Increased activity of the antioxidants systems modulate the oxidative stress in saliva of toddlers with early childhood caries

Assessment of Antioxidant Enzyme Superoxide Dismutase (SOD) in Oral Cancer: Systematic Review and Meta-Analysis

Objective

The present article aims to comprehensively review the existing literature on superoxide dismutase (SOD) levels, an antioxidant enzyme, in oral cancer.

Method

An extensive literature search was conducted across various databases, including PubMed, Wiley Online Library, Science Direct, and Cross Reference, spanning 1998-2023. At the outset, 1,177 articles were initially identified, and 907 studies were excluded due to irrelevance or duplication of the research question. Subsequently, 270 articles underwent screening evaluation, resulting in the selection of 85 articles meeting the inclusion criteria. Following this, 68 articles underwent a full-text comprehensive assessment, and ultimately, 39 were chosen for data extraction. The risk of bias in the designated articles was assessed using the Newcastle-Ottawa Scale. Finally, 13 studies were meticulously selected, offering consistent data for the ensuing meta-analysis. Meta-analysis was executed using comprehensive meta-analysis (CMA) version 3 software (Bio Stat Inc., Englewood, NJ, USA). The meta-analysis findings revealed a statistically significant decrease in SOD levels in both erythrocyte samples (P < 0.001) and tissue samples (P < 0.05) among individuals with oral cancer (OSCC) compared to the normal control group. Conversely, the analysis of three studies on salivary samples demonstrated a significant increase (P < 0.05) in SOD levels in the oral cancer group compared to the healthy controls.

Conclusion

This systematic review underscores a statistically significant decline in SOD levels observed across diverse bio-samples in individuals with oral cancer, indicating an excess of oxidative stress (OS). Additional research is needed to delve into the relationship between SOD levels and clinic-pathological prognostic markers within the oral cancer cohort. Such investigations have the potential to significantly contribute to the development of prognostic tools grounded in OS, thereby guiding strategies for treatment planning.

Comparison of oral cavity protein abundance among caries-free and caries-affected individuals-a systematic review and meta-analysis

Objective

Some salivary proteins seem to be differently abundant among caries-free (CF) and caries-affected (CA) individuals, but previous results are contradictory precluding that definitive conclusion be drawn. A pooled analysis of the available evidence may provide more robust data on identifying oral cavity protein patterns among CF and CA individuals. This systematic review and meta-analysis (PROSPERO CRD42021269079) aimed to compare the oral cavity protein abundance among caries-free and caries-affected individuals.

Methods

This study was conducted following PRISMA guidelines. PubMed, Embase, and Web of Science databases were systematically assessed (up to February 2023) to retrieve clinical studies written in English, German, or in Latin-based languages that compared the oral cavity protein abundance among CF and CA individuals. Data extraction and methodological quality assessment (NIH guidelines) were independently performed by two investigators. Qualitative synthesis was performed from all included studies and meta-analysis was performed using a random-effects model with inverse variance for studies that reported the concentration of proteins or enzymatic activity. Standardized mean difference (SMD) with respective 95% confidence interval (CI) were calculated for each outcome.

Results

A total of 90 studies (two cohort and 88 cross-sectional designs) of more than 6,000 participants were selected for data extraction, being the quality of evidence graded as "fair" for most of them. The oral cavity of CF individuals presented lower total protein concentration [SMD = 0.37 (95% CI: 0.07-0.68; 18 studies)], lower total antioxidant capacity [SMD = 1.29 (95% CI: 0.74-1.85); 17 studies], and lower carbonic anhydrase activity [SMD = 0.83 (95% CI: 0.58-1.09); three studies], whereas CA individuals presented lower carbonic anhydrase concentration [SMD = -0.66 (95% CI: -1.00 to -0.32); three studies], urease [SMD = -0.95 (IC 95%: -1.72 to -0.17); four studies], and arginine deiminase system [SMD = -2.07 (95% CI: -3.53 to -0.62); three studies] activities. Antimicrobial peptides, secretory immunoglobulin-A concentrations and alpha-amylase activity were similar among individuals.

Conclusion

Differences on oral cavity protein abundance were observed among CF and CA individuals. These data indicate some protein patterns for the oral health and dental caries conditions. Even when statistically significant, some of the results were not very consistent. Cohort studies need to be conducted to validate these results.

