Cell culture tests for assessing the tolerance of soft tissue to variouslymodified titanium surfaces

The aim of our research project was to achieve an improvement in the integr ation of enossal dental implants in the region of peri-implantary soft tiss ue. Improvement in the adhesion of the gingiva to the surface of enossal im plants was to be achieved by modification of the titanium surface. The effe ct of different modifications on the biocompatibility of the modified titan ium surfaces was tested: sulfur dioxide plasma treatment of titanium; acety lene plasma treatment of titanium followed by sulfur dioxide plasma etching ; plasma nitration of titanium; replacement of titanium by glycidoxypropylt rimethoxy silane; coating titanium with poly[(ethene-co-vinyl acetate)-graf t-vinyl chloride] and coating titanium with fibronectin. Determination of t he chemical composition of the surface was carried out using X-ray photospe ctroscopy. The adsorption of fibronectin at the surface of the titanium was tested using an Enzyme Linked Immunosorbent Assay. In selected in vitro te sts with human gingival fibroblasts, cell morphology was assessed using sca nning electron microscopy and light microscopy. Cell proliferation and prot ein synthesis, as well as the activity of mitochondrial dehydrogenases were evaluated. By means of centrifugation and by determining initial cell adhe sion, the adhesion of gingival fibroblasts was investigated. According to t he kind of modification made to the titanium surfaces, it was possible to o bserve differences in the cellular behavior of gingiva fibroblasts on the d ifferently modified surfaces of the implants. Coating the titanium using fi bronectin produced optimization of cell growth and improvement in the adhes ion of gingiva fibroblasts to the implant surface. In contrast, modificatio n of the titanium with poly[(ethene-co-vinyl acetate)-graft-vinyl chloride] generally resulted in a deterioration of the biocompatibility of the surfa ce. A marked correlation between the cellular compatibility of the modified titanium and the surface modification made did not become apparent. One re ason for this is the large number of parameters determining the interaction between implant and tissue.