Association of polymicrobial interactions with dental caries development and prevention

Synthesis of novel silver-loaded clay AgF@Hec for the prevention of dental cariesin vitro

Dental caries, a chronic infectious disease characterized by tooth mineral loss caused by plaque, is one of the major global public health problems. Silver diamine fluoride (SDF) has been proven to be a highly effective anti-caries drug due to its high bacterial inhibition and remineralization ability. However, the SDF solution is unstable, which immensely limits its clinical application. Therefore, new silver-load clay named AgF@Hec was designed by replacing the NH3with hectorite in this study. Fourier transform infrared spectroscopy and x-ray diffraction spectroscopy were employed to confirm the structure of AgF@Hec. Dynamic light scattering analysis was used to reveal the effect of different hectorite concentrations on the stability of AgF@Hec. Moreover, AgF@Hec exhibits significant remineralization and hardness recovery of the initial carious lesions. Bacteriostatic experiments also proved that it has a significant inhibitory effect onA. Viscosus, S. mutans, S. sanguinis, S. salivarius, Lactobacillus sp.and both gram-positive and gram-negative bacteria. We therefore believed that AgF@Hec should be a promising biomaterial that can be applied in the prevention of dental caries.

Plant-Derived Compounds: A Promising Tool for Dental Caries Prevention

There is a growing shift from the use of conventional pharmaceutical oral care products to the use of herbal extracts and traditional remedies in dental caries prevention. This is attributed to the potential environmental and health implications of contemporary oral products. This comprehensive review aims at the analysis of plant-derived compounds as preventive modalities in dental caries research. It focuses on data collected from 2019 until recently, trying to emphasize current trends in this topic. The research findings suggest that several plant-derived compounds, either aqueous or ethanolic, exhibit notable antibacterial effects against Streptococcus mutans and other bacteria related to dental caries, with some extracts demonstrating an efficacy comparable to that of chlorhexidine. Furthermore, in vivo studies using plant-derived compounds incorporated in food derivatives, such as lollipops, have shown promising results by significantly reducing Streptococcus mutans in high-risk caries children. In vitro studies on plant-derived compounds have revealed bactericidal and bacteriostatic activity against S. mutans, suggesting their potential use as dental caries preventive agents. Medicinal plants, plant-derived phytochemicals, essential oils, and other food compounds have exhibited promising antimicrobial activity against oral pathogens, either by their anti-adhesion activity, the inhibition of extracellular microbial enzymes, or their direct action on microbial species and acid production. However, further research is needed to assess their antimicrobial activity and to evaluate the cytotoxicity and safety profiles of these plant-derived compounds before their widespread clinical use can be recommended.

Oxidative Stress and Natural Products in Orthodontic Treatment: A Systematic Review

In recent years, orthodontics, a specialized branch of dentistry, has evolved considerably in terms of both techniques and materials used. Aimed at correcting dental malocclusions and craniofacial anomalies, it improves the functionality and aesthetics of the face and oral cavity. However, orthodontic treatment, in its developmental stages, may induce oxidative stress (O.S.) phenomena, with an increase in the production of reactive oxygen species (ROS), damaging the dental and periodontal tissues involved, affecting the short-, medium- and long-term results. Studies on the antioxidant effects of natural products (e.g., resveratrol, green tea, turmeric, etc.) in the medical field have aroused considerable interest in recent years. A systematic literature review was conducted on the PubMed, Scopus, and Web of Science databases using natural products (N.P.s), O.S., and orthodontic as keywords. The study aims to consider the determinants of the increase in ROS occurring during orthodontic treatment and the possibility of natural products being able to control and neutralize biochemical phenomena by restoring the physiological process in which the balance between the production of ROS and the ability of the body's antioxidant system to neutralize them is in favor of the latter.

