Socio-economic status and access to fluoridated water in Queensland: an ecological data linkage study.

OBJECTIVES: To investigate the relationship between access to fluoridated drinking water and area-level socio-economic status in Queensland. STUDY DESIGN: Ecological, geospatial data linkage study. SETTING: Queensland, by statistical area level 2 (SA2), 2021. MAIN OUTCOME MEASURES: Proportion of SA2s and of residents with access to fluoridated drinking water (natural or supplemented); relationship at SA2 level between access to fluoridated water and socio-economic status (Index of Relative Socio-economic Advantage and Disadvantage, IRSAD; Index of Economic Resources, IER). RESULTS: In 2021, an estimated 4 050 168 people (79.4% of the population) and 397 SA2 regions (72.7%) in Queensland had access to fluoridated water. Access was concentrated in the southeastern corner of the state. After adjusting for SA2 population, log area, and population density, the likelihood of access to fluoridated drinking water almost doubled for each 100-rank increase in IRSAD (adjusted odds ratio [aOR], 1.93; 95% confidence interval [CI], 1.59-2.36) or IER (aOR, 1.77; 95% CI, 1.50-2.11). CONCLUSIONS: The 2012 decision to devolve responsibility for water fluoridation decisions and funding from the Queensland government to local councils means that residents in lower socio-economic areas are less likely to have access to fluoridated water than those in more advantaged areas, exacerbating their already greater risk of dental disease. Queensland water fluoridation policy should be revised so that all residents can benefit from this evidence-based public health intervention for reducing the prevalence of dental caries.

Effects of water fluoridation on early embryonic development of zebrafish.

Fluoride has strong electronegativity and exposes diversely in nature. Water fluoridation is the most pervasive form of occurrence, representing a significant threat to human health. In this study, we investigate the morphometric and physiological alterations triggered by fluoride stimulation during the embryogenesis of zebrafish and reveal its putative effects of stage- and/or dose-dependent. Fluoride exhibits potent biological activity and can be extensively absorbed by the yolk sac, exerting significant effects on the development of multiple organs. This is primarily manifested as restricted nutrient utilization and elevated levels of lipid peroxidation, further leading to the accumulation of superoxide in the yolk sac, liver, and intestines. Moreover, pericardial edema exerts pressure on the brain and eye development, resulting in spinal curvature and reduced body length. Besides, acute fluoride exposure with varying concentrations has led to diverse teratogenic outcomes. A low dose of water fluoridation tends to induce abnormal development of the embryonic yolk sac, while vascular malformation is widely observed in all fluoride-treated groups. The effect of fluoride exposure on blood circulation is universally present, even in zebrafish larvae that do not exhibit obvious deformities. Their swimming behavior is also affected by water fluoridation, resulting in reduced activity and delayed reactions. In conclusion, this study provides valuable insights into the monitoring of environmental quality related to water fluoridation and disease prevention.

A quality appraisal of economic evaluations of community water fluoridation: A systematic review.

OBJECTIVES: To critically appraise the methodological conduct and reporting quality of economic evaluations (EE) of community water fluoridation (CWF). METHODS: A systematic literature search was conducted in general databases and specialist directories of the economic literature. The Consensus on Health Economic Criteria list (CHEC) appraised the methodological quality while the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) assessed the reporting quality of included studies. RESULTS: A total of 1,138 records were identified, of which 18 met the inclusion criteria. Cost analysis emerged as the most prevalent type of EE, though a growing trend towards conducting full EEs is observed. CHEC revealed the items most frequently unfulfilled were the study design, measurement and valuation of costs and outcomes, while CHEERS also identified reporting deficiencies in these aspects. Furthermore, the review highlights subtleties in methodological aspects that may not be discerned by CHEC, such as the estimation of the impact of fluoridation and the inclusion of treatment savings within cost estimates. CONCLUSIONS: While numerous studies were conducted before publication of these assessment instruments, this review reveals that a noteworthy subset of studies exhibited good methodological conduct and reporting quality. There has been a steady improvement in the methodological and reporting quality over time, with recently published EEs largely adhering to best practice guidelines. The evidence presented will assist policymakers in leveraging the available evidence effectively to inform resource allocation decisions. It may also serve as a resource for researchers to enhance the methodological and reporting standards of future EEs of CWF.

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.

A scoping review of the links between early childhood caries and clean water and sanitation: the Sustainable Development Goal 6.

