Systematic review of epidemiological and toxicological evidence on health effects of fluoride in drinking water.

INTRODUCTION: Fluoride is a naturally occurring substance that is also added to drinking water, dental hygiene products, and food supplements for preventing dental caries. Concerns have been raised about several other potential health risks of fluoride. OBJECTIVE: To conduct a robust synthesis of evidence regarding human health risks due to exposure to fluoride in drinking water, and to develop a point of departure (POD) for setting a health-based value (HBV) for fluoride in drinking water. METHODS: A systematic review of evidence published since recent reviews of human, animal, and in vitro data was carried out. Bradford Hill considerations were used to weigh the evidence for causality. Several key studies were considered for deriving PODs. RESULTS: The current review identified 89 human studies, 199 animal studies, and 10 major in vitro reviews. The weight of evidence on 39 health endpoints was presented. In addition to dental fluorosis, evidence was considered strong for reduction in IQ scores in children, moderate for thyroid dysfunction, weak for kidney dysfunction, and limited for sex hormone disruptions. CONCLUSION: The current review identified moderate dental fluorosis and reduction in IQ scores in children as the most relevant endpoints for establishing an HBV for fluoride in drinking water. PODs were derived for these two endpoints, although there is still some uncertainty in the causal weight of evidence for causality for reducing IQ scores in children and considerable uncertainty in the derivation of its POD. Given our evaluation of the overall weight of evidence, moderate dental fluorosis is suggested as the key endpoint until more evidence is accumulated on possible reduction of IQ scores effects. A POD of 1.56 mg fluoride/L for moderate dental fluorosis may be preferred as a starting point for setting an HBV for fluoride in drinking water to protect against moderate and severe dental fluorosis. Although outside the scope of the current review, precautionary concerns for potential neurodevelopmental cognitive effects may warrant special consideration in the derivation of the HBV for fluoride in drinking water.

Association between polymorphism and haplotype of ATP2B1 gene and skeletal fluorosis in Han population.

To evaluate the association between ATP2B1 gene polymorphisms and skeletal fluorosis, a cross-sectional study was conducted. In China, 962 individuals were recruited, including 342 cases of skeletal fluorosis. Four TP2BA1 polymorphisms (rs2070759, rs12817819, rs17249754, and rs7136259) were analysed. The results suggested that rs17249754 and rs7136259 were associated with skeletal fluorosis. After controlling confounders, the protective effect of GG genotype in rs17249754 was apparent in individuals over 45 years old, female, with urine fluoride concentration below 1.6 mg/L, serum calcium above 2.25 mmol/L or serum phosphorus between 1.1 and 1.3. Heterozygote TC in rs7136259 increased the risk of skeletal fluorosis in subjects who are elderly, female, with urinary fluoride more than 1.6 mg/L, serum calcium more than 2.25 mmol/L and blood phosphorus between 1.1 and 1.3 mmol/L. Four loci were found to be tightly related by linkage disequilibrium analysis, and the frequency of distribution of haplotype GCGT was lower in the skeletal fluorosis group.

[Spatial correlation between the prevalence of dental fluorosis and the chemical elemental composition of drinking water sources in a typical coal-fired pollution fluorosis area].

