Objective: Although much data has been published regarding the incidence and characteristics of bisphosphonate-related osteonecrosis of the jaws (BRONJ) secondary to intravenous and oral bisphosphonate use, little information is available on the prevalence of BRONJ in patients taking a single yearly intravenous dose of zoledronic acid (Reclast ^® ).

Methods: Osseous specimens from five female patients were submitted for histopathologic evaluation to the University of Florida, Department of Oral Pathology. Each patient reported a single, yearly infusion of zoledronic acid; three reported previous use of an oral bisphosphonate for osteoporosis or osteopenia and four reported a complicating medical condition, an autoimmune disorder and the use of oral steroids and or methotrexate. Four cases presented with stage 1 BRONJ and one case presented with stage 3 BRONJ.

Results: All patients were treated with non-surgical measures of varying duration ranging from 4 to 18 months. The patients in this series had a mild clinical course similar to oral bisphosphonate-related BRONJ. However the onset of symptoms appeared more rapidly than typically seen in oral bisphosphonate-related osteonecrosis.

Conclusion: Clinicians should be aware of the risk of development of BRONJ following the use of Reclast ^® in order to optimize prevention and treatment.

Conflict of interest: D.C. Cohen and I. Bhattacharya have received research funding through Merck & Co. to study oral BRONJ. MF Stavropoulos has been a consultant for Merck & Co.