Fluoride concentration in saliva after consumption of a dinner meal prepared with fluoridated salt

A Qualitative and Comprehensive Analysis of Caries Susceptibility for Dental Fluorosis Patients

Dental fluorosis (DF) is an endemic disease caused by excessive fluoride exposure during childhood. Previous studies mainly focused on the acid resistance of fluorotic enamel and failed to reach a consensus on the topic of the caries susceptibility of DF patients. In this review, we discuss the role of DF classification in assessing this susceptibility and follow the “four factors theory” in weighing the pros and cons of DF classification in terms of host factor (dental enamel and saliva), food factor, bacteria factor, and DF treatment factor. From our analysis, we find that susceptibility is possibly determined by various factors such as the extent of structural and chemical changes in fluorotic enamel, eating habits, fluoride levels in diets and in the oral cavity, changes in quantity and quality of saliva, and/or oral hygiene. Thus, a universal conclusion regarding caries susceptibility might not exist, instead depending on each individual’s situation.

Metabolomics studies in gastrointestinal cancer: a systematic review

Introduction: This systemic review provides an overview of metabolic perturbations and possible mechanisms in gastrointestinal cancer. The authors discuss emerging challenges of technical and clinical applications.Areas covered: In this systemic review, the authors summarized the currently available results of metabolomic biomarkers linked to GI cancer, and discussed the altered metabolism pathways including carbohydrate metabolism, amino acid metabolism, lipids, and nucleotide metabolism and other metabolisms. Furthermore, future efforts need to adhere to normalize analysis procedures, validate with the larger cohort and utilize multiple-omics technologies. The search was conducted in PubMed with the following search terms (biomarker, gastrointestinal cancer, colorectal cancer, and esophageal cancer) from 2013 to 2019.Expert opinion: This systemic review summarized the currently available results of metabolomic biomarkers linked to gastrointestinal cancer, and discussed the altered metabolism pathways. The authors believe that metabolomics will benefit deeper understandings of the pathogenic mechanism, discovery of biomarkers and aid the search for drug targets as we move toward the era of personalized medicine. Personalized medication for tumors can improve the curative effect, avoid side effects and medical resource waste. As a promisingtool, metabolomics that targets the entire cancer-specific metabolite network should be applied more widely in cancer research.

Fluoride Increase in Saliva and Dental Biofilm due to a Meal Prepared with Fluoridated Water or Salt: A Crossover Clinical Study

Knowledge about fluoride delivery to oral fluids from foods cooked with fluoridated water and salt is scarce, and no study has evaluated fluoride concentrations in saliva or biofilm during meal consumption. In this randomized double-blind crossover study, 12 volunteers ingested meals (rice, beans, meat, and legumes) prepared with nonfluoridated water and salt (control group), fluoridated water (0.70 mg F/L; water group), and fluoridated salt (183.7 mg F/kg; salt group). Whole saliva was collected before meal ingestion, during mastication, and up to 2 h after meal ingestion. Dental biofilm was collected before and immediately after meal ingestion. Fluoride concentrations in saliva and dental biofilm were determined by an ion-specific electrode. The mean (±standard deviation; n = 4) fluoride concentrations in meals prepared for the control, water, and salt groups were 0.039 ± 0.01, 0.43 ± 0.04, and 1.71 ± 0.32 μg F/g, respectively. The three groups had significantly different fluoride concentrations in saliva collected during mastication (p < 0.0001) and after meal ingestion (p < 0.04; salt > water > control). The fluoride concentration in saliva returned to baseline 30 min after meal ingestion in the water group but remained high for up to 2 h in the salt group (p = 0.002). The fluoride concentration in biofilm fluid differed only between the salt and control groups (p = 0.008). The mastication of foods cooked with fluoridated water and salt increases fluoride concentrations in oral fluids and may contribute to the local effect of these community-based fluoride interventions on caries control.

