Flow rate, amylase activity, and protein and sialic acid concentrations of saliva from children aged 18, 30 and 42 months attending a baby clinic

Saliva composition from birth to adolescence: a systematic review of the literature

BACKGROUND

This systematic review examined the saliva composition of healthy children from birth to 18 years of age by assessing the salivary flow rate, pH, buffering capacity, and ion levels. This review followed the PRISMA guidelines. A systematic search was performed using PubMed, the Cochrane Library, and Scopus. Information regarding the salivary flow rate, pH, buffering capacity, and ion levels in whole saliva was systematically collected, and a qualitative synthesis was performed. The methodological quality of the studies was assessed using the JBI Critical Appraisal Tools.

HIGHLIGHT

Of the 3,268 retrieved studies, 41 were eligible for inclusion. Unstimulated salivary flow showed an age-related decrease, whereas stimulated salivary flow increased with age. The pH of the saliva remained consistent across different ages, whereas the buffering capacity showed an age-related increase. Salivary sodium, calcium, and potassium levels were lower in the younger children than in the older children. An investigation of salivary ion levels revealed lower average fluoride concentrations in Asian populations than in European populations. Most studies had a low or moderate risk of bias.

CONCLUSION

This systematic review highlights age-dependent differences in salivary flow and composition in healthy children from birth to 18 years of age. The flow rate of unstimulated saliva decreased with age, while the flow rate of stimulated saliva increased. The salivary pH remained stable, whereas the buffering capacity increased with age. Furthermore, salivary sodium, calcium, and potassium levels tend to increase with age. These findings underscore the dynamic nature of salivary composition from childhood to adolescence.

Salivary Protein and Electrolyte Profiles during Primary Teeth Eruption: A Cross-Sectional Study

This study aimed to assess the qualitative changes in the saliva during the process of primary teeth eruption. This cross-sectional study was conducted on 147 children from 2 to 48 months, of which 49 were in group A (no erupted primary teeth), 53 were in group B (at least one active erupting primary tooth), and 45 were in group C (eruption of all 20 primary teeth was completed). Salivary proteins were evaluated by sodium dodecyl sulfate electrophoresis with polyacrylamide gel, while the concentrations of salivary sodium, potassium, chloride, and calcium ions were evaluated by ion selective electrodes. The data were analyzed using ANOVA and Bonferroni tests (alpha = 0.05). The concentration of proteins with molecular weights of 20-30 KDa was significantly higher in group A, and it gradually decreased with age. The concentration of proteins with molecular weights of 50-60 KDa in group B was significantly lower than those of groups A and C. The calcium ion concentration in group A was significantly higher than that of the other groups. The concentration of potassium ions was minimal in group C. The proteins and electrolyte profiles of the subjects' saliva changed in the process of primary tooth eruption. The highest concentrations of proteins such as statherin, histatin, P-B peptide, and cystatin and the lowest concentrations of proteins such as amylase were present in group B.

Formulation Challenges and Strategies to Develop Pediatric Dosage Forms

The development of pediatric-specific dose forms is particularly difficult due to a variety of factors relating to pediatric population differences from adult populations. The buccal dosage form is considered a good alternative to oral dosage form if the latter cannot be used in pediatric patients. Both oral and buccal dosage formulations uphold great application qualities for pediatric patients. This review sheds light on both oral and buccal, as they are the most convenient dosage forms for pediatrics. The use of adult drugs to treat children is a legislation concern, as it may result in incorrect dose, safety, and efficacy. The Best Pharmaceuticals for Children Act (BPCA) and the Pediatric Research Equity Act (PREA) are two key pieces of legislation that encourage and regulate pediatric medication research. Both contribute to a well-balanced approach to emphasizing critical safety and efficacy warnings for the of medications within pediatric populations. These contributions are what enable companies to continue making significant investments in pediatric drug developments. Despite the importance of investigating medicines for children, there is still a demand for pediatric-specific formulations and dosage forms. Many formulations and dosage forms can be designed, among which the buccal drug delivery seems a good modality for pediatric-friendly dosage forms. The main issues associated with these pediatric dosage forms development, particularly clinical and physiological factors, are discussed in this review. In addition, formulation developments and regulatory expectations are highlighted. In turn, suggestions are made to potentially improve future pediatric formulation 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.

