Salivary Protein Roles in Oral Health and as Predictors of Caries Risk

Relationship between salivary flow rate and dental caries in normal and underweight children: a comparative cross-sectional study from district Tharparkar

Background and Objectives

This study aims to explore the relationship between body mass index (BMI), salivary flow rate, and dental caries among children in Tharparkar.

Materials and Methods

A comparative cross-sectional study was conducted over 6 months involving 179 children aged 8-12 years from Tharparkar and Hyderabad. Weight and height were recorded, BMI was computed using height and weight, and salivary flow rate was measured using the spitting method. Dental caries were assessed using the DMFT (decayed, missing, and filled teeth) index. Data were analyzed using SPSS, and independent t-tests were performed to assess group differences.

Results

Underweight children (60.9% male, mean BMI 15.46 ± 2.45 kg/m2) showed higher mean DMFT scores for deciduous teeth (2.44 vs. 1.06, p = 0.009) compared to normal-weight peers. No significant differences were found in permanent teeth DMFT scores or salivary flow rates between BMI groups.

Conclusions

Underweight children exhibited a higher prevalence of dental caries in their primary teeth, underscoring the need for integrated nutritional and oral health interventions in vulnerable populations. However, salivary flow rate did not differ significantly between BMI groups, suggesting other factors may play a more critical role in caries prevention.

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.

Acquired pellicle and biofilm engineering with CaneCPI-5: Insights from proteomic and microbiomics analysis

OBJECTIVE

In this in vivo proof-of-concept study, acquired pellicle engineering was implemented to promote alterations in the protein composition of the acquired enamel pellicle (AEP) and the bacterial composition of the dental biofilm after treatment with Sugarcane cystatin (CaneCPI-5).

DESIGN

After prophylaxis, 10 volunteers rinsed (10 mL, 1 min) with the following solutions: 1) deionized water (H2O- negative control or 2) 0.1 mg/mL CaneCPI-5. The AEP and biofilm were formed along 2 or 3 h, respectively. The AEP was collected with electrode filter papers soaked in 3 % citric acid. After protein extraction, samples were analyzed by quantitative shotgun label-free proteomics. The biofilm microbiome was collected with a dental curette. The DNA was extracted, amplified, and analyzed by 16S-rRNA Next Generation Sequencing (NGS).

RESULTS

Treatment with CaneCPI-5 increased several proteins with antimicrobial, acid-resistance, affinity for hydroxyapatite, structural and calcium binding properties, such as Cysteine-rich-3 (6-fold-p = 0.03), Cystatin-B (5.5-fold-p < 0.01), Neutrophil-defensin 1 (4.7-fold-p < 0.01), Mucin (3.9-fold-p < 0.01), Immunoglobulin-heavy-constant (3.8-fold-p < 0.01) and Lactotransferrin (2.8-fold-p < 0.01). Microbiome revealed that several commensal bacteria had their abundance increased after rinsing with CaneCPI-5, such as Corynebacterium and Neisseria, while Streptococcus and Prevotella nigrescens were decreased. The results indicate the efficiency of CaneCPI-5 in promoting beneficial changes in the AEP and biofilm, making this phytocystatin a potential target for incorporation into dental products.

CONCLUSION

Cane demonstrated the capability to alter the protein composition of the acquired enamel pellicle (AEP) and the initial colonizers of the biofilm, enhancing the presence of proteins and bacteria crucial for dental protection.

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.

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

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

Role of Moringa oleifera irrigation solution on the cell metabolism change of Streptococcus mutans

The principal etiological agent responsible for dental caries is Streptococcus mutans (S. mutans). The Moringa oleifera (M. oleifera) possesses antioxidant and antibacterial properties that function through the response to oxidative stress, which affects bacterial cell metabolism. This research examined M. oleifera impact on S. mutans growth, toxicity, glucan-binding protein (GBP) expression, and nucleic acid structure. Methods included spectrophotometry for growth analysis, enzyme-linked immunosorbent assay for GBP quantification, the (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) MTT assay for cytotoxicity, Fourier transform infrared for nucleic acid changes, and docking simulation for ligand-receptor affinity. Results showed that M. oleifera significantly inhibited S. mutans growth at all concentrations over 24 and 48 h (optical density <0.1), comparable to <300 CFU/mL. At 72 h, 6.25% and 3.125% concentrations were most effective, with chlorhexidine also showing stability at these times. A 3.125% concentration of M. oleifera notably reduced GBP production to below 15% and caused cell toxicity. Furthermore, 25% and 3.125% concentrations significantly altered S. mutans nucleic acids, and M. oleifera showed high binding affinity to the GBP gene receptor. Thus, M. oleifera can inhibit S. mutans growth and GBP production, cause nucleic acid deformation, and strongly bind to the GBP receptor, highlighting its potential in dental caries prevention.

