Do missing teeth cause early-onset cognitive impairment? Re-examining the evidence using a quasi-natural experiment

PURPOSE

Multiple studies have reported a positive association between missing teeth and cognitive impairment. While some authors have postulated causal mechanisms, existing designs preclude assessing this.

METHODS

We sought evidence of a causal effect of missing teeth on early-onset cognitive impairment in a natural experiment, using differential exposure to fluoridated water during critical childhood years (ages 5-20 years) in England as the instrument. We coded missing teeth from 0 (≤ 12 missing) to 3 (all missing) and measured the association with cognitive impairment in the English Longitudinal Study of Ageing data (2014-5), covering 4958 persons aged 50-70 years.

RESULTS

We first replicated previous evidence of the strongly positive association of missing teeth with cognitive impairment (β = 0.25 [0.11, 0.39]), after adjusting for socio-demographic covariates, such as age, gender, education, and wealth. Using an instrumental variable design, we found that childhood exposure to water fluoridation was strongly associated with fewer missing teeth, with being exposed to fluoridated water during childhood (16 years) associated with a 0.96 reduction in the missing teeth scale (β = - 0.06 [- 0.10, - 0.02]). However, when using the instrumented measure of missing teeth, predicted by probability of fluoride exposure, we found that missing teeth no longer had an association with cognitive impairment (β = 1.48 [- 1.22, 4.17]), suggesting that previous oral health-cognitive impairment associations had unobserved confounding.

CONCLUSIONS

Our findings are consistent with the possibility that unobserved confounding leads to the oft-observed association between missing teeth and early-onset cognitive impairment, suggesting that the relationship is spurious rather than causal.

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.

Caries prevalence and water fluoridation in Israel: a cross-sectional study

OBJECTIVES

To assess the effect of Community Water Fluoridation (CWF) in the prevalence of dental caries and dental fluorosis in 12-year-old children living in Israel. Considering that CWF is important in the prevention of dental caries. Between 2002 and 2014, the water in communities of at least 5,000 individuals was fluoridated. In 2014, CWF in Israel stopped.

METHOD AND MATERIALS

Data on 12-year-old children from all areas in Israel from the national cross-sectional epidemiological survey conducted in 2011 to 2012 were stratified by city water fluoridation and by city and school socioeconomic status. Two dependent variables were defined: (1) DMFT index of caries experience in the permanent dentition; (2) dental fluorosis in central incisors using the Thylstrup-Fejerskov classification of fluorosis.

RESULTS

Data from 2,181 12-year-olds were analyzed. The average DMFT was 1.17 ± 1.72, and 49% were caries-free. Based on DMFT, the caries experience was significantly higher in nonfluoridated cities (1.38 vs 0.98 in fluoridated cities) and there were more caries-free children in fluoridated cities (56.4% vs 40.6% in nonfluoridated). DMFT was higher in cities with lower socioeconomic status than high socioeconomic status (1.29 vs 1.05, respectively, P < .001) and there were fewer caries-free children in low socioeconomic status cities (44.5% vs 53.0% in high socioeconomic status cities, P < .0001). Almost all the 10.3% of children with signs of fluorosis (scoring at least 1 in the Thylstrup-Fejerskov index), had questionable to mild fluorosis (9.3%).

CONCLUSIONS

CWF is a cheap, simple method of dental health protection that reaches all socioeconomic levels, and cessation of water fluoridation reduced the health of Israel's children.

CLINICAL SIGNIFICANCE

Water fluoridation provides substantial caries prevention, by reaching a substantial number of people. The relevance of this work is for policymakers to consider CWF as clinically proven method for reducing health inequalities.

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.

Dental caries in children in Ireland: A systematic review

BACKGROUND

Dental caries is the most common childhood disease worldwide. In the mid-1960s, mandatory Community Water Fluoridation (CWF) was introduced in the Republic of Ireland (RoI) aimed at reducing the prevalence and severity of dental caries in the population. In 2017, approximately, 71% of the Irish population was supplied with fluoridated drinking water.

OBJECTIVES

To review all children's dental health surveys at National, Regional and County-levels conducted in the Republic of Ireland from 1950 to 2021 and describe trends in dental caries prevalence. The secondary objective was to compare dental caries experience in children living in areas with and without CWF.

METHODS

Seven databases (Embase, Medline Ovid, PubMed, Cochrane, Web of Science, Scopus and Lenus Ireland) were systematically searched followed by lateral searches from reference lists. Studies reporting the caries experience of Irish children were eligible for inclusion. Two authors independently evaluated the quality of included studies using the Joanna Briggs Institute Critical Appraisal Checklist.

RESULTS

Thirty-one studies were included. Over the last 70 years, at National, Regional and County levels, mean dmft/DMFT (decayed, missing and filled teeth) scores have decreased and the percentage of caries-free children has increased in 5, 8, 12, and 15-year-olds. The decline in dental caries indices observed throughout the country was greater in children living in areas with CWF. Between the 1960s and 2002, the mean dmft scores for 5-year-olds living in the RoI were reduced by approximately 82% and 69% for the fluoridated and non-fluoridated groups respectively. Reduction in the mean DMFT scores for the 12-year-olds were 75% and 71%, respectively, for the fluoridated and non-fluoridated groups. Between 1961 and 2014, reductions in the mean dmft/DMFT scores among 5 and 12-years-olds living in County Dublin were approximately 88% and 90% respectively. These results should be interpreted in the context of widespread use of fluoridated toothpaste in the RoI.

CONCLUSIONS

Large reductions in the prevalence of dental caries in Irish children have been observed over the last seven decades. Greater dental caries reductions have been reported among children living in areas with CWF compared to those without CWF.

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.

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.

Risk Communication in Public Health: Lessons from a Historic Fluoridation Debate in Saskatchewan

Effective risk communication is critical to gain public support when implementing population-level health interventions. Analysis of previous public health campaigns can provide guidance for future efforts. This case study examined a successful community water fluoridation campaign in Saskatoon, Canada, during 1953/54. The key strategies and messaging used by both sides of the debate were assessed using two publicly available historic data sources: documents in the city archives and newspaper coverage. The anti-fluoridation campaign approaches (e.g. misinformation, innuendo, half-truths and scare words, requesting a plebescite) were similar to those used elsewhere by this movement as described in the literature. Key features of the effective pro-fluoridation campaign included extensive community outreach, involvement of local experts, dissemination of supporting evidence while aggressively addressing misinformation, highlighting the support of relevant health organizations, and ensuring key messages received media coverage. This study illustrates how misinformation and public opposition has posed a challenge to public health efforts long before the advent of social media and highlights strategies, consistent with current risk communication principles, that have stood the test of time.

