Espinosa-Cristóbal, L.F., López-Ruiz, N., Cabada-Tarín, D., Reyes-López, S.Y., Zaragoza-Contreras, A., Constandse-Cortéz, D., Donohué-Cornejo, A., Tovar-Carrillo, K., Cuevas-González, J.C. and Kobayashi, T. (2018). Antiadherence and Antimicrobial Properties of Silver Nanoparticles against Streptococcus mutans on Brackets and Wires Used for Orthodontic Treatments. Journal of Nanomaterials, [online] 2018, pp.1–11. doi:https://doi.org/10.1155/2018/9248527
Background
Dental caries is a prevalent, multifactorial oral disease that often presents initially as white spot lesions (WSLs) due to enamel demineralisation. WSLs are linked to prolonged plaque buildup, specific medical, dental, and genetic factors, with Streptococcus mutans (S. mutans) being the primary pathogen. Orthodontic treatments further increase WSL risk by creating areas that trap food and make oral hygiene more challenging. While current prevention strategies focus on fluoride treatments, recent studies suggest that silver nanoparticles (AgNPs) could help reduce plaque and enamel demineralisation in orthodontic appliances. This study investigates AgNPs of two sizes for their effectiveness in inhibiting and preventing S. mutans adherence on orthodontic brackets and wires.
Method
In this study 2 sizes of AgNP (8.1nm and 20.1nm) were synthesised using silver nitrate and gallic acid. The synthesis process involved dissolving 0.01M silver nitrate in deionised water, followed by the addition of different amounts of gallic acid, which influenced the final particle sizes. The AgNPs were then characterised in detail: their sizes were measured using dynamic light scattering (DLS), their shapes were visualised with transmission electron microscopy (TEM), and their elemental composition was confirmed through energy-dispersive X-ray spectroscopy (EDS). The antibacterial effects of these AgNPs against Streptococcus mutans were tested, along with their adherence to orthodontic materials like wires and brackets. To assess bacterial attachment, adherence tests were conducted in controlled conditions. Additionally, scanning electron microscopy (SEM) and atomic force microscopy (AFM) provided detailed images of the orthodontic wires’ surface morphology before and after AgNP exposure, allowing for in-depth examination of any topographical changes related to bacterial adhesion.
Results
The results from this study indicate that AgNPs significantly inhibit Streptococcus mutans adherence to orthodontic brackets and wires, with smaller nanoparticles showing the strongest anti-adherence effects (p < 0.05). Copper-nickel-titanium wires showed the highest bacterial adherence, attributed to their rougher and more irregular surfaces as observed in microscopy analyses, while nickel-titanium and stainless-steel wires had smoother surfaces with fewer adhesion sites. The anti-microbial mechanism of AgNPs is likely due to their ability to interact with bacterial cell enzymes and disrupting bacterial metabolic functions, potentially inducing bacterial death.
Conclusion
Overall, the findings suggest that AgNP coatings on orthodontic appliances could reduce bacterial buildup and potentially prevent white spot lesions (WSLs) during orthodontic treatments, offering a promising approach for enhancing oral hygiene in orthodontic care.
Research Summary Written By: Warshika Gopikrishna, University of Manchester – BDS3