Journal of Medical Microbiology

The study explores the polymicrobial nature of primary endodontic infections using Illumina Next Generation Sequencing. Samples involved in research have been collected from root canals of the patients suffering from pulp and periapical inflammations with no history of endodontic interventions on affected teeth. The study revealed prevalence of different bacterial phyla, classes, orders, and species. Further work will show potential correlations between individual microbiotas and clinical diagnosis.

Type 2 diabetes and its risk factors such as dyslipidemia and/or obesity enhance severe periodontitis with a poorly understood microbiome. Hence, the purpose of the present study was to describe and compare the subgingival microbiomes of Type 2 diabetes subjects classified by periodontal diseases, to determine the association between periodontal severity and metabolic condition. 71 DNA subgingival samples of 36 subjects were evaluated by Human Oral Microbiome Identification Microarray using 16S rRNA gene-probe. Blood chemistries were obtained to test hemoglobin, and serum lipid profile. Obesity classification was obtained by Body-Mass-Index. Kruskal-Wallis, Mann-Whitney, Spearmans correlation, and Multivariate ordinal logistic-regression (periodontal-severity) test were applied (IBM-SPSS-21/Stata 17). Our results suggest samples of subjects with Gingivitis (n=12) presented with higher Bacteroidetes proportion vs. Generalized Periodontitis grouped by severity Stage-I (n=17, NS), Stage-II (n=30, p<0.05), and Stage-III (n=12, p<0.05); and Generalized Periodontitis Stage-II presented higher Firmicutes proportion (p<0.05_MW_vs._Gingivitis). Human-Microbial-Taxon presented significant higher Score-levels (Levels), frequency (%), or Odds Ratio (OR) of *1Cardiobacterium valvarum_HMT-540, Fusobacterium Cluster-AE01 (Generalized Periodontitis-Stage-I vs. Gingivitis_p<0.001_Levels, OR: 9.1 and 4.7), *2Porphyromonas gingivalis HMT-619 (OR: 4.7), Porphyromonas pasteri_HMT-279 (Gingivitis vs. Generalized Periodontitis-Stage-I and II_p<0.01/p<0.001_Levels), *3Streptococcus constellatus_HMT-576/Streptococcus intermedius_HMT-644 (Generalized Periodontitis-Stages-II, III vs. Gingivitis_p<0.05_%), and {dagger}Saccharibacteria (TM7)[G-1]_bacterium_HMT-347,350_Gingivitis_p<0.05_Levels), some of the Human-Microbial-Taxon identified, presented correlation with total triglycerides ([&ge;]150mg/dl, 0.521), total lipids ([&ge;]800mg/dl, {dagger}0.478), and obesity (*10.279, *20.280, *30.312). The microbiome of Type 2 diabetes subjects with gingivitis presented the classical microbial profile with representative pathogenic species, while the Generalized Periodontitis Stage I-II subjects presented a microbiome with representative putative and saccharolytic species, some of them strongly associated with the poor control of lipid profile or obesity, and to periodontal-severity.

Very few 16S rRNA-based studies have conducted a simultaneous analysis to identify the impact of various dental and periodontal parameters and determine which of them have the greatest repercussion for the salivary microbiota. Consequently, this study used 16S rRNA gene amplicon sequencing to assess the impact on salivary microbiome of different grades of dental, periodontal and global oral disease. Our global oral health scale was used to produce a convenience sample of 81 patients from 270 who were initially recruited. These subjects were assigned the following grades: 47 had a periodontal grade (PG) of 0 and dental grades (DGs) between 0-3, and 46 had a DG of 0 and PGs between 0-3. Saliva samples were collected from each participant. Sequencing was performed in Illumina MiSeq with 2 x 300 bp reads, while the raw reads were processed according to the Mothur pipeline. The statistical analysis of the 16S rDNA sequencing data at the species level was conducted using the Phyloseq, DESeq2 and Microbiome packages. The impact on the salivary microbiota of the different DGs, PGs and global oral grades (GGs) was investigated in relation to: 1) indicators of alpha diversity and the structure of the bacterial community; and 2) the composition of the core microbiome and the results of differential abundance tests. The simultaneous presence of dental and periodontal pathology has a potentiating effect on the richness and diversity of the salivary microbiota. The structure of the bacterial community in oral health differs from that present in dental, periodontal or global oral disease, especially in high grades. The non-specific microbiome core contains a greater number of more abundant species than the specific core of a particular dental or periodontal condition (health or pathology). The number of taxa in the salivary microbiota with differential abundances between the DGs, PGs or GGs represents, at most, a quarter of the bacterial community and are mainly non-core species. Supragingival dental parameters influence the microbiotas abundance more than subgingival periodontal parameters, with the former making a greater contribution to the impact that global oral health has on salivary microbiome.