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.

Community Water Fluoridation in Focus: A Comprehensive Look at Fluoridation Levels across America

Objective: This study reports on the number and percentage of community water systems (CWSs) meeting fluoride concentration standards set by the U.S. Department of Health and Human Services (DHHS). The study also explored changes in the population exposed to optimally fluoridated water in these systems between 2006 and 2020. Methods: This study analyzed U.S. Centers for Disease Control and Prevention data from 2006 to 2020, tabulating state-specific CWS fluoridation rates, ranking them, and calculating the percent change. Results: In 2020, 72.7% of the US population received CWS water, with 62.9% of those individuals served by a CWS system meeting DHHS fluoridation standards. This compares to 69.2% receiving CWS water in 2006 and 74.6% in 2012. The overall change in those receiving fluoridated water was 1.4%, from 61.5% in 2006 to 62.9% in 2020. State-specific percentages ranged from 8.5% in Hawaii to 100% in Washington DC in 2020 (median: 76.4%). Conclusions: Although endorsed by the American Dental Association, the percentage of individuals receiving fluoridated water did not increase substantially from 2006 to 2020, indicating that there has not been much progress toward meeting the Healthy People 2030 goal that 77.1% of Americans receive water with enough fluoride to prevent tooth decay.

Masking-efficacy and caries arrestment after resin infiltration or fluoridation of initial caries lesions in adolescents during orthodontic treatment-A randomised controlled trial

OBJECTIVES

The aim of this randomised, controlled, split-mouth trial was to assess the masking results in initial caries lesions (ICL) that were either resin infiltrated or fluoridated during treatment with fixed orthodontic appliances.

METHODS

Adolescent patients (age range:12-18years) with fixed orthodontic appliances who had developed ICL [ICDAS 1 or 2 (International Caries Detection and Assessment System)] during orthodontic treatment were consecutively recruited and randomly assigned to either resin infiltration with up to 3 etching procedures (Group:Inf) or to 3-monthly application of a fluoride varnish (Group:FV). Both interventions were performed according to the manufacturer's recommendations. Primary and secondary outcomes (ΔE, ICDAS, DIAGNOdent) included the evaluation of the appearance of the ICL before (T0), 1 week after (T1) treatment and at the last appointment before debonding (T2).

RESULTS

Fifteen patients (8females, 7males) with 57ICL were included. Mean (SD) observation time at the last appointment before debonding was 0.5 (0.3) years. At T0 FV and Inf did not differ significantly in ΔE (median ΔE0,FV(25th/75th percentiles):11.6 (8.7/20.3): ΔE0,Inf:15.1 (11.4/19.5); pT0 = 0.135), ICDAS (pT0 = 0.920) and DD (pT0 = 0.367). At T1 and T2 ΔE values (pT1<0.001, pT2<0.001), ICDAS scores (pT1<0.001, pT2<0.001) and DIAGNOdent values (pT1 = <0.001, pT2 = <0.001) for Inf were significantly reduced whereas ΔE values (pT1 = 0.382, pT2 = 0.072) and ICDAS scores (pT1 = 0.268, pT2<0.001) for FV remained unchanged.

CONCLUSIONS

Resin infiltration effectively masked ICL during treatment with fixed orthodontic appliances both immediately after application and at the last appointment before debonding. Furthermore, the visual appearance of fluoridated lesions was not as satisfactory as that of the infiltrated ones at both T1 and T2.

CLINICAL SIGNIFICANCE

Resin infiltration effectively masked ICL during treatment with fixed orthodontic appliances both immediately after application and at the last appointment before debonding. Furthermore, the visual appearance of fluoridated lesions was not as satisfactory as that of the infiltrated ones immediately after first application as well as half a year after application.

TRIAL REGISTRATION

German Clinical Trials Register (DRKS-ID: DRKS00011797).

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.

Fluoride hesitancy: A mixed methods study on decision-making about forms of fluoride

OBJECTIVES

To investigate whether professionally applied topical fluoride-hesitant caregivers are also hesitant about other forms of fluoride for their child.

METHODS

This was a mixed methods study of 56 caregivers hesitant about professionally applied topical fluoride for their child recruited from the University of Washington Center for Paediatric Dentistry and Seattle Children's Hospital's Odessa Brown Children's Dental Clinic. A 32-item semi-structured interview script was piloted and finalized. One-time interviews with caregivers were conducted by phone in 2019. Associations between hesitancy of topical fluoride, fluoridated water and toothpaste were assessed quantitatively via two-tailed chi-squared tests. Qualitative data were coded using an inductive approach and content analytic methods to investigate reasons for hesitancy.

RESULTS

There were significant associations between hesitancy in all three pairwise comparisons of fluoride form (p < .01). Similar proportions of caregivers strongly or somewhat opposed fluoridated water compared with toothpaste (75% and 65%, respectively), but four times as many caregivers strongly or somewhat favoured fluoridated toothpaste compared to water for their child (25% and 7%, respectively). Concerns about harm were the most common reason caregivers opposed both fluoridated water and toothpaste. However, fluoride-hesitant caregivers reported being more comfortable with fluoridated toothpaste because amount and frequency can be controlled, and ingestion can be prevented.

CONCLUSIONS

Professionally applied topical fluoride hesitancy is significantly associated with fluoridated water and toothpaste hesitancy, but caregivers who were hesitant about topical fluoride was more comfortable with fluoridated toothpaste than fluoridated water for their child.

Community Water Fluoridation and Rate of Pediatric Fractures

BACKGROUND

The effect of community water fluoridation on bone fragility and fracture has been inconclusive in the literature. The null hypothesis of this study was that no association was observed between water fluoride level and risk of fracture in children.

METHODS

Community fluoridation data were obtained from the Centers for Disease Control and Prevention while data on fracture rates were obtained from the PearlDiver database. The rate of fracture type for each state was then compared with state-level fluoridation data using Pearson correlation coefficients and Wilcoxon rank-sum tests.

RESULTS

Positive correlations were found between the percentage of state water fluoridation and fracture rates for both bone forearm fracture (BBFFx) and femur fracture. Fluoride levels had positive correlations with fracture rates for all fracture types. Increased fracture rates were found between states in the highest quartiles of percentage of state water fluoridation and fluoride water levels for supracondylar humerus fracture and BBFFx.

