Current State and Challenges of the Global Outcomes of Dental Caries Research in the Meta-Omics Era

Evaluation of REFIX Technology on the Remineralization of Artificial Early Enamel Caries Lesion by Laser Speckle Tracking Analysis

OBJECTIVE

To assess the effectiveness of the REFIX technology in the remineralization process of initial caries simulated on bovine enamel. The assessment involved the analysis of backscatter intensity, which was determined from laser speckle images.

METHOD

Twenty-one bovine teeth were divided into three groups: G1 and G7 were submitted to treatment with the REFIX technology for 1 and 7 days, respectively. The control group was treated with deionized water.

RESULTS

A significant difference in backscatter was found between the carious and sound areas in all groups (p = 0.0038, p < 0.0001, and p = 0.0002 for the control group, G1, and G7, respectively). The intergroup comparison revealed no significant difference among the groups studied.

CONCLUSION

REFIX technology did not alter the optical properties of the samples of bovine teeth with simulated initial caries lesions after 1 and 7 days of treatment.

Prevalence of rapid calculus formers and its associated factors amongst patients visiting a dental hospital: a preliminary investigation

BACKGROUND

This study focuses on the determination and classification of patients as rapid or slowcalculusformersbasedontherateofcalculusformationafteroralprophylaxis. It also aims to determine the factors that positively impact the formation and deposition of calculus in patients and identify the factors that accelerate or decelerate the deposition of calculus.

METHODS

The study was conducted in the Department of Periodontology, Dr Harvansh Singh Judge Institute of Dental Sciences and Hospital, Panjab University Chandigarh, India. We examined 51 patients after a month of the oral prophylaxis, recorded the amount of calculus present in the oral cavity, and then recorded a detailed history which was briefly divided into Age, Sex, Residence, Oral habits, and maintenance of oral hygiene.

RESULTS

An evident and meaningful link was found between age and the rate at which dental calculus forms. The average age of individuals differed significantly between the rapid and slow calculus formers, which could be ascribed to the decline in manual dexterity as age increases, resulting in less effective oral hygiene habits, including toothbrushing. None of the other factors dietary and oral hygiene related could be identified distinctly, probably owing to the small sample of the study. The oral health status exhibited a significant difference between slow and rapid calculus formers.

CONCLUSIONS

Within the limitations of the study, the data analyzed, identified age as a significant determinant that impact the rate of formation of calculus in patients and reported a significant difference in the oral health status of rapid and slow calculus formers.

Mass spectrometry-based proteomic approaches for salivary protein biomarkers discovery and dental caries diagnosis: A critical review

Dental caries is a multifactorial chronic disease resulting from the intricate interplay among acid-generating bacteria, fermentable carbohydrates, and several host factors such as saliva. Saliva comprises several proteins which could be utilized as biomarkers for caries prevention, diagnosis, and prognosis. Mass spectrometry-based salivary proteomics approaches, owing to their sensitivity, provide the opportunity to investigate and unveil crucial cariogenic pathogen activity and host indicators and may demonstrate clinically relevant biomarkers to improve caries diagnosis and management. The present review outlines the published literature of human clinical proteomics investigations on caries and extensively elucidates frequently reported salivary proteins as biomarkers. This review also discusses important aspects while designing an experimental proteomics workflow. The protein-protein interactions and the clinical relevance of salivary proteins as biomarkers for caries, together with uninvestigated domains of the discipline are also discussed critically.

Exploring Salivary Metabolic Alterations in Type 2 Diabetes: Implications for Dental Caries and Potential Influences of HbA1c and Vitamin D Levels

Diabetes mellitus is considered to be the most common health issue affecting almost 1 in 11 adults globally. Oral health complications including xerostomia, periodontal disease, dental caries, and soft tissue lesions are prevalent among individuals with diabetes, and therefore an understanding of the potential association between salivary metabolites and dental caries progression would enable the early detection and prevention of this non-communicable disease. Therefore, the aim of this study was to compare salivary biomarkers between individuals with type 2 diabetes (T2DM) with those without this disorder (ND) using 1H NMR-based metabolomics strategies. The objectives were to identify T2DM-associated biomarker signatures and their potential impact on dental caries. In addition, HbA1c and vitamin D levels were also analysed for this purpose.

METHODS

Stimulated whole-mouth saliva (SWS) samples were collected from T2DM and ND (n = 30 in each case) participants randomly selected from a group of 128 participants recruited for this case-control study. All participants were advised to refrain from eating, drinking, and smoking for at least 1-2 h prior to sample collection. Following preparation, SWS supernatants underwent 1H NMR analysis at an operating frequency of 800 MHz, and the dataset acquired was analysed using a range of multivariate metabolomics techniques.

