Imaging and histomorphometric evaluation of mandible and tibia of rats treated with bisphosphonates.

OBJECTIVES: To evaluate the mandible and tibia of rats treated with bisphosphonates (BPs) by imaging and histomorphometric analysis. STUDY DESIGN: Thirty-four rat specimens (Rattus norvegicus, Wistar strain) were distributed into 3 groups: (1) 12 rats treated with zoledronic acid; (2) 12 rats treated with clodronate; and (3) the control group, containing 10 rats that received saline. All bones were exposed to cone beam computed tomography (CBCT). The images were analyzed to determine bone density (BD), using the software OsiriX 7.0. Histological slides were prepared from the specimens and the proportion of bone volume (BV) was quantified using the software Adobe Photoshop CC. RESULTS: There was no statistically significant difference in BD either between the drug groups or between mandible and tibia. BV between BPs and control group did not show a significant difference. However, comparing the two bones, the mandibles in the control group displayed higher BV than did the tibiae in the same group. CONCLUSION: According to our results, we conclude that (1) BD was not altered by bone type or by type of BP administered, and (2) treatment with zoledronic acid or clodronate did not affect BV in the mandible or tibia of test groups.

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.