Antibodies generated against dextransucrase exhibit potential anticariostatic properties in Streptococcus mutans

Photocatalytic TiO2/HAP nanocomposite for antimicrobial treatment, promineralization, and tooth whitening

Early dental caries and tooth staining are prevalent clinical conditions, so it is of great clinical significance to develop a multifunctional material. Photocatalytic therapies play a significant role in the medical field. However, the use of photocatalytic materials in the dental field is relatively limited. In this study, multifunctional titanium dioxide/nanohydroxyapatite (TiO2/HAP) nanocomposites were synthesised using a hydrothermal method and investigated for their antibacterial properties, mineralization-promoting effects, tooth whitening capabilities, and biocompatibility. TiO2 serves as a photocatalyst, facilitating antimicrobial treatment and improving teeth whitening through a photodynamic reaction. HAP, as a mineralization-promoting agent, effectively promotes enamel remineralization following plaque removal. The results of the whitening experiment indicated after treatment by TiO2/HAP combined with blue light irradiation, the tooth color improved from C4 to A1. In a rat molar model of early caries, TiO2/HAP effectively removed dental plaque and increased the calcium-to-phosphorus ratio to 1.58, further validating the results of the microhardness test. Meanwhile, TiO2/HAP nanocomposites demonstrated good biocompatibility in vivo and did not significantly alter the oral microbial community. The results indicate that TiO2/HAP plays a significant role in antimicrobial activity, remineralization, and tooth whitening, offering a novel strategy for the prevention and treatment of early caries and tooth staining.

Immunoinformatics Design of a Multiepitope Vaccine (MEV) Targeting Streptococcus mutans: A Novel Computational Approach

Dental caries, a persistent oral health challenge primarily linked to Streptococcus mutans, extends its implications beyond dental decay, affecting over 4 billion individuals globally. Despite its historical association with childhood, dental caries often persists into adulthood with prevalence rates ranging from 60 to 90% in children and 26 to 85% in adults. Currently, there is a dearth of multiepitope vaccines (MEVs) specifically designed to combat S. mutans. To address this gap, we employed an immunoinformatics approach for MEV design, identifying five promising vaccine candidates (PBP2X, PBP2b, MurG, ATP-F, and AGPAT) based on antigenicity and conservation using several tools including CELLO v.2.5, Vaxign, v2.0, ANTIGENpro, and AllerTop v2.0 tools. Subsequent identification of linear B-cell and T-cell epitopes by SVMTrip and NetCTL/NetMHC II tools, respectively, guided the construction of a MEV comprising 10 Cytotoxic T Lymphocyte (CTL) epitopes, 5 Helper T Lymphocyte (HTL) epitopes, and 5 linear B-cell epitopes, interconnected by suitable linkers. The resultant MEV demonstrated high antigenicity, solubility, and structural stability. In silico immune simulations showcased the MEV's potential to elicit robust humoral and cell-mediated immune responses. Molecular docking studies revealed strong interactions between the MEV construct and Toll-Like Receptors (TLRs) and Major Histocompatibility Complex (MHC) molecules. Remarkably, the MEV-TLR-4 complexes exhibited a low energy score, high binding affinity, and a low dissociation constant. The Molecular Dynamic (MD) simulation analysis suggested that MEV-TLR-4 complexes had the highest stability and minimal conformational changes indicating equilibrium within 40 nanosecond time frames. Comprehensive computational analyses strongly support the potential of the proposed MEV to combat dental caries and associated infections. The study's computational assays yielded promising results, but further validation through in vitro and in vivo experiments is needed to assess its efficacy and safety.

Mechanistic insights into the inhibitory effect of theaflavins on virulence factors production in Streptococcus mutans

Streptococcus mutans is the primary etiological agent associated with cariogenic process. The present study aimed to investigate the antibacterial and anti-virulence activities of theaflavins (TFs) to Streptococcus mutans UA159 as well as the underlying mechanisms. The results showed that TFs were capable of suppressing the acid production, cell adherence, water-insoluble exopolysaccharides production, and biofilm formation by S. mutans UA159 with a dosage-dependent manner while without influencing the cell growth. By a genome-wide transcriptome analysis (RNA-seq), we found that TFs attenuated the biofilm formation of S. mutans UA159 by inhibiting glucosyltransferases activity and the production of glucan-binding proteins (GbpB and GbpC) instead of directly blocking the expression of genes coding for glucosyltransferases. Further, TFs inhibited the expression of genes implicated in peptidoglycan synthesis, glycolysis, lipid synthesis, two-component system, signaling peptide transport (comA), oxidative stress response, and DNA replication and repair, suggesting that TFs suppressed the virulence factors of S. mutans UA159 by affecting the signal transduction and cell envelope stability, and weakening the ability of cells on oxidative stress resistance. In addition, an upregulated expression of the genes involved in protein biosynthesis, amino acid metabolism, and transport system upon TFs treatment indicated that cells increase the protein synthesis and nutrients uptake as one self-protective mechanism to cope with stress caused by TFs. The results of this study increase our current understanding of the anti-virulence activity of TFs on S. mutans and provide clues for the use of TFs in the prevention of dental caries.

Insight into status of dental caries vaccination: A review

Despite advances in the 21st century, dental caries still remains to be one of the most common infectious diseases. Its prevalence was confirmed by the World Health Organization and affirms dental caries as a major health problem in all over the world. Even though the process of tooth decay is multifactorial, the oral bacteria, mutans streptococci, such as Streptococcus mutans and Streptococcus sobrinus, are considered to be causative agents of dental caries in human. Numerous studies carried out on animals and various categories of vaccines were developed such as whole cell vaccine, subunit vaccine, and synthetic peptides. Irrespective of success from active and passive immunization based on animal trials, it is the phenomenon of human heart reactivity that limited the applicability of these trials in humans. Continuous efforts are being made to overcome these limitations and for further success in human trials. With the advent of various antibodies against antigens of mutans streptococci, local passive immunization has become the safer approach in humans against the colonization of bacteria and caries induction. This review provided insight into epidemiology, active and passive immunization in both animal and human trials, as well as the prospects of caries vaccination.