Effect of surface finish on the osseointegration of laser-treated titanium alloy implants

It was the purpose of this study to examine the osseointegration of laser-textured titanium alloy (Ti6Al4V) implants with pore sizes of 100, 200, and 300 microm, specifically comparing 200-microm implants with polished and corundum-blasted surfaces in a rabbit transcortical model. Using a distal and proximal implantation site in the distal femoral cortex, each animal received all four different implants in both femora. The bone-implant interface and the newly formed bone tissue within the pores and in peri-implant bone tissue were examined 3, 6, and 12 weeks post-implantation by static and dynamic histomorphometry. Here we show that additional surface blasting of laser-textured Ti6Al4V implants with 200-microm pores resulted in a profound improvement in osseointegration, 12 weeks postimplantation. Although lamellar bone formation was found in pores of all sizes, the amount of lamellar bone within pores was linearly related to pore size. In 100-microm pores, bone remodeling occurred with a pronounced time lag relative to larger pores. Implants with 300-microm pores showed a delayed osseointegration compared with 200-microm pores. We conclude that 200 microm may be the optimal pore size for laser-textured Ti6Al4V implants, and that laser treating in combination with surface blasting may be a very interesting technology for the structuring of implant surfaces.