Objective: To investigate the spatial distribution characteristics and correlation between the prevalence of dental fluorosis and the chemical elemental composition of drinking water sources in coal-fired fluorosis areas. Methods: Based on the survey data on the prevalence of dental fluorosis at CDC in Guizhou Province in 2022, 274 original surface drinking water sources were collected in typical coal-fired fluorosis areas, and fluoride (F), calcium (Ca), magnesium (Mg), aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), molybdenum (Mo), cadmium (Cd), barium (Ba), lead (Pb) 17 elements; apply Moran's I index, Getis-Ord Gi* hotspot analysis of the global spatial autocorrelation of chemical elements in drinking water and the degree of aggregation of each element on the local area, and correlation analysis with the prevalence of dental fluorosis in the region. Results: Except for Cu, Zn, and Cd, global spatial autocorrelation Moran's I was negative, and all other elements were positive. F, Ca, Al, Ti, As, Mo, Cd, and Cu elements showed high values of aggregation in the southeastern low-altitude area; Mg, Ba, Pb, Cr, Mn, and Fe elements were mainly aggregated in the central altitude terrain transition area, Zn and Se elements in water sources are significantly positively correlated with the prevalence of dental fluorosis (P<0.05). In contrast, F, Mg, Al, Ti, As, Mo, Cd, Ba, and Pb elements negatively correlate (P<0.05). Elements in the central region were high-high aggregation, as a hot spot aggregation area with high disease incidence, while F, Al, Mn, Mo, Cd, and Ba elements in the western region were low-low aggregation, as a cold spot aggregation area with a low incidence of fluorosis. Conclusions: The risk of population fluoride exposure in surface drinking water sources is shallow. However, the chemical element content of drinking water sources in coal-fired polluted endemic fluorosis areas has prominent spatial geographical distribution characteristics. There is a significant spatial aggregation effect with the prevalence of dental fluorosis, which may play a synergistic or antagonistic effect on the occurrence and prevalence of dental fluorosis.

Spatial correlation between the prevalence of dental fluorosis and the chemical elemental composition of drinking water sources in a typical coal-fired pollution fluorosis area / 中华流行病学杂志

Objective: To investigate the spatial distribution characteristics and correlation between the prevalence of dental fluorosis and the chemical elemental composition of drinking water sources in coal-fired fluorosis areas. Methods: Based on the survey data on the prevalence of dental fluorosis at CDC in Guizhou Province in 2022, 274 original surface drinking water sources were collected in typical coal-fired fluorosis areas, and fluoride (F), calcium (Ca), magnesium (Mg), aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), molybdenum (Mo), cadmium (Cd), barium (Ba), lead (Pb) 17 elements; apply Moran's I index, Getis-Ord Gi* hotspot analysis of the global spatial autocorrelation of chemical elements in drinking water and the degree of aggregation of each element on the local area, and correlation analysis with the prevalence of dental fluorosis in the region. Results: Except for Cu, Zn, and Cd, global spatial autocorrelation Moran's I was negative, and all other elements were positive. F, Ca, Al, Ti, As, Mo, Cd, and Cu elements showed high values of aggregation in the southeastern low-altitude area; Mg, Ba, Pb, Cr, Mn, and Fe elements were mainly aggregated in the central altitude terrain transition area, Zn and Se elements in water sources are significantly positively correlated with the prevalence of dental fluorosis (P<0.05). In contrast, F, Mg, Al, Ti, As, Mo, Cd, Ba, and Pb elements negatively correlate (P<0.05). Elements in the central region were high-high aggregation, as a hot spot aggregation area with high disease incidence, while F, Al, Mn, Mo, Cd, and Ba elements in the western region were low-low aggregation, as a cold spot aggregation area with a low incidence of fluorosis. Conclusions: The risk of population fluoride exposure in surface drinking water sources is shallow. However, the chemical element content of drinking water sources in coal-fired polluted endemic fluorosis areas has prominent spatial geographical distribution characteristics. There is a significant spatial aggregation effect with the prevalence of dental fluorosis, which may play a synergistic or antagonistic effect on the occurrence and prevalence of dental fluorosis.

Dietary Fluoride Intake by Children: When to Use a Fluoride Toothpaste?

Fluoride is recommended for its cariostatic effect, but excessive fluoride intake may have health risks. Increased prevalence of dental fluorosis in areas with low fluoride content in drinking water has been attributed to the inappropriate excessive intake of fluoride supplements (tablets and drops) and toothpaste ingestion. The aim of the present study was to estimate the fluoride intake and the risk of fluorosis in children (6 months-6 years) in the Castelli Romani area (province of Rome, Italy), which is volcanic, therefore with a higher concentration of fluorine. Measurements of the fluoride content in drinking water, mineral waters, vegetables and commercial toothpaste for children were performed. The fluoride concentrations of all samples were determined using a Fluoride Ion Selective Electrode (GLP 22, Crison, Esp). Data were analyzed by descriptive statistics. Differences between samples were determined by Student's t-test. The fluoride content in tap water samples collected from public sources averaged from 0.35 to 1.11 ppm. The Pavona area showed the highest content of fluoride with respect to the others (p ≤ 0.05). The fluoride content in mineral water samples averaged from 0.07 to 1.50 ppm. The fluoride content of some vegetables showed increased mean values when compared to control vegetables (p ≤ 0.05). Within the limitations of the present study, considerations should be made when prescribing fluoride toothpaste for infants (6 months-4 years) in the areas with high fluoride content, because involuntary ingestion is consistent.

