Composition of whole unstimulated saliva of healthy children: changes with age

Comparison of Child and Adult Mastication of a Sticky Processed Cream Cheese and Simulation with a Masticator

An advantage of masticators is the calibration and possible standardization of intra- and inter-individual mastication variability. However, mastication of soft, sticky and melting products, such as processed cream cheeses, is challenging to reproduce with a masticator. The objectives of this work were, for the cheese studied: (1) to compare child and adult mastication and (2) to find in vitro parameters which best reproduce their in vivo chewing. Five parameters influencing mastication (mouth volume, quantity consumed, saliva volume, mastication time and number of tongue-palate compressions) were measured in 30 children (5-12 years old) and 30 adults (18-65 years old) and compared between the two populations. They were then transposed to a masticator (Oniris device patent). The initial cheese, a homogeneous white paste, was surface-colored to investigate its in-mouth destructuring. In vivo boli were collected at three chewing stages (33, 66 and 99% of mastication time) and in vitro boli were obtained by varying the number of tongue-palate compressions and the rotation speed. In vivo and in vitro boli were compared by both image and texture analysis. Child masticatory parameters were proportionally smaller than those of adults. The in vivo child boli were less homogeneous and harder than adult ones. Comparison of in vivo and in vitro bolus color and texture enabled the successful determination of two in vitro settings that closely represented the mastication of the two populations studied.

Sources of Variance in Human Tear Proteomic Samples: Statistical Evaluation, Quality Control, Normalization, and Biological Insight

Human tear fluid contains numerous compounds, which are present in highly variable amounts owing to the dynamic and multipurpose functions of tears. A better understanding of the level and sources of variance is essential for determining the functions of the different tear components and the limitations of tear samples as a potential biomarker source. In this study, a quantitative proteomic method was used to analyze variations in the tear protein profiles of healthy volunteers. High day-to-day and inter-eye personal variances were observed in the tear volumes, protein content, and composition of the tear samples. Several normalization and outlier exclusion approaches were evaluated to decrease variances. Despite the intrapersonal variances, statistically significant differences and cluster analysis revealed that proteome profile and immunoglobulin composition of tear fluid present personal characteristics. Using correlation analysis, we could identify several correlating protein clusters, mainly related to the source of the proteins. Our study is the first attempt to achieve more insight into the biochemical background of human tears by statistical evaluation of the experimentally observed dynamic behavior of the tear proteome. As a pilot study for determination of personal protein profiles of the tear fluids of individual patients, it contributes to the application of this noninvasively collectible body fluid in personal medicine.

Block the Spread: Barriers to Transmission of Influenza Viruses

Respiratory viruses, such as influenza viruses, cause significant morbidity and mortality worldwide through seasonal epidemics and sporadic pandemics. Influenza viruses transmit through multiple modes including contact (either direct or through a contaminated surface) and inhalation of expelled aerosols. Successful human to human transmission requires an infected donor who expels virus into the environment, a susceptible recipient, and persistence of the expelled virus within the environment. The relative efficiency of each mode can be altered by viral features, environmental parameters, donor and recipient host characteristics, and viral persistence. Interventions to mitigate transmission of influenza viruses can target any of these factors. In this review, we discuss many aspects of influenza virus transmission, including the systems to study it, as well as the impact of natural barriers and various nonpharmaceutical and pharmaceutical interventions.

The energetics of childhood: Current knowledge and insights into human variation, evolution, and health

How organisms capture and ultimately use metabolic energy-a limiting resource of life-has profound implications for understanding evolutionary legacies and current patterns of phenotypic variation, adaptation, and health. Energetics research among humans has a rich history in biological anthropology and beyond. The energetics of childhood, however, remains relatively underexplored. This shortcoming is notable given the accepted importance of childhood in the evolution of the unique human life history pattern as well as the known sensitivity of childhood development to local environments and lived experiences. In this review, I have three objectives: (1) To overview current knowledge regarding how children acquire and use energy, highlighting work among diverse human populations and pointing to recent advances and remaining areas of uncertainty; (2) To discuss key applications of this knowledge for understanding human variation, evolution, and health; (3) To recommend future avenues for research. A growing body of evidence supports a model of trade-offs and constraint in childhood energy expenditure. This model, combined with advancements on topics such as the energetics of immune activity, the brain, and the gut, provides insights into the evolution of extended human subadulthood and the nature of variation in childhood development, lifetime phenotype, and health.

Differences in susceptibility of deciduous and permanent teeth to erosion exist, albeit depending on protocol design and method of assessment

Controversial results showing that deciduous teeth are more susceptible to erosion than permanent teeth might be related to study designs. We investigated how different conditions (pH: 3.0, 4.0, 5.0; acid agitation: gentle or vigorous; acid exposure times: 1–5 min) affect the susceptibility of both teeth to erosion. Enamel specimens (90 deciduous, 90 permanent) were distributed into groups (n = 15 permanent, n = 15 deciduous) according to acid pH (pH 5, 4 or 3) and agitation (gentle or vigorous) during erosive challenge. Both milder (less incubation time, gentle agitation, and higher pH) and more severe (longer incubation times, vigorous shaking, and lower pH) conditions were used. Demineralization was measured by relative surface microhardness (rSMH) and calcium released to the acid. Demineralization increased gradually for both teeth with increasing incubation time, agitation (gentle or vigorous), and with decreasing acid pH. The differences between deciduous and permanent teeth depended on the protocol design and assessment method. Under milder conditions, demineralization was better detectable with rSMH. Under more severe conditions, differences were more perceptible with calcium analyses. Differences exist in the susceptibility to erosion between deciduous and permanent teeth, but they are only distinguishable when the appropriate assessment method is used for the specific erosive condition.