INTRODUCTION: The United Nation's Sustainable Development Goal (SDG) 6 calls for universal access to clean water, sanitation and hygiene (WASH), which are crucial elements of health and well-being and fundamental for a life in dignity. Early childhood caries (ECC) is a preventable disease affecting health and quality of life of millions of young children worldwide. This scoping review aims to explore the connection between ECC and access to clean water and sanitation. METHODS: This scoping review, registered on the Open Science Framework and following PRISMA-ScR guidelines, conducted a thorough search in databases (PubMed, Web of Science, Embase, Google Scholar, SciELO) and websites (via Google) in November 2023. The search, without date limitations, targeted studies in English and Spanish linking ECC to SDG6. Exclusions were made for studies solely focusing on ECC without a direct connection to clean water and sanitation. Descriptive statistics summarized the retrieved papers. RESULTS: The initial search yielded 303 articles. After removing duplicates, 264 articles remained for title and abstract screening after which 244 were excluded and one report was added through citation searching. The 21 remaining articles underwent full text review. There were no studies on a direct association between access to clean water and sanitation and the prevalence of ECC. There were nine studies that showed indirect associations between ECC and access to clean water and sanitation through the links of: water and sanitation access as a marker for poverty (n = 1), water consumption as a feeding practice (n = 4), and the effectiveness of water fluoridation (n = 4). These were used to develop a conceptual model. CONCLUSIONS: While it is conceivable that a direct link exists between ECC and access to clean water and sanitation, the available body of research only offers evidence of indirect associations. The exploration of potential pathways connecting water access to ECC warrants further investigation in future research.

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.

Water fluoridation in Australia: A systematic review.

Water fluoridation is considered a safe and effective public health strategy to improve oral health. This review aimed to systematically summarize the available evidence of water fluoridation in Australia, focusing on the history, health impacts, cost effectiveness, challenges, and limitations. A systematic search was conducted on the Ovid Medline, Web of Science, Scopus, ProQuest Central, Cinahl, and Informit databases to identify literature on water fluoridation in Australia. A grey literature search and backward snowballing were used to capture additional literature. Primary studies, reviews, letters, and opinion papers were included in the quantitative analysis and summarized based on the year of publication and geographical location. The data were extracted from primary studies and summarized under three subheadings: history, community health impacts and the limitations and challenges. Water fluoridation in Australia was first implemented in 1953 in Tasmania. Most states and territories in Australia embraced water fluoridation by 1977 and currently, 89% of the Australian population has access to fluoridated drinking water. Studies report that water fluoridation has reduced dental caries by 26-44% in children, teenagers, and adults, benefiting everyone regardless of age, income, or access to dental care. It has been recognized as a cost-effective intervention to prevent dental caries, especially in rural and low-income areas. Water fluoridation as a public health measure has faced challenges, including political and public opposition, implementation and maintenance costs, access and equity, communication and education, and ethical concerns. Variations in research activities on water fluoridation across Australian states and territories over the last seven decades can be due to several factors, including the time of implementation, funding, and support. Ongoing monitoring and research to review and update optimal fluoride levels in drinking water in Australia is warranted to ensure sustainable benefits on oral health while preventing any adverse impacts.

Oral Health of Women and Children: Progress, Challenges, and Priorities.

INTRODUCTION: Tooth decay remains the most prevalent chronic disease in children and adults, even though it is largely preventable. Studies show that mothers' oral and overall health is linked to children's oral health and pregnancy outcomes. This paper examines achievements during the last 20 years, assesses current challenges, and discusses future priorities. ORAL HEALTH STATUS: Data show a modest improvement in children's oral health during the last 20 years; however, tooth decay still affects more than half of adolescents. According to national survey data, about 26% of working-age adults had untreated tooth decay. Overall, significant oral health disparities by race/ethnicity and income persist. DENTAL SERVICE UTILIZATION: The annual dental visit rate for children in the 2015 Medical Expenditure Panel Survey was 48%. Among children enrolled in Medicaid, dental visit rates increased from 18% in 1993 to nearly 50% in 2018. About 46% of women are estimated to receive teeth cleaning during pregnancy. Over the years, race or ethnicity and income-level differences in dental visits observed in the early 2000s have narrowed substantially in children but not among pregnant women. DISCUSSION: Many effective interventions are available at the community and individual levels but are underutilized. Lack of integration of oral health into the overall health care system and programs, community conditions, poverty, and limited health literacy make it difficult for families to engage in healthy habits, use preventive interventions, and access treatment promptly. CONCLUSION: To further improve oral health, policy and system reforms are needed to address the factors mentioned above. Therefore, we urge the federal Maternal and Child Health Bureau to take steps to convene a workshop to develop a framework for future actions.

