Histomorphometric and mechanical evaluation of the bone-tissue response to implants prepared with different...

Several studies have shown that in soft tissue, the orientation of surface topography affects cell response. However, the response of hard tissue to the orientation is not fully understood.

This study was undertaken to determine how orientation of the microstructure of implant surfaces influences bone healing.

Forty cylindrical implants were prepared with a dominant orientation of the microstructure (20 with a horizontal orientation and 20 with a vertical orientation) and investigated in vivo. Three methods for surface topographic characterization were used to investigate the topography in different resolution levels.

Topographic analysis showed that a clear orientation was achieved at the implant surface, and a rougher surface structure was found on the vertically oriented grooves than on the horizontal ones. The implants were inserted in the tibia of 10 New Zealand White rabbits. Pull-out tests and histomorphometric analyses of ground-sections were made after 12 weeks of healing. The pull-out test showed a higher mean value for the vertically grooved implants, but the difference was not significant. Histomorphometric analyses showed no statistically significant differences between the horizontally and the vertically grooved implants when measuring bone-to-implant contact or amount of bone area around the implant.

No advantages could be found for either the horizontal or vertical orientation compared with each other, but further studies are needed in which implant roughness should be similar between the different topographies.