Water fluoridation for the prevention of dental caries

Addressing disparities in oral health access and outcomes for aging adults in the United States

Oral health is essential for the overall well-being of aging adults, yet significant disparities persist in the United States, contributing to malnutrition, reduced quality of life, and social isolation. Despite advancements in preventive dentistry, older adults continue to face substantial oral health challenges. This study reviewed the current state of oral health among aging adults in the United States, analyzing national health surveys and existing preventive dentistry protocols to assess their effectiveness. National data indicated that a high percentage of older adults experience tooth loss, periodontal disease, and root caries. Results indicated that almost 40% of adults aged 65 and older have lost a significant number of teeth, and a large proportion of the aging adult population has suffered from high rates of caries and periodontal disease. Socioeconomic factors were found to significantly influence access to dental care. Key barriers included low income, inadequate insurance, and low oral health literacy exacerbating disparities. The study proposes a multifaceted approach to improve oral health equity, including policy changes, community-based preventive programs, enhanced geriatric dentistry education, and the integration of oral health into primary care. Addressing these disparities is needed to improve both oral and overall health outcomes for the growing elderly population in the United States.

Maternal Urinary Fluoride Levels of a Large Pregnancy Cohort in the United States: Findings from the ADORE Study

BACKGROUND

Emerging evidence has suggested negative associations between maternal urinary fluoride adjusted for specific gravity (MUFsg) and offspring intelligence quotient (IQ). Two prior studies report the MUFsg of pregnant women in the US, both in California, and more information is needed on population levels of MUFsg.

OBJECTIVES

The primary objective was to measure MUFsg in a large pregnancy cohort of women recruited from health departments and academic hospitals in Ohio and Kansas. A secondary objective was to compare associations between water fluoridation level and estimated fluoride intake from tap water and MUFsg.

METHODS

Pregnant women (n = 965 ) from the ADORE (Assessment of DHA on Reducing Early Preterm Birth) cohort provided a urine sample and dietary assessment at enrollment between 14 and 20 wk gestation. MUFsg was measured by fluoride-sensitive electrode and corrected for specific gravity. Water fluoridation levels were obtained for public water systems (PWS), matched to participant residence and multiplied by their tap water intake from dietary assessment. The association between MUFsg and water fluoridation level was estimated using a generalized linear model with gamma distribution and log link.

RESULTS

MUFsg (median: 1.0 mg / L ; Q1, Q3: 0.6, 1.5) was correlated with PWS fluoridation (r s = 0.30 ; p < 0.01 ) and self-reported tap water consumption (r s = 0.29 ; p < 0.01 ). For 87% of the cohort, MUFsg was above the 0.45 mg / L safety benchmark for pregnancy proposed in a previous study. Similarly, 76.7% lived in areas with PWS fluoridation ≥ 0.7 mg / L . The median MUFsg (1.0 mg / L ; Q1, Q3: 0.7, 1.5) of those living in areas with a PWS fluoridation level ≥ 0.7 mg / L was higher than the median MUFsg (0.8 mg / L ; Q1, Q3: 0.5, 1.2) of women living in areas with PWS fluoridation < 0.7 mg / L (p < 0.01 ).

DISCUSSION

MUFsg in this population of midwestern US women exceeds the safety benchmark for pregnancy. While we cannot account for all sources of fluoride, MUFsg was correlated to PWS fluoridation. Because so many exceeded the safety benchmark for MUFsg, there is a need for MUFsg evaluation in other US regions, especially where the PWS fluoridation exceeds US Department of Health and Human Services recommendations (≥ 0.7 mg / L ). https://doi.org/10.1289/EHP14711.

The effect of water filter pitchers on the mineral concentration of tap water

OBJECTIVES

To investigate the effect of water filter pitchers on the concentration of different minerals in tap water.

METHODS

Nine water filter pitchers (A-I) were chosen based on consumer preferences and Amazon reviews. Each filter was tested for its ability to modify the concentrations of fluoride, calcium, magnesium, potassium, and sodium in tap water. Tap water samples were collected before and after filtration, at various intervals (1, 5, 10, 30, 50, 75, and 100 L) during filtration, and analyzed using an ion-specific electrode (fluoride) and atomic absorption spectrometry (other minerals). Statistical analyses were conducted to compare filtered and unfiltered water mineral concentrations.

RESULTS

Water filter pitcher effect: Filters F (p < 0.001) and G (p = 0.030) decreased fluoride concentrations. All filters except I (p = 0.235) and H (p = 0.717) decreased calcium concentrations (p < 0.01). Filters E (p = 0.018), D (p = 0.014), and G (p = 0.010) decreased magnesium concentrations. Filters I (p = 0.028) and D (p = 0.009) increased potassium concentrations. Filter A (p = 0.002) increased sodium concentrations, while C (p = 0.034) decreased sodium concentrations. Effect of filter aging: All filters affected mineral concentrations over time but to varying extents. Filter G had the most pronounced effect on reducing mineral concentrations compared to all others. No filter was able to completely remove fluoride from tap water, contrary to the claims made by three manufacturers.

CONCLUSIONS

The present study highlighted that water filter pitchers vary greatly in their ability to affect mineral concentrations in tap water during their use. Further research is needed to develop more effective water treatment solutions.

The ethics of community water fluoridation: Part 2 - how has the ethics of community water fluoridation been appraised in the literature? A scoping review

Aim To examine how the ethics of community water fluoridation has been appraised in the literature.Method A scoping review using an updated Arksey and O'Malley framework. Six electronic databases were searched: Medline via OVID; Scopus; Web of Science; Cochrane Library; StarPlus and Google Scholar. Grey literature and reference lists of included studies were also searched.Results In total, 51 studies from 15 countries were included. Many referred to biomedical ethical principles intended for clinical rather than public health interventions. Some primarily aimed to appraise its ethics whereas others considered it as part of more general discussions on fluoridation. While most acknowledged its complexity, those more supportive of fluoridation often emphasised collective benefit and those less supportive emphasised infringement of autonomy or personal liberty and concerns about harm. Few referred to public health ethics principles and frameworks available in the literature.Conclusion Different approaches have been taken to appraise the ethics of fluoridation. Frequently, these were conceived for individual medical rather than public health interventions and are inadequate to resolve tension between inevitable infringement of individual consent and collective benefit in public health. Other approaches conceived specifically for public health exist that have more utility in debates and ethical decision-making.

Correlation of fluoride intake with haemoglobin level and intelligence quotient in 8-12 year aged children: an observational study from India

BACKGROUND

Fluorosis caused by excess intake of fluoride can affects various soft tissues of the body, such as the gastrointestinal tract, blood, brain tissues and thyroid gland apart from dental fluorosis and skeletal fluorosis. Nonskeletal fluorosis is considered reversible if diagnosed early and treated promptly. Therefore, diagnostic methods that can be easily performed even by primary health care workers and depict any ongoing health problems, should be validated. Dental fluorosis, assessment of fluoride in urine and water are tests that fulfill these requirements. To date, no study has correlated haemoglobin (Hb) with dental fluorosis; moreover, studies focusing on intelligence quotient (IQ) had conflicting results and need further research. Hence, study was conducted to determine any relationship among different fluoride assessment parameters (severity of dental fluorosis, fluoride level in urine and drinking water) with IQ status and hemoglobin level of children aged 8-12 years, affected with or without dental fluorosis.

METHODS

A total of 300 children aged 8-12 years were evaluated for dental fluorosis via Dean's index, IQ level via Raven's coloured progressive matrices test, Hb level, and fluoride content in water and urine.

RESULTS

Water fluoride, age and gender were significantly associated with Hb. Intelligence was significantly related to urinary fluoride levels. Presence or absence of dental fluorosis and its severity were not significantly related to IQ or Hb.

CONCLUSIONS

Excess fluoride intake has adverse effects on hematological parameters and children's cognitive neurodevelopment, which were evaluated by current fluoride exposure markers, i.e., water and urinary fluoride. However, dental fluorosis cannot be used as a definitive assessment marker for these conditions, as it is not significantly correlated with these conditions.

The Oral Microbiome and Systemic Health: Bridging the Gap Between Dentistry and Medicine

The oral microbiome, consisting of a mixture of bacteria, fungi, and viruses, is an important contributor to oral and systemic health. Microbial balance disruptions are associated with oral pathologies like dental caries and periodontitis as well as systemic diseases such as cardiovascular diseases, adverse pregnancy outcomes, and respiratory diseases. This review explores the mechanistic pathways linking oral dysbiosis to systemic inflammation, endothelial dysfunction, and immune modulation. The roles of key microbial species in health and disease are analyzed, with an emphasis on how hematogenous dissemination leads to systemic pathologies through inflammatory signaling. Also, advances in high throughput sequencing are discussed, as well as microbial diversity and its implications for diagnostics and therapeutics. The review highlights the potential of oral microbiota-targeted interventions to mitigate systemic diseases through dentistry and medicine integration, by throwing light on interdisciplinary strategies. Future work should focus on the evaluation of the mechanisms by which the oral microbiome plays a role in systemic diseases through the integration of multi-omics approaches such as metagenomics, transcriptomics, and metabolomics. Furthermore, clinical trials need to be designed in a way to evaluate the efficacy of microbiome-targeted therapies in the prevention of cardiovascular diseases, adverse pregnancy outcomes, and autoimmune disorders.

