Investigation of antimicrobial and anti-adherent properties of fabricated cobalt–chromium alloy modified with TiO2 coating

Cobalt–Chromium alloy is considered a metallic framework for osseointegrated prosthetic implants due to its mechanical properties and biocompatibility. However, the surface of this metal provides a favorable environment for the growth and proliferation of bacteria and funguses. The antimicrobial and anti-adherent properties of titanium dioxide (TiO2) can enhance these alloys. This study investigates the antibacterial properties of TiO2-coated chromium-cobalt alloy in the presence of Streptococcus mutans (S. mutans) bacteria. The TiO2 thin film was coated using RF magnetron sputtering. Its microstructure and thickness were evaluated using field emission scanning electron microscopy (FSEM), surface profilometer (SPM), and micro-scratch tests. X-ray diffraction (XRD) confirmed the anatase phase of TiO2. The coated samples and control samples were placed in artificial culture environments to assess the impact on S. mutans growth. The TiO2 coating thickness was 201 nm with the adhesion of 802 mN. The mean and standard deviation of S. mutans in biofilm structures on TiO2-coated samples were 416.56 × 106 ± 78.74 × 106, compared to 1951.89 × 106 ± 358.79 × 106 in the uncoated group. The mean bacterial count on coated discs was significantly lower (p < 0.001). Additionally, the mean colony counts of S. mutans on TiO2-coated cobalt chrome surfaces were 110.67 ± 18.78, against 2987.44 ± 612.453 in the uncoated group. These results indicate that the TiO2 coating on chromium-cobalt alloy confers antimicrobial and anti-adherent effects.