What Is the Risk for MRONJ?
Many of you have likely had the experience of being contacted by a dentist who is reluctant to do a needed dental procedure for a patient taking a bisphosphonate because of concern about MRONJ. Most of us have previously referred to this condition as bisphosphonate-related, but the more broad terminology is now used in recognition of the association of this condition with other antiresorptive and antiangiogenic therapies.
The reality is that the risk of a bisphosphonate-using patient developing MRONJ is substantially smaller than the likelihood of a complication from not getting a necessary dental procedure to treat an abscess or some other acute condition.
In this scenario, it is important to put the risk of this rare complication associated with the bisphosphonate class of drugs in perspective.
The risk for osteonecrosis in the general population not being treated with a bisphosphonate is unknown but is probably extremely small—on the order of 0.001%.
Estimates of the incidence in patients treated with bisphosphonates have varied. In a survey study of over 13,000 Kaiser Permanente members, the prevalence in patients receiving long-term oral bisphosphonate therapy was reported at 0.1%, which increased to 0.21% among patients with greater than 4 years of oral use. An international task force systematically reviewed studies and reported incidence worldwide in patients using this class of drugs to range from 0% to 0.04%, with the majority of studies reporting an incidence below 0.001%.
Risk in cancer patients. The highest-risk subgroup that we should all worry about is cancer patients treated with intravenous bisphosphonates, especially zoledronate. A meta-analysis conducted in patients with breast cancer reported that the risk for MRONJ in cancer patients not receiving bisphosphonates was extremely small, with only 1 case reported in over 5000 patients. In its 2014 updated position statement on MRONJ, the American Association of Oral and Maxillofacial Surgeons (AAOMS) concluded that risk in the overall cancer population not receiving bisphosphonates ranged from 0% to 0.019% (0-1.9 cases per 10,000 cancer patients).
The study in breast cancer patients found that odds in patients treated with zoledronate increased threefold (odds ratio [OR], 3.23; 95% confidence interval [CI], 1.7-8).However, a longitudinal study of cancer patients with osteonecrosis sought to determine risk factor for the condition and found that having ever received zoledronate increased the risk substantially (adjusted OR [aOR], 28.09; 95% CI, 5.74-137.43), as did each zoledronate dose (aOR, 2.02; 95% CI, 1.15-3.56). The AAOMS concluded in its update that "the risk of ONJ among cancer patients exposed to zoledronate ranges between 50-100 times higher than cancer patients treated with placebo."
Risk with dental procedures. Dental procedures do increase the risk for the development of MRONJ in patients taking bisphosphonates, with use of dentures increasing risk twofold (aOR, 2.02; 95% CI, 1.03-3.96) and a history of dental extraction increasing odds over 30-fold (aOR, 32.97; 95% CI, 18.02-60.31).
What about dental implants? A study examining outcomes in 115 women treated with an oral bisphosphonate who received a dental implant reported no cases of osteonecrosis. The investigators concluded that oral therapy did not increase the risk for development of osteonecrosis, nor did it negatively affect implant success.
I find this data to be reassuring. AAOMS summarizes the research by noting that the most clinically relevant question is: What is the risk for development of MRONJ among patients treated with antiresorptive medications who do need to undergo a tooth extraction or other dentoalveolar or periodontal procedure? The authors concluded that this varied by procedure, with the best current estimate of risk following a tooth extraction estimated at 0.5%; risk following other dentoalveolar procedures is unknown, though the authors concluded that the risk probably approximated the risk seen with tooth extraction.
The exception to this relatively low risk with dental procedures is cancer patients treated with intravenous bisphosphonates. AAOMS estimates that risk in this population ranges from 1.6% to 14.8%.
Medscape Internal Medicine © 2017 WebMD, LLC
Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Clearing the Patient on Bisphosphonates for Dental Procedures: When Should You Do It? - Medscape - Jul 28, 2017.