The effects of nano-chitosan loaded with gallic acid as an antibacterial and remineralizing agent on some properties of orthodontic adhesive

Objective(s): This study aimed to evaluate the effect of adding nano-chitosan loaded with gallic acid to an orthodontic primer as an antimicrobial and remineralizing agent while preserving orthodontic adhesive's physical and chemical properties.Materials and methods: Nano-chitosan loaded with gallic acid was added to Transbond XT primer to form nano-chitosan/gallic acid primer. This study compared three groups: control without additive, 5%, and 10% Nano-Chitosan/Gallic acid Primer (NCGP). In terms of FTIR, Shear Bond Strength (SBS), Adhesive Remnant Index (ARI), Degree of monomer Conversion (DC), antibacterial properties against Streptococcus mutans and Lactobacillus acidophilus, and Field Emission Scanning Electron Microscopy with Energy Dispersive X-ray spectroscopy (FESEM-EDX) were examined to detect remineralization of demineralized enamel.Results: Both the 5% and 10% nano-chitosan/gallic acid primer groups demonstrated significant antibacterial activity, a 15–20% increase in shear bond strength (SBS), a 10–15% enhancement in the degree of monomer conversion (DC), and a 30–40% increase in calcium and phosphate weight percentages compared to the control group. Additionally, no significant differences were observed in Adhesive remnant index (ARI) scores among the groups.Conclusions: The orthodontic adhesive primer modified with nano-chitosan loaded with gallic acid demonstrated enhanced mechanical, chemical, antibacterial, and remineralizing properties compared to the commercial adhesive. Therefore, it can be considered a novel adhesive for treating white spot lesions (WSLs).