CONCLUSIONS

A higher level of water fluoridation was associated with higher rates of supracondylar humerus fracture and BBFFx in children aged 4 to 10 years. These findings do not imply causality, but they suggest that additional investigation into the effect of fluoride on pediatric bone health may be indicated.

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.

Effect of CDC adjustment of state-reported data on community water fluoridation statistics

OBJECTIVES

Advancing community water fluoridation (CWF) coverage is a national health objective. The Centers for Disease Control and Prevention began adjusting state-reported data to calculate CWF coverage in 2012, and then modified methods in 2016. We evaluate improvements attributable to data adjustment and implications for interpreting trends.

METHODS

To assess adjustment, we compared the percentage deviation of state-reported data and data adjusted by both methods to the standard estimated by the U.S. Geological Survey. To assess effects on estimated CWF trends, we compared statistics calculated with data adjusted by each method.

RESULTS

The 2016 method outperformed on all points of evaluation. The CWF national objective measure (percentage of community water system population receiving fluoridated water) was negligibly affected by method. Percentage of US population receiving fluoridated water was lower with the 2016 method versus the 2012.

CONCLUSIONS

Adjustment of state-reported data improved overall quality of CWF coverage measures and had minimal impact on key measures.

Exploring online oral health misinformation: a content analysis

Considering the unfavorable implications of health falsehoods and the lack of dental research into information disorder, this study aimed to identify and characterize online oral health misinformation. A total of 410 websites published in English were retrieved using Google Advanced Search and screened by two independent investigators to compile falsehoods through thematic content analysis. Afterward, 318 pieces of misinformation were consensually divided into four groups concerning their informational interest (G1), financial, psychological, and social interests produced/disseminated by non-dental professionals (G2) or by dental professionals (G3), and political interests (G4). Social media (Facebook and Instagram) and fact-checking tool (Snopes) were also screened to determine the spread of falsehoods by identifying corresponding posts and warnings. As a result, misinformation was mainly associated with gum diseases (12.0%), root canal treatment (11.6%), toothache (10.4%), fluoride (10.4%), and dental caries (9.8%), with a special highlight on recommendations for the usage of natural products, toxicity concerns, and anti-fluoridation propaganda. Additionally, most misinformation was allocated in G3 (41.9%), which presented a statistically higher frequency of financial interests than G4. Finally, falsehoods were considerably identified on Facebook (62.9%) and Instagram (49.4%), especially G3 and G4. Nevertheless, Snopes has debunked only 5.9% of these content items. Therefore, misinformation was predominantly produced or disseminated by dental professionals mainly motivated by financial interests and usually linked to alternative/natural treatments. Although these items were shared on social media, fact-checking agencies seemed to have limited knowledge about their dissemination.

Dissemination and implementation research for oral and craniofacial health: Background, a review of literature and future directions

Oral conditions are highly prevalent globally and have profound consequence on individuals and communities. Clinical (e.g. dental treatments, behavioural counselling) and non-clinical (e.g. community-based programming, water fluoridation, oral health policy) evidence-based interventions have been identified, recommended and applied at the clinic, community and policy levels. Still, the burden of oral conditions persists, with inequitable distribution across populations. A major driver of this lack of progress is poor translation of research findings, which results in an evidence-to-practice gap. Dissemination and implementation science (DIS) has emerged to address this gap. A relatively new field, application of DIS represents an important avenue for achieving good dental, oral and craniofacial health for all. The goal of this introductory article is to provide a brief background on DIS relevant to researchers in dentistry and oral health. The problem of knowledge translation, basic concepts and terminology in DIS, and approaches to doing dissemination and implementation research-including implementation strategies, key outcomes, and implementation theories, models and frameworks-are discussed. Additionally, the article reviews literature applying DIS to dentistry and oral health. Results of published studies and their implications for the field are presented. Drawing on the literature review and contemporary thinking in DIS, current gaps, opportunities and future directions are discussed. Resources for understanding and applying DIS are provided throughout. This article serves as a primer on DIS for dental and oral health researchers of all types working across a range of contexts; it also serves as a call to action for increased application of DIS to address the burden of oral conditions globally.

Public Policies for Fluoride Use in Colombia and Brazil before and during the Adoption of the Right to Health

The use of fluorides is essential in the prevention of dental caries, considered to be the main dental public health problem. The formulation and implementation of public health policies can vary from country to country, depending on multiple factors. This study aims to analyze the interaction model between the knowledge produced about the use of fluorides and its implementation through public policies in two South American countries until the period of constitutional reform in each country. A narrative review was conducted with a systematic search of scientific articles and normative devices regarding the use of fluorides in public health in each country during the period prior to the implementation of the right to health in the Constitution. In both countries, there was an intense interaction among governmental organizations, researchers, academic and professional leaders, and companies involved in sanitation and salt production. Fluoride use strategies in Brazil and Colombia after an initial stage of similar characteristics began to differ in terms of public policy options for systemic fluoride use. In Brazil, the option was to adjust the concentration of fluoride in the water, while in Colombia, the addition of fluoride to table salt was consolidated as a public policy.

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.

Role of renal function in the association of drinking water fluoride and plasma fluoride among adolescents in the United States: NHANES, 2013-2016

CONTEXT

While fluoride has been added to drinking water and dental products for decades in order to prevent tooth decay, there are growing concerns about its potential toxicity. Given that fluoride is primarily excreted in urine, an important question that has not been examined is whether among those whose drinking water is fluoridated, impaired renal function is associated with higher levels of circulating fluoride.

OBJECTIVE

To examine the association between drinking water and plasma fluoride and its modification by renal function.

DESIGN, SETTING, AND PARTICIPANTS

Participants in the National Health and Nutrition Examination Survey (NHANES) between 2013 and 2016 with measures of fluoride in plasma and drinking water and renal function. These measures were only available in adolescent age 12-19 years.

OUTCOMES

Plasma fluoride levels and their modification by strata of renal function, measured by the estimated glomerular filtration rate (eGFR).

RESULTS

Among 1841 healthy adolescents, a 10 ml/min/1.73 m (Penman et al., 1997) lower eGFR and a 1 mg/L higher drinking water fluoride concentration were associated with a 0.02 (95%CI -0.02, -0.03) umol/L and 0.23 (95%CI 0.15,0.30) umol/L higher adjusted plasma fluoride level, respectively. The association of water and plasma fluoride levels was most robust among those with lower renal function (multiplicative interaction p value < 0.001). For adolescents in the lowest eGFR quartile, a 1 mg/L higher drinking water fluoride concentration was associated with a 0.35 (95%CI 0.21,0.48) umol/L higher plasma fluoride level, compared to 0.20 (95%CI 0.14,0.26) umol/L in the highest eGFR quartile. Restriction to those with measurable plasma fluoride levels yielded similar results.