Acquired enamel pellicle and biofilm engineering with a combination of acid-resistant proteins (CaneCPI-5, StN15, and Hemoglobin) for enhanced protection against dental caries - in vivo and in vitro investigations

OBJECTIVE

This study was designed in two-legs. In the in vivo, we explored the potential of a rinse solution containing a combination (Comb) of 0.1 mg/mL CaneCPI-5 (sugarcane-derive cystatin), 1.88 × 10- 5M StN15 (statherin-derived peptide) and 1.0 mg/mL hemoglobin (Hb) to change the protein profile of the acquired enamel pellicle(AEP) and the microbiome of the enamel biofilm. The in vitro, was designed to reveal the effects of Comb on the viability and bacterial composition of the microcosm biofilm, as well as on enamel demineralization.

MATERIALS AND METHODS

In vivo study, 10 participants rinsed (10mL,1 min) with either deionized water (H2O-control) or Comb. AEP and biofilm were collected after 2 and 3 h, respectively, after rinsing. AEP samples underwent proteomics analysis, while biofilm microbiome was assessed via 16 S-rRNA Next Generation Sequencing(NGS). In vitro study, a microcosm biofilm protocol was employed. Ninety-six enamel specimens were treated with: 1)Phosphate-Buffered Solution-PBS(negative-control), 2)0.12%Chlorhexidine, 3)500ppmNaF and 4)Comb. Resazurin, colony-forming-units(CFU) and Transversal Microradiography(TMR) were performed.

RESULTS

The proteomic results revealed higher quantity of proteins in the Comb compared to control associated with immune system response and oral microbial adhesion. Microbiome showed a significant increase in bacteria linked to a healthy microbiota, in the Comb group. In the in vitro study, Comb group was only efficient in reducing mineral-loss and lesion-depth compared to the PBS.

CONCLUSIONS

The AEP modification altered the subsequent layers, affecting the initial process of bacterial adhesion of pathogenic and commensal bacteria, as well as enamel demineralization.

CLINICAL RELEVANCE

Comb group shows promise in shaping oral health by potentially introducing innovative approaches to prevent enamel demineralization and deter tooth decay.

Acquired Pellicle and Biofilm Engineering by Rinsing with Hemoglobin Solution

INTRODUCTION

The identification of acid-resistant proteins, including hemoglobin (Hb), within the acquired enamel pellicle (AEP) led to the proposition of the "acquired pellicle engineering" concept, which involves the modification of the AEP by incorporating specific proteins, presenting a novel strategy to prevent dental demineralization.

OBJECTIVE

Combining in vivo and in vitro proof-of-concept protocols, we sought to reveal the impact of AEP engineering with Hb protein on the biofilm microbiome and enamel demineralization.

METHODS

In the in vivo studies, 10 volunteers, in 2 independent experiments, rinsed (10 mL,1 min) with deionized water-negative control or 1.0 mg/mL Hb. The AEP and biofilm formed along 2 or 3 h, respectively, were collected. AEP was analyzed by quantitative shotgun-label-free proteomics and biofilm by 16S-rRNA next-generation sequencing (NGS). In in vitro study, a microcosm biofilm protocol was employed. Seventy-two bovine enamel specimens were treated with (1) phosphate-buffered solution (PBS), (2) 0.12% chlorhexidine, (3) 500 ppm NaF, (4) 1.0 mg/mL Hb, (5) 2.0 mg/mL Hb, and (6) 4.0 mg/mL Hb. The biofilm was cultivated for 5 days. Resazurin, colony forming units (CFU), and transversal microradiography were performed.