RESULTS

Metabolomics analysis of data acquired demonstrated that, together with up- and downregulated blood HbA1c and vitamin D levels, key salivary discriminators between these two classifications included lactate, taurine, creatinine, α-glucose, and formate to a lesser extent. The bacterial catabolites lactate and formate were both significantly upregulated in the T2DM group, and these have previously been implicated in the pathogenesis of dental caries. Significance analysis of metabolites (SAM)-facilitated AUROC analysis yielded an 83% accuracy for this distinction.

CONCLUSION

In conclusion, this study highlights the significant differences in salivary metabolites between individuals with T2DM and healthy controls. Such differences appear to be related to the development and progression of dental caries in T2DM patients.

Metabolomics for dental caries diagnosis: Past, present, and future

Dental caries, a prevalent global infectious condition affecting over 95% of adults, remains elusive in its precise etiology. Addressing the complex dynamics of caries demands a thorough exploration of taxonomic, potential, active, and encoded functions within the oral ecosystem. Metabolomic profiling emerges as a crucial tool, offering immediate insights into microecosystem physiology and linking directly to the phenotype. Identified metabolites, indicative of caries status, play a pivotal role in unraveling the metabolic processes underlying the disease. Despite challenges in metabolite variability, the use of metabolomics, particularly via mass spectrometry and nuclear magnetic resonance spectroscopy, holds promise in caries research. This review comprehensively examines metabolomics in caries prevention, diagnosis, and treatment, highlighting distinct metabolite expression patterns and their associations with disease-related bacterial communities. Pioneering in approach, it integrates singular and combinatory metabolomics methodologies, diverse biofluids, and study designs, critically evaluating prior limitations while offering expert insights for future investigations. By synthesizing existing knowledge, this review significantly advances our comprehension of caries, providing a foundation for improved prevention and treatment strategies.

Progression from healthy periodontium to gingivitis and periodontitis: Insights from bioinformatics-driven proteomics - A systematic review with meta-analysis

AIM

The current study aimed to: (1) systematically review the published literature regarding the proteomics analyses of saliva and gingival crevicular fluid (GCF) in healthy humans and gingivitis and/or periodontitis patients; and (2) to identify the differentially expressed proteins (DEPs) based on the systematic review, and comprehensively conduct meta-analyses and bioinformatics analyses.

METHODS

An online search of Web of Science, Scopus, and PubMed was performed without any restriction on the year and language of publication. After the identification of the DEPs reported by the included human primary studies, gene ontology (GO), the Kyoto encyclopedia of genes and genomes pathway (KEGG), protein-protein interaction (PPI), and meta-analyses were conducted. The risk of bias among the included studies was evaluated using the modified Newcastle-Ottawa quality assessment scale.

RESULTS

The review identified significant differences in protein expression between healthy individuals and those with gingivitis and periodontitis. In GCF, 247 proteins were upregulated and 128 downregulated in periodontal diseases. Saliva analysis revealed 79 upregulated and 70 downregulated proteins. There were distinct protein profiles between gingivitis and periodontitis, with 159 and 31 unique upregulated proteins in GCF, respectively. Meta-analyses confirmed significant upregulation of various proteins in periodontitis, including ALB and MMP9, while CSTB and GSTP1 were downregulated. AMY1A and SERPINA1 were upregulated in periodontitis saliva. HBD was upregulated in gingivitis GCF, while DEFA3 was downregulated. PPI analysis revealed complex networks of interactions among DEPs. GO and KEGG pathway analyses provided insights into biological processes and pathways associated with periodontal diseases.

CONCLUSION

The ongoing MS-based proteomics studies emphasize the need for a highly sensitive and specific diagnostic tool for periodontal diseases. Clinician acceptance of the eventual diagnostic method relies on its ability to provide superior or complementary information to current clinical assessment procedures. Future research should prioritize the multiplex measurement of multiple biomarkers simultaneously to enhance diagnostic accuracy and large study cohorts are necessary to ensure the validity and reliability of research findings.

Effectiveness of a novel experimental herbal toothpaste against bacterial consortium associated with dental caries

Background

To evaluate the effectiveness of an experimental toothpaste based on Hypericum laricifolium Juss. essential oil against a bacterial consortium associated with dental caries.