We aimed to characterize the relationship of the oral microbiome with diabetes in Pakistan. Saliva samples were collected from diabetic patients (n = 49) and healthy individuals (n = 55). 16S metagenomics saliva was carried out by NGS technology. We observed that the phylum Firmicutes (p-value = 0.024 at 95% confidence interval) was significantly more abundant among diabetic patients than among the controls. We found that the abundance of phylum Actinobacteria did not significantly vary among both groups in contrast to a similar report from the USA (Long et al., 2017). On genus level, acidogenic bacteria Prevotella (p-value = 0.024) and Leptotrichia (p-value = 1.5 x 10-3); and aciduric bacteria Veillonella (p-value = 0.013) were found to be in higher abundance in diabetic patients. These bacteria are found in dental biofilm and involved in the metabolism of fermentable carbohydrates. Stratified analysis by gender revealed healthy and diabetic females to be more divergent. Abundance of Prevotella (p-value = 4.4 x 10-3) and Leptotrichia (p-value = 0.015) was significantly associated with male patients. A comparison of oral bacteriome between two groups revealed the dominance of acidogenic and aciduric bacteria in diabetics which suggested the involvement of these eubacteria in oral dysbacteriosis in diabetes mellitus.

Cell-wall-deficient bacteria are those that lack cell walls and live in a pleomorphic state. The genus Mycoplasma and L-form bacteria are both members of this group. The aim of this study was to search cell-wall-deficient bacteria in periodontal biofilm and link their presence to periodontal disease. Eighty-nine individuals were recruited and divided into three groups: periodontally healthy individuals, individuals with chronic periodontitis, and those with aggressive periodontitis. The presence of cell-wall-deficient bacteria was detected in freshly collected biofilm by light microscopy, transmission electron microscopy (TEM) with and without electron microscopy in situ hybridization, atomic force microscopy and DNA stain (Hoechst). A new dichotomic index of classification for prevalence and morphologic variants was developed to classify cell-wall-deficient bacteria in periodontal biofilm. Cell-wall-deficient bacteria were found in periodontal biofilm and classified into Protoplastic, Everted, Filament and Intracellular forms, the last one mainly associated with aggressive periodontitis. We also assessed the prevalence of periodontopathic bacteria by means of polymerase chain-reaction (PCR) and found no clear, statistically significant, correlation among periodontal pathogens tested (except T. denticola) that allowed individuals with chronic periodontitis to be distinguished from those with aggressive periodontitis. Association between cell-wall-deficient bacteria and periodontal condition was: periodontally healthy, 3.3% (1/30); individuals with chronic periodontitis, 30.6% (11/36); and those with aggressive periodontitis, 100% (23/23). Cell-wall-deficient bacteria were detected in periodontal biofilm and linked to aggressive periodontitis.

ObjectivesThe aim of this study was to investigate the potential association between the formation of oral bacterial biofilms and the occurrence of antibiotic resistance among 294 oral bacterial isolates. Study designA total of 100; 25-65year old patients were chosen. Buccal mucosa swabs were collected and cultured in appropriate media, then bacteria were isolated and identified. Then 294 bacterial isolates were assessed for biofilm production by the phenotypic method, i.e., the tissue culture plate method (TCPM). Finally, antibiotic susceptibility patterns of the 294 isolates were done by the Kirby-Bauer disc diffusion method for 7 {beta}-lactam antibiotics (ampicillin, penicillin, amoxicillin, cephalothin, oxacillin, cloxacillin, and cefoxitin) and 7 non-{beta}-lactam antibiotics (tetracycline, co-trimoxazole, ciprofloxacin, clindamycin, erythromycin, lincomycin, and vancomycin). ResultsWhen isolates were exposed to biofilm detection by the TCP method, 9 (3.1%) showed high biofilm formation capacity, 213 (72.4%) showed moderate biofilm formation capacity, while 72 (24.5%) showed weak/no biofilm formation. The isolated bacterial biofilms positively showed that the bacterial isolates that showed high and moderate biofilm formation capacity have a higher rate of resistance to most antibiotics with significant difference (p < 0.0001) than weak/no biofilm formation. ConclusionThe present study demonstrates that aerobic bacteria are still the major bacteria isolates from the oral cavity. Antibiotic resistance in the oral bacterial isolates was found to be associated with bacterial biofilm formation.