Caries-Preventive Effect of Salt Fluoridation in Preschool Children in The Gambia: A Prospective, Controlled, Interventional Study

The aim of this study was to investigate the anticaries effect of fluoridated salt in a communal feeding program for preschool children. In the Gambian city of Brikama, drinking water had a low fluoride content (0.1 mg F-/L) and young children did not use toothpaste for oral hygiene. Its 2 preschools served as clusters for the trial. Random allocation of the kindergartens was performed by one person not involved in the study, and the clinical examinations were carried out using the envelope method. Meals were prepared with fluoridated salt (250 mg F-/kg salt) in the intervention group but not in the control group. According to the inclusion criteria (complete primary dentition and informed consent from legal guardian), 441 children aged 3-5 years were enrolled. The children were examined by calibrated persons according to WHO criteria, allowing the calculation of d3mft scores. The primary end point was the mean difference in the incidence of caries cavities (Δd3/4mft) after 12 months. After 12 months, the mean caries incidence per person was 1.29 d3/4mf teeth (95% CI: 0.96; 1.62) in the test group (n = 304 children) and 3.83 d3/4mf teeth (95% CI: 2.94; 4.72) in the control group (n = 137 children). Thus, the caries-prevented fraction was 66.3%. No signs of harm due to the intervention were observed. The use of fluoridated salt in a communal feeding program and in an environment with negligible availability of fluoride from other sources yields a considerable caries-preventive effect.

Salivary fluoride levels after toothbrushing with dentifrices containing different concentrations of fluoride

OBJECTIVE

To determine the salivary fluoride levels after toothbrushing with dentifrices containing 458 ppm and 1000 ppm of fluoride and to compare salivary fluoride levels of two dentifrices at different intervals of time.

MATERIALS AND METHODS

In total, 50 children in the age group of 6-12 years were selected. The individuals were randomly divided into two groups using either 458 ppm or 1000 ppm fluoride dentifrice, respectively. Whole saliva samples were collected prior to brushing, immediately after brushing, and at subsequent intervals after brushing into sterile test tubes.

RESULTS

Data collected were evaluated using unpaired t-test. Salivary fluoride level following the use of 458 ppm fluoride dentifrice was significantly lower than the level found following the use of 1000 ppm dentifrice, but the levels were above the baseline values even after 1 h.

CONCLUSION

There was considerable salivary fluoride retention after brushing with fluoride dentifrices.

Fluoridated salt for caries prevention and control - a 2-year field study in a disadvantaged community

BACKGROUND

Salt fluoridation is considered a cost-effective community strategy for reducing caries.

AIM

To evaluate the effect of school-based and domestic distribution of F-salt to schoolchildren residing in a disadvantaged community.

DESIGN

Seven hundred and thirty-three schoolchildren (12-14 years), attending two public schools, were enrolled; one was assigned to intervention (IS), whereas the other served as reference (RS). Subjects in IS were given access to F-salt (250 ppm F) in marked jars at school lunch and through free supply for domestic use. The 2-year caries increment and progression rate, assessed from bitewing radiographs, was scored. Information on diet, oral hygiene, and fluoride exposure was collected through a baseline questionnaire.

RESULTS

The dropout rate was high (IS 27%; RS 18%). At baseline, the IS children displayed more unfavourable risk factors and a higher caries experience than RS children. There were no significant differences in total caries increment or proximal progression rate between the two schools. A negative correlation (r = -0.29; P < 0.05) between the amount of delivered salt and the caries progression rate was, however, noted. No side effects were reported.

CONCLUSIONS

F-salt was not effective in this setting. Still, the findings indicate that salt may be a beneficial source of fluoride in schoolchildren provided that compliance can be secured.

Kinetics of fluoride bioavailability in supernatant saliva and salivary sediment

The assessment of the fluoride kinetics in whole saliva as well as in the different salivary phases (supernatant saliva and sediment) is essential for the understanding of fluoride bioavailability.

OBJECTIVES

To assess the fluoride content, provided by sodium fluoride and amine fluoride, in the supernatant saliva and in salivary sediment.

METHODS

Seven trained volunteers were randomly attributed to 2 groups in a cross-over design and brushed their teeth in the morning for 3 min with a product containing either sodium fluoride or amine fluoride. Saliva was collected before, immediately after tooth brushing and 30, 120, and 360 min later and measured. The samples were centrifuged 10 min at 3024 × g. Fluoride content of the supernatant saliva and of the sediment was analysed using a fluoride sensitive electrode. All subjects repeated the study cycles 2 times, and statistical analyses were made using the nonparametric sign test for related samples, the Wilcoxon-Mann-Whitney-test for independent samples.

