Magister Scientiae Dentium - MSc(Dent) / Introduction: Dental fluorosis is a developmental disturbance of enamel that results from ingestion of high amounts of fluoride during tooth mineralization. Drinking water remains the main source of fluoride. Other sources of fluoride include infant formula, vegetables; canned fish as well as early, improper utilization of fluoridated toothpastes in children. Knowledge of risk factors in the causation of dental fluorosis may improve strategies to prevent dental fluorosis. Objective: To determine the prevalence of dental fluorosis among children aged 12-15 years old in Athi River sub-county, Machakos County, Kenya and assesses the level of knowledge on risk factors for dental fluorosis among their parents. Methodology: This was a descriptive study with an analytic component. A total of 281 children aged 12-15 years attending public primary schools within Athi River sub-county, Machakos County were included. A self-administered questionnaire was send to parents for socio-demographic characteristics and oral health practices. Children whose parents consented were examined and dental fluorosis scored according to the Thylstrup and Fejerskov index. Fourty randomly selected children were requested to bring water samples from their homes. Retail stores located in the area were visited for purchase of six different brands of bottled water. These samples were sent to a certified laboratory for fluoride analysis and reported in milligrams of fluoride per litre. Data analysis: Data was entered into SPSS version 20 and analysed for means, ANOVA of means and chi-square test of significance for categorical variables. All tests for significance were set at 95% confidence level (α≤0.05). Results: A total of 314 self-administered questionnaires were send to parents together with consent forms for their children‟s participation in the study. Two hundred and eighty six responded positively, giving a response rate of 91%. The overall prevalence of dental fluorosis among children aged 12-15 years was 93.4% with only 6.6% (n=19) recording a TFI score of 0. About one quarter 70(24.4%) of children had severe fluorosis with TFI scores of ≥5. The mean TFI score for all children was 3.09 (SD=2.0), with males recording a mean TF score of 3.01 (SD=2.11) and females a mean TF score of 3.16 (SD=1.88). Out of 44 water samples analysed, 29 (65.9%) had a fluoride content of less than 0.6mg/l, 5 (11.4%) had fluoride content of 0.7 - 1.5mg/l while 10 (22.7%) of samples had a fluoride content ≥1.5mg/l. The highest fluoride content recorded was 9.3mg/l, with another sample reflecting 8.9mgF/l. Three of the bottled water samples had a fluoride content of less than 0.6mg/l, while the other half of the bottled water reported 0.7 - 0.8mg/l fluoride. A majority (87.8%) of parents indicated that they had noticed children with brown staining of their permanent teeth in their community. About 80% of parents thought dental fluorosis was caused by salty water, while only 12.9% correctly identified water with high fluoride content as being responsible for the discolored teeth. Conclusion: Although about one in five water sources sampled had fluoride content of ≥1.5mg/l, the prevalence of dental fluorosis in this community was very high. Parental knowledge on the risk factors for dental fluorosis was low. Further research is necessary to identify the water distribution networks to provide sound evidence for engaging with the county authorities on provision of safe drinking water to the community.

Magister Scientiae Dentium - MSc(Dent) / Introduction: Dental fluorosis is a developmental disturbance of enamel that results from ingestion of high amounts of fluoride during tooth mineralization. Drinking water remains the main source of fluoride. Other sources of fluoride include infant formula, vegetables; canned fish as well as early, improper utilization of fluoridated toothpastes in children. Knowledge of risk factors in the causation of dental fluorosis may improve strategies to prevent dental fluorosis. Objective: To determine the prevalence of dental fluorosis among children aged 12-15 years old in Athi River sub-county, Machakos County, Kenya and assess the level of knowledge on risk factors for dental fluorosis among their parents. Methodology: This was a descriptive study with an analytic component. A total of 281 children aged 12-15 years attending public primary schools within Athi River sub-county, Machakos County were included. A self-administered questionnaire was send to parents for sociodemographic characteristics and oral health practices. Children whose parents consented were examined and dental fluorosis scored according to the Thylstrup and Fejerskov index. Fourty randomly selected children were requested to bring water samples from their homes. Retail stores located in the area were visited for purchase of six different brands of bottled water. These samples were sent to a certified laboratory for fluoride analysis and reported in milligrams of fluoride per litre. Data analysis: Data was entered into SPSS version 20 and analysed for means, ANOVA of means and chi-square test of significance for categorical variables. All tests for significance were set at 95% confidence level (α≤0.05). Results: A total of 314 self-administered questionnaires were send to parents together with consent forms for their children's participation in the study. Two hundred and eighty six responded positively, giving a response rate of 91%. The overall prevalence of dental fluorosis among children aged 12-15 years was 93.4% with only 6.6% (n=19) recording a TFI score of 0. About one quarter 70(24.4%) of children had severe fluorosis with TFI scores of ≥5. The mean TFI score for all children was 3.09 (SD=2.0), with males recording a mean TF score of 3.01 (SD=2.11) and females a mean TF score of 3.16 (SD=1.88). Out of 44 water samples analysed, 29 (65.9%) had a fluoride content of less than 0.6mg/l, 5 (11.4%) had fluoride content of 0.7 - 1.5mg/l while 10 (22.7%) of samples had a fluoride content ≥1.5mg/l. The highest fluoride content recorded was 9.3mg/l, with another sample reflecting 8.9mgF/l. Three of the bottled water samples had a fluoride content of less than 0.6mg/l, while the other half of the bottled water reported 0.7 - 0.8mg/l fluoride. A majority (87.8%) of parents indicated that they had noticed children with brown staining of their permanent teeth in their community. About 80% of parents thought dental fluorosis was caused by salty water, while only 12.9% correctly identified water with high fluoride content as being responsible for the discolored teeth. Conclusion: Although about one in five water sources sampled had fluoride content of ≥1.5mg/l, the prevalence of dental fluorosis in this community was very high. Parental knowledge on the risk factors for dental fluorosis was low. Further research is necessary to identify the water distribution networks to provide sound evidence for engaging with the county authorities on provision of safe drinking water to the community.