Condition of mineralized tooth tissue in a population of 15-year-old adolescents living in a region of Ukraine with slightly exceeded fluorine concentration in the water.

INTRODUCTION: Fluorine is a common element in nature; however, the difference between a beneficial dose and a toxic dose for the organisms is small. The main source of fluoride for humans is water in addition to food. OBJECTIVE: The aim of this study was to estimate the degree of severity of pathological changes, namely, caries or fluorosis, in the mineralized tooth tissue of 15-year-old adolescents with respect to their hygienic and nutritional habits, and the content of fluorine in drinking water, soil and plant products. MATERIAL AND METHODS: 100 adolescents aged 15 from schools in Sosnilka, L'viv region, were examined. The condition of mineralized tooth tissue was evaluated by the caries severity, expressed by the mean number D3MFT, caries frequency and value of the SIC index. Fluorine in plant material and soil were determined according to the PN-G-04543:1982 standard, and water according to the PN-EN ISO 10304 - 1: 2009+ AC: 2012 standard. RESULTS: Severity of caries disease expressed by the D3MFT number in the examined group of 15-year-olds was 3.39; in the group of girls - 3.08, and in the group of boys - 3.76. In the examined group, the average number of teeth with fluorosis was 7.59. Value of the SIC index among the examined population of students (n-31) was 6.26: 5.89 (n-18) for girls and 7.31 (n-13) for boys. Fluorine concentration in the water was 0.78 - 1.25(mg·dm-3). In the soil, it also did not vary across the sampled areas and amounted, on average, to 176 mg·dm-3. The biggest fluorine content noted in the dry mass of beetroots was 3.50 (mg F· kg), and the lowest - 3.34 (mg F· kg). CONCLUSIONS: Close to optimal fluorine content lowers caries severity and frequency of fluorosis. Optimal fluorine content in drinking water and food does not require additional diet supplementation.

Brick tea consumption is a risk factor for dental caries and dental fluorosis among 12-year-old Tibetan children in Ganzi.

Brick tea contains high concentration of fluoride. The aim of the present work was to explore whether and how the brick tea is a risk factor for dental caries and dental fluorosis among Tibetan children in Ganzi. A cross-sectional study was conducted with 368 12-year-old Tibetan children in Ganzi. Dental caries was measured by DMFT index, and dental fluorosis severity was measured by Dean's Index. Community Fluorosis Index was used to estimate public health significance of dental fluorosis. Oral health-related behaviors and awareness, dietary habits and socioeconomic status were determined by a questionnaire. Bivariate and multivariate analyses were used to determine risk factors associated with dental caries and dental fluorosis. Dental caries prevalence was 37.50%, mean DMFT was 0.84 ± 1.53, while dental fluorosis prevalence was 62.23%. Community Fluorosis Index was 1.35, indicating a medium prevalent strength of dental fluorosis. Dental fluorosis was associated with mother's regular consumption of brick tea and residence altitude, and dental caries was associated with mother's regular consumption of brick tea. Mother's regular consumption of brick tea was a risk factor for both dental fluorosis and dental caries among children. Reducing mother's brick tea consumption during pregnancy and lactation may improve oral health status of their children.

Prevalence of Brick Tea-Type Fluorosis in the Tibet Autonomous Region.