Advances in knowledge and practice benefiting the health and management of first permanent molars in children

First permanent molars (FPMs) remain the most affected teeth by dental conditions in childhood. Maintaining the health of FPMs should be prioritised by dental professionals. However, if subjected to unfavourable circumstances, FPMs can become compromised and impact the child negatively. In this article, we highlight current thinking and provide practical tips to prevent FPMs from becoming compromised. The importance of including the young person in decision-making and the influence different dental conditions might have on management of FPMs are discussed. Finally, the impact and treatment options available for FPMs should they become compromised are explored, focusing on the main question of whether to restore or extract these teeth.

Ultrastructural evaluation of adverse effects on dentine formation from systemic fluoride application in an experimental mouse model

AIM

Fluoride is widely used in dentistry for its caries prevention. To reduce dental caries, the optimal fluoride concentration of public water supplies in the United States is 0.7 ppm. However, excessive systemic fluoride consumption can lead to dental/enamel fluorosis. Numerous studies have explored the effects of fluoride on enamel and enamel-forming cells. However, research on systemic fluoride's impact on dentine is limited, particularly the effect of fluoride on the structure of the dentine-pulp complex. Therefore, this study aimed to identify how excessive fluoride affects dentine microstructure using an experimental mouse model.

METHODOLOGY

C57BL6/J male mice (6-9 weeks old) were randomized into four groups (Fluoride at 0, 50, 100, or 125 ppm in drinking water) (n = 4/group). Mice were provided water ad libitum for 6 weeks along with fluoride-free food. Thereafter, mandibular incisors were analysed. Enamel phenotypes were evaluated using light microscopy and quantitative light-induced fluorescence (QLF) to measure fluorosis levels. Dentine morphology was evaluated using micro-CT, scanning electron microscopy (SEM), SEM-EDX (energy-dispersive X-ray), microhardness test and histological imaging. Data were analysed using one-way ANOVA with Dunnett's multiple comparisons as a post hoc test and the Kruskal-Wallis test with Dunn's multiple comparisons post hoc test (p < .05).

RESULTS

Mice treated with fluoride at 50-125 ppm developed enamel hypoplasia in their erupting incisors and micro-CT imaging revealed that fluoride 125 ppm caused external resorption of the growing incisor. Dentine mineral density, dentine volume decreased compared with the 0 ppm control, while pulp volume increased compared with the 0 ppm control group. SEM showed wider predentine layer and abnormalities in calcified matrix vesicles derived from odontoblasts in fluoride 100 and 125 ppm groups. Vickers microhardness of dentine significantly decreased in the high-dose group. Fluoride-induced dentine hypoplasia in a dose-dependent manner. Histological evaluation showed excessive fluoride 125 ppm induced micro abscess formation and inflammatory cell infiltration. Fluoride induced dentine dysplasia with a dentine microstructure resembling hypophosphatasia.

CONCLUSIONS

High doses of systemic fluoride can cause dentine dysplasia. Both three-dimensional and microstructural analyses showed the structural, chemical and mechanical changes in the dentine and the mineralized tissue components, along with external resorption and pulp inflammation.

Economic Evaluation of Community Water Fluoridation in an Upper-Middle-Income Country

The aim was to estimate the cost-effectiveness and cost-benefit of CWF for schoolchildren according to different population sizes served in Brazil. The economic evaluation was conducted from a societal perspective. Total costs were estimated using four variables across different population sizes: capital cost of initial installation, chemical product costs, system operational costs, and monitoring costs. The effect of CWF was analyzed in the context of the widespread use of fluoridated toothpaste, based on studies with Brazilian population groups. The total cost of dental treatment was estimated, including both direct and indirect costs, with a discount rate of 3.5%. A one-way sensitivity analysis was conducted to test the robustness of the results based on measured parameter values. The costs averted due to CWF were US$174.40 and US$85.67 for children aged 5-8 and 3-12 years, respectively, and US$46.66 for those aged 7-12 years, according to the average effectiveness of CWF for each age group. The cost-effectiveness and cost-benefit ratio results were favorable in all scenarios where the population served was 6,000 or more inhabitants. Scenarios unfavorable to CWF were observed only in populations of up to 2,000 inhabitants. The economic evaluation of CWF in an upper-middle-income country proved to be a cost-effective oral health intervention and more economically advantageous, especially in larger areas for both deciduous and permanent dentition.

Inequalities in oral health: estimating the longitudinal economic burden of dental caries by deprivation status in six countries

BACKGROUND

The recent World Health Organization (WHO) resolution on oral health urges pivoting to a preventive approach and integration of oral health into the non-communicable diseases agenda. This study aimed to: 1) explore the healthcare costs of managing dental caries between the ages of 12 and 65 years across socioeconomic groups in six countries (Brazil, France, Germany, Indonesia, Italy, UK), and 2) estimate the potential reduction in direct costs from non-targeted and targeted oral health-promoting interventions.

METHODS

A cohort simulation model was developed to estimate the direct costs of dental caries over time for different socioeconomic groups. National-level DMFT (dentine threshold) data, the relative likelihood of receiving an intervention (such as a restorative procedure, tooth extraction and replacement), and clinically-guided assumptions were used to populate the model. A hypothetical group of upstream and downstream preventive interventions were applied either uniformly across all deprivation groups to reduce caries progression rates by 30% or in a levelled-up fashion with the greatest gains seen in the most deprived group.

RESULTS

The population level direct costs of caries from 12 to 65 years of age varied between US10.2 billion in Italy to US$36.2 billion in Brazil. The highest per-person costs were in the UK at US$22,910 and the lowest in Indonesia at US$7,414. The per-person direct costs were highest in the most deprived group across Brazil, France, Italy and the UK. With the uniform application of preventive measures across all deprivation groups, the greatest reduction in per-person costs for caries management was seen in the most deprived group across all countries except Indonesia. With a levelling-up approach, cost reductions in the most deprived group ranged from US$3,948 in Indonesia to US$17,728 in the UK.

CONCLUSION

Our exploratory analysis shows the disproportionate economic burden of caries in the most deprived groups and highlights the significant opportunity to reduce direct costs via levelling-up preventive measures. The healthcare burden stems from a higher baseline caries experience and greater annual progression rates in the most deprived. Therefore, preventive measures should be start early, with a focus on lowering early childhood caries and continue through the life course.

Water fluoridation for the prevention of dental caries

BACKGROUND

Dental caries is a major public health problem in most industrialised countries, affecting 60% to 90% of school children. Community water fluoridation (CWF) is currently practised in about 25 countries; health authorities consider it to be a key strategy for preventing dental caries. CWF is of interest to health professionals, policymakers and the public. This is an update of a Cochrane review first published in 2015, focusing on contemporary evidence about the effects of CWF on dental caries.

OBJECTIVES

To evaluate the effects of initiation or cessation of CWF programmes for the prevention of dental caries. To evaluate the association of water fluoridation (artificial or natural) with dental fluorosis.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase and four other databases up to 16 August 2023. We also searched two clinical trials registers and conducted backward citation searches.

SELECTION CRITERIA

We included populations of all ages. For our first objective (effects of initiation or cessation of CWF programmes on dental caries), we included prospective controlled studies comparing populations receiving fluoridated water with those receiving non-fluoridated or naturally low-fluoridated water. To evaluate change in caries status, studies measured caries both within three years of a change in fluoridation status and at the end of study follow-up. For our second objective (association of water fluoridation with dental fluorosis), we included any study design, with concurrent control, comparing populations exposed to different water fluoride concentrations. In this update, we did not search for or include new evidence for this objective.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. For our first objective, we included the following outcomes as change from baseline: decayed, missing or filled teeth ('dmft' for primary and 'DMFT' for permanent teeth); decayed, missing or filled tooth surfaces ('dmfs' for primary and 'DMFS' for permanent teeth); proportion of caries-free participants for both primary and permanent dentition; adverse events. We stratified the results of the meta-analyses according to whether data were collected before or after the widespread use of fluoride toothpaste in 1975. For our second objective, we included dental fluorosis (of aesthetic concern, or any level of fluorosis), and any other adverse events reported by the included studies.

