Saliva as a diagnostic tool for oral and systemic diseases

Establishing age-group specific reference intervals of human salivary proteome and its preliminary application for epilepsy diagnosis

Salivary proteins serve multifaceted roles in maintaining oral health and hold significant potential for diagnosing and monitoring diseases due to the non-invasive nature of saliva sampling. However, the clinical utility of current saliva biomarker studies is limited by the lack of reference intervals (RIs) to correctly interpret the testing result. Here, we developed a rapid and robust saliva proteome profiling workflow, obtaining coverage of >1,200 proteins from a 50-µL unstimulated salivary flow with 30 min gradients. With the workflow, we investigated protein variation in a cohort of 1,743 healthy individuals. The significant differences in non-linear saliva proteomes among age groups resulted in the establishment of age-related RIs covering 1,123 salivary protein variations. We then utilized a cohort of 30 epilepsy patients as a case study to illustrate the practical application of RIs in identifying disease-enriched outlier proteins, elucidating their cellular origins, determining disease diagnosis, and visualizing outlier proteins in each epilepsy patient. Our study showed the classification model based on the RI achieved PR-AUC of 0.815 (95%CI: 0.813-0.826). Additionally, we validated these results in an independent test set. Furthermore, the epilepsy cohort could be further stratified into 2 major subtypes, with one subtype characterized by disrupted metabolic proteins and containing mostly Focal Cortical Dysplasia (FCD) type III epilepsy patients. Overall, our study provided a proof-of-principle workflow for the use of salivary proteome for health monitoring, epilepsy diagnosis and subtyping.

Salivary alpha amylase as a diagnostic biomarker for dental caries - A systematic review and meta analysis

OBJECTIVE

This systematic review and meta-analysis aimed to assess the association between the dental caries and the level of salivary alpha amylase activity among caries active and caries free individuals.

DESIGN

This review followed the PRISMA guidelines and registered in PROSPERO (CRD42024518973). A comprehensive search across various research databases until January 31, 2024 yielded 1031 articles, where multiple screening ultimately narrowed it to 13 articles. Appropriate cross sectional studies comparing caries active (CA), caries free (CF) group and evaluating their level of salivary alpha amylase activity were included.

RESULTS

The meta-analysis was performed on all 13 included studies utilizing a random effects model and two sub group analysis were performed where studies with salivary alpha amylase activity estimated using spectrophotometer and autoanalyzer were analyzed separately among caries active and caries free group. The pooled data reveals that the salivary alpha amylase activity was significantly higher (p = 0.005) in caries active group compared to caries free group with a standardized mean difference of 1.30.

CONCLUSION

This review indicated the differences in the salivary alpha amylase activity among caries active and caries free individuals which could aid in identifying individuals susceptible to dental caries thereby offering new insights for preventive dentistry by assessing their caries risk, enabling tailored preventive strategies.

Salivary proteomics as signature for molar incisor hypomineralization stages

OBJECTIVE

Saliva is a rich-bodily fluid with recognized clinical diagnosis roles. This research aimed to investigate the salivary proteomic signatures for MIH in children with distinct degrees of severity.

MATERIALS AND METHODS

In this cross-sectional study, 50 schoolers (8-13 years) were equally assigned into the following groups: G1 (Control group-Healthy first permanent molars), G2 (Mild MIH with white/creamy opacity and free of caries), G3 (Mild MIH with yellow/brown opacity and free of caries), G4 (Severe MIH with white/creamy, yellow/brown opacities including post-eruptive fracture and free of caries), G5 (Severe MIH with white/creamy, yellow/brown opacities, post-eruptive fracture, and caries). Unstimulated saliva samples were collected and later explored using mass spectrometry analysis.

RESULTS

In total, 6,471 proteins were found, 5,073 exclusively from MIH children, and 778 overlapping among the different degrees of the disturb. The biological pathways displayed distinct patterns among the groups, which differed according to the MIH degrees. Gene-Ontology differences might not be verified regarding the biological processes and cellular components. Conversely, concerning molecular function, alterations among groups were evident, with proteins that would contribute to MIH in children with the severe condition (i.e., calcium ion binding, microtubule binding, platelet-derived growth factor binding).

CONCLUSION

The results of this study support important salivary proteomics changes in MIH children according to distinct degrees of severity, reinforcing the interplay between the clinical characteristics and changes in the salivary proteome.

CLINICAL RELEVANCE

Changes occurring in the salivary proteomics of children with distinct degrees of severity of Molar Incisor Hypomineralization (MIH) might be promising biomarkers and valuable information in clinical care, helping professionals make better clinical decisions and helping patients to understand their disturbance.

Salivary attenuated total reflectance-fourier transform infrared spectroscopy combined with chemometric analysis: A potential point-of-care approach for chronic kidney disease screening

BACKGROUND

The increasing prevalence of chronic kidney disease (CKD) and its terminal stage, end-stage renal disease (ESRD), raises the importance of an accurate, early, and point-of-care method to diagnose and monitor patients. Saliva is a potential point-of-care diagnostic biofluid for its simple collection and ability to reflect systemic health status. This study investigated salivary spectral signatures in ESRD patients and their diagnostic potential compared to healthy controls.

METHODS

Saliva samples were collected from 24 ESRD patients undergoing hemodialysis and 24 age/sex-matched healthy controls. The dried saliva samples were analyzed using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy in the 4000-400 cm⁻¹ range. Chemometric analyses, including Principal Component Analysis (PCA) and Partial Least Squares Discriminant Analysis (PLS-DA), were applied to preprocessed spectra to identify discriminatory spectral features and establish classification models.

RESULTS

Second derivative spectroscopic analysis of ATR-FTIR spectra revealed distinctive spectral patterns in dried ESRD saliva samples, including characteristic peak shifts observed in both the amide I secondary structures (from 1636 cm-1 in controls to 1629 cm-1 in ESRD) and carbohydrate (from 1037 cm-1 in controls to 1042 cm-1 in ESRD) regions. PCA demonstrated clear clustering patterns across key biological spectral regions, including the lipid CH stretching region (3000-2800 cm-1), the fingerprint region (1800-900 cm-1), and their combination (3000-2800 cm-1 + 1800-900 cm-1). PLS models based on the fingerprint region achieved optimal diagnostic performance (87.5-100 % accuracy, 75-100 % sensitivity, and 100 % specificity). Biochemical markers associated with ESRD revealed variations in lipids, protein, sugar moieties, carbohydrates, and nucleic acids, reflecting the underlying pathological changes in CKD, with the most prominent band at ∼1405 cm-1.

CONCLUSION

ATR-FTIR analysis of dried saliva demonstrated potential as a non-invasive diagnostic tool for ESRD. This approach could complement existing diagnostic methods, particularly in resource-limited settings or for frequent monitoring requirements.

Salivary alpha-amylase activity and its association with early childhood caries and rampant caries experience: a cross-sectional study

Aims

This study aims to evaluate salivary alpha-amylase levels in children diagnosed with Early Childhood Caries (ECC) and Rampant Caries (RC) and compare them to levels in children without ECC or RC. It also examines the relationship between salivary alpha-amylase levels and increased caries activity in the children with ECC or RC.

Materials and methods

A cross-sectional study was conducted at RAK College of Dental Sciences (RAKCODS) with 100 children aged 3-12 years. Participants were divided into ECC and RC groups, each consisting of study and control groups. Salivary alpha-amylase levels were measured using Enzyme-Linked Immunosorbent Assay (ELISA) kits. Statistical analyses, including the Wilcoxon Signed Rank test and Pearson's correlation coefficient, were performed using SPSS version 29 to compare salivary alpha-amylase levels between groups and examine correlation with severity of dental caries.

Results

The study found that children with ECC and RC had significantly higher mean salivary alpha-amylase levels (16.046 U/mL and 20.62 U/mL, respectively) compared to control groups (5.09 U/mL and 12.70 U/mL). The differences were statistically significant (p < 0.0001). Pearson's correlation coefficients indicated a strong positive correlation between salivary alpha-amylase levels and severity of dental caries in both ECC (r = 0.9891, p < 0.0001) and RC (r = 0.9142, p < 0.0001) groups.

Conclusion

The study concludes that elevated salivary alpha-amylase levels, which are statistically significant, are observed in children with ECC and RC. Additionally, it was found that salivary alpha-amylase levels increased with the number of carious lesions. These findings suggest that salivary alpha-amylase could serve as a valuable biomarker for assessing caries risk and guiding preventive strategies.

Salivary proteomics and metaproteomics identifies distinct molecular and taxonomic signatures of type-2 diabetes

BACKGROUND

Saliva is a protein-rich body fluid for noninvasive discovery of biomolecules, containing both human and microbial components, associated with various chronic diseases. Type-2 diabetes (T2D) imposes a significant health and socio-economic burden. Prior research on T2D salivary microbiome utilized methods such as metagenomics, metatranscriptomics, 16S rRNA sequencing, and low-throughput proteomics.

