Bacterial/fungal biofilm-mediated persistent endodontic infections (PEIs) are one of the most frequent clinical lesions in the oral cavity, resulting in apical periodontitis and tooth damage caused by loss of minerals. The conventional root canal disinfectants are poorly bio-safe and harmful to teeth and tissues, making them ineffective in treating PEIs. The development of nanomaterials is emerging as a promising strategy to eradicate disease-related bacteria/fungi. Herein, glucose oxidase (GOx)-modified magnetic nanoparticles (MNPs) were synthesized via a facile and versatile route for investigating their effects on removing PEI-related bacterial/fungal biofilms. It is found that GOx was successfully immobilized on the MNPs by detecting the changes in the diameter, chemical functional group, charge, and magnetic response. Further, we demonstrate that GOx-modified MNPs (GMNPs) exhibit highly effective antibacterial activity against Enterococcus faecalis and Candida albicans. Moreover, the antibacterial/fungal activity of GMNPs is greatly dependent on their concentrations. Importantly, when placed in contact with bacterial/fungal biofilms, the dense biofilm matrix is destructed due to the movement of GMNPs induced by the magnetic field, the formation of reactive oxygen species, and nutrient starvation induced by GOx. Also, the in vitro experiment shows that the as-prepared GMNPs have excellent cytocompatibility and blood compatibility. Thus, GMNPs offer a novel strategy to treat bacteria/fungi-associated PEIs for potential clinical applications.

Enterococcus faecalis (E. faecalis) biofilm-associated persistent endodontic infections (PEIs) are one of the most common tooth lesions, causing chronic periapical periodontitis, root resorption, and even tooth loss. Clinical root canal disinfectants have the risk of damaging soft tissues (e.g., mucosa and tongue) and teeth in the oral cavity, unsatisfactory to the therapy of PEIs. Nanomaterials with remarkable antibacterial properties and good biocompatibility have been developed as a promising strategy for removing pathogenic bacteria and related biofilm. Herein, carbon dots (CDs) derived from fucoidan (FD) are prepared through a one-pot hydrothermal method for the treatment of PEIs. The prepared FDCDs (7.15 nm) with sulfate groups and fluorescence property are well dispersed and stable in water. Further, it is found that in vitro FDCDs display excellent inhibiting effects on E. faecalis and its biofilm by inducing the formation of intracellular and extracellular reactive oxygen species and altering bacterial permeability. Importantly, the FDCDs penetrated the root canals and dentinal tubules, removing located E. faecalis biofilm. Moreover, the cellular assays show that the developed FDCDs have satisfactory cytocompatibility and promote macrophage recruitment. Thus, the developed FDCDs hold great potential for the management of PEIs. Graphical Abstract

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Excellent chemical stability, good corrosion resistance, and compositional controllability make vitrified enamel promising coating materials. The corrosion resistance of the [–Si–O–]/[–Si–O–Al–]‐based enamel coatings decreases in alkaline environments, whereas can be improved by incorporating metal oxides, such as ZrO2 and SnO2. The introduction of these oxides results in an increase in the sintering temperature and a decrease in the toughness of the coatings. It was observed that the corrosion resistance of the coatings in an alkaline medium could be improved using metal powder‐based additives without increasing the sintering temperature and affecting the mechanical properties of the coatings. We used powdered 316L stainless steel as the mill additive, and the effects of this additive on the structure and alkali corrosion resistance of the vitrified enamel coatings were studied. Results indicate that the addition of an appropriate quantity of the additive (4 wt.%) improves the extent of gas consumption during the enamel sintering, decreases the degree of porosity and the size of the pores. Furthermore, the mechanical properties of the skeleton formed between the pores could be improved, because blocklike corrosion products are not peeled off, which increases the corrosion resistance of the coatings. The corrosion products, such as Ca‐based compounds, block the corrosion holes, resulting in a decrease in the corrosion rate also.