Public Water Fluoridation Research Articles

Availability of fluoride from meals given to kindergarten children in Brazil

The aim of this study was to evaluate the amount of fluoride supplied daily in the meals given in 44 public kindergarten schools in Bauru, Brazil. In addition, the fluoride concentration of water supplies and its impact on the amount of fluoride found in the meal samples were also investigated. Meal samples and water were collected during 2 weeks (10 working days) in public kindergarten schools. Samples of meals were homogenized with known volumes of deionized water. Fluoride present in meal samples was analyzed with the ion-specific electrode (Orion 9609), after hexamethyldisilazane-facilitated diffusion. Fluoride in water samples was analyzed with the same electrode, after buffering with TISAB II. All the analyses were made in duplicate. Fluoride analyzed (mean+/-SD) was 0.50+/-0.20 microg/ml, ranging from nondetectable to 1.42 microg/ml for water samples (n=424) and 0.067+/-0.059 mg, ranging from 0.007 to 0.580 mg for meal samples (n=431). A weak but significant correlation was observed between the amount of fluoride in meals and fluoride concentration in water supplies (r=0.139, P=0.0042). Despite the seemingly small role played by school meals in the total daily fluoride intake, they can contribute to the total fluoride intake of children on a chronic basis, when in association with other fluoride products. Additionally, the impact of fluoridated public water supply on the final fluoride concentration of the school meals analyzed may be regarded as low.

Public water fluoridation and dental health in New South Wales

Objectives: To evaluate whether access to fluoridated public water in New South Wales (NSW) is related to both a reduction in caries experience within NSW regions and to better dental health for disadvantaged children.Methods: Cross‐sectional population data on children attending the School Dental Service in NSW in 2000 were used to calculate and compare the number of decayed, missing and filled teeth (dmft/ DMFT) across areas of differing availability of fluoridated water within NSW Area Health Service (AHS) regions. Analyses were also undertaken looking at differences in caries between optimally fluoridated and non‐fluoridated communities across strata of socio‐economic disadvantage and by Indigenous status.Results: A total sample of 248,944 children aged 3–15 years was obtained. Caries experience in the deciduous dentition of 5–6 year‐olds and the permanent dentition of 11–12 year‐olds was significantly lower for children in fluoridated areas than non‐fluoridated areas in six of the eight AHSs and six of the 10 AHSs respectively where comparisons could be made. Children living in fluoridated areas had lower caries experience than children living in non‐fluoridated areas, regardless of socio‐economic disadvantage. Both Indigenous and non‐Indigenous children had reduced caries experience in fluoridated compared with non‐fluoridated areas.Conclusions: Water fluoridation was found to be related to significantly reduced caries experience in the majority of AHSs where comparisons could be made, and to benefit all socio‐economic strata of the community.Implications: Water fluoridation should be extended to those areas of NSW that are yet to benefit from this successful caries preventive public health initiative.

Five steps to conducting a systematic review

Systematic reviews and meta-analyses are a key element of evidence-based healthcare, yet they remain in some ways mysterious. Why did the authors select certain studies and reject others? What did they do to pool results? How did a bunch of insignificant findings suddenly become significant? This paper, along with a book1 that goes into more detail, demystifies these and other related intrigues. A review earns the adjective systematic if it is based on a clearly formulated question, identifies relevant studies, appraises their quality and summarizes the evidence by use of explicit methodology. It is the explicit and systematic approach that distinguishes systematic reviews from traditional reviews and commentaries. Whenever we use the term review in this paper it will mean a systematic review. Reviews should never be done in any other way. In this paper we provide a step-by-step explanation—there are just five steps—of the methods behind reviewing, and the quality elements inherent in each step (Box 1). For purposes of illustration we use a published review concerning the safety of public water fluoridation, but we must emphasize that our subject is review methodology, not fluoridation.

The York Review – A systematic review of public water fluoridation: a commentary

The York Review – A systematic review of public water fluoridation: a commentary

The York review--a systematic review of public water fluoridation: a commentary.