Assessment of glutathione peroxidase enzyme response and total antioxidant status in oral cancer - Systematic review and meta-analysis

BACKGROUND

Oxidative stress induced by free radical accumulation contributes to many pathologies, including cancer. Antioxidant defense system fails to scavenge free radicals when it is excessively accumulated. Assessing individual antioxidant enzymes and total antioxidant capacity could direct the customized therapeutic strategies.

OBJECTIVE

Evaluation of total antioxidant status and enzyme glutathione peroxidase activity in the oral cancer group compared to the healthy control group.

METHOD

The literature search included databases PubMed, Science Direct, Wiley Online Library, Cochrane and Cross Reference between 1999 and 2021. The database search was completed in the month of August 2022. The extracted data were analyzed by Comprehensive Meta-Analysis (CMA) version 3 software (Biostat Inc. Englewood, NJ). Based on search strategies, 1435 articles have been retrieved from the database. In the segregated articles, 1365 were excluded due to duplicated articles, animal studies, low-quality studies, articles unrelated to the research question, and with unmatched objectives. Based on inclusion criteria, 70 articles were selected for full-text valuation. However, 33 articles were found highly suitable for inclusion and data extraction. Finally, 11 articles were selected for meta-analysis.

RESULTS

The meta-analysis of four included studies of tissue samples showed a significantly (p < .001) increased GPx activity in the oral cancer group, when compared to the control group, whereas three included studies of erythrocyte samples displayed a significantly (p < .001) decreased GPx activity in the oral cancer group than the control group with the pooled standardized mean difference value of -2.766 moles/min/g Hb at 95% CI (-3.297 to -2.234). The meta-analysis of the included studies depicted an insignificant (p = .947) reduction of salivary TAS levels in the oral cancer group when compared to the control group.

CONCLUSION

Our systematic review and meta-analysis depict antioxidant GPx enzyme activity in the regional tissue samples of the oral cancer group differs from other systemic biological fluid samples compared to the healthy control group.

Comparison of Total Salivary Antioxidant Capacity of Children with and without Severe Early Childhood Caries before and after Complete Dental Rehabilitation

Introduction

Early childhood caries (ECC) is the most chronic disease affecting children all over the world. Children often complain of pain and need complete rehabilitation, which is often done under general anesthesia due to extensive treatment and behavioral problems that are often encountered. The present study was undertaken to evaluate the total salivary antioxidant capacity of children with severe ECC (S-ECC) before and after complete dental rehabilitation and compare it with caries-free children.

Materials and methods

Salivary samples were obtained from 30 children aged 3-5 years and diagnosed with S-ECC, along with 30 age and sex-matched controls. Complete dental rehabilitation under general anesthesia was performed on the children with S-ECC, and follow-up salivary samples were obtained after 3 and 6 months postoperatively. Total salivary antioxidant capacity was measured using a commercially available Oxygen Radical Absorbance Antioxidant Assay measurement kit. At baseline, children with S-ECC had higher total antioxidant capacity (TAC) compared to the controls.

Results

A significant difference in total salivary antioxidant capacity between both groups was seen at baseline. At 3 months following, the total salivary antioxidant capacity of children treated for S-ECC was slightly higher than controls but had significantly reduced compared to baseline. At 6 months, there was no significant difference between both groups.

Conclusion

Within the limitations of our study, it can be concluded that the total salivary antioxidant capacity associated with children suffering from S-ECC is reduced after complete rehabilitation.

How to cite this article

Mathew MG, Jeevanandan G. Comparison of Total Salivary Antioxidant Capacity of Children with and without Severe Early Childhood Caries before and after Complete Dental Rehabilitation. Int J Clin Pediatr Dent 2023;16(3):474-477.

Dental Caries and Salivary Oxidative Stress: Global Scientific Research Landscape

This study aimed to analyze the research trends on salivary oxidative stress associated with dental caries and to perform bibliometric approaches for existing publications on this association. A search was performed using the Web of Science Core Collection, without any restriction of language or publication year. The number of periodicals with the most published articles in this theme, most published authors and keywords were mapped; other metrics were also evaluated such as the countries that have more research on the subject and the period in which there were more publications on the subject. During the knowledge mapping, the most frequent experimental designs were analyzed, type of saliva collection, stage of caries disease, evaluated oxidative parameters were retrieved and analyzed from each manuscript. Between the 43 selected articles, the Journal of Clinical Pediatric Dentistry was the periodical appearing the most with 4 published articles. The authors who published the most were Celec, P., Tothova, L., Hegde, A.M., Shetty, S., Antoniali, C., and Pessan, JP with three articles each, and a total of 180 keywords representing the evolution of the theme. India and Asia were found to be the country and continent with most publications, respectively. Most articles collected non-stimulated total saliva, with total antioxidant capacity being the parameter most often evaluated. The type of study that appeared the most was cross-sectional studies, and articles published in the period of 2017-2022 were the most frequent. Studies show that dental caries can be associated to the changes in salivary oxidative biochemistry with an increase in lipid peroxidation, a biomarker of oxidative damage, and an increase in antioxidant capacity in chronic caries, in response to cariogenic challenge. Some studies evidence the reduction of lipid peroxidation after treatment of the carious lesion. Our findings reveal worldwide research trends, as well as a clearer knowledge of the evolution and future scenarios of this issue, also showing the mechanisms associating dental caries with changes in salivary oxidative biochemical parameters are not clear.