Material and Methods

The antibacterial activity of the essential oil was evaluated by the disk diffusion and microdilution tests against Streptococcus mutans, Streptococcus sanguinis and Streptococcus salivarius. Petri dishes were incubated at 37°C for 24 h. An experimental toothpaste was prepared at a concentration of 201.76 mg/mL. The antibacterial activity of the experimental and six commercial toothpastes were evaluated by agar well-diffusion method. Petri dishes were inoculated with a bacterial consortium prepared with the three strains. 80 mg of the toothpastes were placed in the wells and the Petri dishes were incubated at 37°C for 24 h. The inhibition zones were measured with a digital compass. The differences between the pastas were evaluated with the one-way ANOVA test, with a 5% level of significance.

Results

The essential oil was more effective than 0.12% chlorhexidine in inhibiting the growth of S. mutans (29.02±1.74 mm) and S. sanguinis (21.92±3.43 mm), being more moderate for S. salivarius (17.66±1.11 mm) . In MBC tests, the EO showed complete inhibition of the growth of S. mutans at a concentration of 5% (50.44 mg/mL), 10% (100.88 mg/mL) for S. sanguinis and 2.5% (25.22 mg/mL) for S. salivarius. The experimental toothpaste was effective in inhibiting the growth of the bacterial consortium (31.88±66 mm), having a similar performance to Total Dent, Colgate Total 12, Kolynos® Herbal and Colgate® Herbal (p> 0.05).

Conclusions

The development of an experimental paste based on H. laricifolium Juss. essential oil (0.28% v/v) showed an important antibacterial activity similar to commercial toothpastes against a bacterial consortium of S. mutans, S. sanguinis and S. salivarius. Key words:Antibacterial agents, toothpastes, medicinal plants, Streptococcus mutans, Streptococcus sanguinis, Streptococcus salivarius.

Proteomic snapshot of saliva samples predicts new pathways implicated in SARS-CoV-2 pathogenesis

BACKGROUND

Information on the microbiome's human pathways and active members that can affect SARS-CoV-2 susceptibility and pathogenesis in the salivary proteome is very scarce. Here, we studied a unique collection of samples harvested from April to June 2020 from unvaccinated patients.

METHODS

We compared 10 infected and hospitalized patients with severe (n = 5) and moderate (n = 5) coronavirus disease (COVID-19) with 10 uninfected individuals, including non-COVID-19 but susceptible individuals (n = 5) and non-COVID-19 and nonsusceptible healthcare workers with repeated high-risk exposures (n = 5).

RESULTS

By performing high-throughput proteomic profiling in saliva samples, we detected 226 unique differentially expressed (DE) human proteins between groups (q-value ≤ 0.05) out of 3376 unambiguously identified proteins (false discovery rate ≤ 1%). Major differences were observed between the non-COVID-19 and nonsusceptible groups. Bioinformatics analysis of DE proteins revealed human proteomic signatures related to inflammatory responses, central cellular processes, and antiviral activity associated with the saliva of SARS-CoV-2-infected patients (p-value ≤ 0.0004). Discriminatory biomarker signatures from human saliva include cystatins, protective molecules present in the oral cavity, calprotectins, involved in cell cycle progression, and histones, related to nucleosome functions. The expression levels of two human proteins related to protein transport in the cytoplasm, DYNC1 (p-value, 0.0021) and MAPRE1 (p-value, 0.047), correlated with angiotensin-converting enzyme 2 (ACE2) plasma activity. Finally, the proteomes of microorganisms present in the saliva samples showed 4 main microbial functional features related to ribosome functioning that were overrepresented in the infected group.

CONCLUSION

Our study explores potential candidates involved in pathways implicated in SARS-CoV-2 susceptibility, although further studies in larger cohorts will be necessary.

Mass spectrometry-based proteomics profiling of dogs with and without oral diseases: a systematic review

BACKGROUND

Understanding the distinct proteomics profiles in dogs' oral biofluids enhances diagnostic and therapeutic insights for canine oral diseases, fostering cross-species translational research in dentistry and medicine. This study aimed to conduct a systematic review to investigate the similarities and differences between the oral biofluids' proteomics profile of dogs with and without oral diseases.

METHODS

PubMed, Web of Science, and Scopus were searched with no restrictions on publication language or year to address the following focused question: "What is the proteome signature of healthy versus diseased (oral) dogs' biofluids?" Gene Ontology enrichment and the Kyoto Encyclopedia of Genes and Genomes pathway analyses of the most abundant proteins were performed. Moreover, protein-protein interaction analysis was conducted. The risk of bias (RoB) among the included studies was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Studies Reporting Prevalence Data.