BACKGROUND: The prevalence of brick tea-type fluorosis is high in Tibet because of the habit of drinking brick tea in this region. Brick tea-type fluorosis has become an urgent public health problem in China. METHODS: A cross-sectional survey was conducted to investigate prevalence of brick tea-type fluorosis in all districts of Tibet using a stratified cluster sampling method. Dental fluorosis in children aged 8-12 years and clinical skeletal fluorosis in adults were diagnosed according to the national criteria. A total of 423 children and 1320 adults participated in the study. Samples of drinking water, brick tea, brick tea infusion (or buttered tea), and urine were collected and measured for fluoride concentrations by the fluoride ion selective electrode method. RESULTS: The fluoride level in all but one of the brick tea samples was above the national standard. The average daily fluoride intake from drinking brick tea in all seven districts in Tibet was much higher than the national standard. The prevalence of dental fluorosis was 33.57%, and the prevalence of clinical skeletal fluorosis was 46.06%. The average daily fluoride intake from drinking brick tea (r = 0.292, P < 0.05), urine fluoride concentrations in children (r = 0.134, P < 0.05), urine fluoride concentrations in adults (r = 0.162, P < 0.05), and altitude (r = 0.276, P < 0.05) were positively correlated with the prevalence of brick tea-type fluorosis. Herdsmen had the highest fluoride exposure and the most severe skeletal fluorosis. CONCLUSIONS: Brick tea-type fluorosis in Tibet is more serious than in other parts of China. The altitude and occupational factors are important risk factors for brick tea-type fluorosis.

Modifying Role of GSTP1 Polymorphism on the Association between Tea Fluoride Exposure and the Brick-Tea Type Fluorosis.

BACKGROUND: Brick tea type fluorosis is a public health concern in the north-west area of China. The association between SNPs of genes influencing bone mass and fluorosis has attracted attention, but the association of SNPs with the risk of brick-tea type of fluorosis has not been reported. OBJECTIVE: To investigate the modifying roles of GSTP1 rs1695 polymorphisms on this association. METHODS: A cross-sectional study was conducted. Brick-tea water was tested by the standard of GB1996-2005 (China). Urinary fluoride was tested by the standard of WS/T 89-2006 (China). Skeletal fluorosis was diagnosed by X-ray, the part we scheduled was forearm, shank, and pelvic, then diagnosed the skeletal fluorosis by the standard of WS/192-2008 (China). Gene polymorphism was tested by Sequenom MassARRAY system. RESULT: The prevalence rate in different ethnical participants was different: Tibetan individuals had the highest prevalence rate of skeletal fluorosis. There were significant differences in genotype frequencies of GSTP1 Rs1695 among different ethnical participants (p<0.001): Tibetan, Mongolian and Han subjects with homozygous wild type (GSTP1-AA) genotype were numerically higher than Kazakh and Russian subjects (p<0.001). Compared to Tibetan participants who carried homozygous A allele of GSTP1 Rs1695, Tibetan participants who carried G allele had a significantly decreased risk of skeletal fluorosis (OR = 0.558 [95% CI, 0.326-0.955]). For Kazakh participants, a decreased risk of skeletal fluorosis among carriers of the G allele was limited to non high-loaded fluoride status (OR = 0. 166 [95% CI, 0.035-0.780] vs. OR = 1.478 [95% CI, 0.866-2.552] in participants with high-loaded fluoride status). Neither SNP-IF nor SNP-age for GSTP1 Rs1695 was observed. CONCLUSION: The prevalence rate of the brick tea type fluorosis might have ethnic difference. For Tibetan individuals, who had the highest prevalence rate, G allele of GSTP1 Rs1695 might be a protective factor for brick tea type skeletal fluorosis.

Water fluoridation and oral health.

UNLABELLED: Water fluoridation, is the controlled addition of fluoride to the water supply, with the aim of reducing the prevalence of dental caries. Current estimates suggest that approximately 370 million people in 27 countries consume fluoridated water, with an additional 50 million consuming water in which fluoride is naturally occurring. A pre-eruptive effect of fluoride exists in reducing caries levels in pit and fissure surfaces of permanent teeth and fluoride concentrated in plaque and saliva inhibits the demineralisation of sound enamel and enhances the remineralisation of demineralised enamel. A large number of studies conducted worldwide demonstrate the effectiveness of water fluoridation. Objections to water fluoridation have been raised since its inception and centre mainly on safety and autonomy. Systematic reviews of the safety and efficacy of water fluoridation attest to its safety and efficacy; dental fluorosis identified as the only adverse outcome. CONCLUSION: Water fluoridation is an effective safe means of preventing dental caries, reaching all populations, irrespective of the presence of other dental services. Regular monitoring of dental caries and fluorosis is essential particularly with the lifelong challenge which dental caries presents.