Comparative evaluation of fluoride-free remineralization agents with and without Er,Cr:YSGG laser on artificial enamel remineralization.

This study aimed to evaluate the efficacy of fluoride-free remineralizing agents in initial enamel caries, with and without combined Er,Cr:YSGG laser application. The remineralization effect of various agents and their combinations on artificial initial caries was investigated using 10 experimental groups (n = 7): NC, negative control; PC, positive control; TM, calcium-phosphate compounds (CPP-ACP); TD, theobromine-containing toothpaste; RG, ROCS® remineralizing gel; L, Er,Cr:YSGG laser (2780 nm; 0.25 W; repetition rate, 20 Hz; pulse duration, 140 µs; tip diameter, 600 µm; without air/water cooling); L + fluoride toothpaste; L + TM; L + TD; and L + RG. The demineralized bovine enamel specimens were subjected to an 8-day pH cycle by daily application of the remineralizing agents and laser therapy once prior to the pH cycle and paste application. The enamel samples underwent the Vickers surface microhardness test, and one sample per group was analyzed with scanning electron microscopy. The Kruskal Wallis test was used to compare the microhardness recovery percentage (SMHR%) for each group, and multiple comparisons were made with the Dunn test. Groups L (p = 0.003), RG (p = 0.019), L + TM (p < 0.001), L + fluoride toothpaste (p = 0.001),and L + RG (p = 0.036) exhibited significant increase in SMHR%. The tested remineralizing agents exhibited no statistically significant difference in effect when used alone and in combination with Er,Cr:YSGG laser. Combined application of Er,Cr:YSGG laser and ROCS® remineralization gel effectively promoted enamel remineralization, while use of CPP-ACP and fluoride toothpaste alone was ineffective. Theobromine-containing toothpaste exhibited the least SMHR%. Long-term evaluation of these agents is recommended.

Association between low fluoride exposure and children's intelligence: a meta-analysis relevant to community water fluoridation.

OBJECTIVES: Previous meta-analyses have mainly focused on studies conducted in endemic fluorosis areas with relatively high fluoride concentrations. These are impoverished rural communities in China, India, and Iran, and the findings cannot be generalised to developed countries. Therefore, we investigated the association between fluoride concentrations relevant to community water fluoridation and children's cognition measured with IQ scores by synthesising effect sizes reported in observational studies. METHODS: A previous meta-analysis and the National Toxicology Program database that included a search of multiple databases and the authors' search of PubMed, Google Scholar, and Mendeley provided the data. Cross-sectional and cohort studies examining the association between fluoride and children's cognition and intelligence scores were selected. Two reviewers abstracted data using standard procedures. We performed three meta-analyses to synthesise the effects using the random effects models. RESULTS: Eight studies of standardized mean difference in IQ scores from non-endemic fluorosis areas found no statistically significant difference between recommended and lower levels of fluoride (standardized mean difference = 0.07; 95% confidence interval: -0.02, 0.17; I2 = 0%), and no significant fluctuation in IQ scores across the differences in fluoride concentrations by non-linear modeling with restricted cubic spline (P = 0.21). Meta-analyses of children's and maternal spot urinary fluoride associated pooled regression coefficients (Betachildren = 0.16; 95% confidence interval: -0.40, 0.73; P = 0.57; I2 = 0%, Betamaternal = -0.92; 95% CI: -3.29, 1.46; P = 0.45; I2 = 72%) were not statistically significant. Further regression analysis by standardizing absolute mean IQ scores from lower fluoride areas did not show a relationship between F concentration and IQ scores (Model Likelihood-ratio test: P-value = 0.34.) CONCLUSIONS: These meta-analyses show that fluoride exposure relevant to community water fluoridation is not associated with lower IQ scores in children. However, the reported association observed at higher fluoride levels in endemic areas requires further investigation.

Mini-publics in dental public health policymaking.