RESULTS

In healthy dogs, the proteomic analysis identified 5,451 proteins, with 137 being the most abundant, predominantly associated with 'innate immune response'. Dogs with oral diseases displayed 6,470 proteins, with distinct associations: 'defense response to bacterium' (periodontal diseases), 'negative regulation of transcription' (dental calculus), and 'positive regulation of transcription' (oral tumors). Clustering revealed significant protein clusters in each case, emphasizing the diverse molecular profiles in health and oral diseases. Only six studies were provided to the JBI tool, as they encompassed case-control evaluations that compared healthy dogs to dogs with oral disease(s). All included studies were found to have low RoB (high quality).

CONCLUSION

Significant differences in the proteomics profiles of oral biofluids between dogs with and without oral diseases were found. The synergy of animal proteomics and bioinformatics offers a promising avenue for cross-species research, despite persistent challenges in result validation.

Bridging the gap between omics research and dental practice

AIM

The burgeoning field of omics research has witnessed exponential growth in both medicine and dentistry. However, despite more than a decade of advancements, clinical dentistry, particularly in Low- and Middle-Income Countries (LMICs), has seen limited progress in integrating omics-based approaches into routine practice. This review aims to provide a comprehensive overview of the integration of omics approaches in dentistry, focusing on the challenges and opportunities for translating research findings into clinical practice.

METHODS

we conducted a literature review using key databases to provide a brief overview of the history of genomics in dentistry. Additionally, we summarised recent breakthroughs in omics relevant to oral health practitioners, emphasising the inadequate translation of omics research into clinical practice.

RESULTS

Despite significant growth in omics research in both medicine and dentistry, its translation into routine clinical practice in dentistry remains limited. We summarise recent breakthroughs in omics and highlight the gap between research advancements and clinical implementation.

DISCUSSION AND CONCLUSION

The integration of omics approaches holds promise for enhancing diagnostics, personalised treatment strategies, and preventive measures in dental practice, ushering in a new era of precision oral healthcare. However, several challenges, including infrastructure limitations, cost-effectiveness, and education gaps, hinder the widespread adoption of omics-based approaches in clinical dentistry. A strong commitment to transforming dentistry is required to embrace this transition. This shift has the potential to revolutionise oral healthcare by advancing precision diagnostics and treatment strategies tailored to individual patient needs.

Host-Guest Mechanism via Induced Fit Fullerene Complexation in Porphin Receptor to Probe Salivary Alpha-Amylase in Dental Caries for Clinical Applications

Salivary α-amylase is the most abundant protein of human saliva that potentially binds to streptococcus and other bacteria via specific surface-exposed α-amylase-binding proteins and plays a significant role in caries development. The detection of α-amylase in saliva can be used as a bioindicator of caries development. Herein, a facile strategy has been applied, tailoring the photochemical properties of 5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphine (TPPOH) and the fullerene C60 complex. The fluorescence emission of TPPOH is quenched by starch-coated fullerene C60 via charge-transfer effects, as determined by UV absorption and fluorescence spectroscopic studies. The starch-coated C60 has been thoroughly characterized via Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), optical microscopy, thermal gravimetric analysis (TGA), static water contact angle measurements, and zeta potential measurements. The analytical response of the assay showed a linear fluorescent response in α-amylase concentrations ranging from 0.001-0.1 Units/mL, with an LOD of 0.001 Units/mL. The applicability of the method was tested using artificial saliva with quantitative recoveries in the range 95-100%. The practicability of the procedure was verified by inspecting saliva samples of real clinical samples covering all age groups. We believe that the proposed method can serve as an alternative analytical method for caries detection and risk assessment that would also minimize the cost of professional preventive measures and treatments.

Application of omics technologies in cariology research: A critical review with bibliometric analysis

OBJECTIVES

To review the application of omics technologies in the field of cariology research and provide critical insights into the emerging opportunities and challenges.

DATA & SOURCES

Publications on the application of omics technologies in cariology research up to December 2022 were sourced from online databases, including PubMed, Web of Science and Scopus. Two independent reviewers assessed the relevance of the publications to the objective of this review.

STUDY SELECTION

Studies that employed omics technologies to investigate dental caries were selected from the initial pool of identified publications. A total of 922 publications with one or more omics technologies adopted were included for comprehensive bibliographic analysis. (Meta)genomics (676/922, 73 %) is the predominant omics technology applied for cariology research in the included studies. Other applied omics technologies are metabolomics (108/922, 12 %), proteomics (105/922, 11 %), and transcriptomics (76/922, 8 %).

CONCLUSION

This study identified an emerging trend in the application of multiple omics technologies in cariology research. Omics technologies possess significant potential in developing strategies for the detection, staging evaluation, risk assessment, prevention, and management of dental caries. Despite the numerous challenges that lie ahead, the integration of multi-omics data obtained from individual biological samples, in conjunction with artificial intelligence technology, may offer potential avenues for further exploration in caries research.