A Comprehensive Evaluation of Zirconia-Reinforced Glass Ionomer Cement's Effectiveness in Dental Caries: A Systematic Review and Network Meta-Analysis

Dental cements are in a constant state of evolution, adapting to better align with the intricacies of tooth structure and the dynamic movements within the oral cavity. This study aims to evaluate the efficacy of zirconia-reinforced glass ionomer cement-an innovative variant of modified glass ionomer cements-in terms of its ability to withstand compressive forces and prevent microleakage during dental caries reconstruction. An extensive search was conducted across various databases, encompassing PubMed-MEDLINE, Scopus, Embase, Google Scholar, prominent journals, unpublished studies, conference proceedings, and cross-referenced sources. The selected studies underwent meticulous scrutiny according to predetermined criteria, followed by the assessment of quality and the determination of evidence levels. In total, 16 studies were incorporated into this systematic review and network meta-analysis (NMA). The findings suggest that both compomer and giomer cements exhibit greater compressive strength and reduced microleakage values than zirconia-reinforced glass ionomer cement. In contrast, resin-modified glass ionomer cement (RMGIC) and high-viscosity glass ionomer cement (GIC) demonstrate less favorable performance in these regards when compared with zirconia-reinforced glass ionomer cement.

A Re-Purposing Strategy: Sub-Lethal Concentrations of an Eicosanoid Derived from the Omega-3-Polyunsaturated Fatty Acid Resolvin D1 Affect Dual Species Biofilms

The fungal species Candida parapsilosis and the bacterial species Staphylococcus aureus may be responsible for hospital-acquired infections in patients undergoing invasive medical interventions or surgical procedures and often coinfect critically ill patients in complicating polymicrobial biofilms. The efficacy of the re-purposing therapy has recently been reported as an alternative to be used. PUFAs (polyunsaturated fatty acids) may be used alone or in combination with currently available traditional antimicrobials to prevent and manage various infections overcoming antimicrobial resistance. The objectives of the study were to evaluate the effects of Resolvin D1 (RvD1) as an antimicrobial on S. aureus and C. parapsilosis, as well as the activity against the mixed biofilm of the same two species. Microdilution assays and time-kill growth curves revealed bacterial and fungal inhibition at minimum concentration values between 5 and 10 μg mL-1. In single-species structures, an inhibition of 55% and 42% was reported for S. aureus and C. parapsilosis, respectively. Moreover, RvD1 demonstrated an eradication capacity of 60% and 80% for single- and mixed-species biofilms, respectively. In association with the inhibition activity, a downregulation of genes involved in biofilm formation as well as ROS accumulation was observed. Eradication capability was confirmed also on mature mixed biofilm grown on silicone platelets as shown by scanning electron microscopy (SEM). In conclusion, RvD1 was efficient against mono and polymicrobial biofilms in vitro, being a promising alternative for the treatment of mixed bacterial/fungal infections.

A Transcriptional Analysis Showing the Effects of GH12 Combined with Fluoride for Suppressing the Acidogenicity of Streptococcus mutans Biofilms

The acidogenicity of Streptococcus mutans is important for caries development. The antimicrobial peptide GH12 can affect the integrity of cellular membranes and the virulence factors of S. mutans. Combining GH12 and NaF (GF) efficiently controlled the development of caries, but its mechanisms remained unrevealed. This research intended to verify the effects of GF on the acidogenicity of S. mutans biofilms and to reveal the mechanisms. Lactic acid production assays and pH monitoring assays were conducted to investigate the regulatory effects of the GF treatment on the acidogenicity of S. mutans biofilms. RNA sequencing and bioinformatics analyses were conducted to screen the transcriptional profile affected by the GF treatment. The results demonstrated the GF group had significantly less lactic acid and maintained the broth's pH values above 5.0 for longer times. Thereafter, GO/KEGG enrichment analyses and RT-qPCR validation revealed that the GF treatment mainly restrained the expression of genes related to the carbohydrates' internalization and metabolism. Compared with NaF, the GF treatment further downregulated the carbohydrates transportation genes. Moreover, compared with GH12, the GF treatment affected the membrane's integrity more significantly. Generally, GF treatment could arrest the acidogenicity of S. mutans biofilms, mainly through suppressing carbohydrates transportation and inhibiting overall metabolism.