RESULTS

We conducted ultrafast, in-depth MS-based proteomic and metaproteomic profiling of saliva from 15 newly diagnosed T2D individuals and 15 age-/BMI-matched healthy controls (HC). Using state-of-the-art proteomics, over 4500 human and bacterial proteins were identified in a single 21-min run. Bioinformatic analysis revealed host signatures of altered immune-, lipid-, and glucose-metabolism regulatory systems, increased oxidative stress, and possible precancerous changes in T2D saliva. Abundance of peptides for bacterial genera such as Neisseria and Corynebacterium were altered showing biomarker potential, offering insights into disease pathophysiology and microbial applications for T2D management.

CONCLUSIONS

This study presents a comprehensive mapping of salivary proteins and microbial communities, serving as a foundational resource for enhancing understanding of T2D pathophysiology. The identified biomarkers hold promise for advancing diagnostics and therapeutic approaches in T2D and its associated long-term complication Video Abstract.

Analysis of Salivary Cytokines in Retinopathy of Prematurity

BACKGROUND/OBJECTIVES

This cohort study aimed to establish a correlation between salivary cytokines and retinopathy of prematurity (ROP) in premature neonates. Additionally, we sought to identify a minimally invasive method for cytokine detection in this population.

METHODS

We recruited premature neonates born at less than 34 weeks gestational age (GA), with no history of maternal or neonatal infections. Salivary samples were collected on their first (D1) and seventh (D7) days of life, and cytokine levels were measured using the MILLPLEXMAP Human multiplex assay.

RESULTS

A total of 125 neonates were included in the study, categorized into two groups based on the severity of ROP: None to Mild and Moderate to Severe. The salivary levels of interleukin (IL)-6, IL-8, vascular endothelial growth factor (VEGF), and tumor necrosis factor (TNF)-α on D1 and D7 were significantly higher in the Moderate to Severe ROP group compared to the None to Mild ROP group (p = 0.005, 0.004, 0.026, 0.018, 0.001, 0.007, 0.025, and 0.002, respectively). After adjusting for GA, the levels of IL-6 and VEGF on D7 were significantly elevated in the Moderate to Severe ROP group compared to the None to Mild ROP group (p = 0.024 and 0.016, respectively).

CONCLUSIONS

This study establishes a novel, non-invasive method for the early prediction of ROP in premature neonates by correlating salivary cytokine levels in early life with the subsequent development of ROP.

Impact of Ramadan Intermittent Fasting on Salivary pH, Flow Rate, and Electrolyte Levels in Healthy Adult Men

This before-and-after design study, which was conducted during Ramadan 2023, aimed to compare salivary flow rate (SFR), potential hydrogen (pH), and electrolyte concentrations before Ramadan (BR), at the end of Ramadan (ER), and after Ramadan (AR). Men aged 20 to 30 years who were fasting during Ramadan were recruited from the University of Monastir (Tunisia). Unstimulated saliva was collected over a 5-minute period between 10 and 11 a.m. at BR, ER, and AR. After recording the SFR, the pH was measured immediately using a pH meter. Concentrations of several salivary electrolytes (e.g., calcium, potassium, sodium, chloride, and phosphate) were determined using inductively coupled plasma-optical emission spectroscopy. Twenty-seven participants completed all three sessions. Ramadan intermittent fasting (RIF) caused significant changes only in calcium levels and pH. The mean (M)±standard deviation (SD) salivary calcium concentration decreased during ER compared to BR and AR (0.10 ± 0.08 vs. 0.21 ± 0.18 [p = .041] vs. 0.22 ± 0.20 [p = .026], respectively). The M±SD salivary pH increased during ER compared to BR (6.88 ± 0.23 vs. 6.69 ± 0.35 [p = .049], respectively). To conclude, RIF decreased salivary calcium, increased salivary pH, and did not significantly affect potassium, sodium, chloride, or phosphate. The pH change, although statistically significant, was clinically insignificant, as values remained normal. The lack of reference values for salivary calcium limits assessment of its clinical impact. There is a need for further research on the effects of RIF on saliva secretion.

Evaluation of Salivary Diagnostics: Applications, Benefits, Challenges, and Future Prospects in Dental and Systemic Disease Detection

Saliva is a multifaceted biological fluid that plays a pivotal role in oral health and overall well-being. It is primarily produced by major salivary glands, with additional contributions from minor glands. Saliva is essential for various physiological functions, including oral lubrication, digestion, and defense against pathogens. Its intricate composition comprises proteins, electrolytes, enzymes, hormones, and microbial DNA, enabling it to act as a dynamic indicator of both local and systemic health. A literature search was conducted using PubMed, Web of Science, and Google Scholar to identify relevant studies published up to June 2024. The included studies involved human participants and provided original data or comprehensive reviews on salivary biomarkers. The findings indicate that salivary diagnostics show promise in diagnosing and monitoring systemic conditions such as diabetes and cardiovascular diseases, with salivary glucose levels correlating well with blood glucose levels. Biomarkers such as C-reactive protein (CRP) have been linked to cardiovascular risk, while saliva has been explored for cancer detection, including pancreatic and prostate cancers. Advances in techniques such as enzyme-linked immunosorbent assay (ELISA), saliva omics, and single-cell sequencing have furthered salivary diagnostics, providing insights into disease mechanisms. Additionally, quantitative mass spectrometry (qMS) and Raman spectroscopy (RS) contribute to non-invasive diagnostics for various conditions, including cancer. Collecting saliva samples from healthy individuals is crucial for early disease detection and evaluating treatment efficacy. This review underscores the growing importance of salivary tests in dental practice and their potential for diagnosing various health conditions. Further research is essential to address challenges related to variability and standardization. Dentists and healthcare professionals should consider incorporating salivary tests into clinical decision-making to enhance patient outcomes.

The expression of salivary EGF, VEGF, endothelin, and transferrin in waterpipe and cigarette smokers

The aim of this study was to evaluate the effects of two forms of tobacco smoking, cigarettes and water pipe smoking (WPS), on the expression of a panel of salivary proteins in healthy adults. Three groups of age and gender-matched participants were enrolled in the study: never-smokers, cigarette smokers and WPS (N = 55 per group). Expression of epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), endothelin and transferrin in unstimulated whole saliva was estimated using enzyme-linked immunosorbent assays. Statistical analysis consisted of one-way ANOVA and Tukey's post hoc tests, in addition to bioinformatics analysis. VEGF expression was the least in WPS (51.1 ± 14.5 pg/ml) compared to both controls (150.1 ± 13.8 pg/ml) and cigarette smokers (93 ± 9.9 pg/ml), with a significant difference in WPS (p < 0.001) and cigarette smokers (p < 0.01) compared to controls. Furthermore, transferrin showed the weakest expression in the WPS group (1238 ± 261.4 pg/ml) compared to controls (2205.6 ± 298.6 pg/ml) (p = 0.05) and cigarette smokers (1805.4 ± 244 pg/ml). Neither EGF nor endothelin expression showed any statistical difference between the groups (p > 0.05). Gene-gene interaction network demonstrated that FLT1, TFRC, KDR, VEGFB and PGF genes had the highest potential for interaction with the studied proteins. Further functional annotations on the identified markers in the interaction network were performed to identify HIF-1 pathways among the most relevant pathways. In conclusion, smoking habits alter the expression of salivary VEGF and transferrin, which may correspond to early sub-clinical changes in the oral mucosa. The clinical relevance of these salivary changes requires further research.

Associations between metabolic disorders and Sjögren's disease

Sjögren's disease (SjD) is a systemic autoimmune disorder characterized by dry eyes and mouth caused by chronic inflammation and is often accompanied by various extra-glandular manifestations, including fatigue and diffuse pain. Although the pathogenesis of the disease remains elusive, several factors (e.g. environmental, genetic and hormonal factors, abnormal metabolic status) are associated with this condition. Accumulating evidence suggests a potential role of cholesterol metabolism in immune and non-immune modulation in various diseases. In this review, we summarize the current findings on the associations between cholesterol metabolism and SjD.

Impact of Calcium Lactate Pretreatment on Enamel Fluoride Uptake: A Comparative In Vitro Study of Different Fluoride Types and Concentrations

(1) Background: This study aimed to establish the effect of calcium lactate enamel pretreatment related to different fluoride types and concentrations on the enamel uptake of alkali-soluble fluorides. (2) Materials: In a blind and randomized in vitro study, a total of 60 teeth are used. The first 30 teeth were cut and randomly allocated into one of the following treatments: (A) calcium lactate pretreatment followed by three different fluoride solutions; (B) the "Fluoride only" group, with slabs treated with three different fluoride solutions; (C) the "Calcium only" group, with slabs treated with calcium lactate solution; (D) slabs treated with deionized water (negative control group). The next 30 teeth underwent all the above described group procedures but were treated with lower fluoride concentrations. Fluoride was extracted from enamel using 1 M KOH solution and analyzed using a fluoride ion-specific electrode. (3) Results: The findings revealed that slabs treated with NaF following calcium lactate pretreatment exhibited significantly greater enamel uptake of alkali-soluble fluoride compared to other substrates. This significant effect was not observed at lower fluoride concentrations. (4) Conclusion: The study demonstrates that pretreatment with calcium lactate followed by treatment with NaF at 226 ppm F significantly enhances the uptake of alkali-soluble fluoride in enamel compared to other fluoride types.