Understanding the Predictive Potential of the Oral Microbiome in the Development and Progression of Early Childhood Caries

BACKGROUND

Early childhood caries (ECC) is the most common chronic disease in young children and a public health problem worldwide. It is characterized by the presence of atypical and fast progressive caries lesions. The aggressive form of ECC, severe early childhood caries (S-ECC), can lead to the destruction of the whole crown of most of the deciduous teeth and cause pain and sepsis, affecting the child's quality of life. Although the multifactorial etiology of ECC is known, including social, environmental, behavioral, and genetic determinants, there is a consensus that this disease is driven by an imbalance between the oral microbiome and host, or dysbiosis, mediated by high sugar consumption and poor oral hygiene. Knowledge of the microbiome in healthy and caries status is crucial for risk monitoring, prevention, and development of therapies to revert dysbiosis and restore oral health. Molecular biology tools, including next-generation sequencing methods and proteomic approaches, have led to the discovery of new species and microbial biomarkers that could reveal potential risk profiles for the development of ECC and new targets for anti-caries therapies. This narrative review summarized some general aspects of ECC, such as definition, epidemiology, and etiology, the influence of oral microbiota in the development and progression of ECC based on the current evidence from genomics, transcriptomic, proteomic, and metabolomic studies and the effect of antimicrobial intervention on oral microbiota associated with ECC.

CONCLUSION

The evaluation of genetic and proteomic markers represents a promising approach to predict the risk of ECC before its clinical manifestation and plan efficient therapeutic interventions for ECC in its initial stages, avoiding irreversible dental cavitation.

Correlation of Carbonic Anhydrase VI Enzyme, Total Proteins, Antioxidant Levels of Saliva and Dental Caries in Caries-Free and Caries-Active Children - A Case-Control Study

Background and Objectives

Factors in the biofilm influence the induction and advancement of the carious process. This study was done to relate and assess the levels of enzyme carbonic anhydrase VI, total protein, and antioxidants (superoxide dismutase [SOD], catalase, lipid peroxidase, and uric acid) in caries-free and caries-active children.

Methods

This case-control study comprised 60 children of age group 6-12 years who were evaluated for decayed missing filled teeth (dmft)/DMFT criteria and distributed into two groups: Group 1 - caries active (case) and Group 2 - caries free (control) for saliva collection with 30 participants in each of the above groups. Stimulated saliva was obtained, and the samples were then evaluated using biochemical lab tests. The data were then statistically evaluated using independent t-test.

Results

Catalase in the caries-free group was significantly higher, but the concentration of carbonic anhydrase (CAVI) enzyme, total protein, and other antioxidant enzyme activity was enhanced in caries-active children in which uric acid demonstrated a statistically significant difference with higher levels in caries-active group.

Conclusion

There is an increased concentration of CAVI enzyme in caries-active group and total protein showed a linear relation with caries activity. Antioxidant parameters such as SOD and lipid peroxidase were increased with caries activity. Uric acid was significantly higher in the caries-active group, whereas catalase showed an indirect relation with dental caries. Significant variations in the levels of these parameters imply that the levels of these components of saliva can act as strong markers of caries status in children.