CLINICAL SIGNIFICANCE

This review presented a comprehensive overview of the application of omics technologies in cariology research and discussed the advantages and challenges of using these methods to detect, assess, predict, prevent, and treat dental caries. It contributes to steering research for improved understanding of dental caries and advancing clinical translation of cariology research outcomes.

Salivary elemental signature of dental caries: a systematic review and meta-analysis of ionomics studies

Trace- and macro-chemical elements are crucial for cellular physiological functioning, and their alterations in biological fluids might be associated with an underlying pathological state. Hence, this study aimed to examine and summarize the published literature concerning the application of salivary ionomics for caries diagnosis. An extensive search of studies was conducted using PubMed, EMBASE, Web of Science, and Scopus, without any language and year restriction for answering the following PECO question: "In subjects (i.e., children, adolescents, or adults) with good systematic health, are there any variations in the salivary concentrations of trace- or macro-elements between caries-free (CF) individuals and caries-active (CA) subjects?" A modified version of the QUADOMICS tool was used to assess the quality of the included studies. The Review Manager Version 5.4.1. was used for data analyses. The analysis of salivary chemical elements that significantly differed between CF and CA subjects was also performed. Thirty-four studies were included, involving 2299 CA and 1669 CF subjects, having an age range from 3 to 64 years in over 16 countries. The meta-analysis revealed a statistically significant difference (p < 0.05) in the salivary levels of calcium, phosphorus, chloride, magnesium, potassium, sodium, and zinc between CA and CF subjects, suggesting higher levels of calcium, phosphorus, potassium, and sodium in CF subjects while higher levels of chloride, magnesium, and zinc in CA patients. Half of the included studies (17/34) were considered high quality, while the remaining half were considered medium quality. Only zinc and chloride ions were found to be higher significantly and consistent in CF and CA subjects, respectively. Conflicting outcomes were observed for all other salivary chemical elements including aluminum, bromine, calcium, copper, fluoride, iron, potassium, magnesium, manganese, sodium, ammonia, nitrite, nitrate, phosphorus, lead, selenium, and sulfate ions.

Illuminating the oral microbiome and its host interactions: recent advancements in omics and bioinformatics technologies in the context of oral microbiome research

The oral microbiota has an enormous impact on human health, with oral dysbiosis now linked to many oral and systemic diseases. Recent advancements in sequencing, mass spectrometry, bioinformatics, computational biology, and machine learning are revolutionizing oral microbiome research, enabling analysis at an unprecedented scale and level of resolution using omics approaches. This review contains a comprehensive perspective of the current state-of-the-art tools available to perform genomics, metagenomics, phylogenomics, pangenomics, transcriptomics, proteomics, metabolomics, lipidomics, and multi-omics analysis on (all) microbiomes, and then provides examples of how the techniques have been applied to research of the oral microbiome, specifically. Key findings of these studies and remaining challenges for the field are highlighted. Although the methods discussed here are placed in the context of their contributions to oral microbiome research specifically, they are pertinent to the study of any microbiome, and the intended audience of this includes researchers would simply like to get an introduction to microbial omics and/or an update on the latest omics methods. Continued research of the oral microbiota using omics approaches is crucial and will lead to dramatic improvements in human health, longevity, and quality of life.

A bibliometric analysis of the global impact of metaproteomics research

Background

Metaproteomics is a subfield in meta-omics that is used to characterize the proteome of a microbial community. Despite its importance and the plethora of publications in different research area, scientists struggle to fully comprehend its functional impact on the study of microbiomes. In this study, bibliometric analyses are used to evaluate the current state of metaproteomic research globally as well as evaluate the specific contribution of Africa to this burgeoning research area. In this study, we use bibliometric analyses to evaluate the current state of metaproteomic research globally, identify research frontiers and hotspots, and further predict future trends in metaproteomics. The specific contribution of Africa to this research area was evaluated.

Methods

Relevant documents from 2004 to 2022 were extracted from the Scopus database. The documents were subjected to bibliometric analyses and visualization using VOS viewer and Biblioshiny package in R. Factors such as the trends in publication, country and institutional cooperation networks, leading scientific journals, author's productivity, and keywords analyses were conducted. The African publications were ranked using Field-Weighted Citation Impact (FWCI) scores.