RESULTS

Proteomics and NGS analysis revealed that Hb increased proteins with antioxidant, antimicrobial, acid-resistance, hydroxyapatite-affinity, calcium-binding properties and showed a reduction in oral pathogenic bacteria. In vitro experiments demonstrated that the lowest Hb concentration was the most effective in reducing bacterial activity, CFU, and enamel demineralization compared to PBS.

CONCLUSION

These findings suggest that Hb could be incorporated into anticaries dental products to modify the oral microbiome and control caries, highlighting its potential for AEP and biofilm microbiome engineering.

A Catalog of Coding Sequence Variations in Salivary Proteins' Genes Occurring during Recent Human Evolution

Saliva houses over 2000 proteins and peptides with poorly clarified functions, including proline-rich proteins, statherin, P-B peptides, histatins, cystatins, and amylases. Their genes are poorly conserved across related species, reflecting an evolutionary adaptation. We searched the nucleotide substitutions fixed in these salivary proteins' gene loci in modern humans compared with ancient hominins. We mapped 3472 sequence variants/nucleotide substitutions in coding, noncoding, and 5'-3' untranslated regions. Despite most of the detected variations being within noncoding regions, the frequency of coding variations was far higher than the general rate found throughout the genome. Among the various missense substitutions, specific substitutions detected in PRB1 and PRB2 genes were responsible for the introduction/abrogation of consensus sequences recognized by convertase enzymes that cleave the protein precursors. Overall, these changes that occurred during the recent human evolution might have generated novel functional features and/or different expression ratios among the various components of the salivary proteome. This may have influenced the homeostasis of the oral cavity environment, possibly conditioning the eating habits of modern humans. However, fixed nucleotide changes in modern humans represented only 7.3% of all the substitutions reported in this study, and no signs of evolutionary pressure or adaptative introgression from archaic hominins were found on the tested genes.

Association of polymicrobial interactions with dental caries development and prevention

Dental caries is a common oral disease. In many cases, disruption of the ecological balance of the oral cavity can result in the occurrence of dental caries. There are many cariogenic microbiota and factors, and their identification allows us to take corresponding prevention and control measures. With the development of microbiology, the caries-causing bacteria have evolved from the traditional single Streptococcus mutans to the discovery of oral symbiotic bacteria. Thus it is necessary to systematically organized the association of polymicrobial interactions with dental caries development. In terms of ecology, caries occurs due to an ecological imbalance of the microbiota, caused by the growth and reproduction of cariogenic microbiota due to external factors or the disruption of homeostasis by one's own factors. To reduce the occurrence of dental caries effectively, and considering the latest scientific viewpoints, caries may be viewed from the perspective of ecology, and preventive measures can be taken; hence, this article systematically summarizes the prevention and treatment of dental caries from the aspects of ecological perspectives, in particular the ecological biofilm formation, bacterial quorum sensing, the main cariogenic microbiota, and preventive measures.

The abundance of lysozyme, lactoferrin and cystatin S in the enamel pellicle of children - Potential biomarkers for caries?

OBJECTIVE

In this study, the abundance of the protective salivary proteins lysozyme, lactoferrin, and cystatin S was quantified in the in situ formed pellicle of caries-free and caries-active children to determine whether they may be possible biomarkers for caries.

DESIGN

Pellicle formation was performed in situ for 10 min on ceramic specimens from the oral cavity of children (5-8 years) with caries (n = 17) and without evidence of caries (n = 17). Additionally, unstimulated saliva was collected. Levels of lysozyme, lactoferrin, and cystatin S were measured in desorbed pellicle eluates and saliva using ELISA.

RESULTS

No statistically significant differences were found in the occurrence of cystatin S and lysozyme in saliva and pellicle between caries-active and caries-free children. However, significantly higher amounts of lactoferrin were detected in the pellicle of caries-active children.

CONCLUSION

The protective salivary protein lactoferrin may be a biomarker for caries susceptibility in children.

Oral Hygiene Instruction – How it Affects the Caries Experience, Oral Hygiene Status, and sCD14 Levels?

Background:

Caries experience, oral hygiene status, and salivary sCD14 level are three essential factors to analyse individual dental caries development risk. Therefore, regular and effective oral hygiene instruction (OHI) is essential for dental caries prevention.