Salivary Enzymatic Activity and Carious Experience in Children: A Cross-Sectional Study

Salivary biomolecules are considered important modulators of the oral microflora, with a potential subsequent impact on dental health. The present study aimed to investigate the relationship between salivary enzymatic activity and carious experience in children. The carious experience of a sample of 22 school children was evaluated by calculating dmf/DMF indices, following WHO recommendations. Unstimulated whole saliva was collected, and salivary alpha-amylase levels, total protease activity, and matrix metalloproteinase levels (MMP-8 and MMP-9) were measured. The data were analyzed using parametric and nonparametric tests. Our findings revealed no significant relationship between the investigated salivary parameters and the carious experience in permanent teeth (DMFT/DMFS scores). Carious indices scores for primary teeth (dmft and dmfs) were positively associated with MMP-8 levels (r = 0.62, p = 0.004 and r_s = 0.61, p = 0.006, respectively) and MMP-9 levels (r = 0.45, p = 0.05 and r_s = 0.48, p = 0.039, respectively) and negatively associated with alpha-amylase levels (r_s = −0.54, p = 0.017 and r_s = −0.59, p = 0.006, respectively). Although with a marginal significance, PEK−054 levels positively correlated with dental caries, while for PFU−089, a negative correlation was observed. These results suggest that salivary alpha-amylase and MMP-8 and MMP-9 levels may be considered potential indicators of carious experience in children. Further studies with a prospective design are needed in order to elucidate the role of these biomolecules in caries development.

Review of paediatric gastrointestinal physiology relevant to the absorption of orally administered medicines

Despite much progress in regulations to improve paediatric drug development, there remains a significant need to develop better medications for children. For the design of oral dosage forms, a detailed understanding of the specific gastrointestinal (GI) conditions in children of different age categories and how they differ from GI conditions in adults is essential. Several review articles have been published addressing the ontogeny of GI characteristics, including luminal conditions in the GI tract of children. However, the data reported in most of these reviews are of limited quality because (1) information was cited from very old publications and sometimes low quality sources, (2) data gaps in the original data were filled with textbook knowledge, (3) data obtained on healthy and sick children were mixed, (4) average data obtained on groups of patients were mixed with data obtained on individual patients, and (5) results obtained using investigative techniques that may have altered the outcome of the respective studies were considered. Consequently, many of these reviews draw conclusions that may be incorrect. The aim of the present review was to provide a comprehensive and updated overview of the available original data on the ontogeny of GI luminal conditions relevant to oral drug absorption in the paediatric population. To this end, the PubMed and Web of Science metadatabases were searched for appropriate studies that examined age-related conditions in the oral cavity, esophagus, stomach, small intestine, and colon. Maturation was observed for several GI parameters, and corresponding data sets were identified for each paediatric age group. However, it also became clear that the ontogeny of several GI traits in the paediatric population is not yet known. The review article provides a robust and valuable data set for the development of paediatric in vitro and in silico biopharmaceutical tools to support the development of age-appropriate dosage forms. In addition, it provides important information on existing data gaps and should provide impetus for further systematic and well-designed in vivo studies on GI physiology in children of specific age groups in order to close existing knowledge gaps and to sustainably improve oral drug therapy in children.

Spectroscopic molecular-fingerprint profiling of saliva

Saliva analysis has been gaining interest as a potential non-invasive source of disease indicative biomarkers due to being a complex biofluid correlating with blood-based constituents on a molecular level. For saliva to cement its usage for analytical applications, it is paramount to gain underpinning molecular knowledge and establish a 'baseline' of the salivary composition in healthy individuals as well as characterize how these factors are impacting its performance as potential analytical biofluid. Here, we have systematically studied the molecular spectral fingerprint of saliva, including the changes associated with gender, age, and time. Via hybrid artificial neural network algorithms and Raman spectroscopy, we have developed a non-destructive molecular profiling approach enabling the assessment of salivary spectral changes yielding the determination of gender and age of the biofluid source. Our classification algorithm successfully identified the gender and age from saliva with high classification accuracy. Discernible spectral molecular 'barcodes' were subsequently constructed for each class and found to primarily stem from amino acid, protein, and lipid changes in saliva. This unique combination of Raman spectroscopy and advanced machine learning techniques lays the platform for a variety of applications in forensics and biosensing.

In vitro models of gut digestion across childhood: current developments, challenges and future trends

The human digestion is a multi-step and multi-compartment process essential for human health, at the heart of many issues raised by academics, the medical world and industrials from the food, nutrition and pharma fields. In the first years of life, major dietary changes occur and are concomitant with an evolution of the whole child digestive tract anatomy and physiology, including colonization of gut microbiota. All these phenomena are influenced by child exposure to environmental compounds, such as drugs (especially antibiotics) and food pollutants, but also childhood infections. Due to obvious ethical, regulatory and technical limitations, in vivo approaches in animal and human are more and more restricted to favor complementary in vitro approaches. This review summarizes current knowledge on the evolution of child gut physiology from birth to 3 years old regarding physicochemical, mechanical and microbial parameters. Then, all the available in vitro models of the child digestive tract are described, ranging from the simplest static mono-compartmental systems to the most sophisticated dynamic and multi-compartmental models, and mimicking from the oral phase to the colon compartment. Lastly, we detail the main applications of child gut models in nutritional, pharmaceutical and microbiological studies and discuss the limitations and challenges facing this field of research.

Nutritional influences on enzyme activities in saliva of Asian and African elephants

Asian and African elephants show morphological adaptations to their ecological niche including the oral cavity. Variety and preferences of forage plants differ between both herbivorous elephant species. Diet can affect salivary enzymes. Asian elephants were shown to have a higher salivary amylase activity than African elephants. Species-specific differences were presumed to be influenced by feeding during collection procedure. This study aimed to determine the influence of feeding on enzyme activities in saliva of both elephant species to differentiate from species-specific effects. Additionally, season and housing conditions on salivary enzyme activities in non-fed elephants of both species were investigated. Salivary amylase (sAA), lysozyme (sLYS) and peroxidase (sPOD) activity were measured photometrically or fluorometrically. Results of this study reinforce previous observations of higher basic sAA activity in Asian elephants compared to African elephants. Salivary LYS and sPOD activity showed neither species-specific nor housing-specific differences. Independent from season, most elephants of both species revealed a lack of or low sPOD activity. Feeding caused a temporary decrease of sAA, sLYS and sPOD activity in both elephant species kept in four of eight tested zoos. Furthermore, sAA activity in Asian elephants was higher and sLYS activity lower in Spring than in Autumn. This study summarizes that sAA and sLYS are components of Asian and African elephant saliva in an active conformation in contrast to sPOD. Diet varying between season and zoos might influence sAA and sLYS activities primarily in Asian elephants but temporary low effects suggest sufficient buffer capacity of elephant saliva of both species.