Natural food mastication capability in preschool children according to their oral condition: A preliminary study

This study investigated, for the first time, the masticatory capability of preschool children using natural foods, and the impact of an early oral health alteration (early childhood caries: ECC) on the granulometry of ready-to-swallow food boluses. Thirteen children with ECC were compared to 13 preschool children with a healthy oral condition. Oral health criteria and NOT-S scores (Nordic Orofacial dysfunction Test-Screening) were recorded. For each child, number of masticatory cycles (Nc), chewing time (Ti), and frequency (Fq = Nc/Ti) were recorded during mastication of raw carrot (CAR), cheese (CHS) and breakfast cereals (CER) samples. Food boluses were collected by stopping children at their food-dependent individual swallowing threshold (Nc), and the median food bolus particle size value (D50) was calculated. Correlations were sought between oral health and masticatory criteria. In the ECC group, mean Fq values were significantly decreased for all three foods (p ≤ .001) and mean D50 values were significantly increased (p ≤ .001) compared to the control group (i.e., D50 CAR = 4,384 μm ± 929 vs. 2,960 μm ± 627). These alterations were related to the extent of ECC. The NOT-S mean global score was significantly increased in children with ECC (2.62 ± 1.37 vs. 1 ± 0.91 in the control group, p ≤ .01), due to "Mastication and swallowing" domain impairment. This study gives granulometric normative values for three foods in preschool children and shows the impact of ECC on D50 values. The progression of children's masticatory capability after dental treatment, and the impact of such modifications of sensory input on future eating habits should be explored.

Effect of fluoride on salivary immunoglobulins and sialic acid

Objective:

The aim of our study was to evaluate the effect of fluoride on salivary immunoglobulin and sialic acid levels in children with dental fluorosis and healthy teeth who live in places with high fluoride concentration in drinking water.

Method:

Fifty-one (51) healthy children between 6 and 12 years old with no caries were randomly selected from primary schools enrolled in the dental-care program operated by the Department of Pediatric Dentistry. The children were divided into two groups: group I comprised 26 children with dental fluorosis [Thylstrup-Fejerskov Dental Fluorosis Index (TFI) = 4] who lived in Isparta (2.7-2.8 ppm), and group II consisted of 25 children without dental fluorosis who were born in low-fluoride areas and had lived in Isparta for only the previous two years. Stimulated and unstimulated saliva were collected and analyzed for fluoride, salivary immunoglobulins and sialic acid levels.

Results:

Sialic acid level was correlated negatively with age. Levels of secretory immunoglobulin A (sIgA) and secretory immunoglobulin G (sIgG) were higher in children with dental fluorosis compared with those in group II, although these differences were not significant.

Conclusion:

Increased sIgA and sIgG levels may arrest the progression of caries in subjects with dental fluorosis. Given the risks of dental fluorosis, further studies of the effects of different fluoride levels in drinking water on salivary composition of children with mixed dentition are needed to confirm the results of our study and to provide data for comparison.

Methylsiloxanes in children silicone-containing products from China: Profiles, leaching, and children exposure

Methylsiloxanes (D4-D6, L5-L16) were detected in children silicone-containing products (n=190, detected frequencies=46-89%) marketed in China. For the 15 target compounds, the average concentrations ranged from <LOQ - 0.005±0.007μg/g in hard toys, 0.084±0.281-22.2±29.6μg/g in pacifiers, 0.020±0.023-20.6±16.0μg/g in teethers, and 0.005±0.009-2.81±3.22μg/g in soft rubber toys. Linear methylsiloxanes were predominant in these four types of children products. In the leaching test, except for L6, the other 14 methylsiloxanes were detected (mean=0.001±0.008-0.770±2.60ng/mL) in saliva leachates for children products, with the detection frequencies ranging from 4 to 46%. The conservative mouthing exposure for children were 6.87-18.05ng/kg bw-day via pacifiers and 0.44-2.29ng/kg bw-day via teether/soft rubber toys for ∑cyclic methylsiloxanes, and 7.89-20.74ng/kg bw-day via pacifiers and 0.41-2.12ng/kg bw-day via teether/soft rubber toys for ∑linear methylsiloxanes. Methylsiloxanes conservative mouthing exposure associated with children products were 1-2 order of magnitudes lower than the sum of children's daily inhalation exposure and dust ingestion exposure in the indoor environment. The above results indicated that although methylsiloxanes, as the impurities of polydimethylsiloxane, distributed in children silicone-containing products, exposure arising from directly mouthing these products may not be the dominated pathway for children exposure of methylsiloxanes.

