The Synthesis, Characterization, and Assessment of Antibacterial Properties of an Orthodontic Adhesive Containing Cerium-Substituted Hydroxyapatite Nanoparticles: An In Vitro Study.

Abstract

Introduction White spotlesions (WSLs) areearlyenamel carieslesionsoftenseen inindividuals receivingfixed orthodontic treatment.These lesions occur due to the buildup ofplaqueand the colonizationof bacteria. WSL formation can be prevented by adequate oral hygiene measures and by the incorporation of antimicrobial nanoparticles (NPs) in orthodontic appliances and bonding systems. The aim of this research was to synthesize cerium-substituted hydroxyapatite nanoparticles (Ce-HAp NPs),characterize them, and assess their antimicrobial activity. Materials and methods This in vitro investigation involved the preparation of Ce-HAp NPs using the co-precipitation method, followed by their characterization using scanning electron microscope (SEM), energy-dispersive X-ray (EDAX), and Fourier transform infrared (FTIR). The NPs were prepared and subsequently added to an orthodontic adhesive. Antibacterial testing was conducted using the disc diffusion method against common oral pathogens (Staphylococcusaureus, Lactobacillus acidophilus, and Streptococcus mutans). The zones of inhibition were measured for two different concentrations of the adhesive. Results The Ce-HAp NPs were successfully prepared and had an irregular agglomerated shape, measuring 63 nm in size. The major characteristic chemical groupsof Ce-HAp were PO43-, OH-, and CO32-,and it was confirmed by the FTIR spectrum. The EDAXresults of the synthesized NPs showed theoretical weight percentages (Wt%) of O, 52.6%; Ca, 20.9%; P, 11.8%; C, 10.3%; and Ce, 4.3%. A higher concentration of 40 µg/mL (30 mm for S. aureus and L. acidophilusand 25 mm for S. mutans) showed good antibacterial activity against the tested bacterial strains, compared to control antibiotics. Conclusion Cerium oxide (CeO2)-HAp NPs were prepared and incorporated intoanorthodontic adhesive.The prepared adhesive exhibited effectiveantibacterial activity againstprevalent oral pathogens.