Bisphosphonate related osteonecrosis of the jaw; a literature review and a new hypothesis

Bisphosphonates are drugs used to reduce normal bone turnover. These medicines are prescribed to patients with diseases like bone malignancies, osteoporosis and Paget’s disease. Since a decade it has been recognized that osteonecrosis of the jaws occurs relatively frequent as a side-effect of the use of these drugs. This phenomenon is referred to as bisphosphonate related osteonecrosis of the jaw (BRONJ). In most cases BRONJ occurs after dental intervention. With respect to the cause of BRONJ several views have been presented, but none of them offers a reliable explanation. Those hypotheses involve the low repair mechanism of the jaws and the angiogenic effect of bisphosphonates. Discussed in this review is the effect of acidosis on bone remodeling, as well as site-specific differences between bone-associated cells in the jaw and elsewhere in the human body; a combination that may help to explain the occurrence of BRONJ.