Evaluation of the soft tissue interface at titanium implants with different surface treatments: experimental study on rabbits.

Recently, a dominant influence of the surface roughness parameters for the soft tissue reaction at the implant tissue interface was found in an experimental study on sheep. The purpose of the present study is to correlate the surface roughness parameters of different experimental bone plates to the results of the histomorphometric analyses of the adjacent soft tissues. Pure titanium plates (35 x 5 x 1 mm) with six different surface treatments and electropolished stainless steel plates were tested. Prior to implantation the surface roughness parameters were determined using a profilometer and a scanning electron microscope. The tibia of adult rabbits served as test sites. At least four plates of each type were implanted. Three months postoperatively the implants were harvested with an intact tissue envelope and were left in situ for the histological preparation. The difference in the roughness parameters is statistically significant for most surface conditions and has an effect on the soft tissue reaction. The histological evaluation shows a significant higher number of blood vessels for steel plates in comparison to titanium plates with handground and blasted surface conditions. For the rough type of anodized titanium surfaces a significantly thinner soft tissue capsule is found, compared to electropolished steel plates. For the steel plates a fluid film was found between the implant and the adjacent tissue layer. The material and the surface roughness of the implant, determine the tissue reaction at the interface. The rough type of anodized titanium implants seems to be preferable.