CONCLUSIONS

Water fluoridation results in higher plasma fluoride levels in those with lower renal function. How routine water fluoridation may affect the many millions of Americans with Chronic Kidney Disease, who are particularly susceptible to heavy metal and mineral accumulation, needs to be further investigated.

Fluoroacetate distribution, response to fluoridation, and synthesis in juvenile Gastrolobium bilobum plants

Like angiosperms from several other families, the leguminous shrub Gastrolobium bilobum R.Br. produces and accumulates fluoroacetate, indicating that it performs the difficult chemistry needed to make a C-F bond. Bioinformatic analyses indicate that plants lack homologs of the only enzymes known to make a C-F bond, i.e., the Actinomycete flurorinases that form 5'-fluoro-5'-deoxyadenosine from S-adenosylmethionine and fluoride ion. To probe the origin of fluoroacetate in G. bilobum we first showed that fluoroacetate accumulates to millimolar levels in young leaves but not older leaves, stems or roots, that leaf fluoroacetate levels vary >20-fold between individual plants and are not markedly raised by sodium fluoride treatment. Young leaves were fed adenosine-¹³C-ribose, ¹³C-serine, or ¹³C-acetate to test plausible biosynthetic routes to fluoroacetate from S-adenosylmethionine, a C₃-pyridoxal phosphate complex, or acetyl-CoA, respectively. Incorporation of ¹³C into expected metabolites confirmed that all three precursors were taken up and metabolized. Consistent with the bioinformatic evidence against an Actinomycete-type pathway, no adenosine-¹³C-ribose was converted to ¹³C-fluoroacetate; nor was the characteristic 4-fluorothreonine product of the Actinomycete pathway detected. Similarly, no ¹³C from acetate or serine was incorporated into fluoroacetate. While not fully excluding the hypothetical pathways that were tested, these negative labeling data imply that G. bilobum creates the C-F bond by an unprecedented biochemical reaction. Enzyme(s) that mediate such a reaction could be of great value in pharmaceutical and agrochemical manufacturing.

The Use of Fluorides in Public Health: 65 Years of History and Challenges from Brazil

Untreated dental caries is the most common disease globally and fluoride use at the population level is crucial for its control. To investigate the economic and political conditions under which the trajectory of population-based fluoride use has occurred is key for a more comprehensive view on its current and future challenges. The objective was to give a brief history and summarize the information on the use of fluorides at the population level in Brazil from 1952 to 2017 and to point to current and future challenges. A critical overview was undertaken based on country-level analyses comprising political and economic conditions. The analytical approach adopted a set of premises applicable to the study of capitalist democracies. Fluoride methods of systemic and topic use began to be employed in Brazilian public health programs in the 1950s and in a combined way from 1974. Differences in political and economic contexts were highlighted for four periods: the first interventions from 1952 to 1974, when the fluoridated water law was approved; the expansion after 1974 until 1988, when a new constitution was enacted; the following time until 2010; and the final period. From the 1980s to 2008, water fluoridation coverage increased progressively, consolidating as a major strategy of systemic use in spite of inequalities among territories. Activities aimed to promote access to topical fluoride use increased and maintained stability until 2014, when they dropped sharply. Regulation of fluoride dentifrice's quality remained insufficient. It was hypothesized that the strengthening of conservative liberalism and the increase in fiscal austerity observed in recent years might produce serious constraints on public investment and limit access to fluorides. To reduce inequities and promote benefits for all, including the most vulnerable groups, policies based on egalitarian and social justice theoretical perspectives are needed more than ever.

A Scopus-Based Bibliometric Analysis of Global Research Contributions on Milk Fluoridation

Fluoridated-milk schemes have been developed and implemented in many countries to prevent dental caries. This study aimed to evaluate the impact/influence of scientific publications, researchers, and institutions conducting research on milk fluoridation; to explore the international and inter-institutional collaboration and illustrate scientific output trends; and to pinpoint research hotspots in milk fluoridation research. This bibliometric analysis of original research articles on milk fluoridation includes all of the original articles published in peer-reviewed journals systematically extracted from the SCOPUS database. In total, 108 articles were included in this study, with a total of 11,789 citations. A majority (67.6%) of these articles were in the subject area of ‘dentistry’, 22.2% externally funded, 14.8% published in the journal, Caries Research, 7.4% authored/co-authored by Twetman S, 6.5% by authors from Universidad de Chile, and the UK had the highest output (24.1%). The network visualizations showed that those countries with current/past histories of implemented milk fluoridation programs were interconnected on the network visualization map, and they were predominantly the hotspots for original research on milk fluoridation. This study also identified inequalities in research outputs on the topic. With the current enormous global burden of dental caries in children, particularly in low- and middle-income countries, there is an urgent need for greater and more equitable funding of milk fluoridation research globally.

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.

Mothers' Sources of Child Fluoride Information and Misinformation From Social Connections

IMPORTANCE

Fluoride delivered either topically (eg, fluoride varnish) or systemically (eg, water fluoridation, prescription fluoride supplements) is widely used as a caries preventive agent in children. The widespread existence of misinformation, including inaccurate information that attaches negative values or suspicion to fluoride treatments, raises concerns that misinformation will lead to underutilization of fluoride and contribute to avoidable increases in caries prevalence.

OBJECTIVE

To describe the social relationships from which mothers obtain child fluoride information and misinformation.

DESIGN, SETTING, AND PARTICIPANTS

This qualitative study analyzed 126 mothers with children aged 3 to 5 years to explore how their social networks were associated with their child's oral health. Mothers were recruited from community-based sites in Pittsburgh, Pennsylvania, and throughout the state of West Virginia from 2018 to 2020. In-person, semi-structured qualitative interviews were conducted. Data were transcribed, coded, and analyzed using Nvivo 12. Three investigators analyzed data using template analysis, a qualitative technique that combines inductive and deductive approaches to identify patterns until primary themes are identified.

MAIN OUTCOMES AND MEASURES

Sources of information regarding fluoride from the mother's social relationships.

RESULTS

Of the 126 mothers with children aged 3 to 5 years in Pittsburgh and West Virginia, 120 (95%) identified as non-Hispanic White and 5 (4%) identified as Hispanic White; 38 (30%) had a bachelor's degree, 77 (61%) had private dental insurance for their child, and 52 (41%) had an income less than $50 000; 82 (65%) reported that they discussed child fluoride information with members of their social network. Mothers described that they obtained fluoride information from family members, health care clinicians, and community members. The receipt of inconsistent child fluoride information from multiple sources resulted in confusion and difficulty assessing whether fluoride information was accurate.

