Can polyphenolic surface modifications prevent fungal colonization of titanium dental implants?

Oral biofilms can be a major health problem causing infections and chronic inflammation of mucosal tissue. While much effort is put in the investigation of bacteria in biofilms, the role of fungi is often neglected, despite Candida albicans playing a key role in the formation of multispecies oral biofilms. With the rise of antibiotic resistance, new strategies to reduce microbial growth need to be found. Therefore, plant derived polyphenolic molecules have been suggested to reduce both adhesion and growth of pathogenic bacteria and fungi. In this study, we investigated the use of polyphenolic coatings to reduce adhesion and biofilm formation of C. albicans BWP17 on titanium implants. Tannic acid and pyrogallol coatings altered the hydrophobic and charge properties of titanium surfaces, and both compounds were gradually released as active molecules over time. Despite such effects, we found no significant inhibition on growth and biofilm formation of C. Albicans, indicating that the release of active molecules from the coatings did not reach relevant inhibitory concentrations. However, a potential antibiofilm effect was observed by the pH-dependent disassembly of the polyphenolic layer, which caused the biofilm to detach. Hence, further efforts are required to create tailored implant surfaces, which sustainably reduce microbial growth and adhesion.