Thesis (Ph.D.)--University of the Witwatersrand, Faculty of Health Sciences, 1997.

Thesis (Ph.D.)--University of Adelaide, Dental School, 2005. / Title from title page of source document (viewed July 20 2005). Bibliography: p. 232-243. Also available in print.

Thesis (DR. P.H.)--University of Michigan.

Thesis (doctoral)--Københavns tandlaegehøjskole.

Thesis (DR. P.H.)--University of Michigan.

Masters of Public Health - see Magister Public Health / Dental fluorosis is an endemic condition in a number of regions of South Africa, varying in degree of affliction according to the drinking water fluoride concentration in the area. Objective: While a number of South African studies have reported on the relationship between fluorosis and fluoride concentration in the drinking water, the purpose of this study was to determine perceptions of dental fluorosis in the Central Karoo District of the Western Cape. Methods: Learners aged 12-15 years and who had been lifelong residents in their respective areas were selected from schools in Leeu Gamka, Merweville, Nelspoort and Murraysburg. All the children meeting the inclusion criteria were included realising a total sample of 189. Drinking water fluoride concentration of each town was determined and concomitant fluorosis affliction was assessed. An interviewer administered questionnaire was used to determine respondents’ self-rated perceptions of fluorosis as well as their responses to a set of statements on clinically defined fluorosis. To this end four photographs, each depicting a different degree of fluorosis: (No fluorosis; Mild fluorosis; Moderate fluorosis; Severe fluorosis) were shown to the respondents. Results: In Leeu Gamka, with the highest fluoride concentration ([F] = 1.62ppm), 82% of respondents were aware of fluorosis stains as opposed to 6%-20% awareness in Merweville ([F] = 0.68), Nelspoort ([F] = 0.70) and Murraysburg ([F] = 0.56). Two thirds of respondents in Leeu Gamka found the appearance of their teeth embarrassing compared to only 2%-10% in the other 3 areas. The majority of respondents in Leeu Gamka (82%) indicated that they would want to remove the fluorosis spots with only 4%-20% in the lower fluoride areas. Two thirds (67%) of the Leeu Gamka respondents were teased compared to 2%-6% in the other areas. Most of the respondents have not tried to do anything to the appearance of the teeth, even in the higher fluoride area of Leeu Gamka. The average response varied little for all the photographs across the geographic areas (the minimum and maximum scores varied between 4.00 and 5.00) and reflected a greater tendency towards strongly disagreeing with the statement on aesthetics-even for the photographs depicting no fluorosis and mild fluorosis. The average response varied between 1 and 2 among all four geographic regions showing a tendency to “agree” and “strongly agree” to the statement on embarrassment. The average response to the statement on neglect varied little for all the photographs across the geographic areas as the minimum and maximum average response scores varied between 1.36 and 2.39 (agree and strongly agree). The response to the statement on disadvantage varied little for all the four photographs across the geographic areas (minimum=1.00, maximum=2.07) and reflected a greater tendency toward strongly agreeing and agreeing with the statement. Conclusion: The respondents from the higher fluoride area were more aware of dental fluorosis, had a greater perception of embarrassment and the strongest desire to remove the fluorosis staining. There was little variation in the average response to the statements on clinically defined fluorosis across the geographic areas. The learners erroneously believed that dental fluorosis was due to neglect, which is an indication that many learners are not aware of the cause of dental fluorosis in their community. The general consensus of the communities was that fluorosis was judged with feelings of negativity (embarrassment and a disadvantage for the child into adulthood).

