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With rising cost of dental care it is important to have a good preventative measure to help improve and keep excellent oral health. The aim of this study is to determine the effect of fluoride on enamel demineralization and therefore future dental decay. There are many forms of fluoride both systemic and topical each with their own types of benefits. The topical forms include toothpastes, mouthwashes, drops and vanishes, whereas the systemic forms are typically ingested examples being water, and other types of food. Fluoride was introduced into water sources previously in many countries and was considered a great public health advancement. It has been shown to help stop demineralization of enamel, the outer surface of teeth, which therefore prevents the formation of dental decay or dental caries. To examine the effectiveness of water fluoridation in particular, a variety of research studies from various countries and reputable sources were examined. There are many studies evaluating the long lasting effects that fluoride can have, but limitations, including funding and confounding variables, have led to less conclusive results. From the research presented here, there is conclusive evidence that introducing fluoride into the local water source is a cost effective way to reach a large number of people and improve the oral health of many people all at once. There are some potentially negative side effects with high doses therefore it is an issue of constant public debate. However, after gathering the results from many of these sources the only negative side effect that has been scientifically supported is the potential for dental fluorosis, and only occurs at high levels of fluoride and often it was only a cosmetic concern. Therefore, in the case of water fluoridation the health benefits outweigh the risks and it should continue to be a part of the community water where ever available.

Thesis (M.S.)--University of Michigan, 1995. / Includes bibliographical references.

Thesis (M.S.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains vi, 47 p. : ill. (some col.) Vita. Includes abstract. Includes bibliographical references (p. 44-46).

High F- groundwaters occur in various parts of South Africa, namely, the larger part of the Karoo, Limpopo, North West and Northern Cape Provinces. The use of these waters for drinking purposes on continual basis can lead to fluorosis. Fluorosis is a debilitating disease caused by drinking water with F- concentrations higher than ca. 1 mg.L-1. The disease is characterized by mottled teeth in dental fluorosis and brittle bones in severe skeletal fluorosis. Solution to this problem involves the implementation of a method for F- removal from water. Defluoridation has become a widely practiced process worldwide due to the problem of fluorosis caused by the presence of F- in drinking waters. Methods such as adsorption, precipitation, ion exchange and membrane processes have been employed for F- removal. Adsorption techniques, in particular using activated alumina have proven successful in removing F- from water. However, this method can not always be used in rural areas because of high costs and technical requirements. In this study, locally available clays were studied as potential substrates for F- removal from water. The first part of the study focused on the explanation of mechanisms and the development of an adsorption model. The exchange of OH- by F- in the clay structure is the principal mechanism that takes place during adsorption. The change in pH during this exchange process was studied to support and verify the fluoride-hydroxide exchange mechanism. In the second part of the study, locally available South African clays were studied as possible adsorbents for F- removal from water. Clays containing aluminium and iron oxide surfaces proved to be useful substrates for F- adsorption. The adsorption of F- onto clay samples was found to be pH dependent. Maximum adsorption was achieved at pH 5 for aluminium oxide type sorbents and pH 4 for iron oxides types such as goethite. The effect of physical and chemical pretreatment improved the adsorption capacity of some clays. Coating clay samples with aluminium and iron oxides enhanced the adsorption capacity of clays. The last part of the study involves the development of a cost-effective and quick way to assess the performance of clays as adsorbents for F- removal using laboratory scale defluoridation columns. / Prof. P.P. Coetzee