CONCLUSIONS AND RELEVANCE

This qualitative study found that mothers received inconsistent child fluoride information from multiple sources, which resulted in confusion and difficulty assessing the accuracy of the fluoride information. These findings suggest that social relationships can be a potential target for interventions to communicate fluoride information related to children.

The Dental Fluoridation Potential of Drinking Water

Water fluoridation is commonly cited as one of the greatest health achievements of the 20th century because of its effectiveness in reducing the incidence of dental caries. Despite the breadth of research on the subject, little is known about how variation in the composition of municipal water may affect the uptake of fluoride by tooth enamel. This study addressed this issue by developing a model system for testing fluoride uptake into hydroxyapatite, the primary mineral of tooth enamel, to investigate how varying water composition influences fluoride uptake. The tested water variables included the pH and degree of water hardness. A representative experiment involving several municipal water sources then examined how this approach can be used to measure fluoride uptake from any sample of drinking water. Aside from an optimal pH of 6 to 7 for fluoride uptake, there was a remarkable constancy to the uptake of fluoride by hydroxyapatite from the many water samples evaluated. These findings, therefore, suggest that for a given individual's personal history, any observed variation in enamel fluoridation is less likely to be the result of variation in the composition and geographical source of the fluoridated water and more likely a consequence of individual behavioral and biological factors that conceivably affect fluoride uptake into tooth enamel.

The Impact of Water Fluoridation on Medicaid-Eligible Children and Adolescents in Alaska

Juneau, Alaska, ceased community water fluoridation (CWF) in 2007, and previous research found a substantial increase in dental caries-related procedures and treatment costs for children from low-income families in Juneau between 2003 and 2012. We collected comparable dental caries-related procedures and treatment cost data for the same years for children in Anchorage, Alaska, where CWF has been continuously maintained. This retrospective study analyzed all Medicaid dental claims records in two separate years for caries-related procedures and associated costs among children (aged 0 to 18 years) residing in Anchorage's 99502 zip code and compared these records to data from Juneau. We obtained descriptive statistics and conducted bivariate analyses and binomial logistic regression. Between 2003 and 2012, children in Anchorage experienced a nonsignificant modest decrease in the mean number of caries-related procedures and only small, statistically nonsignificant changes to the mean inflation-adjusted service costs of caries-related restorative care. The lack of significant change in child dental caries-related procedures and treatment costs in Anchorage between 2003 and 2012 contrasted with the substantial increase in caries-related procedures and treatment costs over the same period in Juneau. Our results are consistent with previous research that has demonstrated a significant protective effect of CWF against dental caries.

The effect of community water fluoridation cessation on children's dental health: a national experience

BACKGROUND

Community water fluoride (CWF) is the proven cornerstone of primary dental health care promotion. In 2002 CWF was made mandatory at a national level in Israel, however a new government revoked these regulations in August 2014. "Maccabi" is the second largest national health care provider with 2.3 million members, "Maccabi-Dent", its dental branch, has 53 clinics, employing 1100 dentists. The aim of this study was to evaluate the cumulative effect on treatment rates 6 years after CWF was terminated in Israel, based on the number of dental treatments provided to children aged 3-12 years in "Maccabi-Dent" clinics.

METHODS

For this retrospective study, computerized dental treatment codes were collected. The "rate of treatment" was calculated by dividing the number of restorative treatments or extractions, by the number of individuals receiving treatment. The population size and the age group visiting the specific clinic were also considered.

RESULTS

The independent variables were fluoride concentration in drinking water, age and socioeconomic position (SEP). There was a significant increase in restorative dental treatments after 2014, (R2 = 0.0402), with approximately twice the number of treatments required in the absence of CWF. Age had a significant association (β =  - 0.389, p < 0.001) as did SEP (β = 0.086, p = 0.019).

CONCLUSION

After CWF cessation in Israel, rates of dental treatments significantly increased.

PRACTICAL IMPLICATION

By examining accepted notions with up-to-date information, new confirmatory evidence helps decision makers understand the importance of adding fluoride to drinking water.

Fluoride Toxicity

Fluoridation of the drinking water is one of the most impactful public health interventions ever done. Dental caries experience importantly decreased in all parts of the world that adopted the intervention. Implementation of fluoridation of the drinking water to populations has always been the focus of criticism, and these discussions often focus on the safety of the intervention. When asked about safety, many people will tend to assume a more cautious position, and the question regarding safety of fluoridation of the drinking water never goes away. Fluoridation of toothpastes also provides the same impact on dental caries experience in populations. It is reasonable to propose that water fluoridation may not be implemented anymore since there is a feasible and effective replacement for it. Finally, this chapter revisits the discussed effects of fluorides on overall health, with particular emphasis on cognition and intelligence.

Urinary Fluoride Levels among Canadians with and without Community Water Fluoridation

Drinking water is a major source of dietary fluoride intake in communities with water fluoridation. We examined the association between urinary fluoride adjusted for specific gravity (UFSG) and tap water fluoride levels, by age and sex, among individuals living in Canada. Participants included 1629 individuals aged 3 to 79 years from Cycle 3 (2012-2013) of the Canadian Health Measures Survey. We used multiple linear regression to estimate unique associations of tap water fluoride levels, age, sex, ethnicity, body mass index (BMI), use of fluoride-containing dental products, smoking in the home, and tea consumption with UFSG. UFSG concentration was significantly higher among participants who received fluoridated drinking water (mean = 1.06 mg/L, standard deviation = 0.83) than among those who did not (M = 0.58 mg/L, SD = 0.47), p < 0.01. UFSG increased over adulthood (ages 19 to 79). Higher UFSG concentration was associated with being female, tea drinking, and smoking in the home. In conclusion, community water fluoridation is a major source of contemporary fluoride exposure for Canadians. Lifestyle factors including tea consumption, as well as demographic variables such as age and sex, also predict urinary fluoride level, and are therefore important factors when interpreting population-based fluoride biomonitoring data.

A cost-effectiveness analysis of community water fluoridation for schoolchildren

BACKGROUND

Community water fluoridation (CWF), the controlled addition of fluoride to the water supply for the prevention of dental caries (tooth decay), is considered a safe and effective public health intervention. The Republic of Ireland (Ireland) is the only country in Europe with a legislative mandate for the fluoridation of the public water supply, a key component of its oral health policy. However, more recently, there has been an increase in public concern around the relevance of the intervention given the current environment of multiple fluoride sources and a reported increase in the prevalence of enamel fluorosis. The aim of this economic analysis is to provide evidence to inform policy decisions on whether the continued public investment in community water fluoridation remains justified under these altered circumstances.

