To the Editor: We read with interest the article by Carter and colleagues reporting five cases of jaw osteonecrosis associated with bisphosphonate use.1 To emphasise the association, we report a further eight cases seen at our institution between February 2004 and June 2005.

After Marx’s report of the condition in 2003,2 we instituted a policy of active screening for jaw osteonecrosis in patients taking bisphosphonates. Patients were asked about suggestive symptoms, such as tooth pain or dental infection, and underwent oral examination by the treating haematologist or oncologist. Suspected cases were referred to our dental oncology unit. Bisphosphonate therapy was discontinued in established cases to prevent further bisphosphonate accumulation and possible worsening of the complication.

Of the eight patients detected with jaw osteonecrosis, five had multiple myeloma, two breast cancer, and one prostate cancer. All were receiving monthly intravenous bisphosphonate therapy: zoledronic acid (4 mg) in seven patients, and pamidronate (90 mg) in the other. Median duration of bisphosphonate therapy before onset of symptoms was 22 months (range, 6–66 months). Five patients were male, and three female. Seven had undergone tooth extraction before presentation (Box), and the five with multiple myeloma had received high-dose corticosteroids. Management was conservative in all eight. No improvement was seen in any patient by 3 months, but, with continued withholding of bisphosphonates, some signs of healing were seen in all by 6 months.

Four of the patients had a change in therapy from pamidronate to zoledronic acid (because of the latter’s shorter infusion time) in the 2–18 months before onset of symptoms. None had experienced osteonecrosis while taking pamidronate. It is postulated that zoledronic acid is more often associated with osteonecrosis than pamidronate.3

Appropriate management for patients who need to resume bisphosphonate therapy after osteonecrosis remains to be determined. Clodronate is an orally administered first-generation bisphosphonate which has been used widely in Europe with no reports of associated osteonecrosis.4 Unlike pamidronate and zoledronic acid, it does not contain a nitrogen ring. On this basis, we recently began clodronate therapy in a patient with complete jaw healing after osteonecrosis.

Avoiding tooth extractions while taking bisphosphonates should minimise the incidence of osteonecrosis. Our active screening policy allowed earlier detection of osteonecrosis and prompt intervention, including cessation of bisphosphonates and avoidance of debridement of necrotic bone (which often exacerbates the condition), thereby limiting the extent of osteonecrosis. It is uncommon for physicians to ask about dental problems and for dentists to ask about bisphosphonate use. This new complication highlights the need for this to change.

Osteononecrosis of the jaw in a patient with multiple myeloma taking zoledronic acid

Necrotic maxillary bone and sequestrum formation which developed after tooth extraction.

Computed tomography scan showing failure of the bone to heal at the extraction site.