Relationship between Sucrose Taste Detection Thresholds and Preferences in Children, Adolescents, and Adults

To address gaps in knowledge, our objectives were to (1) to determine whether there are age-related changes in sweet taste detection thresholds, as has been observed for sweet taste preferences, and (2) determine whether detection thresholds and taste preferences were significantly related to each other from childhood to adulthood. We combined data from studies that used the same validated psychophysical techniques to measure sucrose taste detection threshold and the most preferred sucrose concentration in children (n = 108), adolescents (n = 172), and adults (n = 205). There were significant effects of age group on both sucrose detection thresholds (p < 0.001) and most preferred sucrose concentration (p < 0.001). While children had higher sucrose detection thresholds than adolescents, who in turn tended to have higher detection thresholds than adults, both children and adolescent most preferred sucrose concentrations were higher than that of adults (all p < 0.05). Among each age group, and when combined, the lowest sucrose concentration detected was not significantly correlated with the most preferred sucrose concentration (all p > 0.18). These data provide further evidence that age-related changes in sucrose taste preferences that occur during adolescence cannot be explained by changes in taste sensitivity and that these two dimensions of sweet taste undergo distinct developmental trajectories from childhood to adulthood.

Child Salivary SIgA and Its Relationship to Enteric Infections and EED Biomarkers in Maputo, Mozambique

Characterizing child immunological responses to enteric infections with antibody detection in serum can be challenging in resource-constrained field settings, because sample collection requires trained individuals and its invasive procedure may lead to low response rates, especially among children. Saliva may present a promising non-invasive alternative. The objectives of this research were to compare salivary antibody levels in children to enteric infections and biomarkers of environmental enteric dysfunction (EED). We collected saliva samples from children aged one to six years enrolled in a sanitation trial in Maputo, Mozambique, and characterized salivary secretory immunoglobulin A (SIgA) concentrations with enzyme-linked immunosorbent assays. We used multilevel linear models to analyze cross-sectional associations between salivary SIgA and the number of concurrent enteric pathogen infections, as well as EED biomarkers in matched stool samples. Median salivary SIgA concentrations in this study population were 54 μg/mL (inter-quartile range (IQR): 34, 85 μg/mL), and SIgA levels were similar between children of different ages. SIgA was lower in children experiencing a higher number of concurrent infections -0.04 log μg/mL (95% confidence interval (CI): -0.08 to -0.005 log μg/mL), but was not associated with any of the included EED biomarkers. Contrary to evidence from high-income countries that suggests salivary SIgA increases rapidly with age in young children, the high prevalence of enteric infections may have led to a suppression of immunological development in this study sample and could in part explain the similar SIgA levels between children of different ages.

Salivary Theranostics in Pediatric and Special Care Dentistry

Saliva as a microfluidic system offers numerous advantages for both general and oral health diagnostic and therapeutic procedures since its assembly is quick, stress-free, inexpensive and non-invasive. Moreover, saliva is frequently referred to as a mirror of the body due to the fact that it can reflect the physiological and pathological state of the body. More than a decade ago the term “Salivaomics” has been introduced with the aim of emphasizing the development of research, knowledge and applications of five salivary constituents: proteome, transcriptome, micro-RNA, metabolome, and microbiome. Contemporary oral health care delivery in pediatric and special care dentistry is focused toward the development of new diagnostic and therapeutical procedures that are essentially noninvasive due to common issue of intolerability to invasive procedures among these patients, with the possibility of increasing participation rates. Besides the criteria of being easily and non-invasive collected, there are additional standards that should be met before routine application in everyday clinical practice; the existence of specific biomarkers for a disease, and ability of having its biomarkers detected using present-day equipment. For example, there are recent suggestions that a salivary RNA panel could objectively differentiate children with autism spectrum disorder from their neurotypical peers. In addition, due to the ease of the administration, the oral cavity is an attractive site for the drug delivery systems development because through this route it is possible to realize mucosal and transmucosal, systemic effect. All these contemporary advances extended the salivary diagnostic approach from the oral to general health pointing towards a promising future of salivary diagnostics for personalized medicine devices.

Testosterone is positively and estradiol negatively associated with mucosal immunity in Amazonian adolescents

OBJECTIVES

A core assumption of life history theory and the immunocompetence handicap hypothesis (ICHH) is that testosterone (T) upregulates energetic investment in mating effort at the expense of immunity. This tenet, along with observed positive relationships between estrogens and immunity, may contribute to the higher observed morbidity and mortality of males. In the present study, we examine the association between sex steroid hormones and mucosal immunity as well as sex differences in immunity in a rural Amazonian population of immune-challenged Bolivian adolescents.

METHODS

Salivary steroid hormones (T [males only] and estradiol [E₂ , females only]), Tsimane-specific age-standardized BMI z-scores, and salivary mucosal immunity (sIgA, secretory IgA) were measured in 89 adolescent males and females.

RESULTS

Males had significantly higher sIgA levels than females, which may be due to the observed immune-endocrine associations found in the present study. Controlling for age and phenotypic condition, higher T significantly predicted higher sIgA; whereas higher E₂ was associated with lower sIgA in females.

CONCLUSIONS

Results stood in contrast to common interpretations of the ICHH, that is, that T should be inversely associated with immunity. Findings from the present study support the notion that the endocrine system likely affects immunity in a regulatory fashion, upregulating certain aspects of immunity while downregulating others. An important remaining question is the adaptive reason(s) for sex differences in endocrine-mediated immuno-redistribution.

