Bone Ceramic Filling Rat Calvaria Deffects: An Histometric, Immunohistochemical and 3D Analysis

Objectives: Objectives: To evaluate by histometric , immunohistochemical and micro tomography (micro cT) analysis, the responses of bone resorption and bone formation observed after the insertion of hydroxyapatite granules and beta-tricalcium phosphate (Bone Ceramic - Straumann ®) in critical bone defects created in rat calvaria process.
Methods: Methods: This study received the approval of Ethics Committee on the Use of Animals, of FOA/UNESP (2012-01097). The rats were divided into three groups (n = 8) and submitted to euthanasia at 14 days and 28 days post-surgery. In each animal a 5 mm calvaria bone defect was performed. In Blood Clot Group (CG) the defect was filled only with clot; in the Autogenous Bone Group (AG) the defect was filled with autogenous bone and in Bone Ceramic Group (BC), with alloplastic bone (Straumann ®).The bone tissue area was evaluated in the central region of bone defects. The results were submitted to ANOVA and Tukey’s test at 5% level of significance. For the evaluation of the different stages of the bone healing process, immunohistochemical analysis was performed with primary antibodies against OC, TRAP and VEGF. As an additional analysis, calvaria’s 3D images were obtained in microtomography.
Results: Results: The bone defect treated with BC was filled with a conglomerate of biomaterials and bone formation, which was statistically higher than CG in both periods analyzed. Remnants of BC were visible and were in intimate contact with bone tissue. Furthermore, the AG group observations were similar, but it was observed a complete defect closure after 28 days and there was a greater area of bone formation in all periods analyzed, comparing to other biomaterials (p <0.05). The defects filled with CO showed only a thin connective tissue closing the bone defect. The TRAP protein was lightly immunolabeling, while immunolabeling of VEGF was moderate. The osteocalcin immunostaining was present in all analyzed periods (14 and 28 days). The AG´s group 3D image showed compatibility with full bone formation at 28 days.
Conclusions: Conclusions: The supplementation of tested biomaterial (BC) was favorable to the bone defect filling until the end of analyzed period, although with a lower rate of bone formation when compared to autograft.