Comparison of effects of zoledronic acid and clodronate on the bone structure: imaginological and histomorphometrical study in vivo.

OBJECTIVES: To compare histologically and imaginologically the bone structure of rats' mandibles treated with bisphosphonates (BPs) and rats that did not receive BPs.

METHODS: Thirty-four rat specimens (Rattus novergicus, Wistar strain) were divided into three groups: (i) 12 rats treated with zoledronic acid; (ii) 12 rats treated with clodronate; and (iii) the control group, containing 10 rats that received saline solution. All individuals were exposed to cone beam computed tomography (CBCT). The images were processed and analyzed to obtain the Hounsfield scores, using the software OsiriX 7.0. Sixty-eight histological slides were obtained from the specimens and stained with hematoxylin and eosin (HE). Using the software Adobe Photoshop CS6, the histological areas containing non-vital bone were identified and quantified.

RESULTS: Non-vital bone presented positive association with the zoledronic acid and clodronate groups. Statistically, no significant difference in bone density was observed among the groups.

CONCLUSIONS: Based on the results, the BP therapy alone was sufficient to induce osteonecrosis. In addition, the CBCT was not a sensible method for detection of the early signs of bone modification in individuals under BP therapy.