Optimization of Silver Nanoparticle Coating Methods on Acrylic, Silicone, and Zirconia Facial Prosthetic Materials: Surface Characterization and Antimicrobial Activity Against Pseudomonas aeruginosa

Background/Objectives: One of the ongoing clinical constraints is limiting microbial growth on facial and dental prostheses, justifying the need for material surface enhancements for reducing the associated microbial complications. This study aimed to investigate a clinically applicable and reproducible coating technique to overcome microbial clinical challenges. Methods: Ag nanoparticles (NPs) were applied to three types of facial materials through spray, spin, and dip coating techniques. Surface characterization, elemental composition, and chemical bond formation were assessed by Scanning Electron Microscopy (SEM), Energy-dispersive X-ray Spectroscopy (EDS), and Fourier Transform Infrared (FTIR) spectroscopy, respectively. Subsequent optimization of spray numbers was performed. Antimicrobial performance was examined by agar diffusion, direct contact, and adhesion (time-dependent) assays, with different layers, against Pseudomonas aeruginosa. Results: Spray coating exhibited superior coating uniformity compared with others. 15 sprays was determined as optimal number for a single layer coating. EDS confirmed Ag NP presence, FTIR revealed no chemical alteration of specimens. Disk diffusion tests showed no inhibition zones. Adhesion and direct contact tests displayed antibacterial activity, the effect of which was stronger for the latter. Time-dependent adhesion test of 1-layer coating of acrylic and silicone had a consistent decrease in bacterial amount, whilst zirconia had only a strong initial activity. In general, the 3-layer coating did not showcase an increased antimicrobial activity, suggesting that the increase in layering negatively impacts surface effectiveness. Conclusions: spray coating of Ag NPs can provide a promising, clinically-applicable, large-scale manufacturing strategy for improving dental and facial material antibacterial qualities without altering the inherent prosthetic properties.