Gingival cell attachment and cell adhesion complex formation on TiO2 coated zirconia and titanium

Abstract

Weak gingival attachment to implant surface exposes to easier bacterial invasion to peri-implant tissues, which increases the risk for peri-implant infections. In the worst case, peri-implantitis can lead to the loss of an implant. Therefore, firm peri-implant tissue integration is of a paramount importance.

The aim of the thesis is to find out, if nanoporous, bioactive TiO2-coating is able to enhance gingival cell adhesion and growth on titanium and zirconia, which are commonly used dental implant or abutment materials.

In the study, half of the zirconia and titanium samples were coated with sol gel derived TiO2-coating. In addition, hydrothermal treatment of titanium was used in the third study. Surface properties were measured with contact angle and surface free energy measurements. Further, the scanning electron microscope imaging was accomplished to detect the nanotopography of the coated surfaces. In the study, the adhesion and growth of epithelial cells and fibroblasts were studied on TiO2-coated and non-coated surfaces. The expression of adhesion complexes was studied by western blotting and confocal microscopy. In addition, the effects of saliva exposure to surface properties and cell adhesion were studied.

The results of the thesis demonstrated nanoporous surface and increased hydrophilicity on TiO2-coated zirconia and titanium. Epithelial cell adhesion and proliferation were faster on coated surfaces. Moreover, expression of adhesion proteins was enhanced on coated surfaces. Saliva exposure increased surface hydrophilicity, but decreased cell attachment on titanium surface. To conclude, bioactive TiO2-coating is able to enhance cell adhesion to zirconia and titanium in vitro. However, saliva exposure weakens the positive effects of bioactive surface.