Results

A total of 1,138 documents were included and the number of publications increased drastically from 2004 to 2022 with more publications (170) reported in 2021. In terms of publishers, Frontiers in Microbiology had the highest number of total publications (62). The United States of America (USA), Germany, China, and Canada, together with other European countries were the most productive. Institution-wise, the Helmholtz Zentrum für Umweltforschung, Germany had more publications while Max Plank Institute had the highest total collaborative link strength. Jehmlich N. was the most productive author whereas Hettich RL had the highest h-index of 63. Regarding Africa, only 2.2% of the overall publications were from the continent with more publication outputs from South Africa. More than half of the publications from the continent had an FWCI score ≥ 1.

Conclusion

The scientific outputs of metaproteomics are rapidly evolving with developed countries leading the way. Although Africa showed prospects for future progress, this could only be accelerated by providing funding, increased collaborations, and mentorship programs.

Effect of silver diamine fluoride upon the microbial community of carious lesions: A scoping review

OBJECTIVES

To explore the effects of silver diamine fluoride (SDF) on the microbial community of carious lesions.

DATA

Original studies evaluating the effect of SDF treatment on the microbial community of human carious lesions were included.

SOURCES

A systematic search of English-language publications was performed in PubMed, EMBASE, Scopus, and Web of Science. Gray literature was searched in ClinicalTrials.gov and Google Scholar.

STUDY SELECTION/RESULTS

This review included seven publications reporting the effects of SDF on microbial community of dental plaque or carious dentin, including the microbial biodiversity, relative abundance of microbial taxa, and predicted functional pathways of the microbial community. The studies on microbial community of dental plaque reported that SDF did not have a significant effect on both the within-community species diversity (alpha-diversity) and inter-community microbial compositional dissimilarity (beta-diversity) of the plaque microbial communities. However, SDF changed the relative abundance of 29 bacterial species of plaque community, inhibited carbohydrate transportation and interfered with the metabolic functions of the plaque microbial community. A study on the microbial community in dentin carious lesions reported that SDF affected its beta-diversity and changed the relative abundance of 14 bacterial species.

CONCLUSION

SDF showed no significant effects on the biodiversity of the plaque microbial community but changed the beta-diversity of the carious dentin microbial community. SDF could change the relative abundance of certain bacterial species in the dental plaque and the carious dentin. SDF could also affect the predicted functional pathways of the microbial community.

CLINICAL SIGNIFICANCE

This review provided comprehensive evidence on the potential effect of SDF treatment on the microbial community of carious lesions.

Mechanistic Insights into Bioengineered Antibiofilm Enamel Pellicles

Dental caries remains the most widespread chronic disease worldwide. Basically, caries originates within biofilms accumulated on dental enamel. Despite the nonrenewable nature of the enamel tissue, targeted preventive strategies are still very limited. We previously introduced customized multifunctional proteinaceous pellicles (coatings) for controlling bacterial attachment and subsequent biofilm succession. Stemmed from our whole proteome/peptidome analysis of the in vivo acquired enamel pellicle, we designed these pellicles using hybrid mixtures of the most abundant and complementary-acting antimicrobial and antifouling proteins/peptides for synergetic suppression of early biofilms. In conjugating these domains synthetically, their bioinhibitory efficacy was remarkably boosted. Herein, we sought to explore the key structure-function relationship of these potent de novo hybridized conjugates in comparison with their individual domains, solely or in physical mixtures. Specifically, we interrelated the following facets: physicochemical and 3-dimensional folding characteristics via molecular dynamics simulations, adopted secondary structure by circular dichroism, immobilization capacity on enamel through high-spatial resolution multiphoton microscopy, and biofilm suppression potency. Our data showed consistent associations among the increased preference for protein folding structures, α-helix content, and enamel-immobilization capacity; all were inversely correlated with the attached bioburden. The expressed phenotypes could be explained by the adopted strongly amphipathic helical conformation upon conjugation, mediated by the highly anionic and acidic N-terminal pentapeptide shared region/motif for enhanced immobilization on enamel. In conclusion, conjugating bioactive proteins/peptides is a novel translational approach to engineer robust antibiofilm pellicles for caries prevention. The adopted α-helical conformation is key to enhance the antibiofilm efficacy and immobilization capacity on enamel that are promoted by certain physicochemical properties of the constituent domains. These data are valuable for bioengineering versatile therapeutics to prevent/arrest dental caries, a condition that otherwise requires invasive treatments with substantial health care expenditures.