Are Dental Caries Associated with Oxidative Stress in Saliva in Children and Adolescents? A Systematic Review

Background: This systematic review aimed to assess whether dental caries is associated with oxidative salivary stress. Methods: The searches were carried out in electronic databases, including PubMed, Scopus, Web of Science, the Cochrane Library, LILACS, OpenGrey, and Google Scholar, without restrictions on the date of publication and language. The acronym PECO was used, in which the participants (P) were children and adolescents exposed (E) to dental caries compared (C) to those without dental caries, with the outcome (O) of modulation of oxidative biochemical parameters. After the search retrieval, the duplicates were removed, and the articles were evaluated by title and abstract, following the inclusion and exclusion criteria. Then, the papers were read and thoroughly assessed. After selection, the risk of bias assessment and qualitative synthesis were performed using the Newcastle-Ottawa Scale (NOS) for observational studies. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) tool was used to assess the level of evidence. Results: A total of 5790 studies were found, and 30 articles were considered eligible and were included for the qualitative synthesis and the level of evidence assessment. The studies showed an imbalance of the antioxidant and pro-oxidant parameters in individuals with dental caries, with primarily increases in both total antioxidant capacity and lipid peroxidation. Most articles showed a low risk of bias, having comparability as the main issue. When exploring through GRADE, a very low level of evidence was found. Conclusions: It was possible to observe an association between oxidative stress and dental caries, showing a disbalance of antioxidants and pro-oxidants, but the evidence level was still very low.

Evaluation of Salivary Thiol/Disulfide Homeostasis and Oxidative Stress in Children with Severe Early Childhood Caries Using a Novel Method

Objective This study aimed to assess the role of thiol/disulfide homeostasis and oxidative stress in the saliva of children with severe early childhood caries (S-ECC).

Methods Eighty children aged 3 to 6 years were involved in this case-control study. The study consisted of two groups: the study group (S-ECC) and the control group with no caries. Thiol/disulfide homeostasis and antioxidant levels were calculated after obtaining unstimulated saliva samples from all participating children.

Results The native/total thiol and total oxidant status (TOS) levels of the study group were higher than those of the control group, though not statistically significant (p > 0.05). The oxidative stress index (OSI) value was significantly higher in the study group compared to the control group (p = 0.024).

Conclusion Our results confirmed that the thiol/disulfide homeostasis was reduced, and disulfide formation, which is rereducible to thiol, was insufficient in children with S-ECC to compensate oxidative stress compared with the control group. Also, thiol levels were inadequate to compensate for oxidative stress, and thiol/disulfide homeostasis was not an independent parameter for S-ECC. Besides, the increases in the TOS level and OSI value show that oxidative stress had significant effects on S-ECC's etiopathogenesis.

Salivary biomarkers of oxidative stress in children with dental caries: Systematic review and meta-analysis

OBJECTIVE

To assess the relationship between salivary biomarkers of oxidative stress and dental caries in children.

METHODS

Studies conducted in children up to 12 years old comparing salivary biomarkers of oxidative stress such as malondialdehyde (MDA), superoxide dismutase (SOD), uric acid, and total antioxidant capacity (TAC), considering children with dental caries lesions and caries-free ones were selected. In addition, salivary parameters such as salivary flow, pH, buffering capacity, calcium and total protein levels were evaluated. A systematic literature review was carried out in 8 databases. The standardized mean difference (SMD) was measured using inverse variance as a statistical method and random effects as an analysis model, corresponding to a 95% confidence interval (CI).

RESULTS

The TAC levels were higher in children affected by dental caries compared to caries-free ones (control group), regardless of age (SMD 2.66, CI 1.33, 3.98), or gender (SMD 0.98, CI 0.56, 1.39). When adjusted for normalized protein, MDA levels were lower in the dental caries group than in the control group (SMD -16.51, CI -29.02, -4.00), and SOD levels were higher in the dental caries group (SMD 5.09, CI 0.01.10.18). The total protein concentration in saliva of children with dental caries was higher than in the control group, regardless of age (SMD 0.98, CI 0.27, 1.69), or gender (SMD 0.77, CI 0.45, 1.10). The salivary parameters assessed had lower levels in children affected by dental caries (p < 0.05).

CONCLUSIONS

The levels of oxidative stress biomarkers and salivary parameters are altered in saliva of children with dental caries.

Data of Nebivolol on oxidative stress parameters in hypertensive patients

Oxidative stress is a key feature in hypertension, since reactive oxygen species are involved in all stages of cardiovascular diseases. Saliva is a body fluid that can be used to investigate alterations in the oxidative system with several specific advantages over blood. Nebivolol is a third-generation selective β1-adrenergic receptor antagonist that promotes vasodilation and has been shown to reduce oxidative stress in pre-clinical and clinical studies. The use of Nebivolol in different periods of treatment demonstrated that it is an efficient anti-hypertensive drug. We evaluated the oxidative stress biomarkers and the enzymatic and non-enzymatic antioxidant systems in saliva of hypertensive patients before and after the use of anti-hypertensive therapeutic doses of Nebivolol, since saliva can be used as an auxiliary tool to analyze parameters of oxidative stress.