Trabajo de Investigación Requisito para optar al Título de Cirujano Dentista / Autor no autoriza el acceso a texto completo de su documento / El siguiente trabajo describe los resultados de una investigación que determinó prevalencia y severidad de caries dental y fluorosis en niños y niñas de 8 años, que residen desde su nacimiento en las comunas de Independencia ( suplementada artificialmente con fluoruros en sus aguas de consumo ) y de Maipú ( carente de Flúor en sus aguas ) . Se seleccionó una muestra por conveniencia de 100 niños de 8 años, 50 niños de la comuna de Independencia y 50 de la comuna de Maipú. Para establecer el porcentaje de niños libre de caries se utilizó la metodología descrita por la OMS; para determinar la severidad se utilizaron los índices c.e.o.d. y C.O.P.D. y para diagnosticar prevalencia y severidad de fluorosis se utilizó el Índice de Dean. El estudio reveló que el porcentaje de niños libre de caries alcanzaba el 38% en la comuna de Independencia y el 10% en la de Maipú, sin diferencias significativas entre los géneros. Para la severidad de caries, el índice c.e.o.d. en la comuna de Independencia fue de 2,14 desglosado en: 0,54 cariadas; 0,04 con indicación de extracción y 1,58 obturadas. Para la comuna de Maipú fue de 3,82 desglosado en: 1,56 cariadas; 0,46 con indicación de extracción y 1,84 obturadas. . El índice C.O.P.D. para Independencia fue de 0,92 desglosado en: 0,26 cariadas; 0,66 obturadas y 0 perdidas. Para Maipú el valor fue de 1,48 desglosado en: 1,02 cariadas; 0,36 obturadas y 0,1 perdidas. En ambos índices, no se encontraron diferencias significativas. La prevalencia de fluorosis en la comuna de Independencia fue de un 48,8%. Los casos descritos correspondieron a las categorías Muy Leve y Leve, principalmente. En la comuna de Maipú, la prevalencia de fluorosis fue de 16%. La mayoría de los casos correspondieron a la categoría Muy Leve. Tampoco se encontraron diferencias significativas entre géneros para fluorosis. Se concluye que el aporte de flúor en el agua potable produce en los niños de 8 años una disminución en la prevalencia y severidad de la caries dental, así como un aumento en la prevalencia y severidad de la fluorosis.

The supply of drinking water in Gokwe District (NW Zimbabwe) is almost entirely based on groundwater drawn from boreholes and open dug wells. In certain areas of the district, the occurrence of dental fluorosis has been linked to excessive fluoride in the water supplies. A high prevalence of dental fluorosis (about 62%) was previously recorded among school children in the district. The aim of this study was to determine relationships between the spatial distribution of fluoride content in drinking water supplies in Gokwe, and lateral and vertical geological variation. A total of 224 water samples were collected from 196 water sources in the study area (a further 18 water sources just outside the study area were also sampled). All the samples were analysed for fluoride in the field using the fluoride ion selective electrode method (FISE). One hundred and fifty nine duplicate samples were analysed for fluoride and common anions and cations using High Performance Ion Chromatography (HPIC) in the laboratory. Two main groups of computer programmes were employed: (1) Geographic Information System (ArcView® GIS) was used to store, analyse and display multiple layers of surface geologic and geographic information, and (2) a three-dimensional visualisation programme (Rockworks) was used to interpret and illustrate site stratigraphy based on borehole information. Results indicated that the fluoride content of drinking water in the study area ranges from 0 to 9.65 mg/L. Forty-seven water sources (24%) yielded water containing fluoride in excess of the World Health Organisation's (WHO) health limit of 1.5 mg/L F. Of the 47 high fluoride water sources, 43 were boreholes (pumped or artesian). The shallower water sources (dug wells, streams and dams) largely yielded low-fluoride water. / The groundwater fluoride contamination is stratigraphically controlled and originates from carbonaceous material (carbonaceous shales, carbonaceous mudstones and coaly material) within the Lower Madumabisa and Middle Wankie Members of the Lower Karoo Group. It has been shown that in general the greater the proportion of carbonaceous material intersected by a borehole, the greater the fluoride concentration of the water. Probable mineral sources of fluoride within the carbonaceous material include fluorapatite, kaolinite and trona. Chemical parameters that appear to influence the concentration of dissolved F in the water supplies include total dissolved solids (TDS), NaCl and pH. In relatively low fluoride waters, F concentrations generally increase with TDS and NaCl concentrations, whereas the highest F concentrations are found in moderately alkaline (pH 7.8-9) waters. Based on ranges of fluoride concentration in drinking water, fluorosis-risk zones were identified and have been illustrated on a fluorosis-risk map. The zones are: No Risk Zone (0-1.5 mg/L F), Moderate Risk Zone (1.5-3.0 mg/L F), High Risk Zone (3.0-6.0 mg/L F) and the Very High Risk Zone (6.0-10.0 mg/L F). The map suggests that groundwater available to people occupying 3650 km z (60.8%) of the study area potentially contains excessive fluoride (F>1.5 mg/L), presaging the occurrence of dental fluorosis, skeletal fluorosis and crippling skeletal fluorosis in the area. Different strategies may be employed to ameliorate the fluoride problem in Gokwe. / These include sinking new boreholes to optimal depths and in appropriate locations, promoting the use of surface water and shallow groundwater, resettlement and defluoridation. However in order to fully understand the problem and to prescribe these or other solutions more comprehensively, multi-disciplinary studies may be required. Such studies may consider isotopic dating of water to investigate any relationships between fluoride concentration and residence time of water, geochemical analyses of rocks and soils, detailed fluorosis epidemiology studies and test-scale defluoridation investigations.