Objective:

This study aims to analyse the differences in caries experience, oral hygiene status, and sCD14 levels before and after OHI.

Methods:

An observational study with intervention before and after oral hygiene instruction was conducted on 40 samples of each group taken with an accidental sampling method. The sample was calculated using the sample size formula to determine the difference between two paired means; confidence level 95%; power test 90%. The OHI materials include microbial aspects, plaque control methods and instruments, and directives for visiting the dentist. Caries' experience was obtained using DMF-T index; oral hygiene status using simplified oral hygiene instruction (OHI-S); sCD14 levels obtained from unstimulated saliva using an ELISA kit. Data analysis used the Kolmogorov-Smirnov normality test, paired t-test, and Wilcoxon signed-rank test.

Results:

Kolmogorov normality test showed that the caries experience data were normally distributed, while oral hygiene status and sCD14 were not. The paired-t difference test result for caries experience cannot be determined because the data showed a similar value. The Wilcoxon signed-rank test result for oral hygiene status showed no significant difference, while the sCD14 showed a significant difference.

Conclusion:

Oral hygiene instruction showed a similar value of caries experience before and after oral hygiene, and also no difference was found in oral hygiene status; however, the sCD14 levels showed a difference after oral hygiene instruction.

Investigating changes in salivary microbiota due to dental treatment: A metagenomic analysis study for forensic purposes

The advent of next generation sequencing techniques as well as the existing traditional culture methods has enabled metagenomic studies on the usability of microbiomes for the forensic identification of individuals to gain momentum. However, before the utilization of microbiomes as a potential technique for real forensic case resolutions, it is necessary to understand the stability of the microbiota compositions in an individual's biological samples and the factors responsible for their variations. In the present study, we compared the microbiota compositions present in the saliva of individuals with active dental caries before and after treatment from a forensic and clinical perspective using an approach based on the sequencing of all the variable regions (V1-V9) of the bacterial 16 S rRNA gene. For this purpose, 10 individuals were included in the study comprising of 8 individuals between the ages of 18-50 years with at least 3 deep dentin caries as patients and 2 healthy individuals without any dental or gingival diseases as controls. Saliva samples were collected from the patients at two timepoints, before and after treatment, as well as from the healthy individuals (before and after control) at an interval of 1 month. The collected 20 saliva samples were subjected to metagenomic analysis using the MinION device, which was developed by Oxford Nanopore Technologies (ONT Oxford, UK). Bioinformatic analyses were performed on the obtained data and the results were evaluated using statistical comparison methods and alpha/beta diversity analyses within the scope of the study objective. On evaluation using the distance metrics, it was observed that the microbial compositions in the saliva of individuals with active caries remained relatively stable after treatment. However, the relative abundance levels of bacteria of 28 genera and species showed statistically significant differences before and after treatment (p < 0.05). As a result, although the composition of salivary microbiome remained relatively stable after caries treatment, there were significant changes in many types of bacteria, especially at the species level, between the BT and AT samples. Our results provide a framework for further forensic and clinical investigations regarding the factors that affect human salivary microbiome diversity.

Antimicrobial peptides: Defending the mucosal epithelial barrier

The recent epidemic caused by aerosolized SARS-CoV-2 virus illustrates the importance and vulnerability of the mucosal epithelial barrier against infection. Antimicrobial proteins and peptides (AMPs) are key to the epithelial barrier, providing immunity against microbes. In primitive life forms, AMPs protect the integument and the gut against pathogenic microbes. AMPs have also evolved in humans and other mammals to enhance newer, complex innate and adaptive immunity to favor the persistence of commensals over pathogenic microbes. The canonical AMPs are helictical peptides that form lethal pores in microbial membranes. In higher life forms, this type of AMP is exemplified by the defensin family of AMPs. In epithelial tissues, defensins, and calprotectin (complex of S100A8 and S100A9) have evolved to work cooperatively. The mechanisms of action differ. Unlike defensins, calprotectin sequesters essential trace metals from microbes, which inhibits growth. This review focuses on defensins and calprotectin as AMPs that appear to work cooperatively to fortify the epithelial barrier against infection. The antimicrobial spectrum is broad with overlap between the two AMPs. In mice, experimental models highlight the contribution of both AMPs to candidiasis as a fungal infection and periodontitis resulting from bacterial dysbiosis. These AMPs appear to contribute to innate immunity in humans, protecting the commensal microflora and restricting the emergence of pathobionts and pathogens. A striking example in human innate immunity is that elevated serum calprotectin protects against neonatal sepsis. Calprotectin is also remarkable because of functional differences when localized in epithelial and neutrophil cytoplasm or released into the extracellular environment. In the cytoplasm, calprotectin appears to protect against invasive pathogens. Extracellularly, calprotectin can engage pathogen-recognition receptors to activate innate immune and proinflammatory mechanisms. In inflamed epithelial and other tissue spaces, calprotectin, DNA, and histones are released from degranulated neutrophils to form insoluble antimicrobial barriers termed neutrophil extracellular traps. Hence, calprotectin and other AMPs use several strategies to provide microbial control and stimulate innate immunity.

