Abstract
The purpose of this study was to formulate and characterize functionalized graphene nanoplatelets (GNP) with silver nanoparticles (AgNPs) and evaluate the antimicrobial and mechanical properties of GNP-Ag-modified adhesives bonded to orthodontic brackets. The morphology and physiochemical properties of nanoparticles were studied. The functionalized nanoparticles were incorporated at 0.25 and 0.5 wt% into experimental orthodontic adhesives (Transbond XT) and characterized for their biological, antimicrobial capacity, degree of conversion (DC), shear bond strength (SBS), and adhesive remnant index (ARI). Among the experimental groups, the specimen treated with 0.25 wt% modified experimental adhesive had the highest mean DC score (40.8 +/- 6.5), shear bond strength (9.8 +/- 1.8), lowest mean adhesive remnant index scores (1.35 +/- 0.78), and the lowest cytotoxicity effect after 72 h (p < 0.001). However, 0.5 wt% GNP-Ag modified experimental adhesive specimens showed a greater relative antibiofilm viability against S. mutans after 24 h and 30 days in comparison to 0.25 wt%. Our study found that 0.25 wt% revealed substantial increase in antibacterial properties and therefore could be used for bonding orthodontic brackets to the enamel surface without compromising bond strength.