Graphene oxide-modified dental adhesive for bonding orthodontic brackets

Recently, dental resin adhesives are being incorporated with several nanoparticles to improve their mechanical and biological features. This study aimed to synthesize and characterize silanized graphene oxide (SGO) nanoparticles and assess the spectral, microbiological, and mechanical analysis of SGO-modified adhesive bonded to orthodontic brackets. Graphene oxide, manufactured using Hummer's method, was silanized utilizing tetraethylorthosilicate to synthesize SGO nanoparticles. The adhesive's characterization along with their biological and physical characteristics were assessed using scanning electron microscopy and energy dispersive X-ray spectroscopy; its degree of conversion (DC), cytotoxicity, antibacterial effect, shear bond strength (SBS), and adhesive remnant index (ARI) were examined. Transbond XT (control adhesive) was modified by incorporating 0.25 wt% and 0.5 wt% SGO-modified adhesive, which served as the experimental groups. Sixty orthodontic brackets were bonded to tooth surfaces for each study group (n = 20). Five disks of control and experimental groups were prepared measuring 5 mm in diameter and 1 mm in height each. SGO nanoparticles were synthesized with 100–700 nm in size and 1–2 nm thickness. Among the experimental groups, the samples treated with 0.25 wt% SGO-modified adhesive showed the lowest mean DC score (38.46 ± 5.12), the highest mean SBS values (13.84 ± 2.55 MPa), and the least ARI (post-thermocycling) scores (1.33 ± 0.54). 0.25 wt% SGO-modified adhesive samples showed a greater relative biofilm viability against S. mutans than 0.5 wt% SGO-modified adhesive samples after 24 h and 30 days. 0.25 wt% SGO-modified adhesive group showed higher SBS, sufficient durability, greatest bactericidal and least cytotoxic effect than 0.5 wt% SGO-modified adhesive and Transbond XT.