Global Research Trends in the Detection and Diagnosis of Dental Caries: A Bibliometric Analysis

This study aims to provide an overview of the global research trends in the detection and diagnosis of dental caries in the past 20 years. A literature search was conducted in the Scopus Database to retrieve studies on the diagnostic approaches for dental caries published from January 2003 to December 2023. The diagnostic approaches in the retrieved studies were examined and the studies were categorized according to the diagnostic approaches investigated. Bibliometric data including journals, countries, affiliations, authors, and numbers of citations of the publications were summarised. The publications' keyword co-occurrence was analysed using VOSviewer. This bibliometric analysis included 1879 publications investigating seven categories of caries diagnostic approaches, including visual and/or tactile (n = 459; 19%), radiation-based (n = 662; 27%), light-based (n = 771; 32%), ultrasound-based (n = 28; 1%), electric-based (n = 51; 2%), molecular-based (n = 196; 8%) diagnostic approaches, as well as AI-based diagnostic interpretation aids (n = 265; 11%). An increase in the annual number of publications on caries diagnostic approaches was observed in the past 20 years. Caries Research (n = 103) presented the highest number of publications on caries diagnostic approaches. The country with the highest number of publications was the United States (n = 1092). The University of São Paulo was the institution that published the highest number of articles (n = 195). The publication with the highest citation has been cited 932 times. VOS viewer revealed that the most frequently occurring keywords were 'Deep Learning', 'Artificial Intelligence', 'Laser Fluorescence' and 'Radiography'. This bibliometric analysis highlighted an emerging global research trend in the detection and diagnosis approaches for dental caries in the past 20 years. An evident increase in publications on molecular-based caries diagnostic approaches and AI-based diagnostic interpretation aids was perceived over the last 5 years.

The effect of novel vitamin D3 compounds on saliva samples from COVID-19 patients: a lab study

Vitamin D has shown antimicrobial effects. This study aimed to explore the antiviral effects of vitamin D3 on saliva samples collected from patients with coronavirus disease-19 (COVID-19) and compare saliva and swab results to aid in policy development. Saliva and swab samples were collected from adult patients with a positive test for COVID-19 at the King Faisal Specialist Hospital and Research Centre, Jeddah. Patients who were immunocompromised and pregnant and aged < 18 years were excluded. Vitamin D3 compound (100, 300, 800, and 1,200 IU) was added to the first saliva sample in the laboratory (n = 20); the rest of the swab specimens were compared with the saliva samples via real-time polymerase chain reaction. Of the 257 patients, 236 (94.8%) had positive saliva sample test results, 7 (2.8%) had errors, and 6 (2.4%) had negative results. Of the 236 positive tests, 235 (99.6%) had a cycle threshold (Ct) indicating strong positive reactions, and only one (Ct = 28.86) was weak. Among the 236 positive results, 235 (99.6%) exhibited robust positive reactions, indicating a substantial positive sample size. Thus, saliva might be a dependable alternative testing tool when obtaining swab samples from patients is inconvenient or challenging.

Non-invasive diagnostic test for lung cancer using biospectroscopy and variable selection techniques in saliva samples

Lung cancer is one of the most commonly occurring malignant tumours worldwide. Although some reference methods such as X-ray, computed tomography or bronchoscope are widely used for clinical diagnosis of lung cancer, there is still a need to develop new methods for early detection of lung cancer. Especially needed are approaches that might be non-invasive and fast with high analytical precision and statistically reliable. Herein, we developed a swab "dip" test in saliva whereby swabs were analysed using attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy harnessed to principal component analysis-quadratic discriminant analysis (QDA) and variable selection techniques employing successive projections algorithm (SPA) and genetic algorithm (GA) for feature selection/extraction combined with QDA. A total of 1944 saliva samples (56 designated as lung-cancer positive and 1888 designed as controls) were obtained in a lung cancer-screening programme being undertaken in North-West England. GA-QDA models achieved, for the test set, sensitivity and specificity values of 100.0% and 99.1%, respectively. Three wavenumbers (1422 cm-1, 1546 cm-1 and 1578 cm-1) were identified using the GA-QDA model to distinguish between lung cancer and controls, including ring C-C stretching, CN adenine, Amide II [δ(NH), ν(CN)] and νs(COO-) (polysaccharides, pectin). These findings highlight the potential of using biospectroscopy associated with multivariate classification algorithms to discriminate between benign saliva samples and those with underlying lung cancer.

Salivary Proteins and Metabolites as Caries Biomarkers in Adolescents

INTRODUCTION

The identification of salivary molecules that can be associated to dental caries could provide insights about caries risk and offer valuable information to develop caries prediction models. However, the search for a universal caries biomarker has proven elusive due to the multifactorial nature of this oral disease. We have therefore performed a systematic effort to identify caries-associated metabolites and proteins in saliva samples from adolescents that had a caries experience and those that were caries-free.

METHODS

Quantification of approximately 100 molecules was performed by the use of a wide range of techniques, ranging from nuclear magnetic resonance metabolomics to ELISA, Luminex or colorimetric assays, as well as clinical features like plaque accumulation and gingival index. In addition, simplified dietary and oral hygiene habits questionnaires were also obtained.

RESULTS

The caries-free group had significantly lower consumption of sweetened beverages and higher tooth brushing frequency. Surprisingly, very few compounds were found to individually provide discriminatory power between caries-experienced and caries-free individuals. The data analysis revealed several potential reasons that could underly this lack of association value with caries, including differences in metabolite concentrations throughout the day, a lack of correlation between metabolite concentrations in plaque and saliva, or sex-related differences, among others. However, when multiple compounds were combined by multivariate analysis and random forest modeling, a combination of 3-5 compounds were found to provide good prediction models for morning (with an AUC accuracy of 0.87) and especially afternoon samples (AUC = 0.93).

CONCLUSION

While few salivary biomarkers could differentiate between caries-free and caries-experienced adolescents, a combination of markers proved effective, particularly in afternoon samples. To predict caries risk, these biomarkers should be validated in larger cohorts and longitudinal settings, considering factors such as gender differences, and variations in oral hygiene and diet.

The salivary microbiome as a diagnostic biomarker of periodontitis: a 16S multi-batch study before and after the removal of batch effects

Introduction

Microbiome-based clinical applications that improve diagnosis related to oral health are of great interest to precision dentistry. Predictive studies on the salivary microbiome are scarce and of low methodological quality (low sample sizes, lack of biological heterogeneity, and absence of a validation process). None of them evaluates the impact of confounding factors as batch effects (BEs). This is the first 16S multi-batch study to analyze the salivary microbiome at the amplicon sequence variant (ASV) level in terms of differential abundance and machine learning models. This is done in periodontally healthy and periodontitis patients before and after removing BEs.

Methods

Saliva was collected from 124 patients (50 healthy, 74 periodontitis) in our setting. Sequencing of the V3-V4 16S rRNA gene region was performed in Illumina MiSeq. In parallel, searches were conducted on four databases to identify previous Illumina V3-V4 sequencing studies on the salivary microbiome. Investigations that met predefined criteria were included in the analysis, and the own and external sequences were processed using the same bioinformatics protocol. The statistical analysis was performed in the R-Bioconductor environment.

Results

The elimination of BEs reduced the number of ASVs with differential abundance between the groups by approximately one-third (Before=265; After=190). Before removing BEs, the model constructed using all study samples (796) comprised 16 ASVs (0.16%) and had an area under the curve (AUC) of 0.944, sensitivity of 90.73%, and specificity of 87.16%. The model built using two-thirds of the specimens (training=531) comprised 35 ASVs (0.36%) and had an AUC of 0.955, sensitivity of 86.54%, and specificity of 90.06% after being validated in the remaining one-third (test=265). After removing BEs, the models required more ASVs (all samples=200-2.03%; training=100-1.01%) to obtain slightly lower AUC (all=0.935; test=0.947), lower sensitivity (all=81.79%; test=78.85%), and similar specificity (all=91.51%; test=90.68%).

Conclusions

The removal of BEs controls false positive ASVs in the differential abundance analysis. However, their elimination implies a significantly larger number of predictor taxa to achieve optimal performance, creating less robust classifiers. As all the provided models can accurately discriminate health from periodontitis, implying good/excellent sensitivities/specificities, the salivary microbiome demonstrates potential clinical applicability as a precision diagnostic tool for periodontitis.

Association of Salivary Vitamin D and Vitamin C Levels with Dental Caries in Children: A Cross-sectional Study

Aim

Dental caries is a prevalent chronic disease affecting children worldwide. This study aimed to investigate the association between dental caries and salivary levels of vitamin D and vitamin C in children.