Proteins in Whole Saliva during the First Year of Infancy

During the first year of an infant’s life, the oral environment is subject to drastic changes that coincide with the eruption of teeth. Proteins in saliva are important for protecting oral surfaces and provide receptors for bacterial adhesins. The objective of this longitudinal study was to monitor the general composition and expression of proteins in whole saliva of infants, to prove the hypothesis that expression of certain proteins changes during infant development, and might be associated with tooth eruption. The results showed a remarkable constancy in the overall pattern of salivary proteins and glycoproteins during infancy. Exceptions were the mucins and albumin. The mucins are expressed differentially, with first MUC7 and later MUC5B being predominant. Albumin, a marker of serum leakage, started to rise in whole saliva preceding tooth eruption. Thus, the expression of only few proteins appears to be changed during infant development.

The ontogeny of saliva secretion in infants and esophagoprotection

BACKGROUND

Several studies have reported that severe reflux esophagitis is rare in infants despite the well known high occurrence of regurgitation in early infancy. There is evidence of the importance of saliva for the pre-epithelial protection of the esophageal mucosa.

RESULTS

A longitudinal study conducted on healthy infants indicated that the stimulated capacity of saliva secretion (saliva output per kg of body weight) was significantly higher during their first year of age compared to older children and adults. In addition, this secretion pattern was also observed in low weight newborns during the first weeks of life and persisted in infants with severe protein-calorie malnutrition (marasmus).

CONCLUSION

The greater ability to secrete saliva is an important physiological condition that may protect the infant from acid/pepsin aggression to the esophagus during early stages of development.

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.

Oral transmucosal drug delivery for pediatric use

The formulation of medicines for children remains a challenge. An ideal pediatric formulation must allow accurate dose administration and be in a dosage form that can be handled by the target age group. It is also important to consider the choices and the amount of excipients used in the formulation for this vulnerable age group. Although oral formulations are generally acceptable to most pediatric patients, they are not suitable for drugs with poor oral bioavailability or when a rapid clinical effect is required. In recent years, oral transmucosal delivery has emerged as an attractive route of administration for pediatric patients. With this route of administration, a drug is absorbed through the oral mucosa, therefore bypassing hepatic first pass metabolism and thus avoiding drug degradation or metabolism in the gastrointestinal tract. The high blood flow and relatively high permeability of the oral mucosa allow a quick onset of action to be achieved. It is a simple and non-invasive route of drug administration. However, there are several barriers that need to be overcome in the development of oral transmucosal products. This article aims to provide a comprehensive review of the current development of oral transmucosal delivery specifically for the pediatric population in order to achieve systemic drug delivery. The anatomical and physiological properties of the oral mucosa of infants and young children are carefully examined. The different dosage forms and formulation strategies that are suitable for young patients are discussed.

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.

Age- and sex-associated differences in the glycopatterns of human salivary glycoproteins and their roles against influenza A virus

Recent studies have elucidated that expression of certain glycoproteins in human saliva is increased or decreased according to age; meanwhile, human saliva may inhibit viral infection and prevent viral transmission. However, little is known about the age- and sex-associated differences in the glycopatterns of human salivary glycoproteins and their significant roles against influenza A virus (IVA). Here, we investigate the glycopatterns of human salivary glycoproteins with 180 healthy saliva samples divided into six age/sex groups using lectin microarrays and fabricate saliva microarrays to validate the terminal carbohydrate moieties of glycoproteins in individual saliva samples. Furthermore, we assess the inhibiting and neutralizing activity of saliva against two strains of influenza A (H9N2) virus. We find that seven lectins (e.g., MAL-II and SNA) show significant age differences in both females and males, and seven lectins (e.g., WFA and STL) show significant sex differences in children, adults and elderly people. Interestingly, we observe that elderly individuals have strongest resistance to IVA partly by presenting more terminal α2-3/6-linked sialic acid residues in their saliva, which bind with the influenza viral hemagglutinations. We conclude that age- and sex-associated differences in the glycopatterns of human salivary glycoproteins may provide pivotal information to help understand some age related diseases and physiological phenomena.

Salivary alpha-amylase activity and salivary flow rate in young adults

The secretion of salivary alpha-amylase (sAA) is more associated with psychoneuroendocrinological response to stress than with the flow rate and age. The aim of this cross sectional study is to build an explanatory model based on patterns of relationship between age 20-39 in resting and stimulated saliva under no stressful condition in healthy volunteers. Both resting and stimulated saliva were collected from 40 subjects. The sAA values were log-transformed, the normality assumption was verified with the Shapiro-Wilk test and the reliability of the measurements was estimated by the Pearsons’ r correlation coefficient. The estimated model was based on the theory of the Linear Mixed Models. Significant mean changes were observed in flow rate and sAA activity between resting and stimulated saliva. The final model consists of two components, the first revealed a positive correlation between age and sAA while the second one revealed a negative correlation between the interaction of age × flow rate in its condition (resting or stimulated saliva), with sAA. Both flow rate and age influence sAA activity.

