Bisphosphonate-related osteonecrosis of the jaws: Study of the staging system in a series of clinical cases

Summary Objective The aim of this study was to validate the classification of bisphosphonate-related osteonecrosis of the jaws (BRONJ) published in 2009 in a series of cases. Material and methods This retrospective clinical study included a series of 102 cases (81%) of intravenous BRONJ (iBRONJ, group 1) and 24 cases (19%) of oral BRONJ (oBRONJ, group 2). We recorded all patients’ symptoms and clinical findings and classified each patient into a BRONJ stage (0–3; stage 0 = non-exposed BRONJ). Results Most BRONJ cases ( n = 120, 95.2%) could be classified according to the proposed stages. Exposed necrotic areas of bone were more prevalent in group 1 than in group 2 ( p < 0.05). In contrast, we observed more BRONJ cases without areas of exposed bone in group 2 ( n = 12, 50%) than in group 1 ( n = 14, 13.7%; p < 0.05). We could not assign six cases to any of the proposed stages. These cases had no areas of exposed necrotic bone, but had mandibular fractures, extra-oral fistula or affected maxillary sinuses. Conclusions In our series, iBRONJ cases showed more advanced stages of BRONJ than did oBRONJ cases. We found few cases that could not be classified into any proposed stage because they had findings associated with stages 0 and 3 but lacked exposed necrotic bone.