Enhancing Root Canal Therapy with NIR‐II Semiconducting Polymer AIEgen and Low‐Concentration Sodium Hypochlorite Synergy

Abstract Despite significant efforts to eliminate bacterial biofilm within root canals, achieving effective disinfection remains challenging due to the complex anatomy and limitations of disinfectants. In this study, a second near‐infrared (NIR‐II) semiconducting polymer with aggregation‐induced emission (AIE) properties, named PIDT‐TBT, is deliberately designed and synthesized. This proposes an AIE luminogen‐based sterilization strategy in synergy with a low concentration of sodium hypochlorite (NaClO). Water‐dispersible PIDT‐TBT nanoparticles (NPs) are prepared, demonstrating good biocompatibility, as well as photothermal and photodynamic properties. Subsequent antibacterial tests show that PIDT‐TBT NPs exhibit excellent bactericidal effects against three bacterial strains: Staphylococcus aureus , Streptococcus mutans , and Enterococcus faecalis , upon 808 nm laser irradiation. In synergy with a low concentration of NaClO (0.5%) solution, PIDT‐TBT NPs significantly improves the outcome of root canal treatment under 808 nm laser irradiation in a human extracted tooth root canal infection model. Additionally, it is found that PIDT‐TBT NPs combine with a low concentration of NaClO solution could safely dissolve dentin debris and further increase the efficiency of root canal preparation by altering the elemental composition of the inner root canal wall.