Systematic assessment of salivary inflammatory markers and dental caries in children: an exploratory study

OBJECTIVE

To investigate associations between a wide panel of salivary inflammatory markers and the presence of dental caries among children.

MATERIAL AND METHODS

In this exploratory, cross-sectional study, 176 children, aged 7-9, underwent a dental examination. Information on the children's oral health habits and lifestyles was collected from their mothers. In addition, saliva samples were collected and analyzed using a multiplex immunoassay. Of 92 inflammatory markers measured, 56 were included in the statistical analyses. To identify potential inflammatory markers associated with caries, we applied low to advanced statistical analyses. First, we performed traditional logistic regression analysis followed by Bonferroni corrections. Thereafter, a more robust and less conservative statistical approach, i.e. Least Absolute Shrinkage and Selection Operator (LASSO), was applied. The models were adjusted for potential confounders.

RESULTS

Of the 176 children in the study, 22.2% were affected by caries. Among the 56 salivary inflammatory markers, only macrophage colony-stimulating factor 1 (CSF1) was selected by the LASSO and found to be positively associated with the presence of caries.

CONCLUSIONS

The observed association between CSF1 and the presence of caries may be of clinical value in caries risk management and early diagnosis. Larger studies are warranted to assess the replicability of our findings.

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

Despite significant healthcare advances in the 21st century, the exact etiology of dental caries remains unsolved. The past two decades have witnessed a tremendous growth in our understanding of dental caries amid the advent of revolutionary omics technologies. Accordingly, a consensus has been reached that dental caries is a community-scale metabolic disorder, and its etiology is beyond a single causative organism. This conclusion was based on a variety of microbiome studies following the flow of information along the central dogma of biology from genomic data to the end products of metabolism. These studies were facilitated by the unprecedented growth of the next- generation sequencing tools and omics techniques, such as metagenomics and metatranscriptomics, to estimate the community composition of oral microbiome and its functional potential. Furthermore, the rapidly evolving proteomics and metabolomics platforms, including nuclear magnetic resonance spectroscopy and/or mass spectrometry coupled with chromatography, have enabled precise quantification of the translational outcomes. Although the majority supports 'conserved functional changes' as indicators of dysbiosis, it remains unclear how caries dynamics impact the microbiota functions and vice versa, over the course of disease onset and progression. What compounds the situation is the host-microbiota crosstalk. Genome-wide association studies have been undertaken to elucidate the interaction of host genetic variation with the microbiome. However, these studies are challenged by the complex interaction of host genetics and environmental factors. All these complementary approaches need to be orchestrated to capture the key players in this multifactorial disease. Herein, we critically review the milestones in caries research focusing on the state-of-art singular and integrative omics studies, supplemented with a bibliographic network analysis to address the oral microbiome, the host factors, and their interactions. Additionally, we highlight gaps in the dental literature and shed light on critical future research questions and study designs that could unravel the complexities of dental caries, the most globally widespread disease.

Relationship between Salivary Alpha-Amylase Enzyme Activity, Anthropometric Indices, Dietary Habits, and Early Childhood Dental Caries

Objectives

Although early childhood dental caries (ECC) have the same general etiology as other types of caries, predisposing factors are not well elucidated. This study aimed to investigate the effect of salivary alpha-amylase (sAA) activity, body mass index (BMI), dietary habits, and oral hygiene on ECC.