Following the election of the British government in May 1997, a policy document outlining proposals to improve the health of the nation was published. This document placed a major emphasis on reducing inequalities in health and recognised the continuing poor state of oral health in deprived communities. However, whilst acknowledging the benefits of water fluoridation as a caries preventive measure, the Department of Health suggested that most of the research had been carried out some years ago and furthermore, recognised that strong views were held both for and against fluoridation.

Little high-quality research into public water fluoridation

McDonagh M, Whiting P, Bradley M, Cooper J, Sutton A, Chestnutt I, et al. A Systematic Review of Public Water Fluoridation. York: Publications Office, NHS Centre for Reviews and Dissemination (CRD), University of York. ISBN 1 900640 16 3; 2000

No adequate evidence to assess differences between natural and artificial water fluoridation

Objective Are there differences in the effects of natural and artificial water fluoridation? Data sources See page 37. Study selection See page 37. Results The assessment of the effect of natural versus artificial water fluoridation is greatly limited because of the lack of studies that make the comparison. Very few studies included both natural and artificially fluoridated areas, and direct comparisons were not possible for most outcomes. No major differences were apparent in this review. Conclusions Although no major differences were apparent in this review, the evidence is not adequate to reach a conclusion regarding this objective. McDonagh M, Whiting P, Bradley M, Cooper J, Sutton A, Chestnutt I, et al. A Systematic Review of Public Water Fluoridation. York: Publications Office, NHS Centre for Reviews and Dissemination, University of York. ISBN 1 900640 16 3; 2000

Evidence suggests that water fluoridation has an effect over and above that of fluoridated toothpaste

Objective If water fluoridation is shown to have beneficial effects, what is the effect over and above that offered by the use of alternative interventions and strategies? Data sources See page 37. Study selection Studies were included that were carried out after 1974 in industrialised countries because, in those, any modifying effect of fluoride toothpaste and other sources of dental fluoride (eg, mouthrinses, tablets) should be apparent. Of the 24 studies that met the inclusion criteria for Objective 1, 10 were completed after 1974 (1978–1997). The mean validity score of these 10 studies was 5.0 (range, 3.5–6.8 out of 8). Data extraction and synthesis See page 37. Results Only 10 studies qualified to address this issue, although none of these identified this objective as the purpose of the investigation. The study with the highest validity score showed a statistically-significant difference in caries increment between fluoridated and nonfluoridated areas. Those in the nonfluoridated area had the greatest increment, in spite of fluoridated toothpaste being used by both groups (94% versus 95% used fluoride toothpaste only in the fluoridated and nonfluoridated groups, respectively). Conclusions The evidence suggests that water fluoridation has an effect over and above that of fluoridated toothpaste (and other sources of fluoride). McDonagh M, Whiting P, Bradley M, Cooper J, Sutton A, Chestnutt I, et al. A Systematic Review of Public Water Fluoridation. York: Publications Office, NHS Centre for Reviews and Dissemination, University of York. ISBN 1 900640 16 3; 2000

Fluoridation of drinking water reduces caries prevalence

Objective To determine the effects of fluoridation of drinking water supplies on the incidence of caries. Data sources See page 37. Study selection See page 37. Data extraction and synthesis See page 37. Results Twenty-six studies met the criteria. There were no level ‘A’ studies. All but three were before and after studies, two used prospective cohort designs, and one a retrospective cohort. The most serious defect of these studies was the lack of appropriate analysis. The degree of caries reduction is not clear from the data available. It was estimated that a median of six people need to receive fluoridated water for one extra person to be caries-free [interquartile range of study number-needed-to-treat (NNT), 49]. Studies after withdrawal of water fluoridation (level ‘B’ and limited quantity) indicate that caries prevalence increased, approaching the level of the low fluoride group. The estimates of effect could be biased due to poor adjustment for the effects of potential confounding factors. Conclusions The best available evidence suggests that fluoridation of drinking-water supplies does reduce caries prevalence, both as measured by the proportion of children who are caries-free and by the mean change in dmft/DMFT score. The studies were of moderate quality (level B), but of limited quantity. McDonagh M, Whiting P, Bradley M, Cooper J, Sutton A, Chestnutt I, et al. A Systematic Review of Public Water Fluoridation, September 2000. York: University of York Publications Office, NHS Centre for Reviews and Dissemination. ISBN 1 900640 16 3