What are mini-publics and under what circumstances could they be applied to public health dentistry? This question is explored with reference to water fluoridation in England, a policy intervention characterised by a visceral politics that has embedded a systemic preference for non-decision-making. Mini-publics can nevertheless inform decision-making by inviting a representative sample of the affected citizenry to consider the available evidence and come to a set of conclusions and/or recommendations that if all parties cannot agree, none can reasonably object. In doing so, mini-publics have the potential to break the policy deadlock by adding an additional layer of legitimacy to the decision-making process, albeit this is dependent upon decision-makers granting value to their findings.

Access to community water fluoridation in rural Victoria: It depends where you live .

OBJECTIVE: To explore the water fluoridation status of rural Victorian towns over 1000 population and document the oral health profile in the local government areas (LGAs) currently with no water fluoridation. To assist/inform future LGA planning, we describe a case study of a community-based co-design approach to increase access to fluoridated water in rural communities. DESIGN: A descriptive design and a case study. SETTING: Rural Victorian towns over 1000 population. PARTICIPANTS: Twenty-nine LGAs in rural areas. MAIN OUTCOME MEASURE(S): LGA water fluoridation status and oral health profiles. RESULTS: Sixty-six (33%) of the 203 Victorian rural towns with >1000 population, representing 149 251 people, did not have access to fluoridated water. Towns in 29 rural LGAs were included with 62% without water fluoridation with many having higher than the Victorian average of preventable hospital admissions due to dental conditions in children aged 0-9 years. Over 50% of children aged 0-12 years living in these rural nonfluoridated LGAs had above-the-state average rates of decayed, missing and filled teeth (dmft/DMFT). In those aged 0-5 years, this was the highest with 78% above-the-state average. In the case study, meetings were well attended, and the group resolved to lobby for water fluoridation, which was successful. CONCLUSION: Many Victorian rural towns do not have access to fluoridated water. A community-based co-design approach can dispel ill-informed concerns about dangers of water fluoridation to successfully lobby the state government to fluoridate the local water supply.

Costs and benefits of community water fluoridation in remote Aboriginal communities of the Northern Territory.

OBJECTIVE: To undertake an economic evaluation of community water fluoridation (CWF) in remote communities of the Northern Territory (NT). DESIGN: Dental caries experiences were compared between CWF and non-CWF communities before and after intervention. Costs and benefits of CWF are ascertained from the health sector perspective using water quality, accounting, oral health, dental care and hospitalisation datasets. SETTING AND PARTICIPANTS: Remote Aboriginal population in the NT between 1 January 2008 and 31 December 2020. INTERVENTION: CWF. MAIN OUTCOME MEASURES: Potential economic benefits were estimated by changes in caries scores valued at the NT average dental service costs. RESULTS: Given the total 20-year life span of a fluoridation plant ($1.77 million), the net present benefit of introducing CWF in a typical community of 300-499 population was $3.79 million. For each $1 invested in CWF by government, the estimated long-term economic value of savings to health services ranged from $1.1 (population ≤300) to $16 (population ≥2000) due to reductions in treating dental caries and associated hospitalisations. The payback period ranged from 15 years (population ≤300) to 2.2 years (population ≥2000). CONCLUSIONS: The economic benefits of expanding CWF in remote Aboriginal communities of NT outweigh the costs of installation, operation and maintenance of fluoridation plants over the lifespan of CWF infrastructure for population of 300 or more.

Salt Metathesis: Tetrafluoroborate Anion Rapidly Fluoridates Organoboronic Acids to give Organotrifluoroborates.

Tetrafluoroborate (BF4 - ) has long been used as a spectator counter anion. Herein, we report an unprecedented salt metathesis between a variety of BF4 - salts and a series of organoboronic acids yielding the corresponding organotrifluoroborates. We identified conditions for fast and efficient fluoridation (<1 h) with minimal workup. Fundamentally, this work discloses the proclivity of BF4 - to exchange fluoride atoms with organoboronates, highlighting the lability of BF4 - .

Fluoride alters feeding and memory in Lymnaea stagnalis.

