Objective: The objective of this study was to coat orthodontic nickel titanium (NiTi) archwires with nano-particles (NP) of silver (Ag) combined with nano polytetrafluoroethylene (PTFE) to produce a smooth antimicrobial nanocomposite layer by using a radio frequency (RF) sputtering process and to evaluate the coated surfaces in terms of morphology, nano-roughness, adhesion strength, hardness, and antimicrobial activity. Materials and methods: Super-elastic NiTi archwires (diameter = 0.4 mm, length = 160 mm) were surface cleaned and sterilized prior to the RF sputtering, using a mixture of nano Ag powder (20 nm; purity > 99.95%) and PTFE powder (25 nm; purity > 99.95%). X-ray diffraction apparatus (XRD), flex atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM) were used to characterize the morphology and nano roughness of the coated archwires. Lactobacillus acidophilus (L. acidophilus) and Streptococcus mutans (S. mutans) were selected to evaluate the antimicrobial activity. Results: A uniform and homogeneous nanocomposite coating was obtained without agglomeration. Surface roughness values decreased with increasing sputtering time, while the coated samples exhibited excellent antibacterial activity against both bacterial strains. AFM analysis demonstrated that sputtering time strongly influenced adhesion resistance, hardness, and coating stability, and the antibacterial activity was highly effective against both L. acidophilus and S. mutans. Conclusion: The sputtering time of 30 min gave a smooth coating layer on the surface of NiTi archwire with strong antimicrobial resistance that offers significant potential for dental applications.

This study investigates the effect of Ag–PTFE nanocomposite coatings, prepared by radio frequency (RF) sputtering, on the surface and antimicrobial properties of orthodontic stainless steel archwires (SSW). The novelty lies in combining silver (Ag) and polytetrafluoroethylene (PTFE) nanoparticles into one coating, which has not been widely applied to orthodontics. The motivation is the need to reduce microbial adhesion and biofilm on archwires, which contribute to enamel demineralization, gingival disease, and infections. The problem addressed is the lack of coatings that can simultaneously provide enhanced surface properties, facilitate controlled silver ion release, and deliver durable antibacterial performance. Unlike literature that mainly studied Ag or polymer coatings separately, this work fills the gap by varying Ag and PTFE weight percentages and assessing their combined effects on wettability, roughness, ion release, and antimicrobial activity. Austenitic 316L stainless steel archwires (0.4 mm in diameter and 160 mm in length) were coated using Ag and PTFE nanopowders (30 nm). The coated SSW was characterized using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and contact angle measurements, while silver ion release was analyzed by atomic absorption spectroscopy. Antimicrobial efficacy was tested against Streptococcus mutans and Staphylococcus aureus. The results showed uniform coatings with distinct hydrophobic behavior and antibacterial activity. Increasing Ag content enhanced silver ion release and inhibition zones, while higher PTFE content increased hydrophobicity, reducing bacterial adhesion. These findings highlight Ag–PTFE coatings as a synergistic strategy to improve surface properties and suppress microbial colonization, suggesting potential benefits in preventing caries and periodontal complications.