The main features of early caries are the massive colonization of cariogenic bacteria and demineralization of tooth enamel by the acids that they produce. Owing to the lack of effective treatments, the development of anticaries therapeutics with both antimicrobial and remineralizing properties is urgently required. Black phosphorus nanosheets (BPNs) are ideal therapeutics for the treatment of early caries because they can mediate photothermal antibacterial activity and subsequently promote remineralization by generating PO₄³⁻. However, the dynamic and wet environment of the oral cavity prevents the long‐term adhesion of BPNs to the tooth surface. In this study, using catechol‐modified chitosan and PLGA‐PEG‐PLGA as raw materials, a mussel‐inspired versatile hydrogel, BP@CP5, is presented that can be used to physically load BPNs. BP@CP5 has exceptional injectability and can firmly adhere to tooth surfaces for up to 24 h. Upon irradiation, BP@CP5 can quickly eliminate ≈99% of Streptococcus mutans and Streptococcus sanguinis; furthermore, the PO₄³⁻ generated via degradation also promotes rapid remineralization of enamel slabs. Importantly, the vivo rodent caries modeling results further confirm the excellent caries‐prevention properties of BP@CP5. This study demonstrates that BP@CP5 is a promising anticaries material for caries management.

Background: The main issues faced during the treatment of apical periodontitis are the management of bacterial infection and the facilitation of the repair of alveolar bone defects to shorten disease duration. Conventional root canal irrigants are limited in their efficacy and are associated with several side effects. This study introduces a synergistic therapy based on nitric oxide (NO) and antimicrobial photodynamic therapy (aPDT) for the treatment of apical periodontitis. Results: This research developed a multifunctional nanoparticle, CGP, utilizing guanidinylated poly (ethylene glycol)-poly (ε-Caprolactone) polymer as a carrier, internally loaded with the photosensitizer chlorin e6. During root canal irrigation, the guanidino groups on the surface of CGP enabled effective biofilm penetration. These groups undergo oxidation by hydrogen peroxide in the aPDT process, triggering the release of NO without hindering the production of singlet oxygen. The generated NO significantly enhanced the antimicrobial capability and biofilm eradication efficacy of aPDT. Furthermore, CGP not only outperforms conventional aPDT in eradicating biofilms but also effectively promotes the repair of alveolar bone defects post-eradication. Importantly, our findings reveal that CGP exhibits significantly higher biosafety compared to sodium hypochlorite, alongside superior therapeutic efficacy in a rat model of apical periodontitis. Conclusions: This study demonstrates that CGP, an effective root irrigation system based on aPDT and NO, has a promising application in root canal therapy.

To investigate the effects of ficin on biofilm formation of conditionally cariogenic Streptococcus mutans (S. mutans). Biomass and metabolic activity of biofilm were assessed using crystal violet assay, colony‐forming unit (CFU) counting, and MTT assay. Extracellular polysaccharide (EPS) synthesis was displayed by SEM imaging, bacteria/EPS staining, and anthrone method while acid production was revealed by lactic acid assay. Growth curve and live/dead bacterial staining were conducted to monitor bacterial growth state in both planktonic and biofilm form. Total protein and extracellular proteins of S. mutans biofilm were analyzed by protein/bacterial staining and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE), severally. qRT‐PCR was conducted to detect acid production, acid tolerance, and biofilm formation associated genes. Crystal violet assay, CFU counting, and MTT assay showed that the suppression effect of ficin on S. mutans biofilm formation was concentration dependent. 4 mg/mL ficin had significant inhibitory effect on S. mutans biofilm formation including biomass, metabolic activity, EPS synthesis, and lactic acid production (p < 0.05). The growth curves from 0 mg/mL to 4 mg/mL ficin were aligned with each other. There was no significant difference among different ficin groups in terms of live/dead bacterial staining result (p > 0.05). Protein/bacterial staining outcome indicated that ficin inhibit both total protein and biofilm formation during the biofilm development. There were more relatively small molecular weight protein bands in extracellular proteins of 4 mg/mL ficin group when compared with the control. Generally, ficin could inhibit biofilm formation and reduce cariogenic virulence of S. mutans effectively in vitro; thus, it could be a potential anticaries agent.