Synchrotron X-ray Studies of the Structural and Functional Hierarchies in Mineralised Human Dental Enamel: A State-of-the-Art Review

Hard dental tissues possess a complex hierarchical structure that is particularly evident in enamel, the most mineralised substance in the human body. Its complex and interlinked organisation at the Ångstrom (crystal lattice), nano-, micro-, and macro-scales is the result of evolutionary optimisation for mechanical and functional performance: hardness and stiffness, fracture toughness, thermal, and chemical resistance. Understanding the physical-chemical-structural relationships at each scale requires the application of appropriately sensitive and resolving probes. Synchrotron X-ray techniques offer the possibility to progress significantly beyond the capabilities of conventional laboratory instruments, i.e., X-ray diffractometers, and electron and atomic force microscopes. The last few decades have witnessed the accumulation of results obtained from X-ray scattering (diffraction), spectroscopy (including polarisation analysis), and imaging (including ptychography and tomography). The current article presents a multi-disciplinary review of nearly 40 years of discoveries and advancements, primarily pertaining to the study of enamel and its demineralisation (caries), but also linked to the investigations of other mineralised tissues such as dentine, bone, etc. The modelling approaches informed by these observations are also overviewed. The strategic aim of the present review was to identify and evaluate prospective avenues for analysing dental tissues and developing treatments and prophylaxis for improved dental health.

Novel Lactotransferrin-Derived Antimicrobial Peptide LF-1 Inhibits the Cariogenic Virulence Factors of Streptococcus mutans

We previously developed a novel lactotransferrin-derived antimicrobial peptide, LF-1, with selective antibacterial activity against the characteristic cariogenic bacterium Streptococcus mutans. This study further investigated the effects of LF-1 on the cariogenic virulence factors of S. mutans and evaluated the changes in virulence-associated enzymes and genes; the viability, acidogenicity, and aciduricity of planktonic S. mutans; and initial colonisation and biofilm formation after treatment with LF-1. The method of qRT-PCR was used to evaluate S. mutans virulence-associated gene expression. LF-1 interfered with the cell viability of S. mutans within 6 h. LF-1 inhibited the acidogenicity and aciduricity of S. mutans, with reduced lactic acid production and survival in a lethal acidic environment, and inactivated lactate dehydrogenase and F1F0-ATPase activity. LF-1 decreased surface-adherent S. mutans within 60 min and inhibited S. mutans biofilm formation, where scanning electron microscopy and confocal laser scanning microscopy showed reduced extracellular matrix and bacteria. LF-1 downregulates S. mutans virulence-associated gene expression. LF-1 inhibited the growth and cariogenic virulence factors of S. mutans in vitro with a reduction in key enzymatic activity and downregulation of virulence-associated gene expression. LF-1 has promising application prospects in the fight against S. mutans and dental caries.

Photodynamic nano hydroxyapatite with biofilm penetration capability for dental plaque eradication and prevention of demineralization

Dental caries represents one of the most prevalent diseases worldwide, characteristic of the growth of dental plaque and demineralization of tooth enamel. Current medications for eradication of dental plaques and prevention of demineralization suffer from several limitations to overcome, calling for novel strategies with great potency in eliminating cariogenic bacteria and dental plaque that forms, as well as in inhibiting the demineralization of enamel, into an integrated system. Considering the potency of photodynamic therapy in bacteria inactivation and the composition of enamel, we herein report that the novel photodynamic nano hydroxyapatite (nHAP), named Ce6 @QCS/nHAP, was useful for this purpose. Ce6 @QCS/nHAP, comprised of quaternary chitosan (QCS)-coated nHAP loaded with chlorin e6 (Ce6), exhibited good biocompatibility and non-compromised photodynamic activity. In vitro studies revealed that Ce6 @QCS/nHAP could effectively associate with cariogenic Streptococcus mutans (S. mutans), leading to a significant antibacterial effect through photodynamic killing and physical inactivation against the planktonic microbe. Three-dimensional fluorescence imaging suggested that Ce6 @QCS/nHAP exhibited a superior S. mutans biofilm penetration capacity to free Ce6, resulting in effective dental plaque eradiation when light irradiation was applied. The number of surviving bacteria in biofilm was at least 2.8 log units lower in the Ce6 @QCS/nHAP group compared to that in the free Ce6 group. Further, in the S. mutans biofilm-infected artificial tooth model, treatment with Ce6 @QCS/nHAP also resulted in the significant prevention of hydroxyapatite disks from demineralization, with lower percentage of fragmentation and weight loss These data suggest that our photodynamic nanosystem can effectively eradicate dental plaque while also significantly protecting artificial tooth from demineralization, opening up new possibilities in treating bacterium-associated dental caries.

Dental caries experience among qat chewers in dental college clinics, Jazan, Saudi Arabia

AIMS

There is a considerable debate on the impact of qat chewing on dental and oral health. Thereby, this study aimed at assessing the dental caries among qat chewers (QC) and non-qat chewers (NQC) who attend outpatient dental clinics, College of Dentistry, Jazan, Saudi Arabia.