Fluoride occurs naturally in the terrestrial and aquatic environment and is a major component in tea. Prolonged fluoride exposure alters metabolic activity in several aquatic invertebrates. For the first time, we investigated the effects of fluoride on cognition in the pond snail Lymnaea stagnalis as it is capable of a higher form of associative learning called configural learning. We first showed suppressive effects of black tea and fluoride on feeding (i.e., rasping) behavior. We then investigated how fluoride may alter cognition by introducing fluoride (1.86 mg/L) before, during, after, a day before and a week before the snails underwent the configural learning training procedure. Our results show that any 45-min exposure to fluoride (before, during or after a configural learning training procedure) blocks configural learning memory formation in Lymnaea and these effects are long-lasting. One week after a fluoride exposure, snails are still unable to form a configural learning memory and this result is upheld when the snails are exposed to a lower concentration of fluoride, one which is naturally occurring in ponds that a wild strain of Lymnaea can be found (0.3 mg/L). Thus, fluoride obstructs configural learning memory formation in a fluoride-naïve, inbred strain of Lymnaea.

Effectiveness of the engineered pinecone-derived biochar for the removal of fluoride from water.

Drinking fluoride (F-)-contaminated water (>1.5 mg L-1) causes severe dental and skeletal disorders. In the central province of Pakistan, ∼20 times higher levels of F- in the drinking groundwater (compared with the 1.5 mg L-1 permissible limit of the World Health Organization) are triggering bone abnormalities in teenagers. In this study, we demonstrated the potential of pinecone-derived biochar (pristine) impregnated with Fe- and Al-salts (engineered) to defluoridate water. Batch mode adsorption experiments were carried out under variable conditions of solution pH, F- initial concentration, adsorbent dose, and contact time. The engineered biochars resulted in greater adsorption than that of pristine biochar. Specifically, the AlCl3-modified biochar exhibited a maximum adsorption capacity of 14.07 mg g-1 in spiked water and 13.07 mg g-1 in in-situ groundwater. The equilibrium isothermal and kinetic models predicted monolayer, cooperative, and chemisorption types of the adsorption process. The chemical interaction and outer-sphere complexation of F- with Al, Na, and H elements were further confirmed by the post-adsorption analysis of the AlCl3-modified biochar by FTIR and XRD. The AlCl3-modified biochar resulted in 87.13% removal of F- from the in-situ F--contaminated groundwater, even in the presence of naturally occurring competing ions (such as Cl-, HCO3-, SO42-, and NO3-). We conclude that the AlCl3-modified biochar derived from pinecone could be a promising cost-effective adsorbent for the defluoridation of water.

Who are the 10%? Characteristics of the populations and communities receiving fluoridated water in England.

OBJECTIVES: In England, around 10% of the population receive optimally fluoridated water. This coverage has evolved through a combination of historical local decision-making and natural geography, rather than being strategically targeted at the national level. It is important to understand if the current distribution is equitable according to indicators of oral health need and to identify any population-level differences in socio-demographic characteristics that could introduce bias to studies evaluating the effectiveness of water fluoridation. BASIC RESEARCH DESIGN: Descriptive analysis comparing the census characteristics of populations that received optimally fluoridated (=/⟩ 0.7 mg F/L) and non-fluoridated water (⟨0.7 mg F/L) between 2009 and 2020. RESULTS: Populations receiving fluoridated water between 2009-2020 were on average slightly younger, more urban, more deprived, with lower education levels, higher unemployment and lower car and home ownership than the populations who received non-fluoridated water. They are more ethnically diverse, with a higher proportion of Asian ethnicity and a lower proportion of White ethnicity, compared to the non-fluoridated population. DISCUSSION: This descriptive analysis provides evidence that water fluoridation coverage within England is targeted reasonably equitably in relation to population-level indicators of need. It also confirms the need to consider the impact of underlying differences in age, deprivation, rurality, and ethnicity when evaluating the impact of water fluoridation on health outcomes in England.

Water fluoride concentrations in England, 2009-2020.

OBJECTIVES: Contemporary research, surveillance and monitoring of water fluoridation requires an understanding of the population coverage of this intervention. The aims of this research are to create the first publicly available record of water fluoride concentrations in England and to describe and visualise the observed variation in water fluoride concentrations and optimal fluoridation (⟩/= 0.7 mg F/L) between 2009-2020. BASIC RESEARCH DESIGN: Routine water quality sampling data were requested from water companies in England from 2009-2020 under the provisions of the Environmental Information Regulations 2004. Fluoride concentrations of Water Supply Zones (WSZs) were assigned to Lower Super Output Areas (LSOAs) using population-weighted centroids. RESULTS: Between 2009-2020 4247 LSOAs (12.9%) had an annual mean water fluoride concentration of ⟩/= 0.7 mg F/L in at least one year, and 3019 LSOAs (9.1%) had a grand mean fluoride concentration of ⟩/= 0.7 mg F/L. Coverage of optimal fluoridation varied over time; from 10.9% of LSOAs in 2014 to 6.3% in 2016. DISCUSSION: This study confirms previous work identifying variability in the coverage and achieved concentrations of water fluoridation programmes. The current provision for accessing, collating and utilising these data are a barrier to essential monitoring, surveillance and research. An annually maintained and publicly accessible database of water fluoride concentrations is urgently required.