Materials and methods

This cross-sectional research was conducted at RAK College of Medical Sciences, RAK Medical and Health Sciences University, Ras Al Khaimah, United Arab Emirates, in children between the ages of 4 and 12 years, with a sample of 60 children divided into study and control groups based on the presence or absence of dental caries. Saliva samples were collected, and levels of vitamin D and vitamin C were measured using enzyme-linked immunosorbent assay (ELISA). Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) version 29.

Results

The results showed that children without dental caries had higher salivary vitamin D and vitamin C levels compared to those with caries.

Conclusion

These findings highlight the potential role of these vitamins in preventing dental caries in children and support the need for public health initiatives promoting optimal oral health through appropriate dietary habits and sun exposure.

Clinical significance

The clinical significance of the study lies in its potential to inform preventive strategies and improve oral health outcomes in children. By recognizing the association between salivary vitamin levels and dental caries, healthcare professionals can take proactive steps to promote better oral health and overall well-being in children worldwide.

How to cite this article

Padmanabhan V, Islam MS, Goud M, et al. Association of Salivary Vitamin D and Vitamin C Levels with Dental Caries in Children: A Cross-sectional Study. Int J Clin Pediatr Dent 2024;17(7):773-776.

Salivary Levels of Malondialdehyde and Total Antioxidant Capacity Following Third Molar Surgery - An Evaluative Study

Introduction

Impacted and semi-impacted third molar surgery can lead to considerable distress and discomfort in patients.

Aims

The present study aimed to assess the changes in salivary levels of malondialdehyde (MDA) and total antioxidant capacity (TAC) after third molar surgery.

Materials and Methods

In this study, 210 patients scheduled for third molar surgery were selected. Unstimulated whole saliva samples were collected from patients preoperatively and one week after the surgery, via the 'spitting method'. The collected samples were immediately centrifuged and the supernatants were stored at -20°C until testing. The levels of MDA and TAC were measured with a spectrophotometer.

Results

The results were presented as mean ± standard deviation and paired t-test was used to statistically analyse the changes in pre-operative and post-operative values of MDA and TAC. A decrease of mean salivary TAC (P = 0.031) and an increase of mean salivary MDA (P = 0.034) were detected postoperatively.

Discussion

Following third molar surgery, the increase of mean salivary MDA and the decrease of mean salivary TAC were detected; however, these changes were not statistically significant.

Label-Free Metal-Oxide Transistor Biosensors for Metabolite Detection in Human Saliva

Metabolites are essential molecules involved in various metabolic processes, and their deficiencies and excessive concentrations can trigger significant physiological consequences. The detection of multiple metabolites within a non-invasively collected biofluid could facilitate early prognosis and diagnosis of severe diseases. Here, a metal oxide heterojunction transistor (HJ-TFT) sensor is developed for the label-free, rapid detection of uric acid (UA) and 25(OH)Vitamin-D3 (Vit-D3) in human saliva. The HJ-TFTs utilize a solution-processed In2O3/ZnO channel functionalized with uricase enzyme and Vit-D3 antibody for the selective detection of UA and Vit-D3, respectively. The ultra-thin tri-channel architecture facilitates strong coupling between the electrons transported along the buried In2O3/ZnO heterointerface and the electrostatic perturbations caused by the interactions between the surface-immobilized bioreceptors and target analytes. The biosensors can detect a wide range of concentrations of UA (from 500 nm to 1000 µM) and Vit-D3 (from 100 pM to 120 nm) in human saliva within 60 s. Moreover, the biosensors exhibit good linearity with the physiological concentration of metabolites and limit of detections of ≈152 nm for UA and ≈7 pM for Vit-D3 in real saliva. The specificity is demonstrated against various interfering species, including other metabolites and proteins found in saliva, further showcasing its capabilities.

Saliva assay: a call for methodological standardization

The oral cavity provides an ideal environment for microorganisms, including bacteria, viruses, and fungi, to flourish. Increasing attention has been focused on the connection between the oral microbiome and both oral and systemic diseases, spurring active research into the collection and analysis of specimens for healthcare purposes. Among the various methods for analyzing the oral microbiome, saliva analysis is especially prominent. Saliva samples, which can be collected non-invasively, provide information on the systemic health and oral microbiome composition of an individual. This review was performed to evaluate the current state of the relevant research through an examination of the literature and to suggest an appropriate assay method for investigating the oral microbiome. We analyzed articles published in English in SCI(E) journals after January 1, 2000, ultimately selecting 53 articles for review. Articles were identified through keyword searches in the PubMed, Embase, Cochrane, Web of Science, and CINAHL databases. Three experienced researchers conducted full-text assessments following title and abstract screening to select appropriate papers. Subsequently, they organized and analyzed the desired data. Our review revealed that most studies utilized unstimulated saliva samples for oral microbiome analysis. Of the 53 studies examined, 29 identified relationships between the oral microbiome and various diseases, such as oral disease, Behçet disease, cancer, and oral lichen planus. However, the studies employed diverse methods of collection and analysis, which compromised the reliability and accuracy of the findings. To address the limitations caused by methodological inconsistencies, a standardized saliva assay should be established.

Oral Fluid Biomarkers for Peri-Implantitis: A Scoping Review

Peri-implantitis, a prevalent complication in dental implant therapy, poses a significant threat to long-term implant success. The identification of reliable biomarkers for the early detection and monitoring of peri-implantitis is crucial for timely intervention and improved treatment outcomes. Salivary and peri-implant sulcular fluid (PISF) biomarkers have become promising diagnostic tools in the field of implant dentistry. This scoping review aims to explore current studies in the literature on salivary and PISF biomarkers for peri-implantitis. A systematic search was conducted on 2 databases (PubMed and Scopus) to identify relevant studies published up to January 2023. A total of 86 articles were included, which underwent data extraction and analysis. Several biomarkers have been investigated in salivary and PISF samples for association with peri-implantitis. Investigations included a wide range of biomarkers, including inflammatory markers, matrix metalloproteinases and bone loss markers. The findings suggested that certain salivary and PISF biomarkers demonstrated potential in distinguishing healthy peri-implant conditions from peri-implantitis. Elevated levels of proinflammatory cytokines, such as interleukin-1β (IL-1β) and interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-α), and matrix metalloproteinases, have been consistently associated with peri-implantitis. Additionally, alterations in bone loss markers have shown potential as indicators of disease progression and treatment response. In conclusion, this scoping review provides an overview of current knowledge on salivary and PISF biomarkers for peri-implantitis. The identified biomarkers are promising as noninvasive diagnostic tools for early detection, monitoring, and personalised management of peri-implantitis. Future studies should focus on establishing standardised protocols and conducting well-designed clinical trials to validate the diagnostic accuracy and clinical relevance of these biomarkers.

Evaluation of salivary placental growth factor in Health and Periodontitis

BACKGROUND

Various immune mediators have a role in the progression of periodontitis. Placental Growth Factor (PLGF) is important during pregnancy and also is involved in the pathology of several diseases. Hence, this study aimed to evaluate salivary PLGF in health and periodontitis that seemingly has not been reported earlier.

METHODS

Fifty participants were grouped as healthy and periodontitis patients. Clinical history, periodontal parameters [Plaque Index (PI), Gingival Index (GI), probing pocket depth (PPD), clinical attachment loss (CAL), bleeding on probing (BoP)] were recorded; saliva was collected and PLGF was estimated using a commercially available ELISA kit. The data were statistically analyzed using Shapiro-Wilk's test, Kruskal-Wallis test, Dunn's post hoc test with Bonferroni correction, and Spearman's rank-order correlation coefficient. The significance level was set at p ≤ 0.05 for all tests.

RESULTS

Salivary PLGF levels comparison between the two groups showed no significant difference between both groups. Quantitatively, females had higher salivary PLGF levels than males. No significant association was observed between salivary PLGF levels and the severity of periodontitis. The periodontitis group showed statistically significant correlations between salivary PLGF levels, BoP(p = 0.005) and PPD(p = 0.005), and significant correlations of PLGF with PPD (p = 0.035) for both groups.

CONCLUSIONS

PLGF can be detected and measured in the saliva of healthy individuals and periodontitis patients. However, the role of PLGF in periodontal pathology needs to be further confirmed based on their salivary levels.

Infrared spectroscopy for fast screening of diabetes and periodontitis

SIGNIFICANCE

FT-IR is an important and emerging tool, providing information related to the biochemical composition of biofluids. It is important to demonstrate that there is an efficacy in separating healthy and diseased groups, helping to establish FT-IR uses as fast screening tool.

AIM

Via saliva diagnosis evaluate the accuracy of FT-IR associate with machine learning model for classification among healthy (control group), diabetic (D) and periodontitis (P) patients and the association of both diseases (DP).

APPROACH

Eighty patients diagnosed with diabetes and periodontitis through conventional methods were recruited and allocated in one of the four groups. Saliva samples were collected from participants of each group (n = 20) and were processed using Bruker Alpha II spectrometer in a FT-IR spectral fingerprint region between 600 and-1800 cm-1, followed by data preprocessing and analysis using machine learning tools.

