphosphonates may be associated with clinical complications like vascular osteonecrosis of the jaws.
This effect would seem to be linked to chronic administration of these drugs in concomitance with oral surgery, trauma following accidents, and prolonged administration of corticosteroid drugs.
Although osteonecrosis has been observed above all in patients undergoing intravenous therapy with pamidronate and/or zoledronate, an increasing number of cases are being reported among patients taking oral bisphosphonates 3 such as alendronate or risedronate for the treatment of osteoporosis, Paget’s disease of the bone, hyperparathyroidism and fibrous dysplasia.
Normally the mandible and the upper jaw are the only bones involved in Bisphosphonates-Related Osteonecrosis of the Jaws (BRONJ) . The occurrence of this pathology in the oral cavity may be due to the exposure of these bony structures to the external environment through the gingival socket, or to continuous trauma which can facilitate bone infection and the development of osteomyelitis. In most cases osteonecrosis is first observed with a failure to heal or delay in the healing process of the upper jaw or lower jaw after dental extraction or any other oral surgery5. Early stages of the disease are characterised by a lack of symptoms and by the absence of radiological changes, although acute pain may be experienced as a result of infection of the necrotizing bone area induced by the oral bacterial flora.
Imaging techniques, as a means of evaluation, may not provide any additional information, particularly in the initial stages6. In the case of a differential diagnosis with possible neoplastic pathologies, biopsy should only be carried out if really required in order not to increase the extension of bone necrosis.
When a patient presents with symptoms of osteonecronis, the dentist should require consultation at the Maxillo-Facial Unit.