Methods

This cross-sectional study was performed on 38 ECC-affected and 41 caries-free children, aged 36 to 72 months. Upon the parents' consent, 3 mL of non-stimulated saliva was collected from the participants to measure the level of sAA activity through spectrophotometry. Additionally, parents/caretakers completed a structured questionnaire about demographic factors, oral hygiene, and consumption of sugar-containing foods. BMI, BMI z-scores, and percentile data were calculated by using an online calculator. The independent variables were dichotomized and tested through chi-square test, followed by a stepwise logistic regression, by using SPSS software (α = 0.05).

Results

The sAA activity was significantly higher in caries-free children (P ≤ 0.001). However, the mean BMI was not significantly different between the two groups (P=0.49). Brushing and other measured dietary habits were significantly associated with the development of ECC (P ≤ 0.001). According to the results of the logistic regression, sAA activity was shown to be a predictor for ECC development (Odds ratio (95% confidence interval): 0.9 (0.95-0.98)).

Conclusion

Children with inherently lower levels of sAA activity were more susceptible to dental caries. Improper nutritional habits and poor oral health care could exacerbate the risk of ECC.

Biomarkers of non-communicable chronic disease: an update on contemporary methods

Chronic diseases constitute a major global burden with significant impact on health systems, economies, and quality of life. Chronic diseases include a broad range of diseases that can be communicable or non-communicable. Chronic diseases are often associated with modifications of normal physiological levels of various analytes that are routinely measured in serum and other body fluids, as well as pathological findings, such as chronic inflammation, oxidative stress, and mitochondrial dysfunction. Identification of at-risk populations, early diagnosis, and prediction of prognosis play a major role in preventing or reducing the burden of chronic diseases. Biomarkers are tools that are used by health professionals to aid in the identification and management of chronic diseases. Biomarkers can be diagnostic, predictive, or prognostic. Several individual or grouped biomarkers have been used successfully in the diagnosis and prediction of certain chronic diseases, however, it is generally accepted that a more sophisticated approach to link and interpret various biomarkers involved in chronic disease is necessary to improve our current procedures. In order to ensure a comprehensive and unbiased coverage of the literature, first a primary frame of the manuscript (title, headings and subheadings) was drafted by the authors working on this paper. Second, based on the components drafted in the preliminary skeleton a comprehensive search of the literature was performed using the PubMed and Google Scholar search engines. Multiple keywords related to the topic were used. Out of screened papers, only 190 papers, which are the most relevant, and recent articles were selected to cover the topic in relation to etiological mechanisms of different chronic diseases, the most recently used biomarkers of chronic diseases and finally the advances in the applications of multivariate biomarkers of chronic diseases as statistical and clinically applied tool for the early diagnosis of chronic diseases was discussed. Recently, multivariate biomarkers analysis approach has been employed with promising prospect. A brief discussion of the multivariate approach for the early diagnosis of the most common chronic diseases was highlighted in this review. The use of diagnostic algorithms might show the way for novel criteria and enhanced diagnostic effectiveness inpatients with one or numerous non-communicable chronic diseases. The search for new relevant biomarkers for the better diagnosis of patients with non-communicable chronic diseases according to the risk of progression, sickness, and fatality is ongoing. It is important to determine whether the newly identified biomarkers are purely associations or real biomarkers of underlying pathophysiological processes. Use of multivariate analysis could be of great importance in this regard.

Role of Salivary Biomarkers in Cystic Fibrosis: A Systematic Review

Background

Saliva biomarkers could be easily used as a noninvasive alternative tool for diagnosing cystic fibrosis (CF) disease. In this study, the significance of changes in salivary compositions in patients with CF was systematically reviewed.

Methods

An electronic search was utilized to include studies published in English, with case-control, cohort, or cross-sectional design. The evaluated salivary components were extracted and summarized. The included studies were assessed using the Strengthening the Reporting of Observational Studies in Epidemiology checklist.

Results

Out of 498 identified studies, nine met the eligibility criteria. Salivary electrolytes showed a substantial alteration in the CF group, especially with chloride and sodium. Total protein concentration was higher in patients with CF. However, SCN– concentration was lower in patients with CF. In addition, a reduction in the salivary flow rate and amylase levels was found in patients with CF.

