Evolution of the Antibacterial and Cellular Viability Effects of Silica-Hydroxyapatite Conjugated High Cerium Oxide Nanoparticles on Orthodontic Brackets

Nanomaterials have been utilized as antibacterial agents due to their distinct mechanism of action, which sets them apart from traditional antibiotics. Cerium oxide nanoparticles (CeO2 NPs) play a crucial role as antibacterial agents because of their minimal toxicity towards healthy cells and their unique antibacterial mechanism, which involves the reversible transition between two valence states of Ce(III)/Ce(IV). In the current study, silica microspheres (SiO₂) were applied for the growth of hydroxyapatite (Hap) over the silica surface. Then, the SiO₂/hydroxyapatite (SiO₂/Hap) nanocomposite was applied for stabilization of the in situ green synthesized cerium oxide nanoparticles (CeO₂ NPs) on its surface to assess the antibacterial and cellular viability of orthodontic brackets. The as-prepared SiO₂/Hap-CeO₂ NPs were fully characterized by different techniques such as FT-IR, XRD, FE-SEM, TEM and ICP-OES analyses. The technique employed to coat the orthodontic bands with SiO₂/Hap-CeO₂ NPs nanocomposite was the electrostatic spray-assisted vapor deposition method. The antibacterial efficacy of SiO₂/Hap-CeO₂ NPs nanocomposite against Candida albicans, Streptococcus mutans and Lactobacillus acidophilus was evaluated using the biofilm inhibition test. In the recent study’s cellular and molecular component, the treated cells with SiO₂/Hap-CeO₂ NPs nanocomposite underwent evaluation through MTT assay to determine cytotoxicity on the normal (HUVEC) cell line. In comparison to the control group, the SiO₂/Hap-CeO₂ NPs nanocomposite group exhibited a 2-log10 decrease in the replication ability of all microorganisms. The group of SiO₂/Hap-CeO₂ NPs nanocomposite demonstrated a notable decrease in the quantity of C. albicans, S. mutans and L. acidophilus colonies compared to the control group. Application of SiO₂/Hap-CeO₂ NPs nanocomposite on orthodontic bands resulted in antibacterial properties against oral pathogens.