Acoustofluidic Micromixing Enabled Hybrid Integrated Colorimetric Sensing, for Rapid Point-of-Care Measurement of Salivary Potassium

The integration of microfluidics with advanced biosensor technologies offers tremendous advantages such as smaller sample volume requirement and precise handling of samples and reagents, for developing affordable point-of-care testing methodologies that could be used in hospitals for monitoring patients. However, the success and popularity of point-of-care diagnosis lies with the generation of instantaneous and reliable results through in situ tests conducted in a painless, non-invasive manner. This work presents the development of a simple, hybrid integrated optical microfluidic biosensor for rapid detection of analytes in test samples. The proposed biosensor works on the principle of colorimetric optical absorption, wherein samples mixed with suitable chromogenic substrates induce a color change dependent upon the analyte concentration that could then be detected by the absorbance of light in its path length. This optical detection scheme has been hybrid integrated with an acoustofluidic micromixing unit to enable uniform mixing of fluids within the device. As a proof-of-concept, we have demonstrated the real-time application of our biosensor format for the detection of potassium in whole saliva samples. The results show that our lab-on-a-chip technology could provide a useful strategy in biomedical diagnoses for rapid analyte detection towards clinical point-of-care testing applications.

Salivary Changes before and after Hematopoietic Stem Cell Transplantation: A Systematic Review

Severe oral problems, including oral mucositis (OM) and xerostomia, often occur after conditioning therapy for hematopoietic stem cell transplantation (HSCT). Saliva plays a major role in protecting the oral mucosa and teeth. Alterations in salivary flow rate or salivary components resulting in decreased salivary defence mechanisms may affect oral/mucosal health and may influence the severity of OM. A systematic review was conducted to assess the current scientific knowledge on changes in salivary function and composition before and after HSCT. All English or Dutch articles examining salivary flow rate or salivary components before and after HSCT were included after title/abstract selection by 2 independent reviewers (weighted κ = .91). After quality assessment and exclusion of all research groups with both children age <14 years and adults, 33 articles were included for data analysis. Overall, the salivary flow rate was decreased at several days and months after HSCT. Although several salivary components were studied, most components were examined in only 1 or 2 studies with different patient populations or at different time points after HSCT. At 7 days after HSCT, albumin and proinflammatory cytokines were increased, whereas secretory IgA and components of the salivary antioxidant system were decreased. Secretory IgA levels were still reduced at 1 month after HSCT but returned to pre-HSCT values at 6 months after HSCT. Lactoferrin, secretory leukocyte protease inhibitor, and β₂-microglobulin levels were increased at 6 months after HSCT. Our findings show that changes in saliva reflect an inflammatory response occurring immediately after HSCT, followed by evidence of increased salivary antimicrobial defense mechanisms by 6 months after HSCT.

Differing structural properties of foods affect the development of mandibular control and muscle coordination in infants and young children

The development of chewing is an essential motor skill that is continually refined throughout early childhood. From a motor control perspective, the advancement of textures is dependent upon the fit between a child's oral anatomic and motor system and food properties. The purpose of this exploratory study is to identify age-related changes in chewing motor coordination and control and to determine if these changes are associated with the differing structural properties of solid foods, as well as to explore the role of explanatory variables such as the emergence of teeth and bite force. The masticatory muscle coordination (i.e., coupling of synergistic and antagonistic muscle pairs) and control (i.e., speed, displacement, chewing rate, duration, and number of chews) of fifty children were assessed cross-sectionally at five ages: 9-, 12-, 18-, 24-, and 36-months using electromyography (EMG) and 3D optical motion capture while children ate three foods that had differing structural properties. The results of this study found that children made gains in their chewing motor control (decreased duration of chewing sequences and lateral jaw displacement) and coordination (improved jaw muscle coupling) throughout this period. The structural differences in foods also affected chewing performance at all ages. These preliminary findings suggest that some solid textures are better adapted for immature mandibular control than others and that the development of chewing is a protracted process that may be impacted by the emergence of teeth and changes to bite force.

Circular RNA in Saliva

Although the type and amount of salivary components are influenced by many factors, due to easy, quick, cheap, and noninvasive sampling method alongside with the existence of the vast majority of the substances found in peripheral blood and urine in it, in recent years saliva has been considered as an ideal biofluid for disease research. Salivary circular RNA (circRNA), as an endogenous RNA molecule with a great variety of regulatory potency, is becoming a novel focus for detecting wide range of local or systemic diseases. Expectantly, with characterization of many more circRNAs in saliva, their motifs, and target sites, they can be used routinely in personalized medicine.

Preliminary findings on the correlation of saliva pH, buffering capacity, flow rate and consistency in relation to waterpipe tobacco smoking

The aim of the present comparative study was to compare some salivary characteristics between exclusive waterpipe smokers (EWPS) and non-smokers. 72 males (36 EWPS) were recruited. The volume of stimulated saliva was determined and divided by the duration of saliva collection. The pH was measured directly using a pH meter. The buffering capacity was determined using a quantitative method which involved the addition of 10 µl HCl. Up to a total of 160 µL was titrated up to obtain a pH titration curve. At 50 µL of titrated HCl, buffering capacity was ranked into three categories: high, medium and low. EWPS and non-smoker groups had similar flow rates (1.81 ± 0.79 and 1.78 ± 1.14 mL min-1) and similar baseline pH (6.60 ± 0.37 and 6.76 ± 0.39). Statistically significant differences in the two groups' pH were observed from 30 to 160 µL of titrated up HCl. At 50 µL of titrated up HCl, the EWPS group compared to the non-smoker group had a significantly higher pH (4.79 ± 0.72 vs. 5.32 ± 0.79). To conclude, waterpipe tobacco smoking alters the buffering capacity but does not alter either salivary flow rates or the baseline pH and consistency.

