An experimental study of bisphosphonate-induced jaws osteonecrosis in Sprague–Dawley rats

Abstract

Objective: Patients undergoing treatment with bisphosphonates may develop jaw lesions consisting mainly of bone necrosis. The present study describes a model of maxillary osteonecrosis in Sprague–Dawley rats, applying bisphosphonates and examines the changes occurring after tooth extraction.

Material and methods: A total 200 animals were included in a randomized prospective study involving the following groups: group I (control, 20 rats without drug treatment), group II (60 animals administered dexamethasone 1 mg/kg/day for 7, 14 and 21 days, in subgroups of 20 animals each), group III (60 animals administered pamidronate daily at a dose of 3 mg/kg) and group IV (60 animals administered pamidronate and dexamethasone). In all groups, molar extraction was carried out on the right upper maxillary or mandibular side 8, 15 and 22 days after the start of dosing. The rats were killed 14 and 28 days after extraction in all groups.

Results: A total of 18 cases of osteonecrosis were recorded in the group administered pamidronate and dexamethasone. Osteonecrosis affected the upper maxilla in 10 cases and the mandible in eight cases, and was circumscribed to the extraction zone in all cases. Osteonecrosis was not seen in any of the other groups.

Conclusions: The administration of pamidronate and dexamethasone in rats subjected to molar extraction increases the risk of osteonecrosis.