Conclusion

Alterations in salivary biomarkers among patients with CF could be used as a promising diagnostic tool for cystic fibrosis.

Association of salivary statherin, calcium, and proline-rich proteins: A potential predictive marker of dental caries

Background:

Aim:

Methods:

Results:

Conclusion:

Correlation between BMI, caries prevalence, and sugar-containing beverage intake in 6-10 year old children

Background:

The beverages containing sugar are proven risk factors for obesity and dental caries. Therefore, owing to the shared risk factors, an interrelationship is suspected between BMI, sugar beverage consumption, and dental caries in children.

Aims:

The present trial was carried out to assess the interrelationship between BMI, sugar beverage consumption, and dental caries in children aged 6–10 years.

Materials and Methods:

Eighty-six children within the age range of 6–10 years answered the health questionnaire. The BMI was calculated, intra-oral assessment was done, the frequency of sweetened beverage consumption was recorded, and the collected data were subjected to the statistical evaluation to formulate results.

Results:

On evaluation, a non-significant difference was observed in BMI levels in the four groups (P = 0.12). Whole-milk intake also showed an inverse correlation with dental caries and BMI, but this correlation was statistically non-significant with the respective values of P = 0.57 and 0.55. A similar inverse relationship was seen for low-fat milk for caries and BMI with P = 0.65 and 0.45, respectively. Regarding soft drinks, 44.1% (n = 38) took soft drinks, and a non-significant relation between caries and intake as well as BMI and intake with P = 0.86 and 0.55, respectively.

Conclusion:

Within its limitations, the present study concludes that no correlation exists between BMI and dental caries as well as between sugar-containing beverage consumption and dental caries. Also, BMI and sugar-containing beverage consumption showed no correlation in children aged 6–10 years.

Salivary cystatin S levels in children with early childhood caries in comparison with caries-free children; statistical analysis and machine learning

Background

Early childhood caries is the most common infectious disease in childhood, with a high prevalence in developing countries. The assessment of the variables that influence early childhood caries as well as its pathophysiology leads to improved control of this disease. Cystatin S, as one of the salivary proteins, has an essential role in pellicle formation, tooth re-mineralization, and protection. The present study aims to assess salivary cystatin S levels and demographic data in early childhood caries in comparison with caries-free ones using statistical analysis and machine learning methods.

Methods

A cross-sectional, case–control study was undertaken on 20 cases of early childhood caries and 20 caries-free children as a control. Unstimulated whole saliva samples were collected by suction. Cystatin S concentrations in samples were determined using human cystatin S ELISA kit. The checklist was collected from participants about demographic characteristics, oral health status, and dietary habits by interviewing parents. Regression and receiver operating characteristic (ROC) curve analysis were done to evaluate the potential role of cystatin S salivary level and demographic using statistical analysis and machine learning.

Results

The mean value of salivary cystatin S concentration in the early childhood caries group was 191.55 ± 81.90 (ng/ml) and in the caries-free group was 370.06 ± 128.87 (ng/ml). T-test analysis showed a statistically significant difference between early childhood caries and caries-free groups in salivary cystatin S levels (p = 0.032). Investigation of the area under the curve (AUC) and accuracy of the ROC curve revealed that the logistic regression model based on salivary cystatin S levels and birth weight had the most and acceptable potential for discriminating of early childhood caries from caries-free controls. Furthermore, using salivary cystatin S levels enhanced the capability of machine learning methods to differentiate early childhood caries from caries-free controls.

Conclusion

Salivary cystatin S levels in caries-free children were higher than the children with early childhood caries. Results of the present study suggest that considering clinical examination, demographic and socioeconomic factors, along with the salivary cystatin S levels, could be usefull for early diagnosis ofearly childhood caries in high-risk children; furthermore, cystatin S is a protective factor against dental caries.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-02016-x.