METHODS

Following traditional methods of economic evaluation and using epidemiological data from a representative sample of 5-, 8-, and 12-year-old schoolchildren, this cost-effectiveness analysis, conducted from the health-payer perspective, compared the incremental costs and consequences associated with the CWF intervention to no intervention for schoolchildren living in Ireland in 2017. A probabilistic model was developed to simulate the potential lifetime treatment savings associated with the schoolchildren's exposure to the intervention for one year.

RESULTS

In 2017, approximately 71% of people living in Ireland had access to a publicly provided fluoridated water supply at an average per capita cost to the state of €2.15. The total cost of CWF provision to 5-, 8-, and 12-year-old schoolchildren (n = 148,910) was estimated at €320,664, and the incremental cost per decayed, missing, or filled tooth (d3vcmft/D3vcMFT) prevented was calculated at €14.09. The potential annual lifetime treatment savings associated with caries prevented for this cohort was estimated at €2.95 million. When the potential treatment savings were included in the analysis, the incremental cost per d3vcmft/D3vcMFT prevented was -€115.67, representing a cost-saving to the health-payer and a positive return on investment. The results of the analysis were robust to both deterministic and probability sensitivity analyses.

CONCLUSION

Despite current access to numerous fluoride sources and a reported increase in the prevalence of enamel fluorosis, CWF remains a cost-effective public health intervention for Irish schoolchildren.

Systematic Review of Intervention Studies Aiming at Reducing Inequality in Dental Caries among Children

(1) Background: The objective is to systematically review the evidence on intervention programs aiming at reducing inequality in dental caries among children. (2) Methods: Two independent investigators searched MEDLINE, Cochrane library, and Ovid up to December 2020 to identify intervention studies assessing the impact on socioeconomic inequalities in dental caries among children. The interventions included any health promotion/preventive intervention aiming at reducing caries among children across different socioeconomic groups. Comparison groups included children with alternative or no intervention. Cochrane criteria were used to assess interventional studies for risk of bias. (3) Results: After removal of duplicate studies, 1235 articles were retained. Out of 43 relevant papers, 13 articles were identified and used in qualitative synthesis, and reported quantifiable outcomes. The included studies varied in measurements of interventions, sample size, age groups, and follow-up time. Five studies assessed oral health promotion or health-education, four assessed topical fluorides, and four assessed water fluoridation. Interventions targeting the whole population showed a consistent reduction of socioeconomic inequalities in dental caries among children. (4) Conclusion: The quality of included papers was moderate. High heterogeneity did not allow aggregation of the findings. The overall findings suggest that whole population interventions such as water fluoridation are more likely to reduce inequalities in children’s caries than target population and individual interventions.

EPIDEMIOLOGICAL INDICATORS OF DENTAL MORBIDITY OF CHILDREN AS AN INDICATOR OF ADVERSE ENVIRONMENTAL INFLUENCE

OBJECTIVE

The aim: Is to study the ecological and hygienic situation in the living area of 6-year-old children in terms of drinking water (micro- and macroelements), to identify its relationship with the state of mineral metabolism in children's mouths, prevalence and intensity of temporary and permanent caries.

PATIENTS AND METHODS

Materials and methods:Clinical and laboratory studies were to study the objective condition of the teeth -intensity of dental caries according to the recommendations of the WHO and the method of T.F. Vinogradova. The hygienic condition of the oral cavity was determined by the indices Silness-Loe, Stallard.

RESULTS

Results: The results of our studies have shown that the proposed therapeutic and prophylactic complex, which includes drugs of endogenous (Vitafluor) and exogenous use (osteovitis, deep fluoridation, toothpastes "Splat junior" and "Lacalut fluor"), improves the hygienic state of the oral cavity, increases mineralizing the potential of the oral fluid and, as a result, helps to reduce the intensity of dental caries in children.

CONCLUSION

Conclusions: The data obtained indicated a high caries prophylactic efficacy of the proposed therapeutic and prophylactic complex for 6-year-old children living in the zone of hypophtorosis.

Exogenous Intake of Fluorides in Caries Prevention: Benefits and Risks

Caries incidence and prevalence have decreased significantly over the last few decades due to widespread use of fluoride. However, an increase in the prevalence of dental fluorosis has been reported in both fluoridated and non-fluoridated communities. Care must be taken to ensure that a balance between the optimal fluoride preventive effect at the individual and community level and minimal risk of dental fluorosis is maintained. This review describes the main sources of fluoride intake that have been identified: fluoridated drinking water, dietary fluoride supplement, and topical forms comprising toothpastes, rinses, gels and varnishes. The cited data were taken from meta-analytic studies and reports from Cochrane database systematic reviews up to December 2019. Efficiency, but safety, of topically applied fluorides in individual home care is dependent on the degree of compliance of individuals/parents and on the level of competence of providers of preventive counselling. The broad spectrum of these resources allows individualization of fluoride prevention based on risk analysis of caries attack and taking into consideration other preventive measures.

Childhood obesity and dental caries: an ecological investigation of the shape and moderators of the association

BACKGROUND

Despite sharing a common risk factor in dietary sugars, the association between obesity and dental caries remains unclear. We investigated the association between obesity and dental caries in young children in England in an ecological study.

METHODS

We analysed data from 326 lower tier English local authorities. Data on obesity and dental caries were retrieved from 2014/15 to 2016/17 National Child Measurement Programme and 2016/17 National Dental Epidemiology Programme. We used fractional polynomial models to explore the shape of the association between obesity and dental caries. We also examined the modifying effect of deprivation, lone parenthood, ethnicity, and fluoridation.

RESULTS

Best fitting second order fractional polynomial models did not provide better fit than the linear models for the association between obesity and prevalence and severity of dental caries; therefore, the linear model was found suitable. Despite significant association, after adjusting for the effect of deprivation, obesity was neither associated with prevalence (coefficient = 0.2, 95% CI - 0.71, 0.75), nor with severity (coefficient = 0.001, 95% CI - 0.03, 0.03) of dental caries. In fully adjusted models, the proportion of white ethnicity and being in fluoridated areas were associated with a decrease in dental caries. The association between obesity and dental caries was moderated by the effect of deprivation, white ethnicity, and lone parenthood.

CONCLUSIONS

The association between obesity and dental caries was linear and moderated by some demographic factors. Consequently, interventions that reduce obesity and dental caries may have a greater impact on specific groups of the population.

