A light and electron microscopic study of the effects of surface topography on the behavior of cells attached to titanium-coated percutaneous implants.
Previous studies using light microscopy have demonstrated that micromachined grooved surfaces inhibit epithelial (E) downgrowth and affect cell orientation at the tissue/implant interface. This study investigates the ultrastructure of the epithelial and connective-tissue attachment to titanium-coated micromachined grooved, as well as smooth control, implant surfaces. V-shaped grooves, 3, 10, or 22 microns deep, were produced in silicon wafers by micromachining, replicated in epoxy resin, and coated with 50-nm titanium. These grooved, as well as smooth, titanium-coated surfaces were implanted percutaneously in the parietal area of rats and after 7 days processed for electron microscopy. The tissue preparation technique used in this study enabled us to obtain ultrathin sections with few artifacts from the area of epithelial and connective-tissue attachment. The histological observations demonstrated that E cells closely attached to, and interdigitated with, the 3-microns and 10-microns grooves. In contrast, E cells were not found inside the 22-microns-deep grooves and made contact only with the flat ridges between the grooves. As a general rule, fibroblasts (F) were oriented parallel to the long axis of the implants and produced a connective tissue capsule with 3-microns and 10-microns-deep grooved surfaces as well as smooth surfaces. On the 22-microns-deep grooved surfaces, however, F inserted obliquely into the implant. The attachment of F to the titanium surface was mediated by two zones; a thin (approximately 20 nm), amorphous, electron dense zone immediately contacting the titanium surface, and a fine fibrillar zone extending from the amorphous zone to the cell membrane. As oblique orientation of F has been associated with the inhibition of epithelial downgrowth, micromachined grooved surfaces of appropriate dimensions have the potential to improve the performance of percutaneous devices.
Chehroudi
B
B
University of British Columbia, Faculty of Dentistry, Dept. of Oral Biology, Vancouver, Canada.
Gould
T R
TR
Brunette
D M
DM
D000818:Animals; D001842:Bone and Bones / Q000033:anatomy & histology; D003239:Connective Tissue Cells; D004847:Epithelial Cells; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D019736:Prostheses and Implants; D051381:Rats; D011919:Rats, Inbred Strains; D013242:Sterilization; D013499:Surface Properties; D014025:Titanium
D014025:Titanium