Does fluoride in the water close the dental caries gap between Indigenous and non-Indigenous children?

Water fluoridation for the prevention of dental caries

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

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.

The Global Prevalence and Severity of Dental Caries among Racially Minoritized Children: A Systematic Review and Meta-Analysis

Racially minoritized children often bear a greater burden of dental caries, but the overall magnitude of racial gaps in oral health and their underlying factors are unknown. A systematic review and meta-analysis were conducted to fill these knowledge gaps. We compared racially minoritized (E) children aged 5-11 years (P) with same-age privileged groups (C) to determine the magnitude and correlates of racial inequities in dental caries (O) in observational studies (S). Using the PICOS selection criteria, a targeted search was performed from inception to December 1, 2021, in nine major electronic databases and an online web search for additional grey literature. The primary outcome measures were caries severity, as assessed by mean decayed, missing, and filled teeth (dmft) among children and untreated dental caries prevalence (d > 0%). The meta-analysis used the random-effects model to calculate standardized mean differences (SMD) and 95% confidence intervals (95% CI). Subgroup analysis, tests for heterogeneity (I2, Galbraith plot), leave-one-out sensitivity analysis, cumulative analysis, and publication bias (Egger's test and funnel plots) tests were carried out. The New Castle Ottawa scale was used to assess risk of bias. This review was registered with PROSPERO, CRD42021282771. A total of 75 publications were included in the descriptive analysis. The SMD of dmft score was higher by 2.30 (95% CI: 0.45, 4.15), and the prevalence of untreated dental caries was 23% (95% CI: 16, 31) higher among racially minoritized children, compared to privileged groups. Cumulative analysis showed worsening caries outcomes for racially marginalized children over time and larger inequities in dmft among high-income countries. Our study highlights the high caries burden among minoritized children globally by estimating overall trends and comparing against factors including time, country, and world income. The large magnitude of these inequities, combined with empirical evidence on the oral health impacts of racism and other forms of oppression, reinforce that oral health equity can only be achieved with social and political changes at a global level.

Dental Health Inequalities among Indigenous Populations: A Systematic Review and Meta-Analysis

The aim of this systematic review and meta-analysis was to document the disparity in dental caries experiences among indigenous and nonindigenous populations globally by measuring dental caries prevalence and severity. An electronic database (MEDLINE) was initially searched using relevant keywords. This was followed by use of the search string in the following electronic databases: Scopus, EBSCOhost, Cochrane, and Open Grey. Two independent reviewers conducted the study search and screening, quality assessment, and data extraction, which was facilitated using JBI SUMARI software. The primary outcome was the decayed missing filled teeth (DMFT) score and dental caries prevalence. Subgroup analysis was done by country of publication to identify causes of heterogeneity. Forest plots were used with the standardized mean difference (SMD) and publication bias was assessed using the Egger test with funnel plot construction. For the final review, 43 articles were selected and 34 were meta-analyzed. The pooled mean DMFT for both the permanent dentition (SMD = 0.26; 95% CI 0.13-0.39) and deciduous dentition (SMD = 0.67; 95% CI 0.47-0.87) was higher for the Indigenous population than for the general population. Indigenous populations experienced more decayed teeth (SMD = 0.44; 95% CI 0.25-0.62), a slightly higher number of missing teeth (SMD = 0.11< 95% CI -0.05 to 0.26), and lesser filled teeth (SMD = -0.04; 95% CI -0.20 to 0.13) than their nonindigenous counterparts. The prevalence of dental caries (SMD = 0.27; 95% CI 0.13-0.41) was higher among indigenous people. Globally, indigenous populations have a higher caries prevalence and severity than nonindigenous populations. The factors which have led to such inequities need to be examined.