Dietary behaviours and dental fluorosis among Gaza Strip children.

A high prevalence of dental fluorosis has been identified among children in the Gaza Strip. This study aimed to determine the history of breastfeeding and dietary behaviours among children in the Gaza Strip and to examine potential associations with the prevalence and severity of dental fluorosis. A cross-sectional study recruited a stratified cluster random sample of 350 children aged 12-18 years and their mothers. Data about dietary behaviours in the first 7 years of life were collected by interview questionnaire. Dental fluorosis was determined using the Thyllstrup-Fejerskov index. A majority of children were breastfed exclusively in the first 6 months (82.9%) but 98.1% were given tea in the first year of life. The prevalence of dental fluorosis was 78.0%. Both intake of animal proteins and plant proteins were negatively associated with the prevalence and severity of dental fluorosis. Further studies to investigate fluoride intake is required to plan preventive interventions.

Prevalence and aetiology of juvenile skeletal fluorosis in the south-west of the Hai district, Tanzania--a community-based prevalence and case-control study.

INTRODUCTION: Fluorosis is endemic throughout the East African Rift valley, including parts of Tanzania. The aim of the study was to identify all cases of deforming juvenile skeletal fluorosis (JSF) in a northern Tanzanian village and to document the extent of dental fluorosis (DF). METHODS: Door-to-door prevalence survey of all residents of the village. Residents were assessed for the presence of DF and JSF. Those with JSF and randomly selected controls from the same age range were further assessed for possible JSF risk factors. RESULTS: The village had a population of 1435. DF was endemic within the population, being present in 911 (75.5%; 95% CI, 73.0-77.9) of dentate individuals who were examined (n = 1207). JSF was present in 56 of 1263 people examined, giving a prevalence of 4.4% (95% CI, 3.3-5.6) and was more common in males. Low body mass index, drinking predominantly well water 3 years previously, not being weaned on bananas, the use of fluoride salts in cooking during childhood and drinking more cups of tea per day were independent predictors of JSF. CONCLUSIONS: Juvenile skeletal fluorosis is a common and preventable public health problem. Providing clean, low-fluoride, piped water to affected communities is of obvious health benefit.

Groundwater quality and its health impact: An assessment of dental fluorosis in rural inhabitants of the Main Ethiopian Rift.

This study aims to assess the link between fluoride content in groundwater and its impact on dental health in rural communities of the Ethiopian Rift. A total of 148 water samples were collected from two drainage basins within the Main Ethiopian Rift (MER). In the Ziway-Shala basin in particular, wells had high fluoride levels (mean: 9.4±10.5mg/L; range: 1.1 to 68 mg/L), with 48 of 50 exceeding the WHO drinking water guideline limit of 1.5mg/L. Total average daily intake of fluoride from drinking groundwater (calculated per weight unit) was also found to be six times higher than the No-Observed-Adverse-Effects-Level (NOAEL) value of 0.06 mg/kg/day. The highest fluoride levels were found in highly-alkaline (pH of 7 to 8.9) groundwater characterized by high salinity; high concentrations of sodium (Na⁺), bicarbonate (HCO3⁻), and silica (SiO2); and low concentrations of calcium (Ca²âº). A progressive Ca²âº decrease along the groundwater flow path is associated with an increase of fluoride in the groundwater. The groundwater quality problem is also coupled with the presence of other toxic elements, such as arsenic (As) and uranium (U). The health impact of fluoride was evaluated based on clinical examination of dental fluorosis (DF) among local residents using the Thylstrup and Fejerskov index (TFI). In total, 200 rural inhabitants between the ages of 7 and 40 years old using water from 12 wells of fluoride range of 7.8-18 mg/L were examined. Signs of DF (TF score of ≥ 1) were observed in all individuals. Most of the teeth (52%) recorded TF scores of 5 and 6, followed by TF scores of 3 and 4 (30%), and 8.4% had TF scores of 7 or higher. Sixty percent of the teeth exhibited loss of the outermost enamel. Within the range of fluoride contents, we did not find any correlation between fluoride content and DF. Finally, preliminary data suggest that milk intake has contributed to reducing the severity of DF. The study highlights the apparent positive role of milk on DF, and emphasizes the importance of nutrition in management efforts to mitigate DF in the MER and other parts of the world.

