Prevalence and risk factors of dental fluorosis among children aged 8-12 years in Shandong province of China.

This study was to investigate the prevalence and severity of children's dental fluorosis (DF) in Shandong and identified the potential risk factors for DF. A total of 87 villages in Shandong were investigated to calculate the prevalence of DF and Community Fluorosis Index (CFI) in 2018-2019. Six hundred and seventy children were enrolled to identify the potential risk factors using univariate and multivariate logistic regressions. Goodman-Kruskal Gamma was used to explore the factors related to the severity of DF. In 87 villages, 1249 of 8700 (14.36%) children still have DF. The prevalence of DF in most villages was below 40% in 2018-2019. Water fluorine concentration when selected for the study and urinary fluorine concentration were related to the risk of DF (P < 0.001). Some eating habits, like lower frequency of eating fresh vegetables, eggs, and beans, were associated with the risk of DF (P < 0.001). The high water fluorine concentration, and lower frequency of eating fresh vegetables, eggs, and beans were also related to the severity of DF (P < 0.001). DF in children in Shandong province is still a common endemic disease. This study tries to provide a useful guide for the prevention and control of DF.

Health risk assessment in an area of dental fluorosis disease from high fluoride drinking water: a case study from southeastern Türkiye.

This study focuses on identifying fluoride (F‒) concentrations and its health risk assessment (HRA) in drinking water sources in south-eastern Türkiye. Groundwater quality was assessed using some graphical approaches such as Schoeller and Piper diagrams and GIS mapping. Average daily exposure dosages through oral and dermal contact exposure routes were considered to determine the potential health risk of F‒ in groundwater. Groundwater samples were taken from 53 points in spring, summer, autumn, and winter seasons. The results showed that the average annual F‒ concentrations in water resources in the study area were 0.26‒3.62 mg/L. According to the HRA results, the highest F‒ health risk in this region was observed in children, followed by teenagers and adults. This study indicated that there is a strong relationship between the high health risk (4.28 > 3.5) in children and dental fluorosis caused by high F‒ concentration in groundwater.

The fluorosis conundrum: bridging the gap between science and public health.

Fluorosis, a chronic condition brought on by excessive fluoride ingestion which, has drawn much scientific attention and public health concern. It is a complex and multifaceted issue that affects millions of people worldwide. Despite decades of scientific research elucidating the causes, mechanisms, and prevention strategies for fluorosis, there remains a significant gap between scientific understanding and public health implementation. While the scientific community has made significant strides in understanding the etiology and prevention of fluorosis, effectively translating this knowledge into public health policies and practices remains challenging. This review explores the gap between scientific research on fluorosis and its practical implementation in public health initiatives. It suggests developing evidence-based guidelines for fluoride exposure and recommends comprehensive educational campaigns targeting the public and healthcare providers. Furthermore, it emphasizes the need for further research to fill the existing knowledge gaps and promote evidence-based decision-making. By fostering collaboration, communication, and evidence-based practices, policymakers, healthcare professionals, and the public can work together to implement preventive measures and mitigate the burden of fluorosis on affected communities. This review highlighted several vital strategies to bridge the gap between science and public health in the context of fluorosis. It emphasizes the importance of translating scientific evidence into actionable guidelines, raising public awareness about fluoride consumption, and promoting preventive measures at individual and community levels.

Association between fluoride intake from drinking water and severity of dental fluorosis in Northern and Western Mexico: systematic review and meta-analysis.

BACKGROUND: Dental fluorosis (DF) is caused by excessive exposure to fluoride during odontogenesis and leads to various changes in the development of tooth enamel. Some regions in Mexico are considered endemic fluorosis zones due to the high fluoride content in drinking water. The objective of this study was to perform a systematic review and meta-analysis to identify the association between the concentration of fluoride in drinking water and the severity of dental fluorosis in northern and western Mexico. METHODS: This protocol was registered in the PROSPERO database (ID: CRD42023401519). The search for information was carried out in the PubMed/Medline, Scopus, SpringerLink, and Google Scholar databases between January 2015 and October 2023. The overall relative risk was calculated using the inverse of variance approach with the random effects method. The RoB 2.0 tool was used to construct risk plots. RESULTS: Eleven articles were analyzed qualitatively, and most of the included studies presented at least one level of DF severity; six articles were analyzed quantitatively, dividing them into two regions. In North region it was observed a higher prevalence of severe TF cases, corresponding to ≥ TF 5 category (4.78) [3.55, 6.42]. In the West region, most of the included studies presented a higher prevalence of less severe cases, corresponding to ≤ TF 4, in comparison with the North region (0.01) [0.00, 0.52], interpreted as a protective effect. CONCLUSION: The concentrations of fluorides in drinking water are reportedly high in these regions and are directly related to the severity of dental fluorosis experienced by the inhabitants. In the Northern region exists a major concentration of fluoride in drinking water compared with the Western region as well as a prevalence of higher severity cases of dental fluorosis.