Postnatal Innate Immune Development: From Birth to Adulthood

It is well established that adaptive immune responses are deficient in early life, contributing to increased mortality and morbidity. The developmental trajectories of different components of innate immunity are only recently being explored. Individual molecules, cells, or pathways of innate recognition and signaling, within different compartments/anatomical sites, demonstrate variable maturation patterns. Despite some discrepancies among published data, valuable information is emerging, showing that the developmental pattern of cytokine responses during early life is age and toll-like receptor specific, and may be modified by genetic and environmental factors. Interestingly, specific environmental exposures have been linked both to innate function modifications and the occurrence of chronic inflammatory disorders, such as respiratory allergies. As these conditions are on the rise, our knowledge on innate immune development and its modulating factors needs to be expanded. Improved understanding of the sequence of events associated with disease onset and persistence will lead toward meaningful interventions. This review describes the state-of-the-art on normal postnatal innate immune ontogeny and highlights research areas that are currently explored or should be further addressed.

Salivary Diagnostics in Pediatrics: Applicability, Translatability, and Limitations

In the last decade, technological advances, combined with an improved appreciation of the ability of saliva to inform caregivers about both oral health and systemic disease, have led to the emergence of salivary diagnostic platforms. However, the majority of these assays have targeted diseases that more commonly affect the adult population, largely neglecting infants and children who arguably could benefit the most from non-invasive assessment tools for health monitoring. Gaining access into development, infection, and disease through comprehensive “omic” analyses of saliva could significantly improve care and enhance health access. In this review, we will highlight novel applications of salivary diagnostics in pediatrics across the “omic” spectrum, including at the genomic, transcriptomic, proteomic, microbiomic, and metabolomic level. The challenges to implementing salivary platforms into care, including the effects of age, diet, and developmental stage on salivary components, will be reviewed. Ultimately, large-scale, multicenter trials must be performed to establish normative biomarker values across the age spectrum to accurately discriminate between health and disease. Only then can salivary diagnostics truly translate into pediatric care.

Critical view on drug dissolution in artificial saliva: A possible use of in-line e-tongue measurements

Proper monitoring of drug's dissolution is a prerequisite for assessing of taste masking efficacy of pharmaceuticals. Corresponding dissolution procedure is likely to be performed with water. Since the objective of these tests is to examine fate of a pharmaceutical formulation in oral cavity, this choice of solvent seems unsuitable because physical and chemical properties of human saliva are quite far from those of water. Obviously, dissolution profiles registered in water may differ significantly from what really happens with a drug in a mouth cavity. In order to address this discrepancy we examined three different compositions of artificial saliva in dissolution test context in present study. It was found that certain compositions preclude the employment of traditional UV-vis spectroscopy as a detection tool due to strong light scattering in the media caused by viscosity and protein composition modifiers. This issue was circumvented by the use of in-line applied potentiometric multisensor system (e-tongue) and the potential of this new approach for more biorelevant dissolution tests was demonstrated with two model formulations of quinine and ibuprofen.

Sense of Humor, Childhood Cancer Stressors, and Outcomes of Psychosocial Adjustment, Immune Function, and Infection

The diagnosis, treatment, and side effects of childhood cancer have been described as extremely stressful experiences in the life of a child. Anecdotally, children report that a sense of humor helps them cope with the daily experiences of living with cancer; however, no research has examined sense of humor and childhood cancer stressors. This study investigated the effect of sense of humor on the relationship between cancer stressors and children’s psychosocial adjustment to cancer, immune function, and infection using Lazarus and Folkman’s theory of stress, appraisal, and coping. A direct relationship was observed between sense of humor and psychosocial adjustment to cancer, such that children with a high sense of humor had greater psychological adjustment, regardless of the amount of cancer stressors. A moderating effect was observed for incidence of infection. As childhood cancer stressors increase, children with high coping humor scores reported fewer incidences of infection than low scorers.

Salivary pH and Buffering Capacity as Risk Markers for Early Childhood Caries: A Clinical Study

Background: The diagnostic utility of saliva is currently being explored in various branches of dentistry, remarkably in the field of caries research. This study was aimed to determine if assessment of salivary pH and buffering capacity would serve as reliable tools in risk prediction of early childhood caries (ECC).

Materials and methods: Paraffin-stimulated salivary samples were collected from 50 children with ECC (group I) and 50 caries free children (group II). Salivary pH and buffering capacity (by titration with 0.1 N hydrochloric acid) were assessed using a handheld digital pH meter in both groups. The data obtained were subjected to statistical analysis.

Results: Statistically, no significant difference was observed between both the groups for all salivary parameters assessed, except for the buffering capacity level at 150 μl titration of 0.1 N hydrochloric acid (p = 0.73; significant at 1% level).

Conclusion: Salivary pH and buffering capacity may not serve as reliable markers for risk prediction of ECC.

How to cite this article: Jayaraj D, Ganesan S. Salivary pH and Buffering Capacity as Risk Markers for Early Childhood Caries: A Clinical Study. Int J Clin Pediatr Dent 2015;8(3):167-171.

Age Differences of Salivary Alpha-Amylase Levels of Basal and Acute Responses to Citric Acid Stimulation Between Chinese Children and Adults

It remains unclear how salivary alpha-amylase (sAA) levels respond to mechanical stimuli in different age groups. In addition, the role played by the sAA gene (AMY1) copy number and protein expression (glycosylated and non-glycosylated) in sAA activity has also been rarely reported. In this study, we analyzed saliva samples collected before and after citric acid stimulation from 47 child and 47 adult Chinese subjects. We observed that adults had higher sAA activity and sAA glycosylated levels (glycosylated sAA amount/total sAA amount) in basal and stimulated saliva when compared with children, while no differences were found in total or glycosylated sAA amount between them. Interestingly, adults showed attenuated sAA activity levels increase over those of children after stimulation. Correlation analysis showed that total sAA amount, glycosylated sAA amount, and AMY1 copy number × total sAA amount were all positively correlated with sAA activity before and after stimulation in both groups. Interestingly, correlation r between sAA levels (glycosylated sAA amount and total sAA amount) and sAA activity decreased after stimulation in children, while adults showed an increase in correlation r. In addition, the correlation r between AMY1 copy number × total sAA amount and sAA activity was higher than that between AMY1 copy number, total sAA amount, and sAA activity, respectively. Taken together, our results suggest that total sAA amount, glycosylated sAA amount, and the positive interaction between AMY1 copy number and total sAA amount are crucial in influencing sAA activity before and after stimulation in children and adults.