This study reports genus-level oral rinse microbiota profiles in a population of 3,770 U.S. adults from NHANES 2009-2012. Oral conditions explained more microbial variance than host factors, with diversity and composition differing across health, caries, periodontitis, co-occurring disease, and edentulism. In periodontitis, diversity increased alongside a shift toward anaerobic, inflammation-adapted communities. Additionally, dysbiosis-associated genera increased with disease severity gradient while health-associated ones decreased. A machine learning model based on microbial features achieved moderate accuracy in identifying severe periodontitis (AUROC in leave-one-dataset-out validation = 0.81, 95% CI 0.75-0.87; AUROC in external validation = 0.83, 95% CI 0.77-0.88). Key contributing taxa included Desulfobulbus, Defluviitaleaceae UCG-011, Treponema, Filifactor, Pseudoramibacter, Mycoplasma, Porphyromonas, Bergeyella, and Bifidobacterium were defined in the model. These findings support oral rinses as a non-invasive tool for monitoring oral microbial ecology and assessing the presence and severity of oral disease at the population level.

ObjectiveChronic periodontitis has been proposed to be linked to coronavirus disease (COVID-19) on the basis of its inflammation mechanism. We aimed to evaluate this association by investigating the expression of Angiotensin Converting Enzyme-2 (ACE2) in periodontal compartments, which contain dysbiosis-associated pathogenic bacteria, and how it can be directly or indirectly involved in exacerbating inflammation in periodontal tissue. Material and MethodsThis observational clinical study included 23 adult hospitalized patients admitted to Universitas Indonesia Hospital with PCR-confirmed COVID-19, while 6 non-COVID-19 participants come to periodontal clinic were included as control. Using real time-PCR (qPCR) and gingival crevicular fluids (GCF) samples from COVID-19 patients with and without diabetes and periodontitis, we assessed the mRNA expression of angiotensin-converting enzyme 2 (ACE2), IL-6, IL-8, complement C3, and LL-37 as well as the relative proportion of Porphyromonas gingivalis, Fusobacterium nucleatum, and Veillonella parvula to represent the dysbiosis condition in periodontal microenvironment. All analyses were performed to determine their relationship. ResultsACE2 mRNA expression was detected in the GCF of periodontitis-COVID-19 patients with and without diabetes. However, only periodontitis-COVID-19 patients with diabetes showed a positive relationship between ACE2 expression and inflammatory conditions in the periodontal microenvironment. In addition, the interplay between pro-inflammatory cytokine (IL-6) and complement C3 could be used as a predictor of the severity of periodontal inflammation in COVID-19 patients with diabetes. ConclusionThe study data show that the SARS-CoV-2 entry gene is expressed in the GCF of patients with COVID-19, and its expression correlates with inflammatory markers.

Betel nut addiction is recognized as the causative agent of oral microbiome dysbiosis and other systematic disorders. A number of betel nut preparations containing ingredients such as slaked lime, catechu extract and tobacco are being commonly used particularly in South Asia. The underlying variations in the oral microbiome due to usage of betel nut preparations are poorly understood. We evaluated salivary microbiome in response to chewing of betel nut preparation(s). In order to assess the microbiome dynamics, metagenomic analysis of 16S rRNA gene (V3-V4 hypervariable region) from salivary bacteria in chewers of betel nut preparation (n = 16) and non-chewers (n = 55) was carried out by Greengenes and SILVA ribosomal sequence databases. It was observed that Gutka chewers demonstrated lower alpha diversity and number of bacterial genera than the non-chewers. Taxonomic assignment on phylum level revealed Firmicutes (p-value = 0.042 at 95% confidence interval) to be significantly more abundant in Gutka chewers in comparison with non-chewers. Beta diversity analysis at genus level by weighted unifrac distance matrices unveiled both groups to be divergent from each other. On the genus level, Veillonella (p-value = 0.015), Streptococcus (p-value = 0.026), Leptotrichia (p-value = 0.022) and Serratia (p-value = 0.022) species appeared to be significantly more abundant in Gutka chewers in comparison to non-chewers. The present study suggests salivary dysbiosis in response to gutka chewing and concludes that gutka chewers possess higher abundance of acidogenic and aciduric bacteria. This study contributes additional information regarding oral microbiome variations with response to gutka consumption.