The main drivers for this body of work were a systematic review on water fluoridation by the NHS Centre for Research Dissemination (known as the York Report) and a report by the Medical Research Council entitled 'Water Fluoridation & Health'. Both documents highlighted shortcomings in the evidence base on water fluoridation. Two major projects form the basis of this thesis in an attempt to address some of the issues raised. The first project in Chiang Mai, Thailand aimed to determine the ability of QLF to discriminate between populations with differing exposures to fluoride. Populations with differing exposures to fluoride were identified through the analysis of drinking water and cooking water. Subjects were examined for fluorosis with standardized photographs and QLF to evaluate software techniques for fluorescence image analysis. The results in Thailand demonstrated that QLF was able to discriminate between populations with differing exposures to fluoride in water to a similar degree to blinded, subjective clinical scoring. There was significant agreement between the two methods (ICC 0.65 Spearman's rho). However, confounding factors for QLF were found. The aim of the second project was to assess the use of blinded and objective methods for assessing caries and fluorosis in fluoridated Newcastle and non-fluoridated Manchester in northern England. This study involved clinical and intra-oral photographic caries examinations using ICDAS, together with standardized photography and QLF imaging for fluorosis examinations. The results in Newcastle and Manchester suggested that there were significantly lower levels of caries in the fluoridated population compared to the non-fluoridated population. For early caries (Newcastle mean DMFT 2.94[clinical]/2.51[photo], Manchester mean DMFT 4.48 [clinical]/3.44[photo]) and caries into dentine (Newcastle Mean DMFT 0.65[clinical]/0.58[photo], Manchester mean DMFT 1.07 [clinical]/0.98 [photo]). This was reflected as an increase in caries as the level of deprivation increased (confirmed through intra-oral photographic scoring). The reduction in caries levels was associated with increased levels of fluorosis in Newcastle. The prevalence of fluorosis from photographic scores in fluoridated Newcastle was 55%, in non-fluoridated Manchester it was 27%. In Newcastle, 48% of subjects had TF scores of 1 or 2 and 7.1% of subjects had TF scores of 3 or greater. QLF showed significant associations with the clinical scores for fluorosis (ICC 0.405 Kendall's tau) and suggested a fluorosis prevalence for TF 3 or greater of 19% in Newcastle and 10% in Manchester. The integration of technologies such as intra-oral photographs for blind caries scoring and QLF for the detection and objective quantification of fluorosis may still prove to be useful adjunctive tools when used alongside clinical indices. The data derived from the methodologies under investigation suggest a benefit in caries reduction from community water fluoridation and this may help to reduce inequalities in oral health by reducing the social gradient between deprivation and caries.

published_or_final_version / abstract / Dentistry / Doctoral / Doctor of Philosophy

A importância da fluoretação da água de abastecimento público na prevenção da cárie dentária é reconhecida e exaustivamente estudada desde 1945. O objetivo desta pesquisa foi o de avaliar a concentração de flúor presente na água de abastecimento público de Bauru, SP, antes e depois do processo de fluoretação. Para tanto estabeleceu-se um protocolo para a coleta de amostras de água durante três dias de uma semana, a cada três meses, durante as quatro estações do ano. As amostras foram coletas na ETA e nos 27 poços que abastecem a cidade, antes e depois da fluoretação, e em 63 pontos (residências) estabelecidos a partir do mapa onde estão definidos os 19 setores de abastecimento, com a finalidade de coletar amostras em toda a extensão da rede. A análise das amostras foi realizada em duplicata, utilizando-se o eletrodo íon-sensível (Orion 9609), acoplado ao potenciômetro (Procyon, modelo 720), adicionando 1 mL de TISAB II a 1 mL da amostra. A checagem dos resultados da análise das amostras de água foi feita através de nova leitura de 10% das amostras e com uma reprodutibilidade mínima estabelecida em 90%. Não foram observadas variações na concentração do flúor naturalmente presente na água em função da sazonalidade de cada uma das estações do ano. A concentração, das 318 amostras analisadas, variou entre 0,05 e 0,15 mg F/L. Entretanto, a média das concentrações de flúor verificadas nas 297 amostras obtidas na ETA e nos poços após a fluoretação variou entre 0,26 e 6,23 mg F/L e das 697 amostras das residências, entre 0,10 e 0,91 mg F/L. A concentração de flúor presente na água de abastecimento público de Bauru, antes da fluoretação, mostrou-se constante, diferente daquela verificada após a fluoretação, que apresentou grandes oscilações na sua concentração de flúor, indicando que o sistema de abastecimento de Bauru não mantém constantes os níveis de flúor na água. / The importance of public water fluoridation for the prevention of dental caries has been scientifically recognized. The aim of this study was to evaluate the fluoride concentration of the public water supply of Bauru, SP, before and after the fluoridation, in different seasons. It was established a protocol for collecting water samples during 3 days in a week, every 3 months. Samples were collected at the Water Treatment Station and in 27 wells that supply the city, before and after fluoridation. In addition, samples were also collected in 63 points (houses), which were selected from a city map, corresponding to the 19 sections of supply, in order to represent all the distribution system. Samples were analyzed in duplicates, using an ion-sensitive electrode (Orion 9609), coupled to a potentiometer (Procyon, model SA 720), by adding 1 mL of TISAB to 1 mL of the water sample. Repeatability was checked in 10% of the samples and was higher than 90%. No differences in the natural fluoride concentration in water were observed in the four different seasons. However mean fluoride concentrations found in the 297 samples collected in the Water Treatment Station and in the wells after fluoridation varied between 0.26 and 6.23 mg F/L. For the 697 samples collected in the houses, the ranged was from 0.10 to 0.91 mg F/L. Natural fluoride concentration in the water before fluoridation was constant, differently from fluoride concentration in the public water supply after fluoridation, which spanned a wide range. This indicates that the system of supply of Bauru does not maintain constant water fluoride levels.