Determination of salivary concentrations of leptin and adiponectin, ability to reduce ferric ions and total antioxidant capacity of saliva in patients with severe early childhood caries

INTRODUCTION

One of the most common oral diseases affecting children is early childhood caries (ECC). The link between oxidative stress and ECC has been proven in numerous clinical studies. Technical and biological variability were so high in most of the studies that none of the markers have yet been proven suitable for routine clinical use. This study aimed to evaluate the antioxidant status and the levels of leptin and adiponectin in saliva of children with severe early childhood caries (S-ECC).

METHODS

Morning unstimulated saliva samples were collected from children (n = 40, 0-6 years old) for the evaluation of oxidative stress which were measured by total antioxidant capacity (TAC), and by the ferric reducing antioxidant power (FRAP) assays, as well as to assess the salivary levels of leptin and adiponectin. FRAP, TAC, leptin and adiponectin concentrations were evaluated in S-ECC group (n = 31) and caries free group CF (n = 9). All results were analyzed based on age and sex.

RESULTS

Overall median salivary leptin and adiponectin levels were 5.59 pg/mL and 24.86 ng/mL, respectively. Significantly lower leptin levels were observed in saliva of caries free children (4.66 pg/mL) than in the S-ECC group (6.64 pg/mL, p < 0.01). No significant difference was observed for adiponectin levels (S-ECC and CF, 25.31 and 23.2 ng/mL, respectively, p = 0.961). TAC and FRAP values of saliva had similar values in children with S-ECC and caries free children. TAC and FRAP values also remained stable with the age of the children, without significant differences with respect to sex.

CONCLUSION

The increased concentrations of leptin in saliva of children with S-ECC suggests that leptin may play a role in inflammatory and immune responses in the development of early childhood caries.

Evaluation of salivary thiobarbituric acid reactive substances, total protein, and pH in children with various degrees of early childhood caries: a case-control study

PURPOSE

According to new studies, oxidative stress may play an important role in the beginning and progression of oral diseases. The aim of this study was the evaluation of thiobarbituric acid reactive substances (TBARS) as an indicator of lipid peroxidation, total protein, and pH of saliva in children with various degrees of early childhood caries in comparison with caries-free children.

METHODS

This case-control study was carried out on 90 children 3-5 years old in three equal groups, including caries-free children (CF), early childhood caries (ECC), and severe early childhood caries (S-ECC) who were age- and sex matched. Saliva pH was measured using a paper pH meter and TBARS and total protein were measured by spectrophotometer methods and data were statistically analysed.

RESULTS

TBARS and total protein levels in ECC and S-ECC groups were significantly higher than the CF group (p < 0.001), but pH was not significantly different between groups. There were no significant differences between ECC and S-ECC groups in any of the studied indicators.

CONCLUSION

Considering the limitations of the present study, the results showing the higher salivary TBARS levels in the S-ECC and ECC groups compared to caries-free children, lead to the conclusion that oxidative stress could be considered as a risk factor for early childhood caries.

Salivary Malondialdehyde Level as a Lipid Peroxidation Marker in Early Childhood Caries

Background: Early childhood caries (ECC) is an aggressive and multifactorial form of dental caries in children, in which the biomarkers of oxidative stress may increase. Objectives: This study aimed to compare the salivary malondialdehyde (MDA) levels in children with early childhood caries (ECC) and caries-free (CF) children. Methods: To this end, 42 ECC children and 42 CF children, aged 4 - 6 years, were randomly selected from the kindergartens of four socio-economically different districts of Isfahan. An unstimulated saliva sample was obtained from children fasting during the past night using the spitting method. In the laboratory, the MDA levels were evaluated spectrophotometrically. An independent-samples t-test was used to examine the differences between the two groups. Results: The mean salivary MDA level was significantly higher in the ECC group than in the CF group (P = 0.01), and there was no significant relationship between salivary MDA and gender (P = 0.44 in the ECC group, P = 0.30 in the CF group). Moreover, no significant relationship was noticed between MDA with decayed, missing, filled teeth (dmft). Conclusions: The findings documented a relationship between ECC and MDA as one of the products of oxidative stress reactions. Accordingly, the MDA level of saliva can be a critical indicator in determining the status of caries in children.

