Bone–implant interface shear modulus and ultimate stress in a transcortical rabbit model of open-pore Ti6Al4V implants

This experimental study on laser-textured implants aimed to evaluate periimplant bone elasticity and ultimate stress of the bone–implant interface in a rabbit femur model. After randomization, two cylindrical Ti6Al4 V samples (3.5 mm wide, 5.5 mm long) were transcortically implanted in each femur of 15 female New Zealand White Rabbits. Polished implants had been laser-textured with 100, 200, and 300 μm diameter pores, and another corundum blasted implant was additionally textured with 200 μm pores. Twelve weeks into the experiment, a modified push-out test was performed. The median shear modulus indicating the elasticity of the periimplant bone was 41.12 MPa for the proximal implant location and 25.38 MPa for the distal, without evidence for significant differences between implant types. Taking into account the median ultimate shear stress for 200 μm implants with and without corundum blasting, no significant difference could be demonstrated. However, for blasted 200 μm implants a statistically significant (p<0.025) relative gain in ultimate shear stress of 41% and 17% was proven in comparison with 100 and 300 μm implants, respectively. Non-blasted 200 μm implants reached 48% relative gain in respect of 100 μm samples.