Association between bisphosphonates and jaw osteonecrosis: a study in Wistar rats

Abstract

BACKGROUND: This work aimed at determining whether bisphosphonate therapy produces a sufficient condition for jaw osteonecrosis after tooth extraction. METHODS: Rats were allocated into 3 groups: (1) 11 rats treated with alendronate, (2) 10 rats treated with zoledronic acid, and (3) 10 control rats. The animals were subjected to tooth extractions, and at the end of bisphosphonate therapy, they were humanely killed. Histologic sections of the surgical site were processed and analyzed. RESULTS: The zoledronic acid group showed higher incidences of osteonecrosis, inflammatory infiltrate, and microorganisms. There was no significant difference for epithelial or connective tissue, root fragments, vital bone, and positive staining for vascular endothelial growth factor (VEGF) among the groups. CONCLUSION: Zoledronic acid is associated with jaw osteonecrosis, whereas alendronate did not produce a condition sufficient for osteonecrosis after tooth extraction. Neither zoledronic acid nor alendronate was associated with a reduced immunohistochemical expression of VEGF in vital bone at the tooth extraction site.