MAIN RESULTS

We included 157 studies. All used non-randomised designs. Given the inherent risks of bias in these designs, particularly related to management of confounding factors and blinding of outcome assessors, we downgraded the certainty of all evidence for these risks. We downgraded some evidence for imprecision, inconsistency or both. Evidence from older studies may not be applicable to contemporary societies, and we downgraded older evidence for indirectness. Water fluoridation initiation (21 studies) Based on contemporary evidence (after 1975), the initiation of CWF may lead to a slightly greater change in dmft over time (mean difference (MD) 0.24, 95% confidence interval (CI) -0.03 to 0.52; P = 0.09; 2 studies, 2908 children; low-certainty evidence). This equates to a difference in dmft of approximately one-quarter of a tooth in favour of CWF; this effect estimate includes the possibility of benefit and no benefit. Contemporary evidence (after 1975) was also available for change in DMFT (4 studies, 2856 children) and change in DMFS (1 study, 343 children); we were very uncertain of these findings. CWF may lead to a slightly greater change over time in the proportion of caries-free children with primary dentition (MD -0.04, 95% CI -0.09 to 0.01; P = 0.12; 2 studies, 2908 children), and permanent dentition (MD -0.03, 95% CI -0.07 to 0.01; P = 0.14; 2 studies, 2348 children). These low-certainty findings (a 4 percentage point difference and 3 percentage point difference for primary and permanent dentition, respectively) favoured CWF. These effect estimates include the possibility of benefit and no benefit. No contemporary data were available for adverse effects. Because of very low-certainty evidence, we were unsure of the size of effects of CWF when using older evidence (from 1975 or earlier) on all outcomes: change in dmft (5 studies, 5709 children), change in DMFT (3 studies, 5623 children), change in proportion of caries-free children with primary dentition (5 studies, 6278 children) or permanent dentition (4 studies, 6219 children), or adverse effects (2 studies, 7800 children). Only one study, conducted after 1975, reported disparities according to socioeconomic status, with no evidence that deprivation influenced the relationship between water exposure and caries status. Water fluoridation cessation (1 study) Because of very low-certainty evidence, we could not determine if the cessation of CWF affected DMFS (1 study conducted after 1975; 2994 children). Data were not available for other review outcomes for this comparison. Association of water fluoridation with dental fluorosis (135 studies) The previous version of this review found low-certainty evidence that fluoridated water may be associated with dental fluorosis. With a fluoride level of 0.7 parts per million (ppm), approximately 12% of participants had fluorosis of aesthetic concern (95% CI 8% to 17%; 40 studies, 59,630 participants), and approximately 40% had fluorosis of any level (95% CI 35% to 44%; 90 studies, 180,530 participants). Because of very low-certainty evidence, we were unsure of other adverse effects (including skeletal fluorosis, bone fractures and skeletal maturity; 5 studies, incomplete participant numbers).

AUTHORS' CONCLUSIONS

Contemporary studies indicate that initiation of CWF may lead to a slightly greater reduction in dmft and may lead to a slightly greater increase in the proportion of caries-free children, but with smaller effect sizes than pre-1975 studies. There is insufficient evidence to determine the effect of cessation of CWF on caries and whether water fluoridation results in a change in disparities in caries according to socioeconomic status. We found no eligible studies that report caries outcomes in adults. The implementation or cessation of CWF requires careful consideration of this current evidence, in the broader context of a population's oral health, diet and consumption of tap water, movement or migration, and the availability and uptake of other caries-prevention strategies. Acceptability, cost-effectiveness and feasibility of the implementation and monitoring of a CWF programme should also be taken into account.

Investigating the effectiveness of water fluoridation

DESIGN

This retrospective cohort study used treatment claims data submitted over a 10-year period to explore the effect of water fluoridation on specified National Health Service (NHS) dental treatments, number of Decayed Missing and Filled Teeth (DMFT) and its cost-effectiveness. Ethical approval was granted and data was collected from NHS primary care settings via claims submitted to the NHS Business Services Authority (NHS BSA). To be included, participants must have attended dental services twice in the study period, been 12 years or over and had a valid English postcode. Those with claims related solely to orthodontic care were excluded, as were those who had requested NHS National Data Opt-out. Costs relating to water fluoridation were supplied by Public Health England. NHS BSA data was used to calculate NHS costs at 2020 prices.

COHORT SELECTION

A personalised water fluoride exposure for the 2010-2020 period was assigned to all individuals, who were then split into two groups, above 0.7 mg F/L (optimally fluoridated group) or lower (non-optimally fluoridated group). Individuals in each group were matched for analysis using propensity scores, estimated via logistic regression.

DATA ANALYSIS

Values of absolute standardised mean differences were used to determine covariate balance between the two groups, alongside a generalised linear model with matching weights and cluster robust standard errors and a patient deprivation decile as an interaction term. An Incremental Cost-Effectiveness Ratio (ICER) was calculated and differences in the overall costs to the public sector were illustrated by the return on investment estimate.

RESULTS

The cohort contained data on 6,370,280 individuals. Negative binomial regression models were used to analyse health outcomes. In the optimally fluoridated group, the rate of invasive dental treatments was 3% less than in the non-optimally fluoridated group, and the mean DMFT in the optimally fluoridated group was 2% lower. There was no evidence of a difference in the predicted mean number of missing teeth between groups. There was a small reduction in the predicted number of invasive treatments in the optimally fluoridated group but the largest predicted reduction was in the most deprived decile. DMFT did not exhibit the expected social inequalities gradient, and for the mean number of missing teeth there were small differences in each decile of deprivation between groups but the direct effect was inconsistent. Water fluoridation expenditure between 2010 and 2019 was estimated to be £10.30 for those receiving optimally fluoridated water. The marginal effects estimate illustrated savings of £22.26 per person (95% CI - £21.43, -£23.09), which is a relative reduction in costs to the NHS of 5.5% per patient. A subsequent estimation of cost effectiveness calculated the cost of water fluoridation to avoid one invasive dental treatment (the ICER) as £94.55. The estimated return on investment using a variety of NHS dental attendance estimates all lead to a positive return.

CONCLUSIONS

These results suggest that water fluoridation appears to be producing less impactful effects on oral health, with water fluoridation resulting in 'exceedingly small' health effects and very small reductions in use of NHS dental services. A positive return for the public sector was identified as the costs of NHS dentistry are high and costs of water fluoridation are low, though this study did not include the original set up costs of fluoridation programmes.

Evaluation of fluoride exposure using disability-adjusted life years and health risk assessment in south-western Iran: A novel Monte Carlo simulation

Consumption of fluoride-contaminated water is a worldwide concern, especially in developing countries, including Iran. However, there are restricted studies of non-single-value health risk assessment and the disease burden regarding fluoride intake nationwide. Prolonged exposure to excessive fluoride has been linked to adverse health effects such as dental and skeletal fluorosis. This can lead to under-mineralization of hard tissues, causing aesthetic concerns for teeth and changes in bone structure, increasing the risk of fractures. As such, we aimed to implement probability-based frameworks using Monte Carlo methods to explore the potential adverse effects of fluoride via the ingestion route. This platform consists of two sectors: 1) health risk assessment of various age categories coupled with a variance decomposition technique to measure the contributions of predictor variables in the outcome of the health risk model, and 2) implementing Monte Carlo methods in dose-response curves to explore the fluoride-induced burden of diseases of dental fluorosis and skeletal fractures in terms of disability-adjusted life years (DALYs). For this purpose, total water samples of 8053 (N=8053) from 57 sites were analyzed in Fars and Bushehr Provinces. The mean fluoride concentrations were 0.75 mg/L and 1.09 mg/L, with maximum fluoride contents of 6.5 mg/L and 3.22 mg/L for the Fars and Bushehr provinces, respectively. The hazard quotient of the 95th percentile (HQ>1) revealed that all infants and children in the study area were potentially vulnerable to over-receiving fluoride. Sobol' sensitivity analysis indices, including first-order, second-order, and total order, disclosed that fluoride concentration (Cw), ingestion rate (IRw), and their mutual interactions were the most influential factors in the health risk model. DALYs rate of dental fluorosis was as high as 981.45 (uncertainty interval: UI 95 % 353.23-1618.40) in Lamerd, and maximum DALYs of skeletal fractures occurred in Mohr 71.61(49.75-92.71), in Fars Province, indicated severe dental fluorosis but mild hazard regarding fractures. Residents of the Tang-e Eram in Bushehr Province with a DALYs rate of 3609.40 (1296.68-5993.73) for dental fluorosis and a DALYs rate of 284.67 (199.11-367.99) for skeletal fractures were the most potentially endangered population. By evaluating the outputs of the DALYs model, the gap in scenarios of central tendency exposure and reasonable maximum exposure highlights the role of food source intake in over-receiving fluoride. This research insists on implementing defluoridation programs in fluoride-endemic zones to combat the undesirable effects of fluoride. The global measures presented in this research aim to address the root causes of contamination and help policymakers and authorities mitigate fluoride's harmful impacts on the environment and public health.

Feasibility of increasing calcium content of drinking tap water following quality regulations to improve calcium intake at population level

Background

Calcium intake is below recommendations in several parts of the world. Improving calcium intake has benefits not only for bone health but also helps to prevent pregnancy hypertension disorders. Calcium concentration of tap water is usually low The aim of the present study was to determine the maximum amount of calcium that can be added to tap water while complying with drinking water Argentine regulations.

Methods

Tap water samples were collected from the Province of Buenos Aires (Argentina). Physicochemical properties and saturation index were measured. Different incremental concentrations of calcium chloride were added to the experimental aliquots.