Enduring fluoride health hazard for the Vesuvius area population: the case of AD 79 Herculaneum.

BACKGROUND: The study of ancient skeletal pathologies can be adopted as a key tool in assessing and tracing several diseases from past to present times. Skeletal fluorosis, a chronic metabolic bone and joint disease causing excessive ossification and joint ankylosis, has been only rarely considered in differential diagnoses of palaeopathological lesions. Even today its early stages are misdiagnosed in endemic areas. METHODOLOGY/PRINCIPAL FINDINGS: Endemic fluorosis induced by high concentrations of fluoride in water and soils is a major health problem in several countries, particularly in volcanic areas. Here we describe for the first time the features of endemic fluorosis in the Herculaneum victims of the 79 AD eruption, resulting from long-term exposure to high levels of environmental fluoride which still occur today. CONCLUSIONS/SIGNIFICANCE: Our observations on morphological, radiological, histological and chemical skeletal and dental features of this ancient population now suggest that in this area fluorosis was already endemic in Roman times. This evidence merged with currently available epidemiologic data reveal for the Vesuvius area population a permanent fluoride health hazard, whose public health and socio-economic impact is currently underestimated. The present guidelines for fluoridated tap water might be reconsidered accordingly, particularly around Mt Vesuvius and in other fluoride hazard areas with high natural fluoride levels.

Evidence-based clinical recommendations on the prescription of dietary fluoride supplements for caries prevention: a report of the American Dental Association Council on Scientific Affairs.

BACKGROUND: This article presents evidence-based clinical recommendations for the prescription of dietary fluoride supplements. The recommendations were developed by an expert panel convened by the American Dental Association (ADA) Council on Scientific Affairs (CSA). The panel addressed the following questions: when and for whom should fluoride supplements be prescribed, and what should be the recommended dosage schedule for dietary fluoride supplements? TYPES OF STUDIES REVIEWED: A panel of experts convened by the ADA CSA, in collaboration with staff of the ADA Center for Evidence-based Dentistry, conducted a MEDLINE search to identify publications that addressed the research questions: systematic reviews as well as clinical studies published since the systematic reviews were conducted (June 1, 2006). RESULTS: The panel concluded that dietary fluoride supplements should be prescribed only for children who are at high risk of developing caries and whose primary source of drinking water is deficient in fluoride. CLINICAL IMPLICATIONS: These recommendations are a resource for practitioners to consider in the clinical decision-making process. As part of the evidence-based approach to care, these clinical recommendations should be integrated with the practitioner's professional judgment and the patient's needs and preferences. Providers should carefully monitor the patient's adherence to the fluoride dosing schedule to maximize the potential therapeutic benefit.

Análise dos fatores de risco ou de proteção para fluorose dentária em crianças de 6 a 8 anos em Fortaleza, Brasil / Analysis of protection or risk factors for dental fluorosis in 6 to 8 year-old children in Fortaleza, Brazil

