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.