The soft tissue attachment to dental implants is similar to that found in natural teeth. It has been shown that different parts of the surface of teeth or dental implant can be modified to become more compatible substrates for specific cell types, enhancing attachment formation. In my research I am looking at how physical alterations of implanted surfaces might affect soft tissue attachment. This problem is studied using a model system in which Millipore filters with various surface modifications are used as experimental implants. These implants are inserted into the backskin of animals and are later removed and examined to determine the effects of these modifications on soft tissue attachment. The factors that have been previously examined include surface porosity, a topical coating of cell attachment factors including fibronectin, laminin and solubilized basement membrane, and a surface coating of titanium. It was found that a pore size of at least 3 micro-moles was necessary for the formation of a stable connective tissue attachment, the cell attachment factors had a negligible effect on the formation of soft tissue attachment, and a surface coating of titanium enhanced epithelial adhesion. In these experiments an epithelium formed adjacent to the implant surface, but this was not a junctional type of epithelium as is found in the attachment to natural teeth. The formation of a junctional type of epithelium may depend on an interaction between the epithelium and connective tissue. The next series of experiments will examine the influence of connective tissue components, particularly fibroblasts of different sources including the periodontal ligament on epithelial attachment. In order to determine whether a junctional epithelium has actually formed, the epithelium adjacent to the implant will be characterized by microscopic examination and cell surface staining for blood group antigens and cytokeratins. My project is significant in that it may provide information that is useful in the design of dental implants, where conditions necessary to form a stable soft tissue attachment are currently unknown, but are of considerable importance if inflammatory and resorptive changes are to be avoided.