Gender influence on antioxidant capacity and oxidative damage in saliva of children with autism spectrum disorder: a preliminary study

Abstract Introduction Autism is a complex neurological disorder with multifactorial causes, which compromises physical, psychological, emotional and social skills. This disorder also impairs dental care and patient oral health. Saliva can be easily obtained using a non-invasive technique and has been used in the diagnosis and screening of many pathologies. Total antioxidant capacity of saliva is reduced in the presence of caries in children and has been studied as a possible marker for autism. However, data on salivary antioxidants in children with autism spectrum disorder (ASD) is scarce. Objective This preliminary study evaluated the existence of gender influence on non-enzymatic antioxidant capacity and protein oxidative damage in the saliva of children with this disorder. Our hypothesis is that there are gender differences in these biochemical parameters in children with austim. Material and method Whole saliva samples were collected by aspiration between 8:00-11:00 am from 12 girls and 12 boys aged 5 to 15 years, with previous diagnosis for this disorder. Total antioxidant capacity, uric acid, protein concentration and oxidative damage to proteins were analyzed by spectrophotometry. Values were presented as mean ± standard deviation and tested for adherence to normality (Shapiro-Wilk test). The data were then compared using the Mann-Whitney test, considering a 5% significance level. Result There was no significant difference between groups for all analyzed parameters (P>0.05). Conclusion Based on the results obtained, we concluded that gender does not influence the levels of oxidative stress markers in the saliva of children with ASD.

Salivary Redox Biomarkers in the Course of Caries and Periodontal Disease

Caries are a pathological process of extracorporeal nature, characterized by demineralization of inorganic substances as well as proteolysis triggered by acids produced by bacteria present in dental plaque, as a result of metabolism of sugars of both external and internal origin. Periodontal disease, on the other hand, is a multifactorial degenerative disease associated with inflammation, involving a group of tissues that surround the dental cervix and root of the tooth. It is believed that one of the mechanisms in the etiopathogenesis of caries and periodontitis are disorders of local and/or general oxidative stress (OS) parameters. Numerous clinical studies have confirmed the relationship between oxidative stress markers and oral diseases. In most analyzed studies, technical and biological variability was so high that none of the markers so far has proven suitable for routine clinical use. The aim of systematic reviews of the literature is to present the existing studies on OS parameters, mainly concerning the activity of antioxidant enzymes in saliva of patients with caries and periodontitis.

Amount of Dentifrice and Fluoride Concentration Influence Salivary Fluoride Concentrations and Fluoride Intake by Toddlers

The present study evaluated fluoride (F) concentrations in saliva of toddlers after brushing with dentifrices containing different F concentrations, applied in different quantities, and estimated F intake from toothbrushing. The study comprised a double-blind, crossover protocol, in which toddlers (n = 18, 2-3 years old) were randomly assigned into six groups, according to possible combinations of dentifrices (0/550/1,100 ppm F, as NaF) and amounts (rice grain, pea size, and transverse technique). Volunteers used a F-free dentifrice during 1 week. On the 7th day, saliva samples were collected before (baseline), and at 5/15/30/60 min after toothbrushing. All dentifrice expectorated after brushing was collected. F concentrations (saliva and expectorate) were determined with an ion-specific electrode. Data were submitted to ANOVA or Kruskal-Wallis test, followed by Fisher's LSD or Student-Newman-Keuls' tests (p <0.05). Brushing with 550 ppm F dentifrice (pea size or transversal technique) increased the area under the curve (AUC) at similar levels compared to 1,100 ppm F (rice grain). The highest AUC and salivary F at 5 min after brushing were achieved by 1,100 ppm F (pea size), followed by 550 ppm F (transversal technique). Regarding F intake, the highest values were observed for 550 ppm F (transversal technique), followed by 1,100 ppm F (pea size). It is possible to conclude that the amount of dentifrice and F concentration in the product significantly affected both salivary F concentrations and F intake during toothbrushing.

Carious Lesion Severity Induces Higher Antioxidant System Activity and Consequently Reduces Oxidative Damage in Children's Saliva