This study aims to investigate the distribution of microbial taxa that are present in abundance in the oral cavity of patients diagnosed with Oral Squamous Cell Carcinoma (OSCC). We begin with a search for relevant literature on the OSCC microbiome in electronic databases (PubMed and Google Scholar). From the identified literature, studies were considered for data extraction based on an inclusion criteria according to PRISMA guidelines. From an initial 1217 published studies, a total of 15 relevant studies were identified that fulfilled the inclusion criteria. These studies were conducted for the detection of microbial taxa in the oral cavities of patients with OSCC by correlation with healthy controls for differential microbial abundance. The data from the selected studies provided evidence on microbial taxa in different anatomical sites of the oral cavity i.e. gingival region, tongue, buccal site and floor of the mouth. The most common method for the detection of microbial flora in the literature was 16s rRNA sequencing. Only those studies from the literature were considered for further analysis that showed the association of risk factors i.e. tobacco smoking and smokeless, betel quid, alcohol and periodontitis with OSCC. Risk factors in the resulting 6 studies showed a strong odds ratio (OR) with statistical significance (p-value <0.05). The calculated risk ratio (RR) of these risk factors also demonstrated substantial heterogeneity. These studies showed an increase in the abundance of periodontopathogens belonging to the genus Fusobacterium, Capnocytophaga, Prevotella, Parvimonas and Porphyromonas. The microbial taxa associated in abundance with risk factors of OSCC such as smoked or smokeless tobacco, betel quid and alcohol were quite similar to the microbial taxa that cause periodontitis. The detection for abundance of periodontopathogens in OSCC a class of putative biomarkers at early stages of tumor development in OSCC, in individuals exposed to these risk factors.

ObjectivesThe objectives were to quantify the contributions of internal (self) and external (familial) sources to the recolonization of the bacterial content of the subgingival plaque following professional prophylaxis and assess the effect of close-contact activities on modifying this contribution. Materials and MethodsFamilies, each consisting of at least one preschool-aged child and at least one sibling, were recruited for this interventional cohort pilot study. Microbial samples were collected from various oral sites, including saliva, buccal mucosa, tongue, supragingival plaque, and subgingival plaque in all family members. Following the childs oral prophylaxis, subgingival plaque samples were collected one week later. DNA from these samples was extracted and sequenced using the 16S rRNA gene and estimation of the sources were quantified using Bayesian source tracking models. Additional analyses using generalized linear mixed models, Phylofactorization, and Spearman correlations. Statistical significance was set at p<0.05. ResultsChilds own subgingival plaque was the primary source of recolonization, contributing 63.7% to the microbial community one-week post-prophylaxis. Siblings contributed approximately 8%, a contribution significantly higher than that from parents, who contributed around 3% each (p<0.05). The analysis revealed a statistically significant positive correlation between the number of siblings and their bacterial contribution to the childs subgingival plaque. Several close contact activities between parents and children were statistically associated with higher contribution (p<0.05, Spearman correlation). Additionally, 110 bacteria were statistically significantly different in their internal contribution compared to external, after accounting for household association, sample type, and family members (p<0.05, Phylofactor) ConclusionThe findings challenge the traditional focus on parent-child transmission of oral microbes, highlighting the importance of studying families as a whole.

ObjectiveSelf-adhesive resin cements are easy to use and do not need further preparation but their bonding ability to dentin is somehow questionable.Ddentin preparation with acidic solutions and therefore removing smear layer can increase bond strength of self-adhesive resin cements to dentin. As a matter of fact it is assumed that deproteinization of dentin can increase contact between cement and dentin. In the present study the effect of deproteinization of dentin with different concentrations and times of sodium hypochlorite on the push out bond strength of resin cement to dentin is assessed. Materials and methods60 third molar teeth were selected and divided to 4 groups consisting of 5% and 20% concentrations and 2 and 10 minutes of using. Samples were randomly divided into six groups of ten. All samples used size 2 Whitepost FGM fiber posts (FGM, Joinville, SC, Brazil), with a diameter of 1.2 mm. Samples were cemented using dual-cure self-adhesive TheraCem (Bisco, USA), cured for 40 seconds with an LED Plus device from Woodpecker made in China All the specimens were then mounted in plastic cylinders. After 24 hours they were cut with 0.2 mm thickness diamond disc to two coronal and apical parts. Push out strength test was done with Instron 1122R (Universal Testing Machine). ResultsIncreasing the concentration and using time of sodium hypochlorite increased push out bond strength. DiscussionDeproteinization not only can increase push out bond strength but also increase time and concentration can elevate bond strength measures.