Results

Baseline water had a mean calcium concentration of 22.00 ± 2.54 mg/L, water hardness of 89.9 ± 6.4 mg/L CaCO 3, and a saturation index of -1.50 ± 0.11. After the addition of 0.4554 ± 0.0071 g of salt, water hard-ness reached 355.0 ± 7.1 mg/L CaCO 3, a calcium concentration of 140.50 ± 2.12 mg/L, and a saturation index -0.53 ± 0.02.

Conclusions

This study shows that at laboratory level it is feasible to increase calcium concentration of drinking water by adding calcium chloride while complying with national standards. Calcium concentration of drinking tap water could be evaluated and minimum calcium concentration of tap water regulated so as to improve calcium intake in populations with low calcium intake.

Preventive effects of probiotics on dental caries in vitro and in vivo

BACKGROUND

Dental caries is a common disease in the oral cavity, and the microorganisms in the cavity are colonized in the form of dental plaque biofilm. Streptococcus mutans is the main pathogen causing dental caries. Using probiotics to inhibit the growth and colonization of pathogenic bacteria, regulate mucosal immunity and improve oral microecological balance is an effective way to prevent or treat dental caries. The aim of this study was to evaluate the caries-prevention of probiotics in vitro and in rat caries models.

METHODS

The probiotics used in this study are a combination of 4 strains of bacteria. After the fermentation of 4 strains (L. plantarum, L. salivarius, L. rhamnosus, and L. paracasei) was completed, they were mixed in equal volume proportions and used as samples to be tested. The mixture was then assessed the ability to inhibit the growth of S. mutans in vitro and in vivo. SPSS Statistics 22.0 (SPSS, Inc., Chicago, IL, USA) was used for analysis.

RESULTS

In vitro the probiotics mixture could inhibit the growth of S. mutans and was able to remove biofilms formed by S. mutans. In a 42-day in vivo experiment, the probiotics group significantly reduced the level of S. mutans on the tooth surface of rats, reducing more than half the bacterial quantities compared with the caries model group (P < 0.05). The amount of S. mutans in the antagonist group was low and highly significant compared with the caries model group. Moreover, the mixture of 4 strains significantly reduced the caries scores (modified Keyes scoring method) in both the probiotic and antagonist groups (p < 0.05).

CONCLUSIONS

The study showed that the combination of the four strains can reduce the cavity scores, and the four strains can be used as products in oral care products. At the same time, the study also suggests that probiotic therapy can be an effective way to prevent dental caries.

Oral Health Data Gaps and Needs in North Carolina

Effective oral health-related policymaking and program implementation rely on comprehensive, accurate, and timely data. This commentary will address the lack of data available and the need for a robust data dashboard, in addition to the importance of community water fluoridation.

The factors associated with the knowledge of brushing teeth with fluoridated toothpaste among high school students in Al-Madinah, Saudi Arabia

Objective

The use of fluoridated toothpaste (FT) is essential for controlling caries. This analytical cross-sectional study aimed to determine the proportion of students who brushed their teeth with fluoridated toothpaste/or do not know the content at least once a day and to determine the factors associated with the knowledge of brushing teeth with FT.

Methods

An anonymous questionnaire was distributed during the academic year 2019-2020 among 439 high school students. The data collected included sociodemographic characteristics and oral-health-related variables [e.g., brushing teeth, knowledge of the effect of fluoride on caries (KEFC) and dental service utilisation (DSU)]. The dependent variable was the knowledge of using FT when brushing teeth (Yes or do not know). Descriptive, bivariate, and logistic regression analysis were performed.

Results

The response rate was 98% (n = 432) and usable data was 88% (n = 385). The median (IQR) age of the students was 16.00 (1) years, and 190 (47%) were males. Eighty eight percent of the students brushed their teeth with toothpaste daily with no knowledge of toothpaste content and only 86 (21.8%) knew the content of the toothpaste used for brushing their teeth i.e., FT. The multivariable analyses revealed an association of family income and KEFC with brushing teeth with FT [adjusted odds ratio (AOR): 1.98, 95% confidence interval (CI): 1.14-3.43, p = 0.015 and AOR = 6.11, 95% CI: 3.45-10.83, p < 0.001, respectively].

Conclusions

While the brushing and use of toothpaste among high school students was common, the knowledge of the content of toothpaste used for brushing teeth was less common and was associated with family income and KEFC.

Fishing for the evidence on community water fluoridation: a commentary on the CATFISH study

DATA SOURCE

Goodwin M, Emsley R, Kelly M P et al. Evaluation of water fluoridation scheme in Cumbria: the CATFISH prospective longitudinal cohort study. Southampton: National Institute for Health and Care Research, 2022.

METHODS

This longitudinal, prospective cohort study, recruited two populations - a birth cohort and older school cohort - assessing the effects of community water fluoridation (CWF) over a five-year period. The control group received non-fluoridated drinking water in the East of Cumbria, while the intervention group received fluoridated drinking water in the West of Cumbria. The primary outcome measures were the presence or absence of decay into dentine in primary and permanent teeth. Cost effectiveness was assessed by quality-adjusted life-years.

RESULTS

Birth Cohort: Modest beneficial effect (17.4% with decay, 21.4% in control). Adjusted Odd Ratios (AOR): 0.74 (95% CI: 0.56 to 0.98). Older Cohort: Insufficient evidence of difference (19.1% with decay and 21.9% in control). AOR: 0.80 (95% CI: 0.58 to 1.09).

CONCLUSION

The authors concluded that CWF was effective in the birth cohort and that the modest absolute reduction in caries should be considered in the context of other preventive measures. A longer follow-up period was recommended to fully understand the benefits and risks of CWF in contemporary low-prevalence populations.

Community water fluoride cessation and rate of caries-related pediatric dental treatments under general anesthesia in Alberta, Canada

OBJECTIVE

This study examined the rate of caries-related dental treatments under general anesthesia (GA) in fluoridated and non-fluoridated communities in Alberta, Canada, between 2010 and 2019.

METHODS

This retrospective, population-based study included all children ( < 12 years of age) living in Calgary (non-fluoridated) and Edmonton (fluoridated) who underwent caries-related dental treatments under GA at publicly funded facilities. Demographics and dental data were extracted from health administrative databases for three time periods of 2010/11 (pre-cessation), 2014/15, and 2018/19 (post-cessation).

RESULTS

Among 2659 children receiving caries-related treatments under GA, the mean (SD) and median (IQR) age were 4.8 (2.3) and 4 (3-6) years, respectively, and 65% resided in the non-fluoridated area. The analysis revealed that the cessation of water fluoridation was significantly associated with an increased rate of caries-related GA events per 10,000 children in both age groups (0-5 and 6-11 years), with a more pronounced effect in 0-5-year-olds in non-fluoridated areas. The risk of dental treatments under GA was also positively associated with post-cessation time.

CONCLUSION

Discontinuing water fluoridation appears to negatively affect young children's oral health, potentially leading to a significant increase in caries-related dental treatments under GA and oral health disparities in this pediatric population.

Prevention of suicidal behavior with lithium treatment in patients with recurrent mood disorders

Suicidal behavior is more prevalent in bipolar disorders than in other psychiatric illnesses. In the last thirty years evidence has emerged to indicate that long-term treatment of bipolar disorder patients with lithium may reduce risk of suicide and attempts, with possibly similar benefits in recurrent major depressive disorder. We review and update selected research literature on effects of lithium treatment in reducing suicidal behavior and consider proposals that higher levels of lithium in drinking water may be associated with lower suicide rates. We summarize results of a growing number of randomized, controlled studies of lithium treatment for suicide prevention including comparisons with placebos or alternative treatments, and comment on the severe challenges of such trials. The basis of a proposed protective effect of lithium against suicidal behaviors remains uncertain but may include protective effects against recurrences of depressive phases of mood disorders, especially with mixed features or agitation, and possibly through beneficial effects on impulsivity, agitation and dysphoric mood.

Effect of bottled fluoridated water to prevent dental caries in primary teeth: study protocol for a phase 2 parallel-group 3.5-year randomized controlled clinical trial (waterBEST)

BACKGROUND

Fluoridation of public water systems is known as a safe and effective strategy for preventing dental caries based on evidence from non-randomized studies. Yet 110 million Americans do not have access to a fluoridated public water system and many others do not drink tap water. This article describes the study protocol for the first randomized controlled trial (RCT) of fluoridated water that assesses its potential dental caries preventive efficacy when delivered in bottles.

METHODS

waterBEST is a phase 2b proof-of-concept, randomized, quadruple-masked, placebo-controlled, parallel-group trial designed to estimate the potential efficacy of fluoridated versus non-fluoridated bottled water to prevent dental caries incidence in the first 4 years of life. Two hundred children living in eastern North Carolina, USA, and aged 2-6 months at screening are being allocated at random in a 1:1 ratio to receive fluoridated (0.7 mg/L F) or non-fluoridated bottled water sourced from two local public water systems. Throughout the 3.5-year intervention, study water is delivered monthly in 5-gallon bottles to each child's home with instructions to use it whenever the child consumes water as a beverage or in food preparation. Parents are interviewed quarterly to monitor children's water consumption and health. At annual visits, the presence of dental caries is evaluated with a dental screening examination. Clippings from fingernails and toenails are collected to quantify fluoride content as a biomarker of total fluoride intake. The primary endpoint is the number of primary tooth surfaces decayed, missing, or filled due to dental caries measured by the study dentist near the time of the child's fourth birthday. Tooth decay is assessed at the threshold of macroscopic enamel loss. For the primary aim, a least-squares, generalized linear model will estimate efficacy and its one-tailed, upper 80% confidence limit.