Potential risk of dental fluorosis associated with different baby formulas and water brands marketed in Spain.

Despite efforts to promote breastfeeding, many babies aged <6 months receive only baby formula reconstituted with bottled water. The intake of high levels of fluoride during amelogenesis has been associated with hypomineralization of the tooth enamel, with aesthetic and mechanical repercussions. The objective of this study was to determine the potential risk of dental fluorosis associated with baby formulas marketed in Spain. We measured 26 baby formulas frequently consumed in Spain; 17 brands for babies aged <6 months, 5 for those aged >6 months, and 4 ready-to-use brands. They were prepared with 4 types of water: distilled water and three brands of bottled water with different levels of fluoride. The fluoride concentration (mg/L or ppm F) was measured with an ion-specific electrode coupled to an ion analyzer. Each sample was prepared according to the manufacturer's instructions and analyzed in triplicate. A descriptive analysis was carried out. The minimum fluoride level found was 0.04 mg/L and the maximum was 1.02 mg/L. Considering the daily intake of these formulas, none exceeded the clinically-acceptable daily dose limit risk for fluorosis (0.07 mg F/day/kg body weight) when mixed with bottled water with a low level of fluoride (0.1 mg/L). However, when the same brands of formula were reconstituted with bottled water with a higher fluoride content (0.99 mg/L), they all exceeded the daily dose limit for the risk of fluorosis. As the potential risk of dental fluorosis associated with the formulas tested depends exclusively on the fluoride concentration of the waters used for reconstitution, formula packaging should contain a warning.

Fluoride and children's IQ: evidence of causation lacking.

DATA SOURCES: Human, animal, and in vitro studies. Extensive literature search of multiple bibliographic databases, trial registries, major grey literature sources and bibliographies of identified studies. STUDY SELECTION: The authors aimed to identify studies which could be used to determine the maximum safe level for fluoride in drinking water. To identify new studies published since a 2016 Australian review, the search period was 2016 to July 2021. Studies which evaluated the association between either naturally or artificially fluoridated water (any concentration) and any health outcomes were included. No restrictions on study design or publication status. Articles published in a 'non-Latin language' were excluded. Screening of abstracts and full texts was in duplicate. For IQ and dental fluorosis, a top-up search was conducted between 2021 and Feb 2023. DATA EXTRACTION AND SYNTHESIS: Extensive data extraction. Risk of bias assessment using the OHAT tool. A narrative synthesis of the results was carried out. RESULTS: The review included 89 studies in humans, 199 in animals and 10 reviews of in vitro studies. Where there was consistent evidence of a positive association, in relation to a water fluoride concentration of <20 ppm (mg F/L), and where studies were judged to be acceptable or high quality, health effects were taken forwards for further examination of causality using Bradford Hill's 9 criteria. Of the 39 health outcomes reviewed, 4 were further assessed for causality. The authors reported 'strong' evidence of causality for dental fluorosis and reductions in children's IQ scores, 'moderate' strength evidence for thyroid dysfunction, 'weak' for kidney dysfunction, and 'limited' evidence for sex hormone disruption. CONCLUSIONS: The authors conclude that moderate dental fluorosis and reductions in children's IQ scores are the most appropriate health outcomes to use when setting an upper safe level of fluoride in drinking water. For reductions in children's IQ, the authors acknowledge a biological mechanism of action has not been elucidated, and the dose response curve is not clear at lower concentrations, limiting the ability to set an upper safe threshold.

Community Water Fluoridation Levels To Promote Effectiveness and Safety in Oral Health - United States, 2016-2021.

