The Editorial Executive Committee welcomes letters, which should be less than 250 words. Before a decision to publish is made, letters which refer to a published article may be sent to the author for a response. Any letter may be sent to an expert for comment. When letters are published, they are usually accompanied in the same issue by their responses or comments. The Committee screens out discourteous, inaccurate or libellous statements. The letters are sub-edited before publication. Authors are required to declare any conflicts of interest. The Committee's decision on publication is final.

Letter to the Editor

Editor, – I was very interested in the dental note concerning bone turnover markers (Aust Prescr 2012;35:159). The authors state that the incidence of bisphosphonate-related osteonecrosis of the jaw is 1 in 500 to 1 in 1500. Is this related to oral bisphosphonates used to treat osteoporosis, or does it include intravenous bisphosphonates associated with the treatment of various cancers?

I have recently attended a number of meetings with endocrinologists where they consistently state that the incidence of bisphosphonate-related osteonecrosis of the jaw associated with oral bisphosphonate treatment of osteoporosis is about 1 in 100 000.

There is obviously a wide variation of opinion. I would appreciate comments from the authors regarding this discrepancy on the incidence of osteonecrosis of the jaw.

Graham McNally
General practitioner

Authors' comments

Michael McCullough and Alastair Goss, authors of the dental note, comment:

Our dental note on bone turnover markers was specifically quoting the incidence of bisphosphonate-related osteonecrosis of the jaw relating to patients with osteoporosis on oral bisphosphonates.

The studies quoted are international, independent and not funded by pharmaceutical companies. They are primarily conducted by oral and maxillofacial surgeons and other specialist dentists who diagnose and treat bisphosphonate-related osteonecrosis of the jaw. They very consistently show an incidence of 1 in 500 to 1 in 1500.1-3 In specific patient groups having bone invasive procedures, the incidence is more of the order of 1 in 100. 4, 5It should be noted that Osteoporosis Australia, when they met with the Australian Dental Association to develop an instruction pamphlet, agreed that the incidence was at least in the order of 1 in 1500.6

Some endocrinologists seem to wish to continue to quote the American Society of Bone and Mineral Research report of the task force in 2007 that indicated an incidence of 1 in 10 000 to 1 in 100 000.7 This review was published at a time when the only independent published incidence data was the Australian study.1 The majority of the authors of that task force reported substantial receipt of pharmaceutical company funds. That paper has not been updated in light of the more extensive independent studies.

Another important aspect that has recently received prominence in the medical literature is the length of time a patient with osteoporosis should continue with oral bisphosphonates. In a recent meta-analysis by the US Food and Drug Administration8 it was shown that for most patients the maximum benefit was achieved by five years. The benefit of continued use beyond this was low with increasing risk of serious complications including bisphosphonate-related osteonecrosis of the jaw, spontaneous femur fracture and oesophageal squamous cell cancer.8

Minimising the risk of bisphosphonate-related osteonecrosis of the jaw is straightforward. Prescribers need to be aware of the true incidence of risk and ensure that their patients are dentally fit before commencing oral bisphosphonates. Patients then need to be carefully monitored.


  1. Mavrokokki T, Cheng A, Stein B, Goss A. Nature and frequency of bisphosphonate-associated osteonecrosis of the jaws in Australia. JOral Maxillofac Surg 2007;65:415-23.
  2. Lo JC, O’Ryan FS, Gordon NP, Yang J, Hui RL, Martin D, et al. Predicting the risk of osteonecrosis of the jaw with oral bisphosphonate exposure. J Oral Maxillofac Surg 2010;68:243-53.
  3. Yarom N, Yahalom R, Shoshani Y, Hamed W, Regev E, Elad S. Osteonecrosis of the jaw induced by orally administered bisphosphonates: incidence, clinical features, predisposing factors and treatment outcome. Osteoporos Int 2007;18:1363-70.
  4. Sedghizadeh PP, Stanley K, Caligiuri M, Hofkes S, Lowry B, Shuler CF. Oral bisphosphonate use and prevalence of osteonecrosis of the jaws: an institutional study. J Am Dent Assoc 2009;40:61-6.
  5. Kunchur R, Need A, Hughes T, Goss A. Clinical investigation of C-terminal cross-linking telopeptide test in prevention and management of bisphosphonate-associated osteonecrosis of the jaws. J Oral Maxillofac Surg 2009;67:1167-73.
  6. Osteoporosis Australia. Joint Osteoporosis Australia and Australian Dental Association ‘Bisphosphonates and ONJ’ statement (for Dentists). 2010. [cited 2013 Mar 6]
  7. Khosla S, Burr D, Cauley J, Dempster DW, Ebeling PR, Felsenberg D, et al. Bisphosphonate-associated osteonecrosis of the jaw: report of a task force of the American Society for Bone and Mineral Research. JBone Miner Res 2007;22:1479-91.
  8. Whitaker M, Guo J, Kehoe T, Benson G. Bisphosphonates for osteoporosis – where do we go from here? N Engl J Med 2012;366:2048-51.