Aim & ObjectivesThe aim of the present study was to evaluate the effect of Stevia rebaudiana bertoni on GCF glucose levels and GCF bio-markers in diabetic patients with periodontitis. Patients and methods19 subjects were participated in the study. Randomly, a quadrant was allotted as test site for placing Stevia gel and other quadrant was allotted as a control site for placing placebo in the gingival sulcus having PD[&ge;] 5mm after performing thorough scaling and root planing. GCF samples was collected using sterile paper strips at baseline i.e., after scaling and root planing, 3 months and 6 months using intra-crevicular superficial method. GCF samples was eluted from the strips by placing them in Eppendorf(R) tubes that contained 500 micro-litre of buffer and will be stored at -80 until analysis was done. The levels of GCF glucose and GCF bio-markers was evaluated by using commercially available ELISA kit. ResultsStevia gel was effective in decreasing the GCF glucose and increasing ghrelin levels in diabetic patients with periodontitis. There was significant difference in clinical parameters in both test and control groups. ConclusionThis study concluded that application of Stevia gel in gingival crevice may be of value in controlling diabetes and periodontitis at a time.

AimThis multicenter, randomized controlled trial evaluated the efficacy of the Lumoral(R) dual-light antibacterial photodynamic (aPDT) home care device as an adjunct tool to non-surgical periodontal treatment (NSPT) in chronic periodontitis patients. Materials and MethodsForty-one Stage I-III periodontitis patients were randomized to receive NSPT, including standardized hygiene instructions and scaling and root planing, or NSPT with adjunctive Lumoral(R) treatment, applied daily at home. Clinical examinations were conducted at baseline, three months, and six months. ResultsBoth groups showed significant reductions in Visual Plaque Index (VPI) and Bleeding on Probing (BOP) at three and six months. However, the NSPT + Lumoral(R) group exhibited significantly greater BOP and VPI reductions at six months (p=0.03, p=0.04) compared to the NSPT group. Incidence of Probing Pocket Depth (PPD) [&ge;] 4 mm reduced significantly in the NSPT + Lumoral(R) group at both follow-ups (p=0.0019, p=0.0043) but not in the NSPT group. Periodontal epithelial surface area (PESA) and periodontal inflamed surface area (PISA) significantly decreased in the NSPT + Lumoral(R) group (p<0.01), while no significant changes were observed in the control group. ConclusionRegular adjunctive use of Lumoral(R) after NSPT resulted in improved clinical periodontitis treatment outcomes.

Background The microbial aetiology of early childhood caries (ECC) in sub-Saharan African populations remains poorly characterised, with most studies focusing on conventional cariogenic pathogens like Streptococcus mutans. This study aimed to characterise the salivary microbial profile of children with ECC in urban Kano, northern Nigeria. Methods In this cross-sectional study of 162 children aged 3-5 years in urban Kano, unstimulated saliva samples were collected and analysed using standard bacteriological culture methods. Caries status was assessed using decayed, missing, and filled teeth (dmft) index and International Caries Detection and Assessment System (ICDAS). Microbial isolates were identified through Gram staining, colony morphology, and biochemical tests (catalase, coagulase, oxidase). Results Of 32 microbial isolates obtained, Staphylococcus aureus was the most prevalent (43.8%, n=14), followed by Streptococcus species (28.1%, n=9), Klebsiella species (12.5%, n=4), non-aureus staphylococci (6.3%, n=2), yeast (6.3%, n=2), and Pseudomonas species (3.1%, n=1). Only one isolate demonstrated direct association with dmft-detectable caries. Polymicrobial colonisation occurred in four cases (12.5%), predominantly featuring S. aureus-yeast combinations (n=2). White spot lesions (ICDAS 1-2) were associated with S. aureus and Klebsiella species in two separate cases. Conclusion This study reveals an unexpected predominance of S. aureus in the salivary microbiome of children in northern Nigeria, challenging conventional paradigms of ECC microbiology. The low correlation between microbial isolates and clinical caries suggests complex, multifactorial aetiology. These findings highlight the need for molecular characterisation of oral microbiomes in African populations and reconsideration of caries pathogenesis models in this unique epidemiological context.