RESULTS

There was a significant increase in fluoride immediately after tooth brushing in both groups in saliva and sediment. The distribution of fluoride between salivary sediment and supernatant saliva (ratio) varied considerably at the different collection times: decreased from 17.87 in baseline samples of saliva to 0.07 immediately and to 0.86 half an hour after tooth brushing in the sodium fluoride group and from 14.33 to 2.85 and to 3.09 in the amine fluoride group. Furthermore after 120 min and after 360 min after tooth brushing the ratio increased from 17.6 to 31.6 in the sodium fluoride group and from 20.5 to 25.76 in the amine fluoride group. No difference was found in the sediment-supernatant saliva ratio between the sodium fluoride and the amine fluoride groups 360 min after tooth brushing.

CONCLUSION

For the assessment of fluoride kinetics in whole saliva it is necessary to pay attention to at least four factors: fluoride formulation, time after fluoride application, fluoride concentration in supernatant saliva and fluoride concentration in salivary sediment. This study was approved by the Ethical Committee of the University of Witten/Herdecke permission 21/2008.

Fluoride bioavailability in saliva and plaque

Background

Different fluoride formulations may have different effects on caries prevention. It was the aim of this clinical study to assess the fluoride content, provided by NaF compared to amine fluoride, in saliva and plaque.

Methods

Eight trained volunteers brushed their teeth in the morning for 3 minutes with either NaF or amine fluoride, and saliva and 3-day-plaque-regrowth was collected at 5 time intervals during 6 hours after tooth brushing. The amount of collected saliva and plaque was measured, and the fluoride content was analysed using a fluoride sensitive electrode. All subjects repeated all study cycles 5 times, and 3 cycles per subject underwent statistical analysis using the Wilcoxon-Mann-Whitney test.

Results

Immediately after brushing the fluoride concentration in saliva increased rapidly and dropped to the baseline level after 360 minutes. No difference was found between NaF and amine fluoride. All plaque fluoride levels were elevated after 30 minutes until 120 minutes after tooth brushing, and decreasing after 360 minutes to baseline. According to the highly individual profile of fluoride in saliva and plaque, both levels of bioavailability correlated for the first 30 minutes, and the fluoride content of saliva and plaque was back to baseline after 6 hours.

Conclusions

Fluoride levels in saliva and plaque are interindividually highly variable. However, no significant difference in bioavailability between NaF and amine fluoride, in saliva, or in plaque was found.

Fluoride bioavailability in saliva using DENTTABS® compared to dentifrice

It was the aim of this study to assess fluoride retained in saliva after use of fluoride-containing tablet DENTTABS® compared to toothpaste containing amine fluoride. Four subjects (2 normal saliva secretors, 1 slow secretor, and 1 fast secretor) participated in this crossover study comparing DENTTABS® and ELMEX®. After baseline sample collection, calibrated study personnel brushed the subjects’ teeth with the assigned product for 3 minutes. Saliva samples were taken at baseline (T0), immediately after brushing (T1) and then 10 (T2), 25 (T3) and 85 (T4) minutes post-brushing. The amount of saliva collected was measured, and the fluoride content was analysed. All 4 subjects repeated all study cycles 5 times. Statistical analysis was done using the Mann-Whitney-U test and Spearman correlation. The fluoride retention was significantly higher after brushing with DENTTABS® at T1 and T2. There was a correlation between individual salivary flow rate and the F- content. Flow rate in g/min ranged from 1.1 to 3.8 at T1 and from 0.2 to 1.1 at T4 with much higher F- retention in slow secreting cycles. The saliva fluoride clearance kinetics of two equal amounts of fluoride-containing oral hygiene products demonstrate higher retention for DENTTABS®.

Capillary electrophoresis mass spectrometry-based saliva metabolomics identified oral, breast and pancreatic cancer-specific profiles