The use of fluoride involves a balance between the protective effect against caries and the risk of having fluorosis. Fluorosis in Australian children was highly prevalent in the early 1990s. Policy initiatives were introduced to control fluoride exposure so as to reduce the prevalence of fluorosis. Objective: The study aimed of describing the prevalence, severity and risk factors for fluorosis, and to escribe the trend of fluorosis among South Australian children. The study also aimed of exploring the effect of the change in fluoride exposure on dental fluorosis and caries. Methods This research project was nested in a larger population-based study, the Child Oral Health Study (COHS) in Australia 2002-2005. The parent study's sample was chosen using a multistage, stratified random selection with probability of selection proportional to population size. Fluoride exposure history was retrospectively collected by a parental questionnaire. This nested study sample (n=1401) was selected from the pool of South Australian (SA) COHS participants. Children were selected by year of birth to form three birth cohorts: those born in 1989/90; 1991/92; and 1993/94. Children were approached in two further stages: a dental health perception questionnaire, and a clinical examination for fluorosis. Some 898 children took part in the first stage. Among those, one trained dentist examined 677 children for fluorosis under clinic conditions using two indices (the Fluorosis Risk Index (Pendrys, 1990) and the TF Index (Thylstrup and Fejerskov, 1978)). The Dental Aesthetic Index score (DAI) was also recorded. Caries experience extracted from dental records of all previous visits to school dental linics was used to enable calculation of dmfs/DMFS scores at different anchor ages. Data were re-weighted age and sex to represent the South Australian child population. Per cent lifetime exposure to fluoride in water and patterns of discretionary fluoride use were calculated. Fluorosis data were used to calculate the prevalence and severity of fluorosis. Caries dmfs/DMFS scores were calculated at different anchor ages to enable comparison between birth cohorts. Results A higher proportion of children in the later birth cohorts used low concentration fluoride toothpaste, and a smaller amount of toothpaste was used when they commenced toothbrushing. There was a significant decline in the prevalence of fluorosis across the three successive birth cohorts. Risk factors for fluorosis, defined by the two indices, were use of standard fluoride toothpaste, an eating and/or licking toothpaste habit, and exposure to fluoridated water. Means (SD) of the deciduous caries dmfs scores at age six and eight were 1.45 (3.11) and 2.46 (3.93) respectively. Evaluation of the "trade-off" between fluorosis and caries with fluoride exposure indicated that the use of low concentration fluoride toothpaste and preventing an eating/licking of toothpaste habit could reduce the prevalence of fluorosis without a significant increase in caries experience. Conclusion There was a marked decline in the prevalence of fluorosis across the three successive birth cohorts. The decline was linked with the reduction in exposure to fluoride. Exposure to fluoridated water and several components of toothpaste use were risk factors for fluorosis. Establishing an appropriate use of fluoride toothpaste could be successful in reducing fluorosis without a significant increase in caries experience. / Thesis (Ph.D.)--Dental School, 2004.