Dysbiosis of oral microbiome causes chronic diseases including dental caries and periodontitis, which frequently affects elderly, frail patients receiving long-term care. Severely disabled patients may require nutritional supply via nasogastric (NG) tube, which impacts patients oral condition and possibly microbial composition. However, little is known about the effect of NG tube on oral microbes and its potential ramification. Here, by using 16S rRNA next-generation sequencing, we characterized the tongue microbiome of 27 patients fed with NG tubes and 26 others fed orally. The microbial compositions of NG-tube and oral-feeding patients were substantially different, with more Gram-negative aerobes enriched in the presence of NG tube. Specifically, NG-tube patients presented more opportunistic pathogens like Corynebacterium and Pseudomonas associated with pneumonia, and lower levels of commensal Streptococcus and Veillonella. Together, we present a systematic, high-throughput profiling of oral microbiome with regards to NG tube indwelling, providing empirical evidence for better clinical practice. ImportanceLong-term use of NG tubes on elderly patients often leads to poor oral hygiene and chronic infectious diseases, e.g. periodontitis and tooth decay. More importantly, because patients fed with NG tubes usually have swallowing dysfunctions, they are more likely to suffer from aspiration pneumonia, a life-threatening lung infection caused by inhalation of oral bacteria. Together, clinical implications of chronic NG-tube indwelling are significantly related to oral microbes. Understanding the effects of NG tubes on oral microbiome would generally inform how clinical care should be given, particularly antimicrobial therapy.

PurposeThis study compared the wait-time for treatment completion and pre- and post-treatment outcomes of treating early childhood caries with silver diamine fluoride, sedation, and general anesthesia. MethodsThis retrospective study examined children with early childhood caries treated with either silver diamine fluoride, sedation, or general anesthesia at federally qualified health centers. Demographics, wait-time for treatment completion, and pre- and post-treatment clinical outcomes were compared with analysis of variance for continuous variables and the Chi-square test for categorical variables. This study was reviewed and approved by Southcentral Foundation Research Review. ResultsThe outcomes between the silver diamine fluoride, sedation, and general anesthesia groups were respectively: 1) average wait-times to complete treatment at 49.6, 62.5, and 116.3 days, 2) mean number of pre-treatment visits at 1.08, 1.25, and 1.61, 3) mean number of post-treatment visits at 1.41, 1.29, and 1.45. Multiple negative outcomes were identified when the sedation and general anesthesia groups were compared with the silver diamine fluoride reference group for 1) pre-treatment visits with un-planned visits (for general anesthesia only), pain, intra-oral swelling, and prescriptions for pain and antibiotic medications (general anesthesia only) and 2) post-treatment visits with new carious lesions on permanent molars, new carious lesions on primary teeth (sedation only), intra-oral swelling (sedation only only), broken restorations, displaced restorations, and pulpal therapy (sedation only). ConclusionsSilver diamine fluoride provides timely and effective caries management with lower wait-time for treatment completion, clinical outcomes consistent with minimally invasive treatment, and mitigation for the risk of negative pre- and post-operative clinical outcomes compared to treatment under sedation or general anesthesia.

IntroductionSilver diamine fluoride (SDF) is a simple and non-invasive agent used to arrest early childhood caries (ECC). This study aimed to investigate potential changes to the oral microbiome in children with ECC who were treated with SDF at three different frequency regimens. MethodsForty-five children (n=15 per group) with ECC were recruited into a randomized clinical trial testing three different treatment frequency regimens of SDF. A total of 195 carious lesions were treated with two applications of 38% SDF and 5% sodium fluoride varnish (NaFV) and assessed over three study visits (one month (Regimen 1M), four months (Regimen 4M), or six months (Regimen 6M) apart). Dental plaque samples were collected at each visit. Sequencing of the V4-16S rRNA and ITS1 rRNA genes were used to study the supragingival plaque microbiome. ResultsThe overall arrest rates for treated carious lesions were 75.9% at Visit 2 and 92.8% at Visit 3. Arrest rates were higher for all lesions after two applications of SDF with NaFV, and applications one month and four months apart had higher arrest rates (95.9% and 98.5%) than six months (81.1%) apart. The microbial diversity analyses showed no significant differences in the overall microbiome after SDF treatment. However, significant changes in the abundance of specific bacteria and fungi, particularly Lactobacillus spp., Bifidobacterium spp., and Candida spp. were observed after treatment. Furthermore, overabundance of Streptococcus mutans and Candida dubliniensis at baseline was observed in children who had at least one caries lesion not arrested after one SDF application, compared to those who had 100% arrest rates. ConclusionSDF with NaFV applications were an effective modality for arresting ECC, with higher arrest rates after two SDF applications. No loss of diversity but significant changes in the abundance of specific bacteria and fungi were consequences of SDF treatment.

