Alternative Polyurethane/Gutta-Percha/ZnO Biocomposite for Root Canal Therapy Based on an Efficient Melt Extrusion Additive Manufacturing Strategy

This work aims to investigate dental root filling custom gutta-percha (GP) properties based on melt extrusion 3D printing for periapical periodontal disease treatment. Zinc oxide nanoparticles are incorporated into polyurethane/gutta-percha (PGB) composites. A polyurethane/gutta-percha/ZnO (PGB-Zn) biocomposite including BaSO4, polyurethane (PU), GP, and ZnO nanoparticles is designed and fabricated. To improve the dispersion of ZnO nanoparticles, rosin is chosen to modify the surface of the ZnO nanoparticles. The PGB-Zn biocomposite exhibits a maximum tensile strength of 26.795 ± 1.173 MPa and a flexural strength of 6.037 ± 0.37 MPa. The chemical interaction between the nanoparticles and the matrix is found in the physical and mechanical characterization of the polyurethane/gutta-percha/ZnO (PGB-Zn) biocomposite. The inhibition zone test and absorbance photometry show that the composite material inhibits and kills Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The CCK-8 experimental results show that the PGB-Zn biocomposite has a cytotoxicity level of 0-I. The obtained PGB-Zn biocomposite in this work can be used for accurate root canal therapy as a filling biocomposite by a fused extrusion method, which effectively decreases the potential risk of the clinical implementation of periapical periodontal disease treatment.