Significant effect of a carbon layer coating on interfacial bond strength between bone and Ti implant

We investigated the degree of osseointegration in carbon-coated oxygen-diffused titanium implants (C-ODTi) by means of biomechanical tests of the femoral bones of rabbits. C-ODTi possesses interstitial oxygen atoms into the host titanium lattice and an upper nanometric surface layer of anatase-TiO2 covered with 20 nm carbon layer. Interface shear strength was determined by using a transcortical push-out model at 4, 12 and 24 weeks after implantation. Implants with different surfaces were prepared, including a carbon coating and an abrasion treatment. There was a significant improvement in the bone-bonding shear strength for the C-ODTi. The highest shear strength values were observed in the C-ODTi group at 24 weeks and differed significantly from those of the control group at the same experimental time (p < 0.05). After the in vivo evaluation it was concluded that the coating of a carbon layer on the surface of titanium implant was effective for improving the biocompatibility of titanium, which was evidenced by the superior interface shear strength.