No association between water fluoridation and bone fractures

Objective Does water fluoridation have negative effects? This objective was broken down into four sections: fluorosis, bone fracture and bone development effects, cancer and other possible adverse effects. Data sources See page 37. Study selection All studies were level C except one which was level B. The mean validity score was only 3.4 out of 8. Only four studies used a prospective design, none used any form of blinding and only one study conducted a baseline examination prior to the introduction of fluoridation. Data extraction and synthesis A forest plot of all the bone studies was produced showing the measures of effect and the 95% confidence intervals for all those that provided sufficient data to allow calculation. Results A total of 29 studies met inclusion criteria: 18 studies investigated hip fracture alone. Fourteen found decreased hip fracture associated with increased water fluoride level, of which five were statistically significant (positive association). Thirteen studies, however, showed an increased occurrence of hip fracture with increased water fluoride level, of which four were statistically significant (negative association). The remaining three studies found no association. Three of the 18 studies found the direction of association positive in women but negative in men and one study found a negative effect in women and a positive effect in men. There were no definite patterns of association for any of the fractures Conclusions The best available evidence on the association of water fluoridation and bone fractures (27 out of 29 studies evidence level C) show no association. McDonagh M, Whiting P, Bradley M, Cooper J, Sutton A, Chestnutt I, et al. A Systematic Review of Public Water Fluoridation. York: Publications Office, NHS Centre for Reviews and Dissemination, University of York. ISBN 1 900640 16 3; 2000

Effects of fluoridated drinking water on bone mass and fractures: the study of osteoporotic fractures.

To determine if optimal fluoridation of public water supplies influences bone mass and fractures, we studied 2076 non-black women, all aged > or = 65 years recruited into the Study of Osteoporotic Fractures at the Pittsburgh clinic. Information on fluoride exposure was limited to community water supplies. The variable used in the analysis was years of exposure to fluoridated water in community drinking water supplies. Bone mineral density (BMD) was measured at the spine and hip using dual energy X-ray absorptiometry and at the midpoint and ultradistal radius and calcaneus using single photon absorptiometry. Prevalent and incident vertebral fractures were determined by morphometry. Incident nonspine fractures were ascertained every 4 months and confirmed by radiographic report. Exposure to residential fluoridated water had no effect on bone mass. Women exposed to fluoride for > 20 years had similar axial and appendicular bone mass to women not exposed or women exposed for < or = 20 years. There was some suggestion that women exposed to fluoride for > 20 years had a lower relative risk of nonspine fractures (relative risk, RR, = 0.73; 95% confidence interval [CI] 0.48-1.12), osteoporotic fractures, RR = 0.74 (CI 0.46-1.19), and hip fractures, RR = 0.44 (CI 0.10-1.86), compared with women not exposed, but none of these relative risks was statistically significant. There was no association with wrist or spinal fractures. Our results do not support the findings from recent ecological studies which showed an increased risk of hip fracture among individuals exposed to fluoridated public water.

The association between water fluoridation and hip fracture among white women and men aged 65 years and older. A national ecologic study.

For the past 45 years, there has been a great deal of debate regarding the health issues surrounding the fluoridation of public water supplies. In order to assess the association between fluoridation and hip fracture, we identified 129 counties across the United States considered to be exposed to public water fluoridation and 194 counties without exposure. Data from the Health Care Financing Administration and the Department of Veterans Affairs were used to calculate the incidence of hip fracture among white persons, aged 65 years or older, in fluoridated and nonfluoridated counties. There was a small statistically significant positive association between fracture rates and fluoridation. The relative risk (95% confidence interval) of fracture in fluoridated counties compared to nonfluoridated counties was 1.08 (1.06 to 1.10) for women and 1.17 (1.13 to 1.22) for men. As comparisons were made at the grouped level, it may be inappropriate at this time to draw inferences at the individual level. The relationship observed at the county level needs to be duplicated at the individual level with more precise measures of fluoride exposure.