The COVID-19 pandemic highlighted the need for effective protection and rapid development of tests to track and quantify seroconversion through natural infection and vaccination. Recombinant proteins, consisting of the SARS-CoV-2 nucleocapsid and Spike Receptor Binding Domains (RBD) fused with nanoluciferase reporters (GloBodies) were designed and produced. The SARS-CoV-2 specific antibody within serum, from venous blood or eluted from local or remotely-obtained dried blood spots, form a complex with the GloBody, which can be captured on immobilized Protein G or anti-isotype antibody with the retained nanoluciferase activity being proportional to specific antibody levels. Natural infection, vaccination and human and animal SARS-CoV-2 specific antibodies were detectable. These were used to serially monitor infection and vaccination responses in dental healthcare workers (n=82), medical healthcare workers (n=72) and laboratory-based scientists (n=62) within the Royal London, dental and medical hospitals and associated university research institute in Whitechapel, East London. This indicated temporally distinct infection and vaccination profiles, consistent with hospital deployments and local and national lockdowns by dentists and scientists. As such, medical healthcare workers had twice the odds of experiencing COVID-19 symptoms (2.01 95%CI 1.13- 3.58. P<0.001) compared to dentists, who were more at risk than scientists. Likewise, those who performed virus exposure-prone procedures exhibited twice (1.98. 95% CI 1.18-3.34 P=0.01) the odds of symptoms and exhibited higher nucleocapsid titres (0.21 95%CI 0.05-0.38. P=0.012), indicative of higher infection levels. As predicted vaccination was associated with reduced infection risk as shown by reduced titre of nucleocapsid titres (-0.21 95% CI -0.34- - 0.17. P<0.001 and elevated Log10 RBD GloBody titres (1.18. 95%CI 1.09-1.26. P<0.001). The GloBody technology proved to be a versatile and scalable platform for rapid deployment.

ObjectivesThis umbrella review evaluates systematic reviews and meta-analyses for salivary biomarker concentration and activity in caries-affected versus caries-free children. MethodsA comprehensive literature search identified relevant reviews, which were systematically selected using PRISMA guidelines, assessed qualitatively with AMSTAR 2, and analyzed quantitatively using RevMan software. Certainty of evidence was evaluated via the GRADE assessment tool. ResultsOf 609 identified articles, three reviews were included for quantitative analysis. AMSTAR 2 assessments rated three reviews as high quality and one as low quality. Meta-analysis findings showed that for salivary secretory immunoglobulin-A concentration with a mean of 65.54, with a 2.24 higher concentration (0.59 to 3.89 higher) in caries-affected children; carbonic anhydrase-VI concentration with a mean of 2.18, with a 0.92 lower concentration (2.21 lower to 0.38 higher) in caries-affected children; and carbonic anhydrase-VI activity with a mean of 3698.30, with a 2.89 higher activity level (1.24 to 4.54 higher) in caries-affected children. Heterogeneity was low for carbonic anhydrase, high for Salivary secretory immunoglobulin-A, and publication bias risk was low. The GRADE assessment indicated moderate confidence in evidence suggesting slight differences in Salivary secretory immunoglobulin-A and carbonic anhydrase-VI levels in caries-affected children. ConclusionsCaries-affected children under age nine exhibit higher salivary secretory immunoglobulin-A concentration and carbonic anhydrase-VI activity but lower carbonic anhydrase-VI concentration. Current evidence suggests that screening with these three salivary biomarker tests are likely to benefit and unlikely to harm children. Widespread clinical application remains limited until U.S. commercial laboratories provide standardized saliva-based testing for salivary secretory immunoglobulin-A and carbonic anhydrase-VI.