Oxidative stress biomarkers can be found at detectable concentrations in saliva. These salivary biomarkers reflect specific oxidation pathways associated with caries and periodontitis. Our study evaluated the influence of dental caries severity (assessed using the ICCMS™ criteria) on the levels of oxidative stress biomarkers in saliva from children. Unstimulated saliva samples were collected from patients (from one to three years old) in a day care center in Birigui, SP, Brazil, two hours after fasting. Children were divided into four groups (n = 30/group), according to caries severity: caries free (group A), early carious lesions (group B), moderate carious lesions (group C), and advanced carious lesions (group D). The following salivary biomarkers were determined: total proteins (TP), measured by the Lowry method; oxidative damage, measured by the TBARS method; total antioxidant capacity (TAC); superoxide dismutase (SOD) enzymatic antioxidant activity; and uric acid (UA) non-enzymatic antioxidant activity. Data were analyzed by ANOVA, followed by the Student-Newman-Keuls test, Pearson and Spearman correlation coefficients, and multivariable linear regression (p < 0.05). TP, TAC, SOD enzymatic antioxidant activity, and UA non-enzymatic antioxidant activity increased with caries severity, consequently reducing salivary oxidative damage. It was concluded that higher caries severity increases salivary antioxidant system activity, with consequent reduction in salivary oxidative damage.

Non-invasive assessment of oxidative stress in preterm infants

Preterm newborns have an immature antioxidant defense system and are especially susceptible to oxidative stress. Resuscitation, mechanical ventilation, intermittent hypoxia and apneic episodes require frequently oxygen supplementation which leads to oxidative stress in preterm newborns. The consequences of oxidative damage are increased short and long-term morbidities, neurodevelopmental impairment and increased mortality. Oxidative stress biomarkers are determined in blood samples from preterm children during their stay in neonatal intensive care units especially for research purposes. However, there is a tendency towards reducing invasive and painful techniques in the NICU (Neonatal Intensive Care Unit) and avoiding excessive blood extractions procedures. In this paper, it has been described some studies that employed non-invasive samples to determine oxidative stress biomarkers form preterm infants in order to perform a close monitoring biomarker with a significant greater predictive value. Among these methods we describe a previously developed and validated high-performance liquid chromatography tandem mass spectrometry method that allow to accurately determine the most reliable biomarkers in biofluids, which are non-invasively and painlessly obtained.

Evaluation of enzymatic and non-enzymatic antioxidant status and biomarkers of oxidative stress in saliva of patients with oral squamous cell carcinoma and oral leukoplakia: a pilot study

Objective: The study aimed to evaluate total antioxidant capacity as well as levels of various enzymatic and non-enzymatic antioxidants, and oxidative stress markers in saliva of patients with oral squamous cell carcinoma (OSCC) and oral leukoplakia (OL). Material and methods: Twenty patients with OSCC, 20 patients with OL and 20 healthy subjects were enrolled into this prospective study. Total Antioxidant Capacity (TAC), activity of superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR) as well as levels of total glutathione (tGSH), reduced glutathione (GSH), oxidized glutathione (GSSG), GSH/GSSG ratio, uric acid (UA), 8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) were estimated in saliva using appropriate biochemical methods. Results: The activity of SOD was significantly higher in OSCC group in comparison with OL and control groups. The levels of GSH were markedly lower in OSCC and OL patients as compared to the control group. Likewise, we found that GSH/GSSG ratio was markedly lower in the OSCC and OL groups. Levels of some biomarkers were influenced by clinical staging of OSCC and OL as well as by sociodemographic factors. Conclusions: The results of this pilot study suggest that salivary activity of SOD is higher in OSCC patients, whereas levels of GSH and GSH/GSSG ratio are lower in saliva of patients with OSCC and OL. Clinical staging of OSCC and OL, as well as some sociodemographic factors may also influence salivary antioxidant status.

The Relationship between Salivary Total Antioxidant Capacity and Dental Caries in Children: A Meta-Analysis with Assessment of Moderators

Objective:

There has been variation reported in literature examining the relationship between dental caries and total antioxidant capacity (TAC) of saliva in children. This study aimed to systematically review the literature and conduct a meta-analysis of the association between dental caries and TAC in children.

Methodology:

A systematic review of literature was done using the PubMed, Medline, and EBSCO libraries. Of the total of 68 records found, 11 studies were qualitatively assessed in the final analysis. These studies yielded a total of 13 comparisons to be included in the meta-analysis. The type of dentition of the child and the test used to measure TAC were assigned as moderators. A meta-analysis was done of the mean TAC levels, while a meta-regression was formulated using the moderators. All analyses were performed using OpenMetaAnalyst™ meta-analysis software (Brown University, RI, USA).

Results:

The meta-analysis showed significant increase in TAC in children with dental caries when compared to their caries-free counterparts (P < 0.001). The meta-analysis showed high levels of heterogeneity (I²= 99.48). The meta-regression revealed that, while the type of dentition was a significant moderating factor (P = 0.002), the method used to assess the TAC was not (P = 0.053).

Conclusion:

There is a significant increase in TAC in children with dental caries when compared to their caries-free counterparts.

