Development and Characterization of Novel Orthodontic Adhesive Containing PCL-Gelatin-AgNPs Fibers

Enamel demineralization around brackets is a relatively common complication of fixed orthodontic treatment, which seriously affects the aesthetics of teeth. In this study, a novel orthodontic adhesive containing polycaprolactone−gelatin−silver nanoparticles (PCL−gelatin−AgNPs) composite fibers was prepared to prevent enamel demineralization of orthodontic treatment. First, PCL−gelatin−AgNPs fibers film prepared by electrospinning was made into short fibers and added to traditional orthodontic adhesives (Transbond XT, 3M Unitek) in three different ratios to design a series of composite adhesives containing antibacterial materials. The antimicrobial performance of the control product and the three samples were then evaluated by bacterial live/dead staining, colony-forming unit (CFU) counts, tensile bond strength (TBS), and adhesive residue index (ARI) scores. The composite adhesives’ antimicrobial properties increased with the increasing content of PCL−gelatin−AgNPs short fibers. The addition of complex antimicrobial fibers to 3M Transbond XT adhesive can significantly reduce the CFU of bacterial biofilms (p < 0.05). The bacterial survival rate on the surface of the specimen decreased with the increase of PCL−gelatin−AgNPs short fibers (p < 0.05). The TBS and ARI values (n = 10) indicated that adding PCL−gelatin−AgNPs short fibers had no significant adverse effect on adhesion. Therefore, adding PCL−gelatin−AgNPs short fibers makes it possible to fabricate orthodontic adhesives with strong antibacterial properties without compromising the bonding ability, which is essential for preventing enamel demineralization around the brackets.