Drinking water fluoridated at the level recommended by the U.S. Public Health Service (USPHS) reduces dental caries (cavities) by approximately 25% in children and adults (1). USPHS recommends fluoride levels to achieve oral health benefits and minimize risks associated with excess fluoride exposure. To provide the benefits of community water fluoridation, water systems should target a level of 0.7 mg/L and maintain levels ≥0.6 mg/L (2). The Environmental Protection Agency (EPA) sets a safety standard at 2.0 mg/L to prevent mild or moderate dental fluorosis, a condition that causes changes in the appearance of tooth enamel caused by hypermineralization resulting from excess fluoride intake during tooth-forming years (i.e., before age 8 years). During 2016-2021, fluoride measurements for 16.3% of population-weighted monthly fluoride measurements (person-months) reported by community water systems to CDC's Water Fluoridation Reporting System (WFRS) were <0.6 mg/L; only 0.01% of person-months exceeded 2.0 mg/L. More than 80% of population-weighted fluoride measurements from community water systems reporting to WFRS were above 0.6 mg/L. Although 0.7 mg/L is the recommended optimal level, ≥0.6 mg/L is still effective for the prevention of caries. A total of 4,080 community water systems safely fluoridated water 99.99% of the time with levels below the secondary safety standard of 2.0 mg/L. Water systems are encouraged to work with their state programs to report their fluoride data into WFRS and meet USPHS recommendations to provide the full benefit of fluoridation for caries prevention.

Toothbrushing practices as risk factors for dental fluorosis in an area with varying fluoride levels in drinking water.

BACKGROUND: Despite contributing to a reduction in dental caries, improper use of fluoridated toothpaste could add to the burden of dental fluorosis in children. AIM: To assess the association between tooth-brushing practices such as the type and amount of toothpaste used, frequency of tooth brushing, parental assistance in tooth brushing, timing of tooth brushing and dental fluorosis in school children in Kurunegala district, an endemic area for dental fluorosis in Sri Lanka. METHODS: For this case-control study, a sex-matched sample of 15-year-old school children attending government schools in Kurunegala district and who were lifetime residents of the district was selected. Dental fluorosis was measured using the Thylstrup and Ferjeskov (TF) Index. Those children with a TF⟩1 were considered as cases and those with a TF score of 0 or 1 served as controls. An interview of parents/caregivers of the participants was used to assess risk factors for dental fluorosis. The fluoride concentration in drinking water was measured using spectrophotometry. Data analysis used chi-square tests and conditional logistic regression. RESULTS: Tooth brushing ≥ twice/day, brushing after breakfast and parent/care giver brushing the child's teeth reduced the likelihood of developing fluorosis. CONCLUSION: Use of fluoridated toothpaste adhering to the recommended guidelines could prevent dental fluorosis in children in this endemic area.

The association of high-fluoride and high-iodine combined exposure with dental fluorosis and goiter: a meta-analysis.

It is controversial that high-fluoride and high-iodine combined exposure affects the prevalence of dental fluorosis and goiter. The aim of this study was to explore the potential association between high-fluoride and high-iodine combined exposure with dental fluorosis and goiter. We retrieved relevant articles from PubMed, Cochrane Library, China National Knowledge Infrastructure, Wanfang Database and China Science and Technology Journal Database (VIP). The query format was 1 # "Fluorosis" OR "Fluoride," 2 # "Iodine" OR "Iodide," and 3 # 1 AND 2. A total of 20 papers were included in this study after independent review by two investigators. Our analysis showed that high-fluoride and high-iodine biphasic exposure was significantly associated with the prevalence of goiter (OR = 4.69, 95% CI 2.82-7.80, P < 0.001). The prevalence of dental fluorosis was also significantly raised (OR = 11.71, 95% CI 7.57-18.14, P < 0.001). Sensitivity analysis suggested that combined statistics of multiple studies were reliable. For goiter, subgroup analysis revealed study province, sample size and published year as sources of heterogeneity (P < 0.001). For dental fluorosis, only sample size was the impact factor of heterogeneity. As well, funnel plot, Begg's test and Egger's test suggested there was no publication bias (P > 0.05). Overall, our study demonstrates that high-fluoride and high-iodine combined exposure is a risk factor for occurrence of dental fluorosis and goiter. The chronic of high-fluoride and high-iodine combined exposure is a significant higher risk of disease than normal.