Natural saliva as an adjuvant in a secondary caries model based on Streptococcus mutans

OBJECTIVE

Two factors for secondary caries formation were evaluated using an artificial biofilm model, saliva as additive in culture medium and bonding procedures of composite materials for artificial gap creation.

DESIGN

Standardized cavities were prepared in bovine tooth samples (n = 44), treated with two different bonding pretreatments, restored and after artificial ageing incubated with Streptococcus mutans in a Mueller-Hinton-Broth-Sugar medium with or without human saliva for seven days. Secondary caries formation was analyzed using confocal laser scanning microscopy and transversal microradiography.

RESULTS

Lesions were significantly pronounced in groups using saliva, but were not influenced by the bonding pretreatments.

CONCLUSIONS

The results indicate that the addition of saliva, but not the type of bonding procedure influences the outcome in the present biofilm-based secondary caries model.

Oxidative stress in the oral cavity is driven by individual-specific bacterial communities

The term "bacterial dysbiosis" is being used quite extensively in metagenomic studies, however, the identification of harmful bacteria often fails due to large overlap between the bacterial species found in healthy volunteers and patients. We hypothesized that the pathogenic oral bacteria are individual-specific and they correlate with oxidative stress markers in saliva which reflect the inflammatory processes in the oral cavity. Temporally direct and lagged correlations between the markers and bacterial taxa were computed individually for 26 volunteers who provided saliva samples during one month (21.2 ± 2.7 samples/volunteer, 551 samples in total). The volunteers' microbiomes differed significantly by their composition and also by their degree of microbiome temporal variability and oxidative stress markers fluctuation. The results showed that each of the marker-taxa pairs can have negative correlations in some volunteers while positive in others. Streptococcus mutans, which used to be associated with caries before the metagenomics era, had the most prominent correlations with the oxidative stress markers, however, these correlations were not confirmed in all volunteers. The importance of longitudinal samples collections in correlation studies was underlined by simulation of single sample collections in 1000 different combinations which produced contradictory results. In conclusion, the distinct intra-individual correlation patterns suggest that different bacterial consortia might be involved in the oxidative stress induction in each human subject. In the future, decreasing cost of DNA sequencing will allow to analyze multiple samples from each patient, which might help to explore potential diagnostic applications and understand pathogenesis of microbiome-associated oral diseases.

The role of the saliva antioxidant barrier to reactive oxygen species with regard to caries development

OBJECTIVES

The aim of this study was to evaluate the role of the antioxidant barrier in the saliva of children with caries, and its impact on the colonization of cariogenic bacteria.

METHODS

This is a cross-sectional study of 81 children aged 1-5 years. Antioxidant levels and salivary bacterial profiles were measured. Patients were divided into two groups as follows: initial stage decay, termed non-cavitated (1-2 in International Caries Detection and Assessment System (ICDAS)), and extensive decay, termed cavitated lesions (5-6 in ICDAS). The control group includes children without caries.

RESULTS

The linear regression model demonstrated that the GSH, GSSG, GSH/GSSG, and total antioxidant capacity levels are influenced (P < 0.05) by: the stage of caries and the dominant bacterial strain. Compared with the other groups (P < 0.001), the highest antioxidant parameters were recorded in the saliva of patients with cavitated lesions.

DISCUSSION

Our results indicate that the high levels of antioxidants in saliva increase significantly in children in line with the salivary cariogenic bacterial profiles and caries progression.

Early Childhood Caries: Prevalence, Risk Factors, and Prevention

Early childhood caries (ECC) is major oral health problem, mainly in socially disadvantaged populations. ECC affects infants and preschool children worldwide. The prevalence of ECC differs according to the group examined, and a prevalence of up to 85% has been reported for disadvantaged groups. ECC is the presence of one or more decayed, missing, or filled primary teeth in children aged 71 months (5 years) or younger. It begins with white-spot lesions in the upper primary incisors along the margin of the gingiva. If the disease continues, caries can progress, leading to complete destruction of the crown. The main risk factors in the development of ECC can be categorized as microbiological, dietary, and environmental risk factors. Even though it is largely a preventable condition, ECC remains one of the most common childhood diseases. The major contributing factors for the for the high prevalence of ECC are improper feeding practices, familial socioeconomic background, lack of parental education, and lack of access to dental care. Oral health plays an important role in children to maintain the oral functions and is required for eating, speech development, and a positive self-image. The review will focus on the prevalence, risk factors, and preventive strategies and the management of ECC.