[Fluoride Update]

This article will provide an overview of the principles and modes of action of fluorides in oral care products, followed by a brief outline of the history and current situation regarding salt fluoridation in Switzerland. Recommendations for the use of fluoridated oral care products, current research results on the use of fluoride-containing dental care products and controversies related to fluorides are presented. Finally, the changes in fluoride concentration for children’s toothpastes in Europe and the corresponding implementation in Switzerland as well as changes regarding the use of fluoride in school dentistry are discussed.

A Case-Control Study of Fluoridation and Osteosarcoma

Public health policy decisions in the United States have resulted in 62.4% of the population having access to fluoridated water. The purpose of this study was to examine the association between community water fluoridation and osteosarcoma. A secondary data analysis was performed with data collected from 2 separate but linked studies. Patients for phase 1 and phase 2 were selected from US hospitals via a matched case-control study design. For both phases, cases included patients diagnosed with osteosarcoma, and controls were patients diagnosed with other bone tumors or nonneoplastic conditions. In phase 1, cases (n = 209) and controls (n = 440) were patients of record in the participating orthopedic departments from 1989 to 1993. In phase 2, cases (n = 108) and controls (n = 296) were incident patients who were identified and treated by orthopedic physicians from 1994 to 2000. This analysis included all patients who met eligibility criteria on whom we had complete data on covariates, exposures, and outcome. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% CIs for the association of community water fluoridation with osteosarcoma. A modestly significant interaction existed between fluoridation living status and bottled water use (P = 0.047). The adjusted OR for osteosarcoma and ever having lived in a fluoridated area for nonbottled water drinkers was 0.51 (95% CI, 0.31 to 0.84; P = 0.008). In the same comparison, the adjusted OR for bottled water drinkers was 1.86 (95% CI, 0.54 to 6.41; P = 0.326). Findings from this study demonstrated that community water fluoridation is not associated with an increased risk for osteosarcoma.

Use of public water supply fluoride concentration as an indicator of population exposure to fluoride in England 1995-2015

Public health monitoring of Community Water Fluoridation (CWF) schemes requires estimates of exposure to fluoride in public water supplies (PWS). We aimed to use routine data to estimate population exposure to PWS-fluoride in England and to determine whether PWS-fluoride exposure from 2005 to 2015 could be used as a proxy for exposure for 1995-2004, when fluoride concentration data that could be linked to population health data were unavailable. We calculated annual mean water supply zone PWS-fluoride concentrations from monitoring data for 1995-2015, stratified by fluoridation scheme-flagging. We allocated annual 2005-2015 mean PWS-fluoride concentrations to small area boundaries to describe population exposure within five concentration categories (< 0.1 to ≥ 0.7 mg/L). We compared zone-level 1995-2004 and 2005-2015 mean PWS-fluoride concentrations using Spearman correlation. Most (72%) of the population received PWS with < 0.2 mg/L fluoride and 10% with ≥ 0.7 mg/L. Fluoride concentrations in 1995-2004 and 2005-2015 were similar (median 0.11 mg/L (lower quartile-upper quartile (LQ-UQ) 0.06-0.17) and 0.11 mg/L (LQ-UQ 0.07-0.17), respectively) and highly correlated (coefficient 0.93) if un-fluoridated but differed (1995-2004 median 0.78 mg/L (LQ-UQ 0.59-0.92); 2005-2015 0.84 mg/L (LQ-UQ 0.72-0.95)) and correlated weakly (coefficient 0.31) if fluoridated. Fluoride concentrations in 2005-2015 approximate those in 1995-2004 but with a greater risk of misclassification in fluoridation schemes.

Maternal and fetal exposures to fluoride during mid-gestation among pregnant women in northern California

BACKGROUND

Previous studies have shown a correlation between fluoride concentrations in urine and community water fluoride concentrations. However, there are no studies of the relationship between community water fluoridation, urine, serum, and amniotic fluid fluoride concentrations in pregnant women in the US. The aim of this study was to determine the relationship between maternal urine fluoride (MUF), maternal urine fluoride adjusted for specific gravity (MUF_SG), maternal serum fluoride (MSF), amniotic fluid fluoride (AFF) concentrations during pregnancy, and community water fluoridation in Northern California.

METHODS

Archived samples of urine, serum and amniotic fluid collected from second trimester pregnant women in Northern California from 47 different communities in Northern California and one from Montana (n = 48), were analyzed for fluoride using an ion specific electrode following acid microdiffusion. Women's addresses were matched to publicly reported water fluoride concentrations. We examined whether fluoride concentrations in biospecimens differed by fluoridation status of the community water, and determined the association between water fluoride concentrations and biospecimen fluoride concentrations using linear regression models adjusted for maternal age, smoking, Body Mass Index (BMI), race/ethnicity, and gestational age at sample collection.

RESULTS

Fluoride concentrations in the community water supplies ranged from 0.02 to 1.00 mg/L. MUF, MSF , and AFF concentrations were significantly higher in pregnant women living in communities adhering to the U.S. recommended water fluoride concentration (0.7 mg/L), as compared with communities with less than 0.7 mg/L fluoride in drinking water. When adjusted for maternal age, smoking status, BMI, race/ethnicity, and gestational age at sample collection, a 0.1 mg/L increase in community water fluoride concentration was positively associated with higher concentrations of MUF (B = 0.052, 95% CI:0.019,0.085), MUF_SG (B = 0.028, 95% CI: -0.006, 0.062), MSF (B = 0.001, 95% CI: 0.000, 0.003) and AFF (B = 0.001, 95% CI: 0.000, 0.002).

CONCLUSIONS

We found universal exposure to fluoride in pregnant women and to the fetus via the amniotic fluid. Fluoride concentrations in urine, serum, and amniotic fluid from women were positively correlated to public records of community water fluoridation. Community water fluoridation remains a major source of fluoride exposure for pregnant women living in Northern California.

Drinking Water Practices Among Latino Families in North Carolina: A qualitative study

Purpose: The purpose of this study was to understand the beliefs, experiences and practices regarding drinking water among the North Carolina (NC) Latino community, and to gather information on what would make effective messages to promote fluoridated community water (CW) consumption among Latino families.Methods: Phone interviews were conducted with Latino stakeholders, consisting of parents of young children and key community informants (n=15). The interviews were audio-recorded, and transcripts were analyzed qualitatively using Atlas. ti.8 software.Results: Major themes emerging from the interviews included: poor characteristics of CW misconceptions and lack of knowledge about CW fluoridation and safety, ingrained culture/upbringing that devalued CW consumption, and reasons for consuming CW. Participants suggested that effective efforts to promote fluoridated CW consumption among the NC Latino community should be implemented in a variety of formats and involve a collaborative approach between Spanish-speaking health professionals and community workers.Conclusion: Successful promotion of fluoridated CW consumption among NC Latino communities requires engagement of both health professionals and community stakeholders. Effective interventions aimed to promote fluoridated CW consumption need to be widespread, informative, persuasive, credible, culturally sensitive, and interactive.

