Objectives:The aim of this study was to evaluate the effect of a hydrophilic surface on the osseointegration in grafted areas with deproteinized bovine bone (DBB) andwith biphasic ceramics of hydroxyapatite/β-tricalcium phosphate (HA/TCP).
Material and methods:Fifty-six rats were randomly allocated to four groups with 14 animals each: DBB: DBB+Machined surface; HA/TCP: HA/TCP+Machined surface; DBB-H: DBB+Hydrophilic surface; HA/TCP-H: HA/TCP+Hydrophilic surface. The bone defects were performed at the proximal epiphysis of the tibia. Then, the defects were filled with the biomaterials. After 60 days, the implants were placed in the grafted areas. The animals were submitted to euthanasia at periods of 15 and 45 days after the implants' placement. The osseointegration was assessed by biomechanical, microtomographic, and histometric analyses. In addition, the expression of bone morphogenetic protein-2 (BMP-2), alkaline phosphatase (ALP), and osteocalcin (OCN) was evaluated by immunohistochemistry. Results: The HA/TCP-H group presented higher removal torque values and more mineralized tissue in the vicinity of the implants compared with the HA/TCP group. The DBB-H and HA/TCP-H groups presented higher values of bone-implant contact (at 15 and 45 days), of bone between the threads (45 days), and expression of BMP-2(45 days) than the DBB and HA/TCP groups. Furthermore, the DBB-H group presented a higher expression of ALP than the DBB group (15 days).
Conclusion:In conclusion, implants with a hydrophilic surface improve osseointegration in grafted areas compared to implants with machined surfaces in a rat tibia model.
K E Y W O R D Sbone substitutes, implants surfaces, osseointegration
Objective To evaluate the effect of grafting with strontium (Sr)-loaded deproteinized bovine bone (DBB) on bone healing in calvarial critical size defects (CSD) in rats. Material and methods Two circular bone defects (5 mm in diameter) were created in the calvaria of 42 rats. One of the defects, randomly chosen, was grafted with (a) DBB, (b) DBB loaded with 19.6 μg/g of Sr (DBB/Sr1), or (c) DBB loaded with 98.1 μg/g of Sr (DBB/Sr2). The other defect was left empty as negative control. Groups of seven animals from each of the groups were euthanized 15 and 60 days post-op. Bone healing in the CSD was evaluated by micro-CT and histology/histomorphometry and immunohistochemistry.Results DBB/Sr2-grafted sites showed statistically significantly shorter radiographic residual defect length compared with DBB/ Sr1-and DBB-grafted sites, and with empty controls at 60 days. Further, the amount of new bone formation in the DBB/Sr1-and DBB/Sr2-grafted sites was significantly higher compared with that in the DBB-grafted sites at 60 days. A larger number of DBB/ Sr1-and DBB/Sr2-grafted sites presented with no-or only limited to mild inflammation, compared with the DBB-grafted sites, especially at 60 days. Higher expression of osteocalcin was observed in DBB/Sr1-and DBB/Sr2-grafted sites as compared to DBB-grafted sites. Conclusion Grafting with Sr-loaded DBB enhanced bone formation in CSD in rats, when compared with grafting with nonloaded DBB. Clinical relevance Grafting with Sr-loaded DBB may enhance bone formation in bone defects.
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