The cross-generation transmission of oxytocin in humans

Animal studies demonstrated that the neuropeptide oxytocin (OT), implicated in bond formation across mammalian species, is transmitted from mother to young through mechanisms of early social experiences; however, no research has addressed the cross-generation transmission of OT in humans. Fifty-five parents (36 mothers and 19 fathers) engaged in a 15-min interaction with their infants. Baseline plasma OT was sampled from parents and salivary OT was sampled from parents and infants before and after play and analyzed with ELISA methods. Interactions were micro-coded for parent and child's socio-affective behavior. Parent and infant's salivary OT was individually stable across assessments and showed an increase from pre- to post-interaction. Significant correlations emerged between parental and infant OT at both assessments and higher OT levels in parent and child were related to greater affect synchrony and infant social engagement. Parent-infant affect synchrony moderated the relations between parental and infant OT and the associations between OT in parent and child were stronger under conditions of high affect synchrony. Results demonstrate consistency in the neuroendocrine system supporting bond formation in humans and other mammals and underscore the role of early experience in shaping the cross-generation transmission of social affiliation in humans.

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.

Molecular characterization of group A Streptococcus maltodextrin catabolism and its role in pharyngitis

We previously demonstrated that the cell-surface lipoprotein MalE contributes to GAS maltose/maltodextrin utilization, but MalE inactivation does not completely abrogate GAS catabolism of maltose or maltotriose. Using a genome-wide approach, we identified the GAS phosphotransferase system (PTS) responsible for non-MalE maltose/maltotriose transport. This PTS is encoded by an open reading frame (M5005_spy1692) previously annotated as ptsG based on homology with the glucose PTS in Bacillus subtilis. Genetic inactivation of M5005_spy1692 significantly reduced transport rates of radiolabelled maltose and maltotriose, but not glucose, leading us to propose its reannotation as malT for maltose transporter. The DeltamalT, DeltamalE and DeltamalE:malT strains were significantly attenuated in their growth in human saliva and in their ability to catabolize alpha-glucans digested by purified human salivary alpha-amylase. Compared with wild-type, the three isogenic mutant strains were significantly impaired in their ability to colonize the mouse oropharynx. Finally, we discovered that the transcript levels of maltodextrin utilization genes are regulated by competitive binding of the maltose repressor MalR and catabolite control protein A. These data provide novel insights into regulation of the GAS maltodextrin genes and their role in GAS host-pathogen interaction, thereby increasing the understanding of links between nutrient acquisition and virulence in common human pathogens.

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.

Factors influencing oral colonization of mutans streptococci in young children

This paper aims to critically review current knowledge about the key factors involved in oral colonization of the cariogenic group of bacteria, mutans streptococci (MS) in young children. MS, consisting mainly of the species Streptococcus mutans and Streptococcus sobrinus, are commonly cultured from the mouths of infants, with prevalence of infection ranging from around 30 per cent in 3 month old predentate children to over 80 per cent in 24 month old children with primary teeth. MS is usually transmitted to children through their mothers, and the risk of transmission increases with high maternal salivary levels of MS and frequent inoculation. Factors that affect the colonization of MS may be divided into bacterial virulence, host-related and environmental factors. Complex interaction among these factors determine the success and timing of MS colonization in the child. As clinical studies have shown that caries risk is correlated with age at which initial MS colonization occurred, strategies for the prevention of dental caries should include timely control of colonization of the cariogenic bacteria in the mouths of young children.

Buffer capacity, pH, and flow rate in saliva of children aged 2-60 months with Down syndrome

This study measured the flow rate, pH, and buffer capacity of saliva from children with Down syndrome aged 2-60 months. We compared 25 children with Down syndrome with 21 children without Down syndrome. The whole saliva was collected under slight suction and the pH and the buffer capacity were determined using a digital pHmeter. The buffer capacity was measured by titration with 0.01 N HCl. The Down syndrome group demonstrated higher buffer capacity than the control group in the pH ranges of 6.9-6.0, 5.9-5.0, and 4.9-4.0. The flow rate was low in the Down syndrome group. Boys from the Down syndrome group demonstrated higher buffer capacity in the pH ranges 6.9-6.0, 5.9-5.0, and 4.9-4.0 than controls, while girls from the Down syndrome group showed no difference compared with controls. Girls with Down syndrome demonstrated significant difference only in the range of pHi-pH 7.0. Conclusion. These data suggest that the Down syndrome persons present a better buffer capacity, supporting the results observed in several studies which found the low dental caries in persons with Down syndrome.