Comparative study on novel test systems to determine disintegration time of orodispersible films

OBJECTIVES

Orodispersible films (ODFs) are a promising innovative dosage form enabling drug administration without the need for water and minimizing danger of aspiration due to their fast disintegration in small amounts of liquid. This study focuses on the development of a disintegration test system for ODFs.

METHODS

Two systems were developed and investigated: one provides an electronic end-point, and the other shows a transferable setup of the existing disintegration tester for orodispersible tablets. Different ODF preparations were investigated to determine the suitability of the disintegration test systems. The use of different test media and the impact of different storage conditions of ODFs on their disintegration time were additionally investigated.

KEY FINDINGS

The experiments showed acceptable reproducibility (low deviations within sample replicates due to a clear determination of the measurement end-point). High temperatures and high humidity affected some of the investigated ODFs, resulting in higher disintegration time or even no disintegration within the tested time period.

CONCLUSIONS

The methods provided clear end-point detection and were applicable for different types of ODFs. By the modification of a conventional test system to enable application for films, a standard method could be presented to ensure uniformity in current quality control settings.

Individual differences in the cortisol and salivary α-amylase awakening responses in early childhood: relations to age, sex, and sleep

Recent studies have examined post-waking changes in cortisol as a marker of HPA functioning, but questions remain about the stability of this response, as well as its relation to sleep and other ANS markers. The purposes of this study were to a) examine the presence and developmental changes in the cortisol awakening response (CAR) and salivary α-amylase awakening (sAA-AR) in a toddler sample and b) determine whether and how sleep relates to these responses in this age group. We measured cortisol and sAA upon awakening (and 30 min post-waking) and sleep characteristics using actigraphy (e.g., total sleep time, sleep efficiency, number of awakenings) in toddlers (N = 47; 36% female, ages 12-24 months). Forty-six percent of toddlers demonstrated a CAR and 52% demonstrated a sAA-AR. Strength of either response did not change linearly with age. Additionally, likelihood of demonstrating the CAR and sAA-AR was unrelated to age, sex, awakening time, time between samples, and time since feeding. Higher waking cortisol levels were associated with a shorter total sleep time and an earlier awakening. No associations were observed between sleep characteristics and the sAA-AR, ps > .05. Our findings suggest that these awakening responses function independently of sleep in toddlers. Additionally, the lack of change in percentage of children showing a CAR or sAA-AR across these ages suggests that these responses are stable and not emerging reliably across the second year of life.

Diurnal profiles of salivary cortisol and alpha-amylase change across the adult lifespan: evidence from repeated daily life assessments

Salivary cortisol and alpha-amylase are known to have distinctive diurnal profiles. However, little is known about systematic changes in these biomarkers across the adult lifespan. In a study of 185 participants (aged 20-81 years), time-stamped salivary cortisol and alpha-amylase were collected 7 times/day over 10 days. Samples were taken upon waking, 30 min later, and then approximately every 3 h until 9 pm. Multilevel models showed that older age was associated with increased daily cortisol secretion as indicated by greater area under the curve, attenuated wake-evening slopes, and more pronounced cortisol awakening responses. Further, older age was related to greater daily alpha-amylase output and attenuated wake-evening slopes. No age differences were observed regarding the alpha-amylase awakening response. Our findings may contribute to a better understanding of age-related differences in functioning of stress-related systems.

Mucosal pH, dental findings, and salivary composition in pediatric liver transplant recipients

BACKGROUND

Oral health and dental maintenance have become part of the standard of care for pediatric liver transplant recipients. These individuals tend to suffer particularly from dental problems, such as gingival enlargement, gingivitis, poor oral hygiene, dental hypoplasia, and caries. Saliva composition influences oral hygiene and disease states. We investigated saliva composition and its association with the oral health of young recipients of liver transplants.

METHODS

In 70 patients, 36 liver transplant recipients (ages 2-23 years) and 34 healthy controls (ages 4-21 years), we measured the following variables: (a) oral hygiene, (b) gingival inflammation, (c) caries status, (d) dental calculus formation, (e) oral mucosal pH, and (f) salivary protein composition.

RESULTS

Lower mean decayed, missing, and filled teeth index (P=0.0038), higher mean gingival index (P=0.0001), and higher mean calculus score (P=0.003) were found in the transplanted study group compared with the control. The mean mucosal pH for seven intraoral sites was higher in the transplant group (P=0.0006). The median salivary albumin concentration was significantly lower in the transplant group (P=0.01), as was the median salivary albumin/total protein ratio (P=0.0002).

CONCLUSIONS

In post-liver transplant pediatric recipients, low incidence of caries, together with high incidence of dental calculus, could be attributed to elevated oral mucosal pH. Salivary albumin and immunoglobulin A levels were relatively low in these patients. Clinicians should pay particular attention to the oral health and dental care of liver transplanted children.

The relationship between the level of salivary alpha amylase activity and pain severity in patients with symptomatic irreversible pulpitis

Objectives

Assessment of dental pain severity is very challenging in dentistry. Previous studies have suggested that elevated salivary alpha amylase may contribute to increased physical stresses. There is a close association between salivary alpha amylase and plasma norepinephrine under stressful physical conditions. The aim of this study was to evaluate the relationship between pain severity and salivary alpha amylase levels in patients with symptomatic irreversible pulpitis.

