Zirconia is known as a strong and bioinert load-bearing material for dental implants. It typically exhibits no antibacterial activity. Inflammation is a crucial problem for dental implant surgery: about 3–5% of all dental implants experience inflammation. This study demonstrates that either fullerene C60 films or a tribomechanical loading of zirconia without the fullerene C60 coating can cause an improvement in antibacterial activity against Gram-positive Staphylococcus aureus. This moderate antibacterial activity is especially important, because a strong antibacterial effect could disturb the sensitive and beneficial oral bacterial biota. In the present study, different fullerene C60 films were examined. In addition to fullerene C60 film in an “as deposited” condition, treatment with nitrogen plasma as well as tribomechanical produced surface patterns with and without plasma post-treatment were tested. An 85.8% (log reduction 0.85) reduction in Gram-positive Staphylococcus aureus bacterial formation was observed on the zirconia with fullerene C60 film. Plasma treatment of the C60 film increases the antibacterial impact to 72.2% (log reduction 0.56) in comparison to zirconia without fullerene C60 film. Also, tribomechanical loaded fullerene C60 films suppress the growth of Gram-positive Staphylococcus aureus. The tribomechanical loading seems to compensate for the effect of the plasma treatment. ZrO2 samples with fullerene C60 film and tribomechanical loading achieve an increase in antibacterial impact of 83.36% (log reduction 0.78). Furthermore, surprisingly yttria-stabilized zirconia bioceramic without fullerene C60 film also shows an improved antibacterial efficacy after a tribomechanical patterning procedure. The addition of surface patterning on the ZrO2 by scratching microgroove arrangements with a diamond tip, increased the antibacterial effect against Gram-positive Staphylococcus aureus by 70.46% (log reduction 0.53).
Dorner-Reisel et al. (Tue,) studied this question.