DISCUSSION

waterBEST is the first evaluation of a randomized intervention of fluoridated drinking water in bottles to prevent dental caries in the primary dentition. This innovative method of delivering fluoridated water has the potential to prevent early childhood caries in a large segment of the US population that currently does not benefit from fluoridated public water.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04893681. Registered on March 2022. Last update posted on 10 October 2023. https://clinicaltrials.gov/study/NCT04893681?cond=Dental%20Caries%20in%20Children&term=fluoride&locStr=North%20Carolina,%20USA&country=United%20States&state=North%20Carolina&distance=50&rank=1.

Prevalence and risk factors of dental fluorosis among children aged 8-12 years in Shandong province of China

This study was to investigate the prevalence and severity of children's dental fluorosis (DF) in Shandong and identified the potential risk factors for DF. A total of 87 villages in Shandong were investigated to calculate the prevalence of DF and Community Fluorosis Index (CFI) in 2018-2019. Six hundred and seventy children were enrolled to identify the potential risk factors using univariate and multivariate logistic regressions. Goodman-Kruskal Gamma was used to explore the factors related to the severity of DF. In 87 villages, 1249 of 8700 (14.36%) children still have DF. The prevalence of DF in most villages was below 40% in 2018-2019. Water fluorine concentration when selected for the study and urinary fluorine concentration were related to the risk of DF (P < 0.001). Some eating habits, like lower frequency of eating fresh vegetables, eggs, and beans, were associated with the risk of DF (P < 0.001). The high water fluorine concentration, and lower frequency of eating fresh vegetables, eggs, and beans were also related to the severity of DF (P < 0.001). DF in children in Shandong province is still a common endemic disease. This study tries to provide a useful guide for the prevention and control of DF.

Fluoride varnish applications provided in general dental practice for children of primary school age in three areas of the UK

Introduction Dental guidelines recommend professional application of fluoride varnish (FV) at least twice a year for children from the age of three.Methods NHS dental claims data were reviewed for children born in 2009 for the five-year period 2015-2019 and who attended the dentist in one of three geographical areas, labelled as Bristol, Birmingham and Cardiff. Data for 14,566 children were included in the study.Results Only 3.5% of children had been provided with ten or more FV applications at the dentist in the five-year period. Children in the Cardiff region fared less well for fluoride applications than their Bristol and Birmingham counterparts, including children that were seemingly at high risk of caries for part of the time period reviewed. For all three regions, the mean number of FV applications increased with an increase in the number of fillings provided.Conclusion Awareness of the apparent lack of FV application in the dental surgery may provide an opportunity to improve child dental health.

Dental Caries among the Elderly in Iran: A Meta-analysis

Background

The prevalence of dental caries among the elderly is high worldwide, and dental caries cause the major burden of oral diseases. This meta-analysis aimed to determine the dental caries experience among the elderly in Iran.

Methods

A systematic review of the published and grey literature on Iranians aged 65 years or older was performed. Six international and local databases provided the most comprehensive population-based studies. National oral health surveys and national disease and health surveys were considered other primary data sources. The quality of remained studies was assessed by a modified tool designed based on the STROBE statement checklist to evaluate the cross-sectional studies. R Version 3.6.0 was used for statistical analysis. Heterogeneity was assessed using Cochran's Q and F statistics. Subgroup analysis was performed to detect the source of heterogeneity. Funnel plots and Egger's regression intercept test were used to assess publication bias and selective reporting.

Results

Overall, 3099 sources were found. After excluding ineligible studies, 46 data points with 10411 people ≥65 years were included in the meta-analysis. The mean pooled decayed, missing, and filled teeth (DMFT) among older people was 26.84 (range, 26.41-27.28). The DMFT was 26.78 (range, 26.12-27.43) in women and 26.91 (range, 26.32-27.50) in men. The mean number of decayed teeth was 1.48 (range, 1.32-1.65). The mean pooled missing teeth was 24.83 (range, 24.20-25.46), and the mean pooled filled teeth was 0.14 (range, 0.12-0.17). The majority (92%) of the DMFT was related to missing teeth.

Conclusion

Iranian elderly have almost 5 sound teeth in their mouth on average. The Iranian oral health policymakers should address this considerable burden of dental caries in designing and implementing better oral health policies for the population, especially older Iranian adults.

The fluorosis conundrum: bridging the gap between science and public health

Fluorosis, a chronic condition brought on by excessive fluoride ingestion which, has drawn much scientific attention and public health concern. It is a complex and multifaceted issue that affects millions of people worldwide. Despite decades of scientific research elucidating the causes, mechanisms, and prevention strategies for fluorosis, there remains a significant gap between scientific understanding and public health implementation. While the scientific community has made significant strides in understanding the etiology and prevention of fluorosis, effectively translating this knowledge into public health policies and practices remains challenging. This review explores the gap between scientific research on fluorosis and its practical implementation in public health initiatives. It suggests developing evidence-based guidelines for fluoride exposure and recommends comprehensive educational campaigns targeting the public and healthcare providers. Furthermore, it emphasizes the need for further research to fill the existing knowledge gaps and promote evidence-based decision-making. By fostering collaboration, communication, and evidence-based practices, policymakers, healthcare professionals, and the public can work together to implement preventive measures and mitigate the burden of fluorosis on affected communities. This review highlighted several vital strategies to bridge the gap between science and public health in the context of fluorosis. It emphasizes the importance of translating scientific evidence into actionable guidelines, raising public awareness about fluoride consumption, and promoting preventive measures at individual and community levels.

Systems mapping of multilevel factors contributing to dental caries in adolescents

Dental caries is a prevalent chronic disease among adolescents. Caries activity increases significantly during adolescence due to an increase in susceptible tooth surfaces, immature permanent tooth enamel, independence in pursuing self-care, and a tendency toward poor diet and oral hygiene. Dental caries in permanent teeth is more prevalent among adolescents in low-income families and racial/ethnic minority groups, and these disparities in adolescent dental caries experience have persisted for decades. Several conceptual and data-driven models have proposed unidirectional mechanisms that contribute to the extant disparities in adolescent dental caries experience. Our objective, using a literature review, is to provide an overview of risk factors contributing to adolescent dental caries. Specifically, we map the interactive relationships of multilevel factors that influence dental caries among adolescents. Such interactive multilevel relationships more closely reflect the complex nature of dental caries experience among the adolescent population. The methods that we use are two-fold: (1) a literature review using PubMed and Cochrane databases to find contributing factors; and (2) the system dynamics approach for mapping feedback mechanisms underlying adolescent dental caries through causal loop diagramming. The results of this study, based on the review of 138 articles, identified individual, family and community-level factors and their interactions contributing to dental caries experience in adolescents. Our results also provide hypotheses about the mechanisms underlying persistence of dental caries among adolescents.

Conclusions

Our findings may contribute to a deeper understanding of the multilevel and interconnected factors that shape the persistence of dental caries experience among adolescents.

A review of water fluoridation studies and the effect on dental caries and treatment costs, undertaken in Scotland

Objectives This review aimed to investigate the effect of water fluoridation on the dental health of Scottish people by comparing results of starting and discontinuing fluoridation in Scotland.Data sources Data sources were retrieved from electronic databases. The grey literature was also searched. Articles were selected if the population of interest was Scottish. The objective was to evaluate the influence of water fluoridation on dental caries using the dmft/s, DMFT/S (decayed, missing and filled teeth/surfaces) or deft/s indices (decayed, extraction needed, filled teeth/surfaces).Data extraction Name of the authors, publication years, location of the study, sample size, type of study design, age of participants, method of assessing the outcome, data related to the exposure and the outcome, and the overall result of each study were extracted. The data were collected based on the effect of water fluoridation and its cessation on dental caries and the type of dentition.Results Nine studies were included in the review. The findings revealed that the introduction of water fluoridation led to reductions in caries. Moreover, after the cessation of fluoridation, caries levels continued to remain lower in the fluoridated groups. Additionally, fluoridation had the effect of reducing the cost of dental treatment.Conclusion Water fluoridation was effective in improving dental caries among the Scottish child population. New studies are required to provide contemporary evidence for water fluoridation in Scotland.

Regional and racial/ethnic inequalities in public drinking water fluoride concentrations across the US

BACKGROUND

Although the US Centers for Disease Control and Prevention (CDC) considers fluoridation of community water systems (CWSs) to be a major public health achievement responsible for reducing dental disease, recent epidemiologic evidence suggests that chronic exposure to population-relevant levels of fluoride may also be associated with adverse child neurodevelopmental outcomes. To our knowledge, a nationally representative database of CWS fluoride concentration estimates that can be readily linked to US epidemiologic cohorts for further study is not publicly available. Our objectives were to evaluate broad regional and sociodemographic inequalities in CWS fluoride concentrations across the US, and to determine if county-level racial/ethnic composition was associated with county-level CWS fluoride.