Materials and Methods

Thirty-six patients (20 females and 16 males) with severe tooth pain due to symptomatic irreversible pulpitis were selected. The visual analogue scale (VAS) score was used to assess the pain severity in each patient. Unstimulated whole saliva was collected, and the level of alpha amylase activity was assessed by the spectrophotometric method. Statistical analysis was performed using SPSS 13.

Results

The level of alpha amylase was significantly increased in the saliva in association with pain severity assessed by VAS. The salivary alpha amylase was also elevated with increased age and in males.

Conclusions

There was a significant correlation between the VAS pain scale and salivary alpha amylase level, which indicates this biomarker may be a good index for the objective assessment of pain intensity.

Association of dental caries and salivary sIgA with tobacco smoking

BACKGROUND

Salivary secretory IgA (sIgA) is said to play an important role in the immune response against dental caries. This study aimed to determine the salivary sIgA levels in healthy smokers and non-smokers, and its correlation with dental caries.

METHODS

A total of 70 healthy subjects were selected and classified into four groups according to dental caries and tobacco smoking habits: smoking with caries (Group 1, n = 15); smoking without caries (Group 2, n = 15); non-smoking with caries (Group 3, n = 15); and non-smoking without caries (Group 4, n = 25). Salivary sIgA was measured using ELISA. The fissure and proximal caries were examined clinically and radiographically. Caries status was determined according to the decay surface index.

RESULTS

Smokers showed a higher number of caries and the lowest concentration of sIgA. The highest levels of sIgA were observed in non-smoking and caries-free subjects compared to caries-active smokers (123.2 ± 19.9 vs. 13.3 ± 4.1 μg/ml respectively, p < 0.001). Also, the mean level of sIgA in Group 4 was significantly higher than Group 3 (p = 0.009). More importantly, higher and significant levels of sIgA were found in Group 3 versus Group 1 (p < 0.0001) and Group 2 (p = 0.0004).

CONCLUSIONS

Our findings indicate that low concentrations of salivary sIgA are correlated with a higher prevalence of dental caries in smokers.

Salivary peptide profile and its association with early childhood caries

BACKGROUND

As dietary management during early childhood is a great barrier in caries control, there is a need for the identification of intrinsic risk factors, capable of allowing the use of a more cost-effective approach to early childhood caries (ECC).

OBJECTIVE

To evaluate the salivary peptide profile of children with and without ECC and its association with caries experience.

METHODS

One hundred and six 10- to 71-month-old children participated in the study. Caries experience was determined through the visual/tactile method, based on the number of decayed, missing, and filled teeth, and surface scores (dmft/dmfs). Whole saliva was collected for mutans streptococci (MS) detection and peptide analysis.

RESULTS

Chromatograms from CF (children without caries experience, n = 58) and CE (children with caries experience, n = 48) saliva pools expressed different patterns. Identification of molecular masses suggested the presence of nine peptides. Three of them were significantly related with caries experience. HNP-3 (α-defensin 3) (P = 0.019) and HBD-3 (β-defensin 3) (P = 0.034) reduced the chances of experiencing ECC. Proline-rich peptides IB-4 significantly increased caries experience (P = 0.035). Age (P = 0.020) and MS counts (P = 0.036) increased caries experience; however, gender was not associated with dental caries (P = 0.877).

CONCLUSION

Specific salivary peptides of CF or CE children in early childhood predispose to a higher or lower risk of caries experience.

Measurements of salivary alpha amylase and salivary cortisol in hominoid primates reveal within-species consistency and between-species differences

Salivary alpha amylase (sAA) is the most abundant enzyme in saliva. Studies in humans found variation in enzymatic activity of sAA across populations that could be linked to the copy number of loci for salivary amylase (AMY1), which was seen as an adaptive response to the intake of dietary starch. In addition to diet dependent variation, differences in sAA activity have been related to social stress. In a previous study, we found evidence for stress-induced variation in sAA activity in the bonobos, a hominoid primate that is closely related to humans. In this study, we explored patterns of variation in sAA activity in bonobos and three other hominoid primates, chimpanzee, gorilla, and orangutan to (a) examine if within-species differences in sAA activity found in bonobos are characteristic for hominoids and (b) assess the extent of variation in sAA activity between different species. The results revealed species-differences in sAA activity with gorillas and orangutans having higher basal sAA activity when compared to Pan. To assess the impact of stress, sAA values were related to cortisol levels measured in the same saliva samples. Gorillas and orangutans had low salivary cortisol concentrations and the highest cortisol concentration was found in samples from male bonobos, the group that also showed the highest sAA activity. Considering published information, the differences in sAA activity correspond with differences in AMY1 copy numbers and match with general features of natural diet. Studies on sAA activity have the potential to complement molecular studies and may contribute to research on feeding ecology and nutrition.

Salivary flow rate and oral findings in Prader-Willi syndrome: a case-control study

BACKGROUND. Prader-Willi syndrome (PWS) is a rare complex multisystemic genetic disorder. AIM. The objective of this study was to provide a systematic assessment of whole saliva secretion and oral manifestations associated with PWS. DESIGN. Fifty individuals (5-40 years) with PWS and an age- and sex-matched control group were included. Whole saliva was collected. All participants underwent an anamnestic interview. Radiological and dental clinical examinations were carried out to identify hypodontia, dental caries, enamel defects and gingival inflammation. RESULTS. Mean whole salivary flow rate was 0.12 ± 0.11 mL/min in the study group compared with 0.32 ± 0.20 mL/min in the control group (P < 0.001). Hypodontia was significantly more common in PWS (P < 0.001), and dental caries in the age group >19 years was significantly lower in PWS (P = 0.04) compared with the controls. There was no significant difference in the prevalence of dental caries in the primary dentition or in the frequency of enamel defects in the permanent dentition between the two groups. Median Gingival Index was significantly higher in the Prader-Willi group compared with the controls (P = 0.02). CONCLUSIONS. Low salivary flow is a consistent finding in PWS. Nevertheless, despite dry mouth and dietary challenges, dental caries is not increased in Norwegian individuals with PWS.