RESULTS

Various FTI-R peaks were detectable and attributed to specific vibrational modes, which were classified based on confusion matrices showed in paired groups. The highest true positive rates (TPR) appeared between groups C vs D (93.5 % ± 2.7 %), groups C vs. DP (89.2 % ± 4.1 %), and groups D and P (90.4 % ± 3.2 %). However, P vs DP presented higher TPR for DP (84.1 % ±3.1 %) while D vs. DP the highest rate for DP was 81.7 % ± 4.3 %. Analyzing all groups together, the TPR decreased.

CONCLUSION

The system used is portable and robust and can be widely used in clinical environments and hospitals as a new diagnostic technique. Studies in our groups are being conducted to solidify and expand data analysis methods with friendly language for healthcare professionals. It was possible to classify healthy patients in a range of 78-93 % of accuracy. Range over 80 % of accuracy between periodontitis and diabetes were observed. A general classification model with lower TPR instead of a pairwise classification would only have advantages in scenarios where no prior patient information is available regarding diabetes and periodontitis status.

Changes in the nasopharyngeal and oropharyngeal microbiota in pediatric obstructive sleep apnea before and after surgery: a prospective study

OBJECTIVE

To explore the changes and potential mechanisms of microbiome in different parts of the upper airway in the development of pediatric OSA and observe the impact of surgical intervention on oral microbiome for pediatric OSA.

METHODS

Before adeno-tonsillectomy, we collected throat swab samples from different parts of the oropharynx and nasopharynx of 30 OSA patients and 10 non-OSA patients and collected throat swab samples from the oropharynx of the above patients one month after the adeno-tonsillectomy. The 16 S rRNA V3-V4 region was sequenced to identify the microbial communities. The correlation analysis was conducted based on clinical characteristics.

RESULTS

There was a significant difference of alpha diversity in different parts of the upper airway of pediatric OSA, but this difference was not found in children with non-OSA. Beta diversity was significantly different between non-OSA and pediatric OSA. At the genus level, the composition of flora in different parts is different between non-OSA and pediatric OSA. The correlation analysis revealed that the relative abundance of Neisseria was significantly correlated with obstructive apnea hypopnea index. Furthermore, the functional prediction revealed that pathways related to cell proliferation and material metabolism were significantly different between non-OSA and pediatric OSA. Besides, the adeno-tonsillectomy has minimal impact on oral microbiota composition in short term.

CONCLUSION

The changes in upper airway microbiome are highly associated with pediatric OSA. The relative abundance of some bacteria was significantly different between OSA and non-OSA. These bacteria have the potential to become new diagnostic and early warning biomarkers.

Salivary IgA and vimentin differentiate in vitro SARS-CoV-2 infection: A study of 290 convalescent COVID-19 patients

SARS-CoV-2 initially infects cells in the nasopharynx and oral cavity. The immune system at these mucosal sites plays a crucial role in minimizing viral transmission and infection. To develop new strategies for preventing SARS-CoV-2 infection, this study aimed to identify proteins that protect against viral infection in saliva. We collected 551 saliva samples from 290 healthcare workers who had tested positive for COVID-19, before vaccination, between June and December 2020. The samples were categorized based on their ability to block or enhance infection using in vitro assays. Mass spectrometry and enzyme-linked immunosorbent assay experiments were used to identify and measure the abundance of proteins that specifically bind to SARS-CoV-2 antigens. Immunoglobulin (Ig)A specific to SARS-CoV-2 antigens was detectable in over 83% of the convalescent saliva samples. We found that concentrations of anti-receptor-binding domain IgA >500 pg/µg total protein in saliva correlate with reduced viral infectivity in vitro. However, there is a dissociation between the salivary IgA response to SARS-CoV-2, and systemic IgG titers in convalescent COVID-19 patients. Then, using an innovative technique known as spike-baited mass spectrometry, we identified novel spike-binding proteins in saliva, most notably vimentin, which correlated with increased viral infectivity in vitro and could serve as a therapeutic target against COVID-19.

Aggregation and beyond: alpha-synuclein-based biomarkers in synucleinopathies

Parkinson's disease is clinically known for the loss of dopaminergic neurons in the substantia nigra pars compacta and accumulation of intraneuronal cytoplasmic inclusions rich in alpha-synuclein called 'Lewy bodies' and 'Lewy neurites'. Together with dementia with Lewy bodies and multiple system atrophy, Parkinson's disease is part of a group of disorders called synucleinopathies. Currently, diagnosis of synucleinopathies is based on the clinical assessment which often takes place in advanced disease stages. While the causal role of alpha-synuclein aggregates in these disorders is still debatable, measuring the levels, types or seeding properties of different alpha-synuclein species hold great promise as biomarkers. Recent studies indicate significant differences in peptide, protein and RNA levels in blood samples from patients with Parkinson's disease. Seed amplification assays using CSF, blood, skin biopsy, olfactory swab samples show great promise for detecting synucleinopathies and even for discriminating between different synucleinopathies. Interestingly, small extracellular vesicles, such as exosomes, display differences in their cargoes in Parkinson's disease patients versus controls. In this update, we focus on alpha-synuclein aggregation and possible sources of disease-related species released in extracellular vesicles, which promise to revolutionize the diagnosis and the monitoring of disease progression.

Assessment of self-rated pain perception and whole salivary cortisol levels among adolescents with and without temporomandibular disorders

OBJECTIVE

To assess the self-perceived pain perception (PP) and whole salivary cortisol levels (CL) among adolescents with and without temporomandibular disorders (TMD).

METHODS

Adolescents between 15 and 17 years were included. Participants were categorized into three groups: Group 1: patients with TMD; Group 2: nocturnalbruxers without TMD; and Group 3: controls. Demographic data CL and self-rated PP were assessed. A p-value < 0.05 was proposed as statistically significant.

RESULTS

Fifty-four patients (18 per group) were included. Scores of self-rated PP in the affected TMJ were higher in Group 1 than Group 2 (p < 0.001). Whole salivary CL were higher in groups 1 and 2 (p < 0.01) than in Group 3. Whole salivary CL were higher in Group 2 than Group 3 (p < 0.05).

CONCLUSION

Whole salivary CL are higher in adolescents with TMD, and there is a direct relationship between self-rated PP in the TMJ area and salivary CL.

The role and mechanism of tight junctions in the regulation of salivary gland secretion

Tight junctions (TJs) are cell-cell interactions that localize at the most apical portion of epithelial/endothelial cells. One of the predominant functions of TJs is to regulate material transport through paracellular pathway, which serves as a selective barrier. In recent years, the expression and function of TJs in salivary glands has attracted great interest. The characteristics of multiple salivary gland TJ proteins have been identified. During salivation, the activation of muscarinic acetylcholine receptor and transient receptor potential vanilloid subtype 1, as well as other stimuli, promote the opening of acinar TJs by inducing internalization of TJs, thereby contributing to increased paracellular permeability. Besides, endothelial TJs are also redistributed with leakage of blood vessels in cholinergic-stimulated submandibular glands. Furthermore, under pathological conditions, such as Sjögren's syndrome, diabetes mellitus, immunoglobulin G4-related sialadenitis, and autotransplantation, the integrity and barrier function of TJ complex are impaired and may contribute to hyposalivation. Moreover, in submandibular glands of Sjögren's syndrome mouse model and patients, the endothelial barrier is disrupted and involved in hyposecretion and lymphocytic infiltration. These findings enrich our understanding of the secretory mechanisms that link the importance of epithelial and endothelial TJ functions to salivation under both physiological and pathophysiological conditions.

Digital methylation-specific PCR: New applications for liquid biopsy

Epigenetic analysis is a fundamental part of understanding pathophysiological processes with potential applications in diagnosis, prognosis, and assessment of disease susceptibility. Epigenetic changes have been widely studied in chronic obstructive pulmonary disease (COPD), but currently, there is no molecular marker used to improve the treatment of patients. Furthermore, this progressive disease is a risk factor for the development of more severe COVID-19. Methylation-specific polymerase chain reaction (MSP-PCR) plays an important role in the analysis of DNA methylation profiles, and it is one of the most widely used techniques. In this context, the combination of MSP-PCR with emerging PCR technologies, such as digital PCR (dPCR), results in more accurate analyses of the DNA methylation profile of the genes under study. In this study, we propose the application of the MSP-dPCR technique to evaluate the methylation profile of the ADAM33 gene from saliva samples and lung tissue biopsies of patients with COPD and COVID-19. MSP-dPCR generated a measurable prediction of gene methylation rate, with the potential application of this combined technology for diagnostic and prognostic purposes. It has also proven to be a powerful tool for liquid biopsy applications.