METHODS

We generated CWS-level (N = 32,495) and population weighted county-level (N = 2152) fluoride concentration estimates using over 250,000 routine compliance monitoring records collected from the US Environmental Protection Agency's (EPA) Third Six Year Review (2006-2011). We compared CWS-level fluoride distributions across subgroups including region, population size served, and county sociodemographic characteristics. In county-level spatial error models, we also evaluated geometric mean ratios (GMRs) of CWS fluoride per 10% higher proportion of residents belonging to a given racial/ethnic subgroup.

RESULTS

4.5% of CWSs (serving >2.9 million residents) reported mean 2006-2011 fluoride concentrations ≥1500 µg/L (the World Health Organization's guideline for drinking water quality). Arithmetic mean, 90th, and 95th percentile contaminant concentrations were greatest in CWSs reliant on groundwater, located in the Southwest and Eastern Midwest, and serving Semi-Urban, Hispanic communities. In fully adjusted spatial error models, the GMR (95% CI) of CWS fluoride per a 10% higher proportion of county residents that were Hispanic/Latino was 1.16 (1.10, 1.23).

IMPACT STATEMENT

We find that over 2.9 million US residents are served by public water systems with average fluoride concentrations exceeding the World Health Organization's guidance limit. We also find significant inequalities in community water system fluoride concentration estimates (2006-2011) across the US, especially for Hispanic/Latino communities who also experience elevated arsenic and uranium in regulated public drinking water systems. Our fluoride estimates can be leveraged in future epidemiologic studies to assess the potential association between chronic fluoride exposure and related adverse outcomes.

Systematic review of epidemiological and toxicological evidence on health effects of fluoride in drinking water

INTRODUCTION

Fluoride is a naturally occurring substance that is also added to drinking water, dental hygiene products, and food supplements for preventing dental caries. Concerns have been raised about several other potential health risks of fluoride.

OBJECTIVE

To conduct a robust synthesis of evidence regarding human health risks due to exposure to fluoride in drinking water, and to develop a point of departure (POD) for setting a health-based value (HBV) for fluoride in drinking water.

METHODS

A systematic review of evidence published since recent reviews of human, animal, and in vitro data was carried out. Bradford Hill considerations were used to weigh the evidence for causality. Several key studies were considered for deriving PODs.

RESULTS

The current review identified 89 human studies, 199 animal studies, and 10 major in vitro reviews. The weight of evidence on 39 health endpoints was presented. In addition to dental fluorosis, evidence was considered strong for reduction in IQ scores in children, moderate for thyroid dysfunction, weak for kidney dysfunction, and limited for sex hormone disruptions.

CONCLUSION

The current review identified moderate dental fluorosis and reduction in IQ scores in children as the most relevant endpoints for establishing an HBV for fluoride in drinking water. PODs were derived for these two endpoints, although there is still some uncertainty in the causal weight of evidence for causality for reducing IQ scores in children and considerable uncertainty in the derivation of its POD. Given our evaluation of the overall weight of evidence, moderate dental fluorosis is suggested as the key endpoint until more evidence is accumulated on possible reduction of IQ scores effects. A POD of 1.56 mg fluoride/L for moderate dental fluorosis may be preferred as a starting point for setting an HBV for fluoride in drinking water to protect against moderate and severe dental fluorosis. Although outside the scope of the current review, precautionary concerns for potential neurodevelopmental cognitive effects may warrant special consideration in the derivation of the HBV for fluoride in drinking water.

Tap water natural fluoride and parent-reported experience of child dental caries in Japan: Evidence from a nationwide birth cohort survey

INTRODUCTION

Water fluoridation is an effective measure to prevent dental caries. In Japan, artificial water fluoridation is not implemented, and tap water natural fluoride concentration geographically differs because of various soil natures. This study aimed to examine the association between tap water natural fluoride and parent-reported experience of dental caries in children.

METHOD

Data from the Longitudinal Survey of Newborns in the twenty-first century, a national birth cohort study following all infants born between January 10-17 and July 10-17, 2001, were analysed. Caregivers answered the child's caries treatment history, a proxy for dental caries, yearly from 5.5 to 12 years of age (N = 202 517 observations from 34 998 children). The annual data on tap water natural fluoride concentration in the municipality of residence were obtained from the national statistics. Cross-classified multilevel Poisson regression models were fitted, adjusting for child, household and municipality characteristics, including average income and dental clinic density.

RESULTS

The average tap water natural fluoride concentration across municipalities was 0.0887 ppm (SD = 0.0422). The proportion of parent-reported experience of child dental caries treatment ranged from 24.9% (at 12 years) to 40.3% (at 7 years) and was lower among children living in municipalities with high natural fluoride concentrations, which were 35.0%, 35.4%, 33.4% and 32.3% for <0.10, 0.10-0.19, 0.20-0.29 and ≥0.30 ppm respectively. A 0.1 ppm increment in tap water natural fluoride after controlling for all covariates was significantly associated with a lower prevalence of parent-reported child dental caries treatment by 3.3% (prevalence ratio = 0.967, 95% credible interval: 0.939, 0.996).

CONCLUSION

Natural fluoride in tap water showed a protective effect for the parent-reported experience of child dental caries in Japan.

Comments on recent community water fluoridation studies

Water fluoridation is a public health measure to reduce levels of dental caries in populations. A report of the recently completed CATFISH study has been published. This was the first UK evaluation of fluoridation introduction for many years; it was carefully designed and executed and is welcomed. The purpose of this article is to highlight the 180-page report of the study and comment on some aspects to aid interpretation of the findings. Significant features were that two cohorts, from birth and from five years, were followed for six years in a fluoridated and a non-fluoridated area, and clinical and cost analyses were reported. Areas of the report which deserve comment are: a) interruption of fluoridation for a year for half the children in the intervention area and its effect; b) clinical results were reported as absolute reduction in caries prevalence, with the preventive fraction for caries severity downplayed; c) the power of the study was diminished by an unexpected lower caries increment; and d) control for differences in diet was not possible. Nevertheless, this major UK study showed clinical and cost benefits of water fluoridation. The risk of cessation of water fluoridation is highlighted in examples of three recently published studies.

Unraveling molecular characteristic of fluoride neurotoxicity on U87 glial-like cells: insights from transcriptomic and proteomic approach

The potential of fluoride (F) as a neurotoxicant in humans is still controversial in the literature. However, recent studies have raised the debate by showing different mechanism of F-induced neurotoxicity, as oxidative stress, energy metabolism and inflammation in the central nervous system (CNS). In the present study, we investigated the mechanistic action of two F concentration (0.095 and 0.22 μg/ml) on gene and protein profile network using a human glial cell in vitro model over 10 days of exposure. A total of 823 genes and 2,084 genes were modulated after exposure to 0.095 and 0.22 μg/ml F, respectively. Among them, 168 were found to be modulated by both concentrations. The number of changes in protein expression induced by F were 20 and 10, respectively. Gene ontology annotations showed that the main terms were related to cellular metabolism, protein modification and cell death regulation pathways, such as the MAP kinase (MAPK) cascade, in a concentration independent manner. Proteomics confirmed the changes in energy metabolism and also provided evidence of F-induced changes in cytoskeleton components of glial cells. Our results not only reveal that F has the potential to modulate gene and protein profiles in human U87 glial-like cells overexposed to F, but also identify a possible role of this ion in cytoskeleton disorganization.

A National Study Exploring the Association Between Fluoride Levels and Dental Fluorosis

Importance

While the effects of fluoride on health have been widely researched, fewer high-quality studies examine the association of fluoride levels in water and dental fluorosis.

Objective

To investigate the association between fluoride exposure from drinking water and dental fluorosis.

Design, Setting, and Participants

This cross-sectional study used the 2013-2014 and 2015-2016 National Health and Nutrition Examination Survey (NHANES) data (January 1, 2013, through December 31, 2016). NHANES uses a complex sampling technique to develop nationally representative sample estimates of the US population that consists of interviews and physical assessments. Children and adolescents aged 6 to 15 years were included because NHANES contains their data for all 3 forms of fluoride measures: plasma fluoride levels, water levels of fluoride, and dietary fluoride supplementation. Data were analyzed from January 1 to April 30, 2023.

Exposures

Water and plasma fluoride levels were measured by laboratory personnel. Dietary fluoride supplement data were self-reported.

Main Outcomes and Measures

The Dean's Fluorosis Index was used to evaluate fluorosis status for each tooth. The dental fluorosis severity value was based on the second most affected tooth. Independent variables included plasma and water fluoride concentrations and dietary fluoride supplementation. An independent samples t test was used to compare fluoride exposures between groups, and Pearson correlation assessed the association between plasma and water fluoride levels. To assess whether fluoride exposures were associated with dental fluorosis, logistic regression analyses were conducted.

