Understanding bisphosphonates and osteonecrosis of the jaw: uses and risks

Bisphosphonates are chemically stable analogs of pyrophosphate compounds, which have been used to treat multiple disorders of calcium metabolism. Although bisphosphonates have been employed for many years and have demonstrated an excellent safety profile, severe osteonecrosis of the jaw (ONJ) has been described in patients with bone metastases who have been treated with bisphosphonates.

In this review we describe the reasons for ONJ and discuss the varying effects of different bisphosphonates on the development of ONJ. Bisphosphonates tend to accumulate in bone, subject to remodeling (such as the jaw) and can affect osteoclast-mediated bone resorption and osteoclast formation, leading to the osteonecrosistic phenomenon.

Risk factors for previously -treated patients include the type of bisphosphonates (amino or non-amino), length of treatment and route of administration, the presence of co-morbidities and/or treatment with immune-suppressing drugs, and the presence of other risk factors in addition to the type of intervention required. In oncological patients currently in treatment with receiving intravenous bisphosphonates, greater consideration must be taken depending on the length of treatment already undertaken and concomitant therapies. In these patients, a preventive dental surgery visit and examination of the case would be advisable prior to beginning treatment with bisphosphonates.

Practical approaches in the prevention of ONJ include thorough pre-treatment evaluation and performing any preventative procedures (treat periodontal conditions, extract loose teeth, provide protective and endodontic therapies); initiating amino-bisphosphonates only after any gum tissue damage has healed; establishing a regimented check-up schedule and hygieneic precautions the patient can take; and during bisphosphonate treatment conduct any dental procedures in the least invasive manner during bisphosphonate treatment.