Consistent evidence confirms that the addition of fluoride to achieve an optimal concentration in potable water supplies is both safe and effective in reducing community caries experience. While public acceptance and use of water fluoridation in Australia has been high for forty years, its implementation in Queensland remained low until December 2008. Political and social scientists have long recognised that the formation and maintenance of public policy in Australia is a complex interactive process involving inter alia government, bureaucracy, pressure groups and voters. However, explanations of the factors influencing the outcome of a proposal to fluoridate a municipal water supply remain inadequate. The long evolution of adjusted fluoridation has its genesis in pre-1930 North American concerns over the disfigurement associated with endemic dental mottling. Throughout the 1930s and 1940s, many perceived this affliction as the visible manifestation of a public health problem: chronic fluoride intoxication. Reports of environmental contamination of the food chain from naturally over-fluoridated water and agrarian and industrial practices only increased community doubts about the accumulative and toxic potential of fluoride. For these and other reasons the public perception of fluoride was poor. Between 1937 and 1945, USPHS dental researcher and later Director of the National Institute of Dental Research HT Dean and co-workers emerged as the few who understood the fine line between fluoride therapy and toxicity. Their investigations involved not only specialised interpretations of human dental epidemiology but also multidisciplinary studies of human and animal fluoride exposure and homeostasis. However, decisions to implement water fluoridation had to come from the relevant government authorities. Here scientific knowledge faced political reality. Apart from perceived safety issues and resistance to the compulsory nature of water fluoridation, many other barriers to water fluoridation emerged: incompletely understood pharmacodynamics of fluoride; confounding issues in the initiation and propagation of caries; community acceptance of this epidemic; and political sensitivities regarding water. This scientific and social background explained why adjusted fluoridation was amenable to both challenge and misrepresentation. In the US, the constitutional, institutional and financial network provided the basis for an enduring culture of dental research that eventually provided the multidisciplinary evidence to endorse the safety and efficacy of water fluoridation. Although Australians did not experience a widespread human mottling problem akin to that in the United States, Australian fluoride advocates faced similar opposition. The Australian constitution, state parochialism and decentralisation compounded by vast distances fragmented the responsibilities for research, health and water treatment. Each state had limited resources and faced these responsibilities in its own way. Although there were several early attempts in some states at regional dental field studies, meaningful national dental epidemiology did not emerge until 1993. Hence, much of the supportive evidence for fluoridation in Australia had to be imported from North America. This background meant that wherever fluoridation was widely implemented in Australia, state authority played a role. In addition to the general social and scientific concerns about fluoride and fluoridation, before 1957 there were a number of unresolved scientific factors relating to naturally over-fluoridated ground water, climate, tea consumption and fluid homeostasis involving canecutters. These made Queensland different in the Australian context. After 1957, as these scientific concerns in Queensland diminished, the political landscape changed and provided new foundations for political hesitance and expedience. The timing and circumstances of the promulgation of the Fluoridation of Public Water Supplies Act (1963) influenced its nature to the extent that until 2008, this legislation with its link to various local government acts was unique within Australia. Although there were notable exceptions such as the decisions to fluoridate water supplies at Townsville and Mareeba, this legislative background established the “Queensland difference” as a fixture in fluoride debates across the state. When combined with inadequate state funding and a lack of political resolve from parliamentarians and councillors, prospects for fluoridation in Queensland were virtually paralysed. Nonetheless, while inquiry into the political reasons for the implementing or the failure to implement fluoridation remains thin, developments in Queensland after December 2007 lend significant weight to the finding that a politically resolute centralised authority with the responsibility for both health and water are key components in the outcome.