Enhanced Bacterial and Biofilm Adhesion Resistance of ALD Nano-TiO2 Coatings Compared to AO Coatings on Titanium Abutments

Yu Pan,1,* Lili Cao,2,* Libing Chen,1,* Linjuan Gao,2 Xia Wei,1 Honglei Lin,1 Lei Jiang,1 Yinghui Wang,1,2 Hui Cheng1,2 1Department of Prosthodontics, Institute of Stomatology & Research Center of Dental Esthetics and Biomechanics, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, Fujian, People’s Republic of China; 2Department of Prosthodontics, Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Laboratory of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, Fujian, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yinghui Wang; Hui Cheng, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, Fujian, People’s Republic of China, Email wyh9519@fjmu.edu.cn; ch.fj@fjmu.edu.cnPurpose: The study was intended to compare the surface properties and the bacterial and biofilm adhesion resistance of two potential antibacterial nanometer titanium dioxide (nano-TiO2) coatings on dental titanium (Ti) abutments prepared by atomic layer deposition (ALD) and the anodic oxidation (AO) techniques.Methods: Nano-TiO₂ coatings were developed using ALD and AO techniques and applied to Ti surfaces. The surface properties and the bacterial and biofilm adhesion resistance of these coatings were evaluated against commonly used Ti and Zirconia (ZrO₂) surfaces. The chemical compositions, crystalline forms, surface topography, roughness and hydrophilicity were characterized. The antibacterial performance was assessed by the scanning electron microscope (SEM), the Colony-forming unit (CFU) assay and the 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT) assay using in vitro models of Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans), and Porphyromonas gingivalis (P. gingivalis) in both single- and mixed-species bacterial compositions.Results: ALD-prepared nano-TiO₂ coatings resulted in a dense, smooth, and less hydrophilic surface with an anatase phase, significantly reducing the adhesion of the three bacteria by over 50%, comparable to ZrO₂. In contrast, AO-prepared coatings led to a less hydrophilic surface, characterized by various nano-sized pores within the oxide film. This alteration, however, had no impact on the adhesion of the three bacteria. The adhesion patterns for mixed-species bacteria were generally consistent with single-species results.Conclusion: ALD-prepared nano-TiO₂ coatings on Ti abutments demonstrated promising antibacterial properties comparable to ZrO₂ surfaces, suggesting potential in preventing peri-implantitis. However, the bacterial and biofilm adhesion resistance of AO-produced nano-TiO₂ coatings was limited. Keywords: atomic layer deposition, anodic oxidation, titanium dioxide, dental abutment, surface properties, antibacterial effect