Electrochemical deposition of silver nanoparticles on nickel-titanium rotary files: An in vitro study

The present study aimed to deposit and characterize silver nanoparticle (AgNP)-chitosan composite coatings on nickel-titanium (NiTi) rotary files using an electrochemical deposition method and to evaluate the elemental composition and silver and nickel ions release from the coated instruments.

Silver and chitosan nanoparticles were deposited onto Plex V NiTi rotary files (size 25, 0.06 taper) (Orodeka, Jining, China) using an electrochemical deposition method. Group 1: 0.005 g AgNPs +100 mL of 1 Vol.% acetic acid +0.1 g of chitosan, 5V, 1 min. Group 2: 0.005 g AgNPs +100 mL of 1 Vol.% acetic acid +0.1 mL of Polysorbate 20, 0.25 g of Eudragit E 100 + 0.1 g of chitosan, 5V, 1 min. Group 3: 0.005 g AgNPs +100 mL of 1 Vol.% acetic acid +0.1 mL of Polysorbate 20, 0.25 g of Eudragit E 100 + 0.1 g of chitosan,5V, 3 min. Group 4: 0.01 g AgNPs +100 mL of 1 Vol.% acetic acid +0.1 mL of Polysorbate 20, 0.25 g of Eudragit E 100 + 0.1 g of chitosan, 5V, 1 min. Group 5:0.01 g AgNPs +100 mL of 1 Vol.% acetic acid +0.1 mL of Polysorbate 20, 0.25 g of Eudragit E 100 + 0.1 g of chitosan, 5V, 3 min. Deposition was performed with the NiTi file serving as the cathode and a platinum mesh as the anode, while maintaining a fixed interelectrode distance of 10 mm. Following deposition, the coated samples were thoroughly rinsed with distilled water and air-dried. The surface morphology and coating characteristics were evaluated using scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDAX). The release of silver and nickel ions from the coated files after immersion in simulated body fluid was quantified using inductively coupled plasma-optical emission spectrometry (ICP-OES).

SEM analysis revealed shallow depressions and irregular texturing on the NiTi rotary files, representing the presence of embedded silver and chitosan nanoparticles. EDAX confirmed the presence of silver along with the underlying NiTi substrate elements, indicating successful coating formation. ICP-OES analysis demonstrated controlled silver ion release from all coated groups, while nickel ion release was not detected, suggesting that the electrochemical deposition process did not adversely affect the NiTi alloy.

Based on the findings of this study, electrochemically deposited AgNP-chitosan coatings on NiTi rotary files demonstrate effective surface modification with controlled silver release, indicating their potential usefulness in enhancing antimicrobial properties during root canal instrumentation.