OBJETIVO: Investigar os fatores de risco ou de proteção para a fluorose dentária na dentição permanente de crianças de 6 a 8 anos em um bairro no Município de Fortaleza, Brasil. MÉTODOS: Este estudo de caso-controle incluiu 67 crianças com fluorose nos incisivos superiores e inferiores permanentes erupcionados, conforme o índice de Dean, e 57 controles. A presença de fluorose foi determinada como variável dependente. Os dados acerca das variáveis independentes foram obtidos através de entrevistas com os pais das crianças. O teste exato de Fisher foi utilizado para verificar a existência de associação entre fluorose e as variáveis independentes. Foi calculada a razão de chances (odds ratio, OR) para verificar a associação e a probabilidade de fluorose no grupo-caso, ambos com significância de 95 por cento. RESULTADOS: Houve associação significativa da fluorose com tipo de moradia (própria, alugada ou ocupada), mas não com fonte de água para consumo ou uso de dentifrícios fluoretados e suplementos de flúor. Na análise univariada, o risco de fluorose foi maior em crianças que iniciaram o consumo de leite em pó reconstituído com água antes dos 2 anos de idade (OR = 4,53; IC95 por cento: 1,07 a 26,74) e nas que não mamaram (OR = 6,66; IC95 por cento: 1,61 a 38,62). Na análise multivariada, somente a amamentação apresentou associação com a fluorose (4,54; IC95 por cento: 1,21 a 16,66). CONCLUSÕES: A amamentação se configurou como fator de proteção contra a fluorose. É preciso estabelecer critérios de classificação mais específicos para permitir a investigação de relações entre fluorose e classe socioeconômica.

OBJECTIVE: To investigate protection or risk factors for dental fluorosis in permanent teeth of 6 to 8 year-old children in a neighborhood of Fortaleza, Brazil. METHODS: This case-control study included 57 controls and 67 children with fluorosis affecting superior and inferior incisors teeth as determined by the Dean classification criteria. Presence of fluorosis was considered as the dependent variable. Data concerning independent variables were obtained through interviews with the parents. Fisher's exact test was used to determine associations between fluorosis and the independent variables. Odds ratios (OR) were calculated to investigate associations and likelihood of fluorosis in the case group, with 95 percent significance level. RESULTS: Fluorosis was significantly associated with type of housing (owned, rented or squatted), but not with the source of drinking water or use of fluoridated toothpaste and fluoride supplements. Univariate analysis showed that the risk of fluorosis was higher in children who began drinking powdered milk mixed with water before 2 years of age (OR = 4.53; IC95 percent: 1.07-26.74) and in those who did not breastfeed (OR = 6.66; IC95 percent: 1.61-38.62). In the multivariate analysis, only breastfeeding was associated with fluorosis (4.54; IC95 percent: 1.21-16.66). CONCLUSIONS: Breastfeeding was a protection factor against fluorosis. More specific categorization criteria must be established to investigate relationships between fluorosis and socioeconomic class.

Prevalence of dental fluorosis in children taking part in an oral health programme including fluoride tablet supplements from the age of 2 years.

AIM: To investigate the prevalence of dental fluorosis in children who had participated in an oral health programme between the ages 2-5 years, including fluoride tablets from the age of 2 years. DESIGN: The study group consisted of 135 10- to 11-year-old children who had participated in the programme, including parent education, tooth-brushing instruction and prescribed fluoride tablets (0.25 mg NaF) (2-3 years: 1 tablet/day; 3-5 years: 2 tablets/day). The prevalence of dental fluorosis in the study group was compared with that in a nonintervention reference group consisting of 129 children of the same ages. The analysis was based on photos of the permanent maxillary front teeth using the Thylstrup & Fejerskov (TF) Index. RESULTS: No statistically significant difference in prevalence of dental fluorosis was seen between the two groups. Forty-three percent of the children in the study group and 38% in the reference group had fluorosis, the majority of a mild nature (TF-score 1). None had a TF score above 2. The pattern was the same after correction for parent reported intake of tablets at 3 and 5 years of age. CONCLUSION: Introduction of fluoride tablets at the age of 2 years did not result in increased prevalence of dental fluorosis.

Assessment of dental fluorosis prevalence in Swiss populations.

