Competitive dynamics and balance between Streptococcus mutans and commensal streptococci in oral microecology.

Dental caries, as a biofilm-related disease, is closely linked to dysbiosis in microbial ecology within dental biofilms. Beyond its impact on oral health, bacteria within the oral cavity pose systemic health risks by potentially entering the bloodstream, thereby increasing susceptibility to bacterial endocarditis, among other related diseases. Streptococcus mutans, a principal cariogenic bacterium, possesses virulence factors crucial to the pathogenesis of dental caries. Its ability to adhere to tooth surfaces, produce glucans for biofilm formation, and metabolize sugars into lactic acid contributes to enamel demineralization and the initiation of carious lesions. Its aciduricity and ability to produce bacteriocins enable a competitive advantage, allowing it to thrive in acidic environments and dominate in changing oral microenvironments. In contrast, commensal streptococci, such as Streptococcus sanguinis, Streptococcus gordonii, and Streptococcus salivarius, act as primary colonizers and compete with S. mutans for adherence sites and nutrients during biofilm formation. This competition involves the production of alkali, peroxides, and antibacterial substances, thereby inhibiting S. mutans growth and maintaining microbial balance. This dynamic interaction influences the balance of oral microbiota, with disruptions leading to shifts in microbial composition that are marked by rapid increases in S. mutans abundance, contributing to the onset of dental caries. Thus, understanding the dynamic interactions between commensal and pathogenic bacteria in oral microecology is important for developing effective strategies to promote oral health and prevent dental caries. This review highlights the roles and competitive interactions of commensal bacteria and S. mutans in oral microecology, emphasizing the importance of maintaining oral microbial balance for health, and discusses the pathological implications of perturbations in this balance.

Roles of DNA methylation in influencing the functions of dental-derived mesenchymal stem cells.

OBJECTIVE: DNA methylation as intensively studied epigenetic regulatory mechanism exerts pleiotropic effects on dental-derived mesenchymal stem cells (DMSCs). DMSCs have self-renewal and multidifferentiation potential. Here, this review aims at summarizing the research status about application of DMSCs in tissue engineering and clarifying the roles of DNA methylation in influencing the functions of DMSCs, with expectation of paving the way for its in-depth exploration in tissue engineering. METHOD: The current research status about influence of DNA methylation in DMSCs was acquired by MEDLINE (through PubMed) and Web of Science using the keywords 'DNA methylation', 'dental-derived mesenchymal stem cells', 'dental pulp stem cells', 'periodontal ligament stem cells', 'dental follicle stem cells', 'stem cells from the apical papilla', 'stem cells from human exfoliated deciduous teeth', and 'gingival-derived mesenchymal stem cells'. RESULTS: This review indicates DNA methylation affects DMSCs' differentiation and function through inhibiting or enhancing the expression of specific gene resulted by DNA methylation-related genes or relevant inhibitors. CONCLUSION: DNA methylation can influence DMSCs in aspects of osteogenesis, adipogenesis, immunomodulatory function, and so on. Yet, the present studies about DNA methylation in DMSCs commonly focus on dental pulp stem cells (DPSCs) and periodontal ligament stem cells (PDLSCs). Little has been reported for other DMSCs.

Clinical validation of near-infrared imaging for early detection of proximal caries in primary molars.

OBJECTIVES: The aim of this study was to validate the near-infrared imaging (NIRI) in comparison with visual inspection (VI) for early detection of proximal caries in primary molars. METHODS: VI and intraoral scans were performed on 126 patients aged 3-12 years with at least one non-cavitied and non-restored proximal tooth surface, who were scheduled for bite wing radiography (BWR) as part of their standard care. Teeth with signs of proximal cavities, restorations or residual caries were excluded in this study. BWR, a gold standard to diagnose proximal caries in primary molars, was used to validate the findings of NIRI and VI. The accuracy, sensitivity, specificity and the area under the curve (AUC) of NIRI and VI were calculated. RESULTS: The accuracy, sensitivity and specificity of NIRI were 82.89%, 74.10% and 90.97%, while those of VI were 71.64%, 43.88% and 97.14%, respectively. NIRI showed higher accuracy and sensitivity, and lower specificity (P < 0.001). The AUC of NIRI was higher than that of VI (0.826 vs 0.706; P < 0.05). CONCLUSIONS: NIRI showed higher sensitivity and lower specificity compared with VI when detecting proximal caries in primary molars. Therefore, it is recommended to use NIRI in combination with BWR to improve the detection rate of proximal caries in primary molars. CLINICAL SIGNIFICANCE: In children, there is a high incidence of proximal caries in primary molars, which require high technical sensitivity for detection. NIRI shows high sensitivity in detecting proximal caries, which may improve their detection rate in primary molars. THE CLINICAL TRIAL REGISTRATION NUMBER: ChiCTR2300070916.

Molecularly imprinted polymers-coated magnetic covalent organic frameworks for efficient solid-phase extraction of sulfonamides in fish.

In this study, covalent organic frameworks (COFs) were grown in situ on magnetic nitrogen-doped graphene foam (MNGF), and the resulting composite of COFs-modified MNGF (MNC) was wrapped by molecularly imprinted polymers (MNC@MIPs) for specifically capturing SAs. A magnetic solid phase extraction (MSPE) method for SAs was established using MNC@MIPs with good magnetic responsiveness. The adsorption performance of MNC@MIPs was superior to that of non-molecularly imprinted polymers (MNC@NIPs), with shorter adsorption/desorption time and higher imprinting factors. A high-efficiency SAs analytical method was developed by fusing HPLC and MNC@MIPs-based MSPE. This approach provides excellent precision, a low detection limit, and wide linearity. By analyzing fish samples, the feasibility of the approach was confirmed, with SAs recoveries and relative standard deviations in spiked samples in the ranges of 77.2-112.7 % and 2.0-7.2 %, respectively. This study demonstrated the potential use of MNC@MIPs-based MSPE for efficient extraction and quantitation of trace hazards in food.