Role of lead in dental diseases

Lead (Pb) is ubiquitous in our environment and causes many pathophysiological health effects, including dental diseases. Dental Pb levels are considered good biological indicators of environmental and occupational Pb exposure. Pb in blood and saliva causes imbalances in the growth of oral microflora. The pH of saliva decreases, interferes with and interacts with bone-seeking elements, changes oral inflammatory parameters, generates reactive oxygen species, causes oxidative damage, and delays the mineralization process, leading to dental diseases. Pb's dental diseases include periodontitis, enamel lesions and defects, fluorosis, Burton's line, and tooth loss. Environmental and physiological factors, including age, gender, tooth type and position, pregnancy and lactation, eating and drinking habits, smoking habits, and exposures from Pb-contaminated residential and occupational areas, affect the distribution of Pb in blood, bone, and saliva, which contributes to dental diseases. However, living and working in Pb free areas can prevent environmental and occupational Pb exposure. Healthy lifestyles and eating habits, prohibiting smoking and alcohol drinking, further help prevent Pb exposure. Also, the fluoridation of water, salt, and milk provide nutritional supplements of trace elements, which can help prevent teeth from absorbing Pb from the environment, thereby reducing the risk of dental diseases.

Dental health status and its indicators in adult Brazilian Indians without exposition to drinking water fluoridation: a cross-sectional study

Water fluoridation is considered a cost-effective and practical method for controlling and preventing dental caries in the general population. The objective of this study was to evaluate the dental health status and risk indicators for dental caries in adult Brazilian Indians without exposition to dental caries-preventive effects of water fluoridation. Decayed (DT), missing (MT), and filled (FT) permanent teeth (DMFT), as well as plaque index, unstimulated salivary flow rate, salivary buffering capacity, and fasting blood glucose were examined in 225 adult Indians. Smoking habits and sociodemographic data were evaluated using a structured questionnaire. Drinking water samples from 10 Indian villages were analyzed for the natural fluoride concentration. The mean DMFT was 10.33 ± 6.91 (DT, 4.19 ± 3.99; MT, 4.99 ± 5.64; FT, 1.14 ± 1.75). DMFT index ≥ 9 was associated with age ≥ 35 years (p = 0.000), lower education (p = 0.03), and plaque index > 40% (p = 0.003). DT was associated only with plaque index (p = 0.03). MT was associated with age (p < 0.001) and plaque index (p = 0.01). FT was negatively associated with age (p = 0.02) and income (p = 0.02). Fluoride concentration varied from 0.01 to 0.07 mg/L and was not associated with dental health status (p ≥ 0.29). In conclusion, poorer dental health status was associated with older age, higher plaque index, and lower education and income levels. The fluoride level in the drinking water of Kiriri villages was lower than the level recommended for preventing dental caries. Water fluoridation may be recommended for this population.

The use of urinary fluoride excretion to facilitate monitoring fluoride intake: A systematic scoping review

BACKGROUND

As a recognised effective and economical agent for dental caries prevention, fluoride has been used in many different fluoridation schemes implemented across the world. Considering the narrow 'dose-gap' between the benefit of caries reduction and the risk of dental fluorosis, it is recommended that fluoride intake is monitored by measuring urinary fluoride excretion. The aim of this scoping review is to map the current literature/evidence on fluoride intake and excretion studies in relation to the study population, settings, type of study design, methodology, and analytical approach.

METHODS

Embase/Ovid, MEDLINE/Ovid, CINAHL/EBSCO, Scopus/Elsevier were searched for relevant articles until April 2018. Studies were included if they reported intake and excretion of fluoride in healthy humans of all age groups. Findings were explored using a narrative synthesis to summarise studies characteristics and outcome measures.

RESULTS

Removal of duplicates from the originally 2295 identified records yielded 1093 studies of which 206 articles were included. Only 21.6% of the studies were conducted in children (<8-year-olds). Most studies (38.8%) used drinking water concentration as a proxy for fluoride intake, whereas only 11.7% measured fluoride intake from all sources. Of the 72 studies that measured dietary fluoride intake, only 10 reported the validity of the employed dietary assessment method. Only 14 studies validated the urine sample collection methods. No information on the validity of the employed analytical method was reported by the majority (64.6%) of studies. Only a small proportion (8.7%) of the included studies investigated the association between fluoride intake and excretion.

CONCLUSION

The findings reveal much variability in terms of conducting the studies and reporting the findings, illustrating a high heterogeneity in data collection across settings and populations. Future studies should provide more detail on sampling technique, measurement protocols (including validation), and on clearly defining the relationship between intake and urinary excretion of fluoride.

Facile synthesis of fluorinated nanophotosensitizers with self-supplied oxygen for efficient photodynamic therapy

Tumor hypoxia severely reduces the efficiency of photodynamic therapy (PDT) through the insufficient supply of oxygen. In this work, we reported on a design of fluorinated nanophotosensitizers (NPSs) prepared by a facile reprecipitation-encapsulation method, with the aim of addressing the issue of hypoxia. The fluorinated NPSs consisted of a hybrid particle core of perfluorosiloxane-polystyrene, doped with a fluorinated photosensitizer, and a biocompatible poly-l-lysine shell. Compared with non-fluorinated counterpart NPSs that are similarly prepared except for the replacement of perfluorosiloxane with alkoxysilane, the fluorinated NPSs saturated with O₂ exhibit approximately 3.5 fold higher singlet oxygen production yield and higher in vitro PDT efficiency due to the O₂-carrying capability of intra-particle 'F-C' bonds.

Children Who Live in Mainly Fluoridated us Counties Have Less Tooth Decay

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Water Fluoridation and Dental Caries in U.S. Children and Adolescents. Slade GD, Grider WB, Maas WR, Sanders AE. J Dent Res 2018;97(10):1122-8.

SOURCE OF FUNDING

National Institute of Dental and Craniofacial Research of the National Institutes of Health under award number UH2DE025494.

TYPE OF STUDY/DESIGN

Cross-sectional study.