Metabolomics to Diagnose Oxidative Stress in Perinatal Asphyxia: Towards a Non-Invasive Approach

There is a need for feasible and non-invasive diagnostics in perinatal asphyxia. Metabolomics is the study of small molecular weight products of cellular metabolism that may, directly and indirectly, reflect the level of oxidative stress. Saliva analysis is a novel approach that has a yet unexplored potential in metabolomics in perinatal asphyxia. The aim of this review was to give an overview of metabolomics studies of oxidative stress in perinatal asphyxia, particularly searching for studies analyzing non-invasively collected biofluids including saliva. We searched the databases PubMed/Medline and included 11 original human and 4 animal studies. In perinatal asphyxia, whole blood, plasma, and urine are the most frequently used biofluids used for metabolomics analyses. Although changes in oxidative stress-related salivary metabolites have been reported in adults, the utility of this approach in perinatal asphyxia has not yet been explored. Human and animal studies indicate that, in addition to antioxidant enzymes, succinate and hypoxanthine, as well acylcarnitines may have discriminatory diagnostic and prognostic properties in perinatal asphyxia. Researchers may utilize the accumulating evidence of discriminatory metabolic patterns in perinatal asphyxia to develop bedside methods to measure oxidative stress metabolites in perinatal asphyxia. Although only supported by indirect evidence, saliva might be a candidate biofluid for such point-of-care diagnostics.

Does Growth Stunting Correlate with Oral Health in Children?: A Systematic Review

Growth stunting is when children tend to be shorter than their peers through the World Health Organization child growth standard measurement. The condition may affect the development of the brain and other parts of the body, including the oral cavity, which manifests in oral hygiene and overall oral health. This systematic approach literature study aimed to evaluate the correlation between growth stunting and oral health in children. This study was conducted by using a literature review method with a systematic approach by searching for articles related to research topics on PubMed and Google Scholar. The search was adjusted to the inclusion category, which is research that discusses malnutrition and oral health published between 2010 and 2020—research conducted on boys and girls—from birth to 18 years. The exclusion categories used were articles that did not discuss growth stunting and oral health, and grey literature was excluded. The selection of articles was carried out by using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach and resulted in 10 selected articles with details as follows: the correlation between growth stunting and oral health in three articles. A high plaque index in growth stunting children was found in two articles, and a decrease in saliva composition in growth stunting children was also found in two articles. Four articles showed a relationship between growth stunting and salivary flow rate. Lastly, one article showed the relationship between growth stunting and the incidence of dental caries. Despite the limitation of the review, the correlation between growth stunting and overall oral health in children can be seen through the oral hygiene index as moderate to low, high plaque index, decreased salivary flow rate, salivary composition, and dental caries in children with growth stunting.

The role of sugar-rich diet and salivary proteins in dental plaque formation and oral health

BACKGROUND

Dental plaque is a complex colorless film of bacteria that develops on the surfaces of teeth. Different mechanisms of microbial adhesion to tooth surfaces exist. Both non-specific and specific types of adherence have been anticipated.

HIGHLIGHT

The present review evaluated the effect of sugar-rich diet and salivary proteins on oral hygiene and dental plaque development.

CONCLUSION

The oral microbiota is essential for maintaining and reestablishing a healthy oral cavity. Different types of sugars have different effects on the inhibition and formation of dental plaque. The peptides, proteins, and amino acids secreted by parotid glands in the oral cavity facilitate neutralizing the acidity in dental plaque and preventing dental caries. A properly balanced diet is crucial for both a healthy oral cavity and the oral microbiome.

Proteomic Analysis of Whole Saliva in Relation to Dental Caries Resistance

Saliva contains possible biomarkers that are associated with dental caries. The present study aimed to analyse differences in the abundance of proteins in the saliva between caries-positive (CP; N = 15) and caries-free (CF; N = 12) males and to compare differences in the abundance of proteins between two saliva sample fractions (supernatant and pellet). We found 14 differently significantly expressed proteins in the CF group when comparing the supernatant fractions of the CP and CF groups, and three proteins in the pellet fractions had significantly higher expression in the CP group. Our results indicate very specific protein compositions of the saliva in relation to dental caries resistance (the saliva of the CP group mainly contained pellet proteins and the saliva of the CF group mainly contained supernatant proteins). This was the first time that the saliva pellet fraction was analysed in relation to the dental caries status. We detected specific calcium-binding proteins that could have decalcified enamel in the saliva pellet of the CP group. We also observed significantly up-regulated immune proteins in the saliva supernatant of the CF group that could play an important role in the caries prevention. The particular protein compositions of the saliva pellet and supernatant in the groups with different susceptibilities to tooth decay is a promising finding for future research.