Artificial intelligence in salivary biomarker discovery and validation for oral diseases

Salivary biomarkers can improve the efficacy, efficiency, and timeliness of oral and maxillofacial disease diagnosis and monitoring. Oral and maxillofacial conditions in which salivary biomarkers have been utilized for disease-related outcomes include periodontal diseases, dental caries, oral cancer, temporomandibular joint dysfunction, and salivary gland diseases. However, given the equivocal accuracy of salivary biomarkers during validation, incorporating contemporary analytical techniques for biomarker selection and operationalization from the abundant multi-omics data available may help improve biomarker performance. Artificial intelligence represents one such advanced approach that may optimize the potential of salivary biomarkers to diagnose and manage oral and maxillofacial diseases. Therefore, this review summarized the role and current application of techniques based on artificial intelligence for salivary biomarker discovery and validation in oral and maxillofacial diseases.

Scalable noninvasive amplicon-based precision sequencing (SNAPseq) for genetic diagnosis and screening of β-thalassemia and sickle cell disease using a next-generation sequencing platform

β-hemoglobinopathies such as β-thalassemia (BT) and Sickle cell disease (SCD) are inherited monogenic blood disorders with significant global burden. Hence, early and affordable diagnosis can alleviate morbidity and reduce mortality given the lack of effective cure. Currently, Sanger sequencing is considered to be the gold standard genetic test for BT and SCD, but it has a very low throughput requiring multiple amplicons and more sequencing reactions to cover the entire HBB gene. To address this, we have demonstrated an extraction-free single amplicon-based approach for screening the entire β-globin gene with clinical samples using Scalable noninvasive amplicon-based precision sequencing (SNAPseq) assay catalyzing with next-generation sequencing (NGS). We optimized the assay using noninvasive buccal swab samples and simple finger prick blood for direct amplification with crude lysates. SNAPseq demonstrates high sensitivity and specificity, having a 100% agreement with Sanger sequencing. Furthermore, to facilitate seamless reporting, we have created a much simpler automated pipeline with comprehensive resources for pathogenic mutations in BT and SCD through data integration after systematic classification of variants according to ACMG and AMP guidelines. To the best of our knowledge, this is the first report of the NGS-based high throughput SNAPseq approach for the detection of both BT and SCD in a single assay with high sensitivity in an automated pipeline.

Evaluation of Diagnostic Significance of Salivary miRNA-184 and miRNA-21 in Oral Squamous Cell Carcinoma and Oral Potentially Malignant Disorders

BACKGROUND

Altered levels of miRNAs might affect the pathogenesis of oral squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMD). This study evaluated the diagnostic potential of salivary miRNA-21 and miRNA-184 in OSCC and OPMD.

METHODS

We recruited a total of 90 subjects including OSCC, OPMD, and healthy controls. RNA was isolated from the saliva samples of the study subjects. Expression of miRNA-21 and miRNA-184 was analyzed using qRT-PCR. Their levels were compared and the diagnostic cut-off was determined using the ROC curve.

RESULTS

There was a significant increase in miRNA-21 and a decrease in miRNA-184 in OSCC and OPMD as compared to healthy controls (p < 0.001). Levels of salivary miRNA-21 and miRNA-184 can differentiate OSCC and OPMD from controls and premalignant conditions from malignant conditions.

CONCLUSION

Salivary miRNA-21 and miRNA-184 may be beneficial for the early detection of OSCC and OPMD. Also, saliva can be used for detecting neoplastic transformation of oral mucosa since it is non-invasive and easily accessible.

Metabolomics analysis in saliva from periodontally healthy, gingivitis and periodontitis patients

OBJECTIVE

The aim of this study was to investigate metabolomics markers in the saliva of patients with periodontal health, gingivitis and periodontitis.

BACKGROUND

The use of metabolomics for diagnosing and monitoring periodontitis is promising. Although several metabolites have been reported to be altered by inflammation, few studies have examined metabolomics in saliva collected from patients with different periodontal phenotypes.

METHODS

Saliva samples collected from a total of 63 patients were analysed by nuclear magnetic resonance (NMR) followed by ELISA for interleukin (IL)-1β. The patient sample, well-characterised clinically, included periodontal health (n = 8), gingivitis (n = 19) and periodontitis (n = 36) cases, all non-smokers and not diabetic.

RESULTS

Periodontal diagnosis (healthy/gingivitis/periodontitis) was not associated with any salivary metabolites in this exploratory study. Periodontal staging showed nominal associations with acetoin (p = .030) and citrulline (p = .047). Among other investigated variables, the use of systemic antibiotics in the previous 3 months was associated with higher values of the amino acids taurine, glycine and ornithine (p = .002, p = .05 and p = .005, respectively, at linear regression adjusted for age, gender, ethnicity, body mass index and staging).

CONCLUSION

While periodontal staging was marginally associated with some salivary metabolites, other factors such as systemic antibiotic use may have a much more profound effect on the microbial metabolites in saliva. Metabolomics in periodontal disease is still an underresearched area that requires further observational studies on large cohorts of patients, aiming to obtain data to be used for clinical translation.

Oxidative Stress Enzyme as Markers in Oral Potentially Malignant Disorders and Oral Squamous Cell Carcinoma Patients

Oxidative stress is a recognized factor that poses a significant risk for the development of Oral Squamous Cell Carcinoma (OSCC) and Oral Submucous Fibrosis (OSMF), as it leads to the generation of Reactive Oxygen Species. In recent years, there has been significant research on the enzymes MDA (malondialdehyde) and SOD (superoxide dismutase), investigating their potential role in the development of OPMD and OSCC. These enzymes have emerged as promising biomarkers due to their ability to provide a less invasive, cost-effective, and objective diagnostic method. Furthermore, they can be used to monitor disease progression and assess the effectiveness of therapy. The aim of this study was to assess the levels of MDA and SOD in the serum of patients diagnosed with OSCC and OSMF. Study group comprised of 60 patients, out of which 20 cases of clinically diagnosed OSCC patients and 20 cases of OSMF and 20 cases pf control comprising of healthy patients were recruited. Estimation MDA and SOD was done by ELISA. The statistical analysis was done using SPSS analysis. When comparing the levels of MDA and SOD between the OSCC and OSMF groups and the control group, statistically significant findings indicated elevated levels of malondialdehyde and reduced levels of superoxide dismutase in both the OSCC and OSMF groups. In this study, the assessment of lipid peroxidation through MDA levels revealed elevated concentrations in both the OSCC and OSMF groups when compared to the control group. Specifically, the order of MDA levels was observed as OSCC > OSMF > Control. Conversely, antioxidant enzyme levels, such as SOD, exhibited decreased concentrations in the OSCC and OSMF groups compared to the control group, with the order of SOD levels being Control > OSMF > OSCC. Consequently, the findings suggest that MDA and SOD can be considered potential biomarkers for identifying and monitoring OSCC and OSMF diseases.

Distribution of common and rare drug resistance patterns in Mycobacterium tuberculosis clinical isolates revealed by GenoType MTBDRplus and MTBDRsl assay

Background

Tuberculosis (TB) remains a significant global health emergency caused by Mycobacterium tuberculosis (Mtb). The epidemiology, transmission, genotypes, mutational patterns, and clinical consequences of TB have been extensively studied worldwide, however, there is a lack of information regarding the epidemiology and mutational patterns of Mtb in Pakistan, specifically concerning the prevalence of multi-drug resistant TB (MDR-TB).

Methods

This study aimed to investigate the incidence of Mtb and associated mutational patterns using the line probe assay (LPA). Previous studies have reported a high frequency of mutations in the rpoB, inhA, and katG genes, which are associated with resistance to rifampicin (RIF) and isoniazid (INH). Therefore, the current study utilized LPA to detect mutations in the rpoB, katG, and inhA genes to identify multi-drug resistant Mtb.

Results

LPA analysis of a large pool of Mtb isolates, including samples from 241 sputum-positive patients, revealed that 34.85% of isolates were identified as MDR-TB, consistent with reports from various regions worldwide. The most prevalent mutations observed were rpoB S531L and inhA promoter C15T, which were associated with resistance to RIF and INH, respectively.

Conclusions

This study highlights the effectiveness of GenoType MTBDRplus and MTBDRsl assays as valuable tools for TB management. These assays enable rapid detection of resistance to RIF, INH, and fluoroquinolones (FQs) in Mtb clinical isolates, surpassing the limitations of solid and liquid media-based methods. The findings contribute to our understanding of MDR-TB epidemiology and provide insights into the genetic profiles of Mtb in Pakistan, which are essential for effective TB control strategies.

Recent advances of drugs monitoring in oral fluid and comparison with blood

The use of alternative matrices in toxicological analyses has been on the rise in clinical and forensic settings. Oral fluid (OF), as non-invasive fluid, has attracted attention in the field of drug screening, both for therapeutic and forensic purposes, as well as for medical diagnosis, clinical management, on-site (real time) doping and for monitoring environmental exposure to toxic substances. A good correlation between OF and blood is now established for drug concentrations. Therefore, OF might be a potential substitute of blood, especially for long-term surveillance (e.g., therapeutic drugs) or to screen a large number of patients, as well as for the development of salivary point-of-care technologies. In this review, we aimed to summarize and critically evaluate the current literature that focused on the comparison of drugs detection in OF and blood specimens.

