Histological and morphometrical evaluation of non-critical bone defects after treatment with biomaterial and bisphosphonates

Background: The primary goal of this in vivo study was to ascertain if systemic bisphosphonates (BPs) positively affect bone repair in non-critical defects when assisted with a carbonated hydroxyapatite graft biomaterial (Biomat). Material and Methods: Thirty-six female rats were allocated into two control groups (blood clot [BC] and alloplastic biomaterial); two groups with zoledronate (third-generation BPs): Zol.BP and Zol.BP+Biomat; and two groups with clodronate (first-generation BPs): Clod.BP and the Clod.BP+Biomat. The experimental groups started the application of BP 60 days before surgery. Then, a 2 mm non-critical defect was performed in the rats’ femur and filled according to the group. All animals were euthanized 30 days after surgery, and the samples were collected for histological and histomorphometry analysis, respectively, for descriptive and quantitative analyses. Results: Zol.BP+Biomat had greater new bone formation, whereas clodronate presented high osteogenic potential, significantly increasing the observed levels of newly formed bone even in the absence of the biomaterial. Histomorphometrically, BC had 2% bone formation compared to the biomaterial group (5%). Zol.BP and Col.BP achieved bone formation of 6-fold (12%, p>0.05) and 9.5-fold (19%, p<0.05), respectively, when compared with BC. Zol.BP+Biomat group presented the highest value found for newly formed bone (24%), 12-fold more than BC (p<0.001) and 4.8-fold more than the biomaterial group (p<0.01). Conclusions: It is possible to conclude that the systemic use of BP positively affected non-critical bone defects when associated with biomaterials, mainly when the third generation of BPs was used in this association.