Results

There were 1543 participants in the 2013-2014 NHANES cycle (weighted proportion male, 51.9%; mean [SD] age, 11.0 [2.7] years) and 1452 in the 2015-2016 cycle (weighted proportion male, 52.6%; mean [SD] age, 11.1 [2.8] years). A weighted 87.3% exhibited some degree of fluorosis in the 2013-2014 cycle and 68.2% in the 2015-2016 cycle. Higher fluoride levels in water and plasma were significantly associated with higher odds of dental fluorosis (adjusted odds ratios, 2.378 [95% CI, 2.372-2.383] in the 2013-2014 cycle and 1.568 [95% CI, 1.564-1.571] in the 2015-2016 cycle).

Conclusions and Relevance

The findings of this cross-sectional study suggest that exposure to higher concentrations of fluoride in water and having higher plasma levels of fluoride were associated with a greater risk of dental fluorosis. Further research can help policy makers develop policies that balance substantial caries prevention with the risk of dental fluorosis.

A Bibliometric Analysis of the Top 100 Most-Cited Papers Concerning Dental Fluorosis

A high number of citations can indicate the potential of any specific paper to influence other research and generate changes in clinical practice. Analyzing the most-cited papers in a certain scientific field may assist researchers to identify the influential papers as well their main characteristics. The present study aimed to analyze the 100 most-cited papers concerning dental fluorosis (DF) through a bibliometric review. A search was performed in the Web of Science Core Collection (WoS-CC) database in November 2021. The papers were displayed in descending order according to the number of citations in WoS-CC. Two independent researchers performed the selection. Scopus and Google Scholar were used to compare the number of citations with WoS-CC. The following data were extracted from the papers: title, authors, number and density of citations, institution, country, continent, year of publication, journal title, keywords, study design, and theme. Collaborative networks were generated using the VOSviewer software. The top 100 most-cited papers were published between 1974 and 2014 and were cited 6,717 times (ranging from 35 to 417). Community Dentistry and Oral Epidemiology (24%), Journal of Dental Research (21%), Journal of Public Health Dentistry (17%), and Caries Research (13%) published the most papers. Observational studies (60%) and literature reviews (19%) were the most common study designs. The main topics were epidemiology (44%) and fluoride intake (32%). The countries with the highest number of papers were the USA (44%), Canada (10%), and Brazil (9%). The University of Iowa (USA) had the most papers (12%). Levy SM was the author with the highest number of papers (12%). The 100 most-cited papers on DF were mainly observational studies focused on epidemiology and originated in North America. There were few interventional studies and systematic reviews among the most-cited papers concerning this topic.

Fluoride exposure and cognitive neurodevelopment: Systematic review and dose-response meta-analysis

Many uncertainties still surround the possible harmful effect of fluoride exposure on cognitive neurodevelopment in children. The aim of this systematic review and meta-analysis was to characterize this relation through a dose-response approach, by comparing the intelligence quotient (IQ) scores in the highest versus the lowest fluoride exposure category with a random-effects model, within a one-stage dose-response meta-analysis based on a cubic spline random-effects model. Out of 1996 potentially relevant literature records, 33 studies were eligible for this review, 30 of which were also suitable for meta-analysis. The summary mean difference of IQ score, comparing highest versus lowest fluoride categories and considering all types of exposure, was -4.68 (95% confidence interval-CI -6.45; -2.92), with a value of -5.60 (95% CI -7.76; -3.44) for drinking water fluoride and -3.84 (95% CI -7.93; 0.24) for urinary fluoride. Dose-response analysis showed a substantially linear IQ decrease for increasing water fluoride above 1 mg/L, with -3.05 (95% CI -4.06; -2.04) IQ points per 1 mg/L up to 2 mg/L, becoming steeper above such level. A weaker and substantially linear decrease of -2.15 (95% CI -4.48; 0.18) IQ points with increasing urinary fluoride emerged above 0.28 mg/L (approximately reflecting a water fluoride content of 0.7 mg/L). The inverse association between fluoride exposure and IQ was particularly strong in the studies at high risk of bias, while no adverse effect emerged in the only study judged at low risk of bias. Overall, most studies suggested an adverse effect of fluoride exposure on children's IQ, starting at low levels of exposure. However, a major role of residual confounding could not be ruled out, thus indicating the need of additional prospective studies at low risk of bias to conclusively assess the relation between fluoride exposure and cognitive neurodevelopment.

Education-related inequalities in oral health among older adults: Comparing Singapore and Japan

OBJECTIVES

Oral health inequalities exist worldwide, and cross-country comparisons can provide valuable insights into country-level characteristics contributing to such inequalities. However, comparative studies in Asian countries are limited. This study examined the magnitude of education-related oral health inequalities in older adults in Singapore and Japan.

METHODS

Longitudinal data for older adults, aged ≥65 years, from the Panel on Health and Ageing of Singaporean Elderly (PHASE; 2009, 2011-2012, and 2015) and Japan Gerontological Evaluation Study (JAGES; 2010, 2013, and 2016) were used. Dependent variables were being edentate and having a minimal functional dentition (MFD; i.e. ≥20 teeth). The absolute and relative inequalities were calculated using the slope index of inequality (SII) and relative index of inequality (RII) for educational level [low (<6 years); middle (6-12 years); high (>12 years)] in each country.

RESULTS

A total of 1032 PHASE participants and 35 717 JAGES participants were included. At baseline among PHASE participants, 35.9% were edentate and 24.4% had MFD, while among JAGES participants, 8.5% were edentate and 42.4% had MFD. The prevalence of low, middle and high educational levels for PHASE was 76.5%, 18.0% and 5.5%, and for JAGES were 0.9%, 78.1% and 19.7%, respectively. Older adults in Japan had lower education-related inequalities for being edentate [for both SII (-0.53, 95% CI = -0.55 to -0.50) and RII (0.40, 95% CI = 0.33-0.48)] and for not having MFD for both SII (-0.24, 95% CI = -0.27 to -0.20) and RII (0.83, 95% CI = 0.79-0.87) compared to Singapore.

CONCLUSIONS

Education-related inequalities for being edentate and not having MFD were higher among older adults in Singapore compared to Japan.

The Safety of Fluoride Compounds and Their Effect on the Human Body-A Narrative Review

Fluoride is one of the elements commonly present in the human environment. Due to its characteristics, it is very widely used in medicine, dentistry, industry or agriculture. On the other hand, its universality possesses a real threat to the human body in the form of acute and chronic poisoning. The aim of this paper is to characterize the properties of fluoride and its effects on the human body, as well as the sources of its occurrence. Particular emphasis is placed on the safety of its use and optimal dosage intake, which prevents accumulation and reduces its potential side effects. The positive effect of proper fluoride supply is widely described. In order to avoid overdose, it is best to consult a specialist to properly select the dosage.

A comprehensive review of the application of probiotics and postbiotics in oral health

Oral diseases are among the most common diseases around the world that people usually suffer from during their lifetime. Tooth decay is a multifactorial disease, and the composition of oral microbiota is a critical factor in its development. Also, Streptococcus mutans is considered the most important caries-causing species. It is expected that probiotics, as they adjust the intestinal microbiota and reduce the number of pathogenic bacteria in the human intestine, can exert their health-giving effects, especially the anti-pathogenic effect, in the oral cavity, which is part of the human gastrointestinal tract. Therefore, numerous in vitro and in vivo studies have been conducted on the role of probiotics in the prevention of tooth decay. In this review, while investigating the effect of different strains of probiotics Lactobacillus and Bifidobacteria on oral diseases, including dental caries, candida yeast infections, periodontal diseases, and halitosis, we have also discussed postbiotics as novel non-living biological compounds derived from probiotics.

Retrospective summary analysis on the results of oral health epidemiological investigations in China

Objective

Comparative analysis of the results of the four national oral health epidemiological investigations conducted in 1983, 1995, 2005 and 2015 respectively, to understand the changes in the oral health status of the Chinese people with economic development, and provide a scientific basis for the country to formulate effective oral health defense measures.

Methods

Collect the data of four large-scale oral health epidemiological investigations conducted in the past 40 years, make a retrospective summary and comparative analysis of the list below to understand the changes in Chinese oral health-related indicators such as dental caries and analyze the reason.

Results

Since 1995, the preventive counseling rate was increased. Since 1983, the incidence of caries has decreased, but it has increased in children aged 5 and 12 in the last ten years. Four investigations have examined gingivitis and the situation has not improved significantly. Tooth loss was mainly concentrated in the old group, the repair rate of denture was significantly increased. There are significant differences between the gender and urban and rural distribution of oral health.

Conclusions

There is an imbalance in the degree of oral health knowledge of Chinese people, and the incidence of caries and periodontal diseases is still relatively high. It is necessary to strengthen hygiene guidance for different age groups, focusing on prevention and combining prevention and treatment to jointly promote oral health.

Evaluation of water fluoridation scheme in Cumbria: the CATFISH prospective longitudinal cohort study

Background

Water fluoridation was introduced in the UK against a background of high dental decay within the population. Levels of decay have dramatically reduced over the last 40 years following widespread use of fluoride toothpaste.