Epidemiological profile of caries and need for dental extraction in a Kaingang adult Indigenous population

ABSTRACT: Introduction: The epidemiological profile of dental caries for Indigenous Peoples is complex and heterogeneous. The oral health of the Kaingang people, third largest Indigenous population from Brazil, has not been investigated so far. Objective: The purpose of this study was to assess the prevalence and severity of dental caries, in addition to the associated factors of the need of dental extraction among Kaingang adult Indigenous. Methods: A cross-sectional oral health survey was conducted among Kaingang adults aged from 35 to 44 years old living in the Guarita Indigenous Land, Rio Grande do Sul. Clinical exams were performed to analyze the conditions of dental crown and treatment needs. Results: A total of 107 Indigenous adults were examined. Mean DMFT score was 14.45 (± 5.80). Two-thirds of the DMFT score accounted for missing teeth. Anterior lower dentition presented the highest rates of sound teeth, whereas the lower first molars had the lowest. Need for dental extraction was observed in 34.58% and was associated with village location, time of last dental visit, and higher number of decayed teeth. Conclusion: The high frequencies of caries and missing teeth observed in this population indicate a lack of adequate assistance. It is essential to discuss health care models in order to combat avoidable social and health injustices.

Flying blind: trying to find solutions to Indigenous oral health

Objective The aim of the present study was to identify all published evidence about oral health in Indigenous children in Australia and to determine trends in Indigenous oral health over time. Methods PubMed was used to search for published peer-reviewed articles that reported caries (decay) prevalence rates and/or caries experience (based on caries indices) in Indigenous children. Studies included in the analysis needed to report clinical oral health data (not self-reported dental experiences), and articles were excluded if they reported caries in only a select, specific or targeted sample (e.g. only children undergoing hospital admissions for dental conditions). Results The review identified 32 studies that met the inclusion criteria. These studies reported data from the Northern Territory (n=14), Western Australia (n=7), South Australia (n=7), Queensland (n=7), New South Wales (n=1), Australian Capital Territory (n=1) and Tasmania (n=1). Of the studies, 47% were in rural locations, 9% were in urban locations and 44% were in both rural and urban locations. Data are limited and predominantly for Indigenous children living in rural locations, and there are no published studies on caries in Indigenous children living in Victoria. Conclusions The present study documents the published prevalence and severity of caries in Indigenous children living in Australia and highlights that limited oral health data are available for this priority population. Although risk factors for oral disease are well known, most of the studies did not analyse the link between these factors and oral disease present. There is also inconsistency in how caries is reported in terms of age and caries criteria used. We cannot rely on the available data to inform the development of policies and programs to address the oral health differences in Indigenous populations living contemporary lives in metropolitan areas. What is known about the topic? Many studies report that Indigenous people have poorer general health in Australia compared with non-Indigenous people. What does this paper add? This paper documents the available published prevalence and experience of caries for Indigenous children in Australia. It demonstrates significant limitations in the data, including no Victorian data, inconsistency with reporting methods and most data being for Indigenous children who are living in rural locations. What are the implications for practitioners? It is important for practitioners to have access to oral health data for Indigenous children in Australia. However, the present study highlights significant knowledge gaps for this population group and identifies ways to collect data in future studies to enable more meaningful comparisons and policy development.

Associations of Community Water Fluoridation with Caries Prevalence and Oral Health Inequality in Children

This study aimed to confirm the association between the community water fluoridation (CWF) programme and dental caries prevention on permanent teeth, comparing to a control area, neighbouring population without the programme, and verifying whether the programme can reduce the socio-economic inequality related to the oral health of children in Korea. Evaluation surveys were conducted among 6-, 8-, and 11-year-old children living in Okcheon (CWF) and neighbouring Yeongdong (non-CWF, control area) towns in South Korea. Data on monthly family income, caregiver educational level, and Family Affluence Scale scores were evaluated using questionnaires that were distributed to the parents. The effectiveness of CWF in caries reduction was calculated based on the differences in decayed, missing, and filled teeth and decayed, missing, and filled tooth surfaces indices between the two towns. The data were analysed using logistic regression and univariate analysis of variance. Both 8- and 11-year-old children living in the CWF area had lower dental caries prevalence than those living in the non-CWF community. Differences in dental caries prevalence based on educational level were found in the control area but not in the CWF area. Socio-economic factor-related inequality in oral health were observed in the non-CWF community. Additionally, 8- and 11-year-old children living in the CWF area displayed lower dental caries prevalence in the pit-and-fissure and smooth surfaces than those living in the non-CWF community. These results suggest that CWF programmes are effective in the prevention of caries on permanent teeth and can reduce oral health inequalities among children. The implementation of CWF programmes should be sustained to overcome oral health inequalities due to socio-economic factors and improve children's overall oral health.