Effects of surface coating methods on roughness and bacterial adhesion of implant overdenture abutments

In implant-supported removable dentures, the surface characteristics of the abutments play a critical role in maintaining peri-implant tissue health. This study aimed to evaluate the effects of abutments with different surface coating techniques on surface roughness and bacterial adhesion after fatigue testing. The study used 10 Titanium Nitride (TiN) coated and 10 Diamond-like Carbon (DLC) coated abutments. Initial surface roughness values were measured using an atomic force microscope (AFM). All samples were exposed to tensile force equivalent to 12 months of clinical use on a universal micro tensile device. After fatigue testing, surface roughness was re-measured, and surface morphology was evaluated by Scanning Electron Microscopy (SEM). Streptococcus mutans was used for bacterial adhesion analysis. Normality of the data was evaluated by Kolmogorov-Smirnov and Shapiro-Wilk tests, and the Levene test evaluated homogeneity of variance. Differences between groups were analyzed by an independent samples t-test. Statistical analysis revealed a significant decrease in surface roughness in both groups after fatigue testing. However, no statistically significant difference was found in bacterial adhesion between the groups (P>.05). The findings indicate that adhesion on abutments may also be influenced by other factors.