Effectiveness of water fluoridation in an upper-middle-income country: A systematic review and meta-analysis.

AIM: To summarize the information on the effectiveness of community water fluoridation (CWF) on the reduction of dental caries in the context of the wide use of fluoridated toothpaste in Brazil. DESIGN: A systematic review was conducted regarding the effect of CWF based on studies with Brazilian population groups using the following electronic databases: MEDLINE/PubMed, LILACS, SciELO, and SCOPUS. The literature search was conducted up to August 2019. Studies that compared caries experience in at least two areas, one fluoridated and the other non-fluoridated, by mean dmft/DMFT (decayed, missing, and filled teeth) index or caries prevalence (caries vs. caries-free) were included. Considering the beginning of widespread use of fluoride dentifrice and the time for producing dental caries decline, studies published before 1995 were excluded. Descriptive analysis and meta-analyses were carried out. The effect size was measured by mean difference for dmft and DMFT ± SD and odds ratios on a logarithmic scale for caries prevalence. RESULTS: Of the 574 studies retrieved, 16 and 10 were included in the qualitative and quantitative analysis, respectively. Fluoridated areas exhibited lower mean dmft/DMFT than non-fluoridated areas did. The mean difference in the dmft between non-fluoridated and fluoridated areas was -2.28 (95% CI -3.26; -1.30) for children aged 5-8 years and -1.12 (95% CI -1.93; -0.32) for those aged 3-12 years; the mean difference in the DMFT was -0.61 (95% CI -0.80; -0.42) for the children aged between 7 and 12 years. The caries prevalence was 1.4 times and 57% lower, respectively, at primary and permanent dentition in fluoridated areas. Heterogeneity was observed in all age groups, ranging from 77.6% to 98.2%. CONCLUSION: Community water fluoridation remains effective in preventing dental caries in children younger than 13 years, even with the widespread use of fluoridated toothpaste.

Critical windows of fluoride neurotoxicity in Canadian children.

BACKGROUND: Fluoride has been associated with IQ deficits during early brain development, but the period in which children are most sensitive is unknown. OBJECTIVE: We assessed effects of fluoride on IQ scores across prenatal and postnatal exposure windows. METHODS: We used repeated exposures from 596 mother-child pairs in the Maternal-Infant Research on Environmental Chemicals pregnancy and birth cohort. Fluoride was measured in urine (mg/L) collected from women during pregnancy and in their children between 1.9 and 4.4 years; urinary fluoride was adjusted for specific gravity. We estimated infant fluoride exposure (mg/day) using water fluoride concentration and duration of formula-feeding over the first year of life. Intelligence was assessed at 3-4 years using the Wechsler Preschool and Primary Scale of Intelligence-III. We used generalized estimating equations to examine the associations between fluoride exposures and IQ, adjusting for covariates. We report results based on standardized exposures given their varying units of measurement. RESULTS: The association between fluoride and performance IQ (PIQ) significantly differed across prenatal, infancy, and childhood exposure windows collapsing across child sex (p = .001). The strongest association between fluoride and PIQ was during the prenatal window, B = -2.36, 95% CI: -3.63, -1.08; the association was also significant during infancy, B = -2.11, 95% CI: -3.45, -0.76, but weaker in childhood, B = -1.51, 95% CI: -2.90, -0.12. Within sex, the association between fluoride and PIQ significantly differed across the three exposure windows (boys: p = .01; girls: p = .01); among boys, the strongest association was during the prenatal window, B = -3.01, 95% CI: -4.60, -1.42, whereas among girls, the strongest association was during infancy, B = -2.71, 95% CI: -4.59, -0.83. Full-scale IQ estimates were weaker than PIQ estimates for every window. Fluoride was not significantly associated with Verbal IQ across any exposure window. CONCLUSION: Associations between fluoride exposure and PIQ differed based on timing of exposure. The prenatal window may be critical for boys, whereas infancy may be a critical window for girls.