Objective

The aim of the CATFISH (Cumbrian Assessment of Teeth a Fluoride Intervention Study for Health) study was to address the question of whether or not the addition of fluoride to community drinking water, in a contemporary population, lead to a reduction in the number of children with caries and, if so, is this reduction cost-effective?

Design

A longitudinal prospective cohort design was used in two distinct recruited populations: (1) a birth cohort to assess systemic and topical effects of water fluoridation and (2) an older school cohort to assess the topical effects of drinking fluoridated water.

Setting

The study was conducted in Cumbria, UK. Broadly, the intervention group (i.e. individuals receiving fluoridated drinking water) were from the west of Cumbria and the control group were from the east of Cumbria.

Participants

Children who were lifetime residents of Cumbria were recruited. For the birth cohort, children were recruited at birth (2014–15), and followed until age 5 years. For the older school cohort, children were recruited at age 5 years (2013–14) and followed until the age of 11 years.

Intervention

The provision of a ‘reintroduced fluoridated water scheme’.

Main outcome measures

The primary outcome measure was the presence or absence of decay into dentine in the primary teeth (birth cohort) and permanent teeth (older school cohort). The cost per quality-adjusted life-year was also assessed.

Results

In the birth cohort (n = 1444), 17.4% of children in the intervention group had decay into dentine, compared with 21.4% of children in the control group. The evidence, after adjusting for deprivation, age and sex, with an adjusted odds ratio of 0.74 (95% confidence interval 0.56 to 0.98), suggested that water fluoridation was likely to have a modest beneficial effect. There was insufficient evidence of difference in the presence of decay in children in the older school cohort (n = 1192), with 19.1% of children in the intervention group having decay into dentine, compared with 21.9% of children in the control group (adjusted odds ratio 0.80, 95% confidence interval 0.58 to 1.09). The intervention was found to be likely to be cost-effective for both the birth cohort and the older school cohort at a willingness-to-pay threshold of £20,000 per quality-adjusted life-year. There was no significant difference in the performance of water fluoridation on caries experience across deprivation quintiles.

Conclusions

The prevalence of caries and the impact of water fluoridation was much smaller than previous studies have reported. The intervention was effective in the birth cohort group; however, the importance of the modest absolute reduction in caries (into dentine) needs to be considered against the use of other dental caries preventative measures. Longer-term follow-up will be required to fully understand the balance of benefits and potential risks (e.g. fluorosis) of water fluoridation in contemporary low-caries populations.

Limitations

The low response rates to the questionnaires reduced their value for generalisations. The observed numbers of children with decay and the postulated differences between the groups were far smaller than anticipated and, consequently, the power of the study was affected (i.e. increasing the uncertainty indicated in the confidence intervals).

Study registration

This study is registered as Integrated Research Application System 131824 and 149278.

Funding

This project was funded by the National Institute for Health and Care Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 10, No. 11. See the NIHR Journals Library website for further project information.

Fluoride Content of Ready-to-Eat Infant Foods and Drinks in Australia

The use of fluoride is effective in preventing dental caries. However, an excessive intake of fluoride leads to dental fluorosis, making it necessary to regularly monitor the fluoride intake especially for infants. There is hitherto a lack of information on fluoride content in infant foods from an Australian perspective. Therefore, this study aims to estimate the amount of fluoride content from a range of commercially available ready-to-eat (RTE) infant foods and drinks available in Australia. Based on an external calibration method, potentiometry involving a fluoride ion selective electrode and a silver|silver chloride reference electrode was conducted to analyse the fluoride content of a total of 326 solid food samples and 49 liquid food samples in this work. Our results showed an overall median (range) fluoride content of 0.16 (0.001-2.8) µg F/g of solid food samples, and 0.020 (0.002-1.2) µg F/mL of liquid food samples. In addition, ~77.5% of the liquid samples revealed a fluoride content < 0.05% µg F/mL. The highest variation of fluoride concentration (0.014-0.92 µg F/g) was found in formulas for ≥6 month-old infants. We have attributed the wide fluoride content variations in ready-to-eat infant foods and drinks to the processing steps, different ingredients and their origins, including water. In general, we found the fluoride content in most of the collected samples from Australian markets to be high and may therefore carry a risk of dental fluorosis. These results highlight the need for parents to receive appropriate information on the fluoride content of ready-to-eat infant food and drinks.

Knowledge and Attitudes of Pregnant Women with and without Children about Fluoride and Herbal Toothpastes

Objective: Objective: Pregnant women may be vulnerable to dental caries due to their inability to fully implement oral hygiene practices. Toothpastes are main component of oral hygiene and the most important tool for the primary prevention of caries. The study aimed to examine the knowledge and attitudes of pregnant women with children (PC) and without children (PNC) about fluoride and herbal toothpastes. Methods: A self-administered and validated 20-item questionnaire was completed by a total of 219 pregnant participants, 85 PC and 134 PNC. Statistical analyses were performed using the SciPy v1.2.3. program. Results: Most of the PC (57.65%; 69.41%) and PNC (72.39%; 47.76%) participants responded with “no idea” when asked about fluoride sources and the optimal amount of fluoride added to tap water by local health authorities (p= .006). The majority of the PC (62.4%) and the PNC (47.0%) had no preference for herbal toothpastes during pregnancy (p= .03). In addition, 86.6% of the PNC showed low knowledge about the nonfluoride content of herbal toothpastes (p= .023). While 51.5% of the PNC responded with “no idea” about a preference for herbal toothpastes for their children, 56.47% of the PC stated that they might not prefer using herbal toothpastes for their children’s routine oral hygiene. Conclusion: The findings show that both PC and PNC participants had little knowledge of toothpastes and their contents. Considering that toothpastes are the most common self-applied oral hygiene tools, knowledge and awareness of fluoride and herbal toothpastes should be raised via antenatal programs.

The environmental impact of community caries prevention - part 3: water fluoridation

Introduction Community-level interventions for the prevention of dental caries in children include fluoride varnish in schools, supervised toothbrushing in schools, the provision of toothbrushes and toothpaste and water fluoridation. The environmental impact of these interventions is an important factor to consider when commissioning these services.Materials and methods A comparative life cycle assessment (LCA) was conducted to quantify the environmental impact of fluoridation of the public water supply for a five-year-old child over a one-year period. These results were compared to LCA data for fluoride varnish in schools, supervised toothbrushing and the provision of toothbrushes and toothpaste.Results When comparing community-level caries prevention programmes, water fluoridation had the lowest environmental impact in all 16 categories and had the lowest disability-adjusted life years impact.Discussion All community-level caries prevention programmes have an associated environmental cost. Water fluoridation performed well in this LCA study in all measures of environmental sustainability. The results of this study could be used, along with cost and clinical effectiveness data, to inform public healthcare policy.

Role of Glycolysis/Gluconeogenesis and HIF-1 Signaling Pathways in Rats with Dental Fluorosis Integrated Proteomics and Metabolomics Analysis

Fluoride is widely distributed, and excessive intake will lead to dental fluorosis. In this study, six offspring rats administrated 100 mg/L sodium fluoride were defined as the dental fluorosis group, and eight offspring rats who received pure water were defined as the control group. Differentially expressed proteins and metabolites extracted from peripheral blood were identified using the liquid chromatography tandem mass spectrometry and gas chromatography mass spectrometry, with the judgment criteria of fold change >1.2 or <0.83 and p < 0.05. A coexpression enrichment analysis using OmicsBean was conducted on the identified proteins and metabolites, and a false discovery rate (FDR) < 0.05 was considered significant. Human Protein Atlas was used to determine the subcellular distribution of hub proteins. The Gene Cards was used to verify results. A total of 123 up-regulated and 46 down-regulated proteins, and 12 up-regulated and 2 down-regulated metabolites were identified. The significant coexpression pathways were the HIF-1 (FDR = 1.86 × 10−3) and glycolysis/gluconeogenesis (FDR = 1.14 × 10−10). The results of validation analysis showed the proteins related to fluorine were mainly enriched in the cytoplasm and extrinsic component of the cytoplasmic side of the plasma membrane. The HIF-1 pathway (FDR = 1.01 × 10−7) was also identified. Therefore, the HIF-1 and glycolysis/gluconeogenesis pathways were significantly correlated with dental fluorosis.

Expert consensus on early childhood caries management

Early childhood caries (ECC) is a significant chronic disease of childhood and a rising public health burden worldwide. ECC may cause a higher risk of new caries lesions in both primary and permanent dentition, affecting lifelong oral health. The occurrence of ECC has been closely related to the core microbiome change in the oral cavity, which may be influenced by diet habits, oral health management, fluoride use, and dental manipulations. So, it is essential to improve parental oral health and awareness of health care, to establish a dental home at the early stage of childhood, and make an individualized caries management plan. Dental interventions according to the minimally invasive concept should be carried out to treat dental caries. This expert consensus mainly discusses the etiology of ECC, caries-risk assessment of children, prevention and treatment plan of ECC, aiming to achieve lifelong oral health.