Willingness for Medical Screening in a Dental Setting-A Pilot Questionnaire Study

An important way to manage noncommunicable diseases (NCDs) is to focus on prevention, early detection, and reducing associated risk factors. Risk factors can be detected with simple general health checks, which can also be performed in dental clinics. The purpose of this study was to investigate participants' willingness to participate in general health checks at the dentist, in particular the difference in opinion between medical patients and random healthy dental attendees. A total of 100 medical patients from an outpatient internal medicine clinic and 100 dental clinic attendees were included (total of 200 participants). The participants were asked for their opinion using six closed-ended questions. Overall, 91.0% of participants were receptive to information about the risk of diabetes mellitus (DM) and cardiovascular diseases (CVD). The majority (80-90%) was receptive to screening for DM and CVD risk, such as weight and height measurements, blood pressure measurement, saliva testing for CVD and to measure glucose and cholesterol via finger stick. No significant differences were found in the frequencies of the responses between the different groups based on health status, age, sex, or cultural background. This study shows that most participants are willing to undergo medical screening at the dentist for early detection and/or prevention of common NCDs.

Non-invasive, ultrasensitive detection of glucose in saliva using metal oxide transistors

Transistor-based biosensors represent an emerging technology for inexpensive point-of-care testing (POCT) applications. However, the limited sensitivity of the current transistor technologies hinders their practical deployment. In this study, we developed tri-channel In2O3/ZnO heterojunction thin-film transistors (TFTs) featuring the surface-immobilized enzyme glucose oxidase to detect glucose in various biofluids. This unusual channel design facilitates strong coupling between the electrons transported along the buried In2O3/ZnO heterointerface and the electrostatic perturbations caused by the interactions between glucose and surface-immobilized glucose oxidase. The enzyme selectively binds to glucose, causing a change in charge density on the channel surface. By exploring this effect, the solid-state biosensing TFT (BioTFT) can selectively detect glucose in artificial and real saliva over a wide range of concentrations from 500 nM to 20 mM with limits of detection of ∼365 pM (artificial saliva) and ∼416 nM (real saliva) in less than 60 s. The specificity of the sensor towards glucose has been demonstrated against various interfering species in artificial saliva, further highlighting its unique capabilities. Moreover, the BioTFTs exhibited good operating stability upon storage for up to two weeks, with relative standard deviation (RSD) values ranging from 2.36% to 6.39% for 500 nM glucose concentration. Our BioTFTs are easy to manufacture with reliable operation, making them ideal for non-invasive POCT applications.

Wearable sensor platforms for real-time monitoring and early warning of metabolic disorders in humans

Nowadays, the prevalence of metabolic syndromes (MSs) has attracted increasing concerns as it is closely related to overweight and obesity, physical inactivity and overconsumption of energy, making the diagnosis and real-time monitoring of the physiological range essential and necessary for avoiding illness due to defects in the human body such as higher risk of cardiovascular disease, diabetes, stroke and diseases related to artery walls. However, the current sensing techniques are inconvenient and do not continuously monitor the health status of humans. Alternatively, the use of recent wearable device technology is a preferable method for the prevention of these diseases. This can enable the monitoring of the health status of humans in different health domains, including environment and structure. The use wearable devices with the purpose of facilitating rapid treatment and real-time monitoring can decrease the prevalence of MS and long-time monitor the health status of patients. This review highlights the recent advances in wearable sensors toward continuous monitoring of blood pressure and blood glucose, and further details the monitoring of abnormal obesity, triglycerides and HDL. We also discuss the challenges and future prospective of monitoring MS in humans.

Oral squamous cell carcinomas: state of the field and emerging directions

Oral squamous cell carcinoma (OSCC) develops on the mucosal epithelium of the oral cavity. It accounts for approximately 90% of oral malignancies and impairs appearance, pronunciation, swallowing, and flavor perception. In 2020, 377,713 OSCC cases were reported globally. According to the Global Cancer Observatory (GCO), the incidence of OSCC will rise by approximately 40% by 2040, accompanied by a growth in mortality. Persistent exposure to various risk factors, including tobacco, alcohol, betel quid (BQ), and human papillomavirus (HPV), will lead to the development of oral potentially malignant disorders (OPMDs), which are oral mucosal lesions with an increased risk of developing into OSCC. Complex and multifactorial, the oncogenesis process involves genetic alteration, epigenetic modification, and a dysregulated tumor microenvironment. Although various therapeutic interventions, such as chemotherapy, radiation, immunotherapy, and nanomedicine, have been proposed to prevent or treat OSCC and OPMDs, understanding the mechanism of malignancies will facilitate the identification of therapeutic and prognostic factors, thereby improving the efficacy of treatment for OSCC patients. This review summarizes the mechanisms involved in OSCC. Moreover, the current therapeutic interventions and prognostic methods for OSCC and OPMDs are discussed to facilitate comprehension and provide several prospective outlooks for the fields.

Physical and chemical properties of saliva and its role in Early Childhood caries - A systematic review and meta-analysis

Background

Early Childhood Caries is a chronic disease of childhood and salivary parameters are considered as one of the prime etiological factors of Early Childhood Caries.

Aim

To develop a systematic review based on the relation between physical and chemical properties of saliva and Early childhood caries by comparing children with and without Early childhood caries.

Methods

PubMed, Cochrane, Lilacs, Embase, Scopus, and additional manual search was done up to April 2021 to identify the original cross-sectional observational studies published in English. The risk of bias and quality of the included papers were assessed based on New castle Ottawa guidelines.

Results

From a total of 1709 identified studies, only 22 articles were included in this systematic review and 10 studies were qualified for meta-analysis. Eight studies were classified as ''moderate risk of bias'' and fourteen studies were classified as ''high risk of bias''.

Conclusion

There was a significant difference in physical and chemical properties of saliva in children with and without Early childhood caries. Since wide disparity were evident in available studies, further studies are needed to arrive to a definitive conclusion.

The Role of Uroguanylin in Regulation of Ion Transport in Salivary Glands

Objectives

Guanylin peptides are considered to be the only intrinsic regulators of salivary glands secretion. Therefore, the aim of this study was to determine the effects of systemic uroguanylin (UGN) of the salivary flow and ion composition. Besides, the objective was to investigate whether those effects include activation of guanylate cyclase C (GC-C).

Material and Methods

This study was conducted on 7 months old C57Bl6NCrl (wild type, WT) and GC-C knockout (KO) mice. Salivary flow rate and ion composition were determined after pilocarpine stimulation with UGN (30 µg/animal) or saline i.p. application. The expression of mRNA for AQPs, NHEs, NBCn1, Slc26a3/a6 and CFTR were determined by qPCR in submandibular salivary glands.

Results

When applied i.p., UGN decreased the pilocarpine stimulated saliva flow rate and increased the concentration of Na+, H+ and Cl-. In GC-C KO mice, UGN showed no effect on saliva flow rate, while the concentrations of Na+, H+ and Cl- are the same in GC-C KO littermates when compared to WT mice. UGN increased expression of Slc26a6 while in GC-C KO mice Slc26a6 had a higher expression when compared to WT mice, suggesting involvement of GC-C independent signalling pathway for UGN. The difference in Slc26a6 in GC-C KO mice is not unique for salivary glands because it was also found in duodenum and kidney cortex.

Conclusions

The effects of UGN via basolateral membrane of salivary glands cells have not been considered up to date. In our study, UGN, when applied i.p., decreased salivary flow rate, pH, and changed the composition of other ions. Therefore, plasma UGN, an hour after a meal, could have physiological and pathological importance (development of cavities, inflammations or demineralizations), and the inhibition of systemic UGN effects could be considered a new approach in treatment of those conditions.

Association between Salivary Cortisol Levels, Dental Anxiety, and Dental Caries in Children: A Cross-Sectional Study

AIM

This study aimed to investigate the relationship between dental caries, dental anxiety, and salivary cortisol levels in children visiting pediatric dental clinics and their implications on pediatric oral health.

MATERIALS AND METHODS

A cross-sectional study was conducted at a dental university in the UAE. A total of 60 children, aged 4-12 years, were included. Salivary cortisol levels were measured using an Enzyme-Linked Immunosorbent Assay (ELISA) kit. Dental caries status was evaluated, and dental anxiety levels were assessed using the Modified Dental Anxiety Scale (MDAS). Statistical analyses, including Mann-Whitney U test and Pearson's correlation coefficient, were performed to determine significant differences and associations.

RESULTS

The study group showed significantly higher salivary cortisol levels compared to the control group (p < 0.0001). A strong positive correlation was found between salivary cortisol levels and dental caries status (p < 0.001). However, no significant difference in dental anxiety levels was observed between the study and control groups (p = 0.85). A strong positive correlation was found between dental anxiety levels and dental caries status (p < 0.001).

CONCLUSION

The findings indicate a significant association between salivary cortisol levels and dental caries, suggesting that higher cortisol levels are associated with active caries. Dental anxiety levels were positively correlated with dental caries. Understanding the relationship between these variables can contribute to better oral health strategies and interventions for children, emphasizing the importance of managing dental anxiety and stress in pediatric dental care.

