Study on the Preparation and Properties of 3D ‐Printed PETG / AgNPs Antibacterial Coatings for Clear Aligners

ABSTRACT This study presents a fused deposition modeling 3D‐printed poly (ethylene terephthalate) glycol (PETG)/silver nanoparticles (AgNPs) coatings for clear aligners, evaluating their mechanical, antibacterial, and biocompatible properties. Melt‐compounding and FDM printing were conducted to integrate AgNPs into the PETG matrix. Mechanical tests showed enhanced Young's modulus (929 MPa at 1 wt% AgNP) with preserved tensile strength (45.5–46.8 MPa). Antibacterial assays revealed dose‐dependent efficacy, with 10 wt% AgNPs coatings achieving an eight‐log reduction in Streptococcus mutans (0.001 × 10 ⁵ CFU/mL vs. 23,000 × 10 ⁵ CFU/mL in controls) and elevating pH to 5.43 under cariogenic conditions. Cytocompatibility tests with human gingival fibroblasts showed ≥ 95% viability across all groups. This work demonstrates a feasible, eco‐friendly approach to incorporate effective antimicrobial functionality into clear aligners while preserving mechanical properties and biocompatibility.