MATERIALS AND METHODS

A sample of 100 QC and 100 NQC were recruited amongst those attended dental clinics, college of dentistry, Jazan University during the 2018-2019 academic year. Their dental health was assessed by three pre-calibrated male interns using DMFT index. The Care Index, Restorative Index and Treatment Index were calculated. Comparisons between both subgroups were done using independent t test. Multiple linear regression analyses were further conducted to stand on the independent determinants of the oral health among this population.

RESULTS

QC were unintentionally older (36.55 ± 8.74 years) than NQC (32.96 ± 8.49 years; P = 0.004). Fifty-six percent of QC reported brushing their teeth compared to only 35% (P = 0.001). NQC with university and postgraduate educational levels were more than QC. The mean Decayed [5.91 (5.16)] and DMFT [9.15 (5.87)] were higher among QC compared to NQC [3.73 (3.62) and 6.7 (4.58); P = 0.001 and 0.001, respectively]. The other indices were not different between both subgroups. The multiple linear regression revealed that qat chewing and age, individually or together, as independent determinants for the dental decay, missing, DMFT and TI.

CONCLUSION

Qat chewing habit has a detrimental impact on dental health. It is associated with higher dental caries and missing teeth, and a lower treatment index.

Illuminating the oral microbiome and its host interactions: tools and approaches for molecular ecological studies

A more comprehensive understanding of oral diseases like caries and periodontitis is dependent on an intimate understanding of the microbial ecological processes that are responsible for disease development. With this review, we provide a comprehensive overview of relevant molecular ecology techniques that have played critical roles in the current understanding of human oral biofilm development, interspecies interactions, and microbiome biogeography. The primary focus is on relevant technologies and examples available in the oral microbiology literature. However, most, if not all, of the described technologies should be readily adaptable for studies of microbiomes from other mucosal sites in the body. Therefore, this review is intended to serve as a reference guide used by microbiome researchers as they inevitably transition into molecular mechanistic studies of the many significant phenotypes observed clinically.

Managing Oral Health in the Context of Antimicrobial Resistance

The oral microbiome plays a major role in shaping oral health/disease state; thus, a main challenge for dental practitioners is to preserve or restore a balanced oral microbiome. Nonetheless, when pathogenic microorganisms install in the oral cavity and are incorporated into the oral biofilm, oral infections, such as gingivitis, dental caries, periodontitis, and peri-implantitis, can arise. Several prophylactic and treatment approaches are available nowadays, but most of them have been antibiotic-based. Given the actual context of antimicrobial resistance (AMR), antibiotic stewardship in dentistry would be a beneficial approach to optimize and avoid inappropriate or even unnecessary antibiotic use, representing a step towards precision medicine. Furthermore, the development of new effective treatment options to replace the need for antibiotics is being pursued, including the application of photodynamic therapy and the use of probiotics. In this review, we highlight the advances undergoing towards a better understanding of the oral microbiome and oral resistome. We also provide an updated overview of how dentists are adapting to better manage the treatment of oral infections given the problem of AMR.

Functional signatures of ex-vivo dental caries onset

Background

The etiology of dental caries remains poorly understood. With the advent of next-generation sequencing, a number of studies have focused on the microbial ecology of the disease. However, taxonomic associations with caries have not been consistent. Researchers have also pursued function-centric studies of the caries microbial communities aiming to identify consistently conserved functional pathways. A major question is whether changes in microbiome are a cause or a consequence of the disease. Thus, there is a critical need to define conserved functional signatures at the onset of dental caries.

Methods

Since it is unethical to induce carious lesions clinically, we developed an innovative longitudinal ex-vivo model integrated with the advanced non-invasive multiphoton second harmonic generation bioimaging to spot the very early signs of dental caries, combined with 16S rRNA short amplicon sequencing and liquid chromatography-mass spectrometry-based targeted metabolomics.

Findings

For the first time, we induced longitudinally monitored caries lesions validated with the scanning electron microscope. Consequently, we spotted the caries onset and, associated with it, distinguished five differentiating metabolites - Lactate, Pyruvate, Dihydroxyacetone phosphate, Glyceraldehyde 3-phosphate (upregulated) and Fumarate (downregulated). Those metabolites co-occurred with certain bacterial taxa; Streptococcus, Veillonella, Actinomyces, Porphyromonas, Fusobacterium, and Granulicatella, regardless of the abundance of other taxa.

Interpretation

These findings are crucial for understanding the etiology and dynamics of dental caries, and devising targeted interventions to prevent disease progression.