In 1996 and 2006, recruits of the Swiss army participated in a dental survey. Similarly in 1995/96 and 2004/05, randomly selected schoolchildren from 16 rural communities of the Canton of Zurich participated in a dental survey. As part of these surveys, color slides were taken of the incisor teeth of all recruits, as well as of third and fourth grade schoolchildren. The slides (N = 2049) were examined for the presence of fluoride-associated enamel opacities (FOP), using the Thyl-strup-Fejerskov (TF) index. Two examiners (A and B) assessed all slides. The examiners were blind as to the year of survey. Examiner A recorded prevalences of FOP between 18% and 27% depending on population; examiner B recorded prevalences between 7% and 12%. The examiners' influence on the estimation of the prevalence was obvious. The prevalences reported should, therefore, be considered as rough estimates. FOP of TF score 2 were only observed in approximately 1% of the participants. One examiner recorded a TF score 3 in a single individual. FOP therefore are not a cosmetic problem and certainly not a public health concern. The prevalence of FOP decreased slightly during observation period I (recruits born 1975-77 vs 1985-87) and period II (school children born 1985-87 vs 1994-96). However, the decline was statistically supported in only one instance (Period I, Examiner B).

[Analysis of protection or risk factors for dental fluorosis in 6 to 8 year-old children in Fortaleza, Brazil]. / Análise dos fatores de risco ou de proteção para fluorose dentária em crianças de 6 a 8 anos em Fortaleza, Brasil.

OBJECTIVE: To investigate protection or risk factors for dental fluorosis in permanent teeth of 6 to 8 year-old children in a neighborhood of Fortaleza, Brazil. METHODS: This case-control study included 57 controls and 67 children with fluorosis affecting superior and inferior incisors teeth as determined by the Dean classification criteria. Presence of fluorosis was considered as the dependent variable. Data concerning independent variables were obtained through interviews with the parents. Fisher's exact test was used to determine associations between fluorosis and the independent variables. Odds ratios (OR) were calculated to investigate associations and likelihood of fluorosis in the case group, with 95% significance level. RESULTS: Fluorosis was significantly associated with type of housing (owned, rented or squatted), but not with the source of drinking water or use of fluoridated toothpaste and fluoride supplements. Univariate analysis showed that the risk of fluorosis was higher in children who began drinking powdered milk mixed with water before 2 years of age (OR = 4.53; IC95%: 1.07-26.74) and in those who did not breastfeed (OR = 6.66; IC95%: 1.61-38.62). In the multivariate analysis, only breastfeeding was associated with fluorosis (4.54; IC95%: 1.21-16.66). CONCLUSIONS: Breastfeeding was a protection factor against fluorosis. More specific categorization criteria must be established to investigate relationships between fluorosis and socioeconomic class.

Comparative study of dental caries and dental fluorosis in populations of different dental fluorosis prevalence.

INTRODUCTION: There is evidence that the prevalence of dental fluorosis in many countries has increased over the last three decades along with a noted decrease of dental caries. To date no comparative studies of dental caries and dental fluorosis have been conducted in Bulgaria reflecting the present-day conditions of life. AIM: To study comparatively the prevalence of dental fluorosis and dental caries and to establish what relationship, if any, there is between them. MATERIAL AND METHODS: We performed a comparative analysis of three epidemiological studies carried out in Plovdiv and Dimitrovgrad in 2004, 2005 and 2008. The hypothesis tested was that dental caries was less frequent in populations with higher prevalence of dental fluorosis (with predominance of mild fluorosis cases). Dental fluorosis was diagnosed using Dean's criteria, and dental caries was scored using the WHO criteria. The results were analysed using the alternative analysis and analysis of variance at a level of significance P < 0.05. RESULTS: The prevalence of dental fluorosis in the studied populations in Dimitrovgrad in 2004 was 56.99%, in Plovdiv in 2005--7.80%, and in 2008--23.18%. The comparison of the studies in Dimitrovgrad and Plovdiv in 2005 showed lower prevalence of dental caries and lower DMFT values in all age groups (P < 0.001) in Dimitrovgrad, where the prevalence of dental fluorosis was greater than that in Plovdiv (P < 0.001). The comparison between the studies in Plovdiv alone in 2005 and 2008 showed an increase in dental fluorosis in 2008 (P < 0.001). The prevalence of dental caries was higher in almost all groups, but the differences failed to reach statistical significance (P < 0.001). The DMFT index was higher in 2008 (P < 0.001) with the exception of some age groups. CONCLUSION: The higher prevalence of dental fluorosis does not necessarily lead to low prevalence of dental caries and low DMFT values in the specific population.