Analysis of osseointegration of implants with hydrophilic surfaces in grafted areas: A Preclinical study

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) and with biphasic ceramics of hydroxyapatite/β-tricalcium phosphate (HA/TCP).

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.

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).

In conclusion, implants with a hydrophilic surface improve osseointegration in grafted areas compared to implants with machined surfaces in a rat tibia model.