Saliva is a readily accessible and informative biofluid, making it ideal for the early detection of a wide range of diseases including cardiovascular, renal, and autoimmune diseases, viral and bacterial infections and, importantly, cancers. Saliva-based diagnostics, particularly those based on metabolomics technology, are emerging and offer a promising clinical strategy, characterizing the association between salivary analytes and a particular disease. Here, we conducted a comprehensive metabolite analysis of saliva samples obtained from 215 individuals (69 oral, 18 pancreatic and 30 breast cancer patients, 11 periodontal disease patients and 87 healthy controls) using capillary electrophoresis time-of-flight mass spectrometry (CE-TOF-MS). We identified 57 principal metabolites that can be used to accurately predict the probability of being affected by each individual disease. Although small but significant correlations were found between the known patient characteristics and the quantified metabolites, the profiles manifested relatively higher concentrations of most of the metabolites detected in all three cancers in comparison with those in people with periodontal disease and control subjects. This suggests that cancer-specific signatures are embedded in saliva metabolites. Multiple logistic regression models yielded high area under the receiver-operating characteristic curves (AUCs) to discriminate healthy controls from each disease. The AUCs were 0.865 for oral cancer, 0.973 for breast cancer, 0.993 for pancreatic cancer, and 0.969 for periodontal diseases. The accuracy of the models was also high, with cross-validation AUCs of 0.810, 0.881, 0.994, and 0.954, respectively. Quantitative information for these 57 metabolites and their combinations enable us to predict disease susceptibility. These metabolites are promising biomarkers for medical screening. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11306-009-0178-y) contains supplementary material, which is available to authorized users.

Caries preventive effect of fluoride in milk, salt and tablets: a literature review

BACKGROUND

There are a number of studies in the literature about the effectiveness of fluoride in tablets, fluoride added to frequently-consumed food like milk, or to food additives like salt, in prevention of dental caries. This literature has been evaluated in different evidence based reviews.

AIM

The scope of this paper was to identify the most recent evidence-based reviews on the effect in caries prevention from added fluoride in milk, salt and fluoride tablets/drops including newer RCT studies, and to synthesize the findings into practice guidelines. The key question was as follows: Does regular use of fluoride in milk, salt and fluoride tablets/ drops prevent dental caries among children and adolescents?

METHODS

MEDLINE, EMBASE and EBM reviews (Cochrane database of systematic reviews) were searched using modified filters from a Cochrane review. One evidence-based report on fluoridated milk was identified. Salt fluoridation was covered by three HTA reviews. One Cochrane protocol on the caries preventive effect of fluoridated salt was identified.

RESULTS

Very few studies of good quality were identified in general. Two studies on fluoridated milk were tabulated and seven studies dealing with fluoride tablets/ drops were analysed. One study showed a 78% reduction in caries in newly erupted permanent teeth among 8 year olds after 3 years with fluoridated milk. For primary teeth one study showed 31% caries reduction. The differences between fluoride-group and control were statistically significant. The reduction in caries prevalence in the fluoride tablet group compared with a negative control varied from 81% (carious surfaces in permanent teeth erupted in the study period) to 49% in DMFS for all permanent teeth. No RCT studies on fluoridated salt were identified.

CONCLUSION

There is limited evidence that F tablets and drops are effective, and compliance is a key factor. There are good reasons to believe that fluoride in different applications and formulas does work as caries preventive agents under supervision. There is a need for new, well-designed studies within this field, but the use of negative controls without any fluoride exposure is difficult due to ethical reasons. In particular new research is needed concerning possible caries preventive effect of fluoridated milk and salt.

Effect of a fluoridated food item on enamel in situ

After the consumption of food items prepared with fluoridated salt elevated fluoride concentrations can be observed in saliva, whereby enamel mineralization is supposed to be positively affected. The aim of this double-blind (with respect to fluoride), placebo-controlled, randomized, cross-over study was to evaluate the effects of the consumption of either a fluoridated (effect) or a placebo food item on the mineral content of sound and pre-demineralized human enamel in situ. During both phases of the study 8 enamel specimens in each of 10 intraoral appliances were positioned, either recessed or flush with the acrylic surface. One of the flanges was brushed twice daily with fluoride-free toothpaste prior to the storage of the appliance in sucrose solution. The subjects were asked to refrain from other sources of fluorides except for the consumption of either a highly fluoride-containing (0.5 mg) or a placebo cookie (3 times daily) during the respective study phase. Mineral content and lesion depth were measured in the enamel specimens and fluoride concentrations in saliva and urine. Significantly increased urinary and salivary (immediately after food consumption) fluoride concentrations compared to baseline were observed during the effect phase. In the absence of fluorides more pronounced demineralization was observed, especially for the recessed specimens of both surface conditions. Brushing was shown to inhibit demineralization, particularly during the placebo phase. In conclusion, fluorides added to food items seem to be efficacious to inhibit enamel demineralization in plaque-covered enamel but might be less effective if oral hygiene is adequate.