Análisis coste-beneficio de la fluoración de las aguas de abastecimiento público de la ciudad de málaga

The aim of the present study was to assess the cost-benefit of the program of fluoridation of the public water supply in the city of Málaga. Marginal benefits and the rate cost/benefit were the two parameters used to evaluate the cost-benefit. We have considered all the information available about similar experiences performed in other countries and about the particular aspects of the city in which this program was going to be set up. The cost of fluoridation per inhabitant per year and the effects of the cost of fluoridation on the price of the water supplied were also estimated. The program for the fluoridation of the public water supply in Málaga is profitable from the first year, as for each peseta spent we will benefit 2.10 pesetas. After 20 years of public water fluoridation the net benefit of this program will reach between 519 and 5,300 millions pesetas.

Public water fluoridation in Ireland: twenty-five years on'

Public water fluoridation in Ireland: twenty-five years on'

Public water fluoridation in Ireland: twenty-five years on.

In July of this year, 1989, Ireland celebrates 25 years of fluoridation of the public water supplies. No other country has had such a long experience of a national mandatory public water supply fluoridation programme. There is good reason therefore to review experiences and attempt to draw some conclusions.

The Community Innovation Process

Previous research into the community innovation process has tended to emphasize either intercommunity information flows and imitation or local need and political factors. This paper presents a conceptualization incorporating both sets of factors and stressing, in particular, the distinction between community innovations supported by a central pro pagator and those adopted solely on the basis of local initiative. In empirical analysis the former are represented by public housing and urban renewal, the latter by automated data processing and public water fluoridation. The major findings of the empirical analysis are that both information-related and local need and political factors are critical to the community innovation process, and that the distinction between sponsored and local initiative community innovations is particularly useful in explaining the decision to adopt.

Fluoride in treated sewage and in rain and snow.

The liquid effluent of a sewage treatment plan contained 1.21 ppm ionic and total fluoride, which was higher than 1.0 ppm fluoride in the fluoridated public water supply. The discharge of the effluent into a river did not greatly raise the fluoride content of the river water because of dilution and other factors. The semisolid waste of sewage treatment also contained fluoride, but very little was volatilized on burning. Rain and snow were found to contain detectable quantities of fluoride, and the fluoride content of snow increased markedly during exposure to an urban environment.

Breast-Feeding and Fluoride

The value of fluoride treatment in dental caries prevention was again well emphasized by Ripa1 and the Leskes2 in the August issue of Pediatrics. One problem not discussed and of great practical importance to patient and physician is the child living in an area with a fluoridated public water supply who neither drinks water nor ingests it via tap water used for cooking, mixed frozen juices, etc. In our area and among our private patients, most infants are on preprepared formulas or on breast milk and take little or no tap water.

Status of Fluoridation in the United States and Canada, 1964: Task Group Report

This annual report of Task Group 2620 P commemorates the twentieth anniversary of the first fluoridation installation at Grand Rapids, Michigan, by including the names of all the fluoridated public water supply systems in the United States and Canada. The list includes all those systems that were included in a similar list covering the years up to 1960, in addition to all those systems added during the intervening years, including 1964, and the names of 1,612 water supply systems in the United States and 174 in Canada. The systems in the United States serve 2,803 communities containing more than 48,300,000 people; in Canada, 243 communities with a total population of more than 4,100,000 are served.

The prevalence of malocclusion, related to dental caries and lost first permanent molars, in a fluoridated city and a fluoride-deficient city

The data from this study, as well as from previous studies reported, suggest that children who have the benefit of ingested water fluorides continuously from birth have significant protection against dental caries. They also have a significantly lower rate of loss of permanent teeth, specifically first permanent molars, than children who do not get water-borne fluorides at the optimum concentration. The study adds further substantiation to Salzmann's previous large-scale study regarding the potential hazard of developing malocclusion as a result of early first permanent molar loss. Other factors, such as untreated caries and filled teeth with poor contact points, should be studied. Thus, the benefits which accrue from public water fluoridation programs may be measured not only in terms of significant protection against detal caries but also with respect to a reduced hazard of malocclusion, especially severe malocclusion which may be regarded as physically handicapping.