CLINICAL SIGNIFICANCE

This study highlights the potential of salivary cortisol as a biomarker for assessing stress and its impact on oral health in children. By addressing dental anxiety and stress, dental professionals can provide child-friendly dental care, enhance preventive measures, and improve oral health outcomes in pediatric patients.

Evaluation of Salivary Alkaline Phosphatase Levels in Passive Smokers of Different Age Groups

Background The smoke inhaled by a nonsmoker from the smoldering end of a cigarette is referred to as passive smoke. The nicotine present in smoke is known to cause tissue damage and alter the enzymatic composition of the body. Alkaline phosphatase (ALP) is a group of intracellular hydrolytic enzymes known to partake in cellular metabolism. ALP levels are affected by smoking as well as passive smoking (PS) with a change in the pH of the oral cavity. The association of salivary alkaline phosphatase (S-ALP) levels in different age groups, gender, and times of exposure is not thoroughly explored yet, which was the primary aim of this study. Material and methods A total of 64 samples were collected from passive smokers and non-smokers. Unstimulated saliva (2-2.5 mL) was collected from each subject after obtaining their consent, followed by centrifuging and mixing with ALP reagent in a semi-autoanalyzer to obtain the S-ALP levels. Results Higher S-ALP levels were seen in passive smokers (34.70 IU/L) compared to healthy individuals (12 IU/L), which came to be statistically significant (p<0.01). S-ALP levels, when compared to different age groups and gender, were statistically insignificant (p>0.05). However, higher levels were seen in association with time of exposure in passive smokers where the data was statistically significant (p<0.01), suggesting tissue damage possibly due to oxidative stresses and tissue inflammation on continuous exposure for a minimum of 30-60 minutes daily as per our study. Conclusion Significantly high levels of S-ALP were found in passive smokers in comparison to non-smokers. This suggests that passive smoking has negative effects on the body tissues. Age, gender, and time of exposure of a non-smoker to tobacco smoke can lead to alterations in S-ALP levels. High levels of S-ALP were seen in individuals with prolonged exposure to tobacco smoke on a daily basis. Salivaomics can thus be used as a non-invasive, economical, and accurate alternative in tissue damage diagnosis.

Characteristics of the Salivary Microbiota in Periodontal Diseases and Potential Roles of Individual Bacterial Species To Predict the Severity of Periodontal Disease

The purposes of this study were to examine the compositional changes in the salivary microbiota according to the severity of periodontal disease and to verify whether the distribution of specific bacterial species in saliva can distinguish the severity of disease. Saliva samples were collected from 8 periodontally healthy controls, 16 patients with gingivitis, 19 patients with moderate periodontitis, and 29 patients with severe periodontitis. The V3 and V4 regions of the 16S rRNA gene in the samples were sequenced, and the levels of 9 bacterial species showing significant differences among the groups by sequencing analysis were identified using quantitative real-time PCR (qPCR). The predictive performance of each bacterial species in distinguishing the severity of disease was evaluated using a receiver operating characteristic curve. Twenty-nine species, including Porphyromonas gingivalis, increased as the severity of disease increased, whereas 6 species, including Rothia denticola, decreased. The relative abundances of P. gingivalis, Tannerella forsythia, Filifactor alocis, and Prevotella intermedia determined by qPCR were significantly different among the groups. The three bacterial species P. gingivalis, T. forsythia, and F. alocis were positively correlated with the sum of the full-mouth probing depth and were moderately accurate at distinguishing the severity of periodontal disease. In conclusion, the salivary microbiota showed gradual compositional changes according to the severity of periodontitis, and the levels of P. gingivalis, T. forsythia, and F. alocis in mouth rinse saliva had the ability to distinguish the severity of periodontal disease. IMPORTANCE Periodontal disease is one of the most widespread medical conditions and the leading cause of tooth loss, imposing high economic costs and an increasing burden worldwide as life expectancy increases. Changes in the subgingival bacterial community during the progression of periodontal disease can affect the entire oral ecosystem, and bacteria in saliva can reflect the degree of bacterial imbalance in the oral cavity. This study explored whether the specific bacterial species in saliva can distinguish the severity of periodontal disease by analyzing the salivary microbiota and suggested P. gingivalis, T. forsythia, and F. alocis as biomarkers for distinguishing the severity of periodontal disease in saliva.

Utilization of a Glucometer Test Strip and Enzymatic Reactions to Quantify Anti-SARS-CoV-2 Spike RBD IgG Antibody and SARS-CoV-2 Virus in Saliva and Serum

A sensor capable of quantifying both anti-SARS-CoV-2 spike receptor-binding domain (RBD) antibody levels and the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in saliva and serum was developed. This was accomplished by exploiting the enzymatic reaction of maltose and orthophosphate (PO43-) in the presence of maltose phosphorylase to generate an equivalent amount of glucose that was detected using a commercial glucometer test strip and a potentiostat. Important for this approach is the ability to generate PO43- in an amount that is directly related to the concentration of the analytes. RBD-modified magnetic microparticles were used to capture anti-SARS-CoV-2 spike RBD antibodies, while particles modified with anti-SARS-CoV-2 nucleocapsid antibodies were used to capture SARS-CoV-2 nucleocapsid protein from inactivated virus samples. A magnet was used to isolate and purify the magnetic microparticles (with analyte attached), and alkaline phosphatase-conjugated secondary antibodies were bound to the analytes attached to the respective magnetic microparticles. Finally, through enzymatic reactions, specific amounts of PO43- (and subsequently glucose) were generated in proportion to the analyte concentration, which was then quantified using a commercial glucometer test strip. Utilizing glucose test strips makes the sensor relatively inexpensive, with a cost per test of ∼US $7 and ∼US $12 for quantifying anti-SARS-CoV-2 spike RBD antibody and SARS-CoV-2, respectively. Our sensor exhibited a limit of detection of 0.42 ng/mL for anti-SARS-CoV-2 spike RBD antibody, which is sensitive enough to quantify typical concentrations of antibodies in COVID-19-infected or vaccinated individuals (>1 μg/mL). The limit of detection for the SARS-CoV-2 virus is 300 pfu/mL (5.4 × 106 RNA copies/mL), which exceeds the performance recommended by the WHO (500 pfu/mL). In addition, the sensor exhibited good selectivity when challenged with competing analytes and could be used to quantify analytes in saliva and serum matrices with an accuracy of >94% compared to RT-qPCR.

Evaluating Pre-Analytical Variables for Saliva Cell-Free DNA Liquid Biopsy

Liquid biopsy utilizing cell-free DNA (cfDNA) has become an emergent field of study for cancer screening and monitoring. While blood-based liquid biopsy has been investigated extensively, there are advantages to using other body fluids. Using saliva is noninvasive, repeatable, and it may be enriched with cfDNA from certain cancer types. However, the lack of standardization in the pre-analytical phase of saliva-based testing is a concern. In this study, we evaluated pre-analytical variables that impact cfDNA stability in saliva specimens. Using saliva from healthy individuals, we tested different collection devices and preservatives and their effects on saliva cfDNA recovery and stability. Novosanis's UAS preservative helped stabilize cfDNA at room temperature for up to one week. Our study provides useful information for further improvements in saliva collection devices and preservatives.

Salivary leukocyte esterase activity by SillHa is a risk indicator of periodontal disease

BACKGROUND

There is increasing evidence that diagnostic salivary tests measuring inflammatory biomarkers are being developed to assess inflammatory status for early detection, prevention, and progression of periodontal disease. Therefore, the aim of the present study was to investigate and identify the salivary biomarker that can predict the inflammatory status of periodontal disease.

METHODS

A total of 36 patients (28 women and 8 men) with an average age of 57 years were investigated. Unstimulated saliva was collected from the recruited subjects and analyzed using SillHa, a saliva-testing device that measures bacteria count, saliva buffer capacity, acidity, leukocyte esterase, protein, and ammonia. Periodontal parameters were then obtained by clinical examination and initial periodontal therapy was performed. Data obtained with SillHa were compared with clinical periodontal parameters at baseline, re-examination (three months from baseline), and final examination (six months from re-examination).

RESULTS

Leukocyte esterase activity in saliva measured by SillHa; BOP and PCR measured by clinical examination showed a significant difference between baseline and final examination and between re-examination and final examination. Patients in the lower median group (group 1) had a significant difference in leukocyte esterase activity between baseline and final examination and re-examination and final examination. In addition, patients in Group 1 had significantly lower BOP between baseline and final examination. While patients in the higher median group (group 2) showed a modest decrease in leukocyte esterase activity, which was significant only between baseline and final examination, no significant changes were observed concerning BOP. Furthermore, the associated systemic disease was observed in 30% and 81.2% of group 1 and 2 patients, respectively.

CONCLUSION

The results suggest that leukocyte esterase activity in saliva measured by SillHa could serve as a reliable diagnostic marker for monitoring inflammatory status in periodontal disease.