A comparison of the sialochemistry, oral pH, and oral health status of Down syndrome children to healthy children

BACKGROUND

The aetiology of low caries incidence in Down syndrome (DS) children is not entirely clear. Aim. To compare sialochemistry and oral mucosal pH between Down syndrome children with caries (DS-Ca) and caries free (DS-CaF), and healthy children with caries (C-Ca) and caries free (C-CaF).

DESIGN

The study group comprised 70 children with DS (mean age 4.41 +/- 1.9 years); 32 healthy children (mean age 9.22 +/- 2.7 years) served as control. Groups were further subdivided according to caries status: DS-Ca, DS-CaF, C-Ca and C-CaF. Sialochemistry analysis included calcium (Ca), sodium (Na), potassium (K), and chloride (Cl). Mucosal pH, plaque and gingival indices (PI and GI), and caries status were recorded.

RESULTS

DMFT/dmft were significantly lower in the DS group. Cl and Ca levels were significantly higher in the DS-Ca compared to the C-Ca and the C-CaF children. Na and K were significantly higher in DS-Ca group compared to DS-CaF group. PI and GI were significantly higher in DS-C children compared to DS-CaF children.

CONCLUSIONS

DS may manifest itself in the salivary glands. Consequently, different electrolyte salivary environment may form, leading to lower caries rates among DS children.

Autologous saliva transfusion: treatment for HIV?

The HIV-1 pandemic is a complex mix of diverse epidemics within and between countries and regions of the world, and is undoubtedly the defining public-health crisis of our time. Any therapeutic or prophylactic measure which holds promise or provides clues of eliminating or inhibiting the infection is worthy of investigation. As our body's own saliva is suspiciously escaping from the infection and providing clues regarding the resistance/inhibition of HIV; in this paper, a treatment approach is suggested with the rationale of in vitro effective antiviral action of autogenous saliva may also have a better therapeutic potential by its intravenous administration along with dextran.

A simplified quantitative test--adapted Checkbuf test--for resting saliva buffering capacity compared with a standard test

OBJECTIVE

The aim of this study was to adapt a quantitative test for stimulated saliva, known as the Checkbuf test, to measure the buffering capacity of resting saliva and to evaluate its correlation with the Ericsson test for resting saliva.

STUDY DESIGN

Resting saliva was collected from 112 patients. Buffering capacity was assessed with the adapted Checkbuf test and 4 other methods: Ericsson test for resting saliva, Checkbuf test, and commercially available paper and liquid colorimetric tests for stimulated saliva. Data were analyzed by Cohen kappa coefficient to evaluate the agreement between the Ericsson test and the other tests.

RESULTS

There was a significant positive agreement between the Ericsson test for resting saliva and adapted Checkbuf test (kappa = 0.708). However, there were no agreements between the Ericsson test and the 3 other tests.

CONCLUSIONS

This study demonstrated that the adapted Checkbuf test is useful for measuring resting saliva buffering capacity, even for subjects with low salivary flow rates.

Determinants of salivary alpha-amylase in humans and methodological considerations

Salivary alpha-amylase (sAA) has been proposed as a marker for activity of the sympathetic nervous system (SNS). Recent studies in support of this hypothesis have led to an increased number of researchers integrating amylase measurements into their study designs. Salivary alpha-amylase is produced locally in the salivary glands, controlled by the autonomic nervous system. This entails some methodological consequences and potential pitfalls that might lead to increased error variance and thus prevent successful testing of hypotheses. The goal of this review is to summarize basic and recent findings on methodological issues and potential factors influencing sAA measurement, and to derive a set of recommendations enabling researchers to successfully using sAA in psychoneuroendocrinological experiments.

Relationship between quantitative assessments of salivary buffering capacity and ion activity product for hydroxyapatite in relation to cariogenic potential

BACKGROUND

The ion activity product for hydroxyapatite (Ip(HA)) is a comprehensive parameter reflecting pH, calcium and phosphate ion concentration in saliva which govern the degree of saturation with respect to the dissolving tooth mineral. The aim of this study was to evaluate the relationship between quantitative assessments of salivary buffering capacity and Ip(HA) in relation to cariogenic potential.

METHODS

Stimulated whole saliva was collected from 33 patients, and the initial pH of samples was measured using a hand-held pH meter. Then samples were titrated with 0.1 N HCl to evaluate buffering capacities and divided into three groups (high, medium and low). After measuring concentrations of calcium and phosphate ions in the samples, Ip(HA) was calculated using the values of the ion concentrations and pH. Differences in the mean pH values, the concentrations of calcium, phosphate ions and log[Ip(HA)] among three groups were analysed using the Kruskal Wallis and the Mann-Whitney non-parametric test, p < 0.05.

RESULTS

After HCl 50 microL titration, there were statistical differences of the mean pH and Ip(HA) among each buffering capacity group. Moreover, after 50 microL HCl titration, there was an excellent correlation between the buffer capacity and log[Ip(HA)].

CONCLUSIONS

The pH change for saliva after HCl titration has a significant influence on the rate of Ip(HA).

Salivary parameters in infants aged 12 to 60 months with Down syndrome

The purpose of this study was to measure certain components in whole saliva from children with Down syndrome aged 12 months to 60 months. Twenty children with Down syndrome were compared with 18 children without Down syndrome. Whole saliva was collected under slight suction and the salivary pH was measured with a portable pH meter soon after collection. Electrolyte concentrations were determined by inductively coupled argon plasma with atomic emission spectrometry. Sialic acid was determined by thiobarbituric acid assay. Amylase was assayed measuring the maltose produced by the breakdown of starch and peroxidase with ortho-dianisidine. No statistically significant differences were observed in sialic acid, calcium, phosphorus and magnesium concentrations between the group with Down syndrome and the control group. Protein and sodium concentration were higher in the group with Down syndrome compared to the control group. On the other hand, the flow rate, pH, amylase and peroxidase activities and potassium concentration were lower in those with Down syndrome compared to those children in the control group.