Fabrication of N-halamine coatings with long-lasting bacterial inhibition and bacterial biofilm disruption functions for invisible aligner applications.

Enamel white spot lesions (WSLs) not only compromise the efficacy of orthodontic treatments but also pose risks to dental health. Although clear aligners offer the advantage of facilitating oral hygiene maintenance, their full-coverage crown design impedes the self-cleaning function of saliva, potentially leading to extensive white spot formation. This study pioneers the application of a PA@PEI-Cl coating to transparent aligners. A colloidal polymer formed via electrostatic interactions between phytic acid (PA) and polyethyleneimine (PEI), combined with a broad-spectrum antibacterial N-halamine polymer, enables this coating to achieve synergistic antibacterial efficacy. The preparation protocols and reaction conditions were optimized in detail. Systematic experiments confirmed the stable adhesion of coating to aligners and the long-lasting antibacterial performance, enhancing the safety of orthodontic treatment. This simple and low-cost method is suitable for large-scale industrial production. It provides an innovative solution to enhance aligner functionality and demonstrates a significant clinical potential for preventing orthodontic complications.