Fuzzy logic-based health risk assessment of fluoride in groundwater used as drinking source in Sira region, Tumkur, India.

Fluoride contamination in drinking water is a serious public health concern across the world, and more than 90 million people in India are affected by health risks associated with fluoride. Though the fatality due to fluoride chronic toxicity is uncommon, the exposure to fluoride at different concentration levels shows various adverse health effects such as dental and skeletal fluorosis, multiorgan failure, cognitive and behavioural effects. Hence, the objectives of the present study are to understand the hydrogeochemistry and drinking water suitability of groundwater of the Sira region, Karnataka, India, and to understand the occurrence of fluoride and its health risks using the United State Environmental Protection Agency (US EPA) method and fuzzy logic concepts. Forty-six samples were collected from each pre and post-monsoon season. The hydrogeochemistry studied through Chadha's diagram and Gibb's diagram indicated that the groundwater in this region is of Na-Cl type and the hydrogeochemistry is majorly controlled by rock-water interaction and followed by evaporative dominance. Water quality parameters were compared with drinking water standards guidelines, and the results showed that around 50% of the samples were contaminated with fluoride. The occurrence of high levels of fluoride in the study region is associated to the presence of granitic rocks and it is influenced by high pH and low calcium dissolution in the groundwater. Based on US EPA method, the order of population group under the risk of dental and skeletal fluorosis, is children > adolescents > adults. A fuzzy inference system model is developed to assess the health risk due to fluoride and its output gives severity levels of each type of health risk, i.e. dental caries, dental fluorosis and skeletal fluorosis. The results of the application of the fuzzy inference system model in the Sira region showed that the children (< 8 Yr.) are more susceptible to the moderate risk of dental caries, dental fluorosis and skeletal fluorosis. Whereas adolescents (8-18 Yr.) and adults (> 18 Yr.) are less susceptible to low-very low risk. Hence, health risks associated with fluoride can be better addressed with the help of a fuzzy inference system model which can be used for more reliable and grounded results to improve the quality of decision-making.

Effects of chronic fluorosis on the brain.

This article reviews the effects of chronic fluorosis on the brain and possible mechanisms. We used PubMed, Medline and Cochraine databases to collect data on fluorosis, brain injury, and pathogenesis. A large number of in vivo and in vitro studies and epidemiological investigations have found that chronic fluorosis can cause brain damage, resulting in abnormal brain structure and brain function.Chronic fluorosis not only causes a decline in concentration, learning, and memory, but also has mental symptoms such as anxiety, tension, and depression. Several possible mechanisms that have been proposed: the oxidative stress and inflammation theory, neural cell apoptosis theory, neurotransmitter imbalance theory, as well as the doctrine of the interaction of fluorine with other elements. However, the specific mechanism of chronic fluorosis on brain damage is still unclear. Thus, a better understanding of the mechanisms via which chronic fluorosis causes brain damage is of great significance to protect the physical and mental health of people in developing countries, especially those living in the endemic areas of fluorosis. In brief, further investigation concerning the influence of fluoride on the brain should be conducted as the neural damage induced by it may bring about a huge problem in public health, especially considering growing environmental pollution.

Potential fluoride exposure from selected food crops grown in high fluoride soils in the Makueni County, south-eastern Kenya.

Makueni County, located in south-eastern Kenya, faces challenges such as limited potable water and restricted food supplies as the result of semi-aridity. High fluoride (F) concentrations have been reported in drinking water with resultant dental fluorosis affecting the local population. To determine the potential F exposure through the consumption of food crops grown in the area, F concentration was assessed in the main five locally grown and consumed crops. Additionally, the water-soluble F fraction was determined from 30 soil samples with mineralogical determination of 20 samples. Mean F concentration in the food crops was in the order; 700, 288, 71.2, 36.6, and 29 mg/kg in kale, cowpeas leaves, green grams, cowpeas (legume portion), and maize, respectively. The F concentration in farm soils ranged from 0 to 3.47 mg/kg (mean of 0.87 mg/kg) and showed a significant strong positive correlation (p = 0.03, r = 0.89) with F values in the crops. Apatite, muscovite, and biotite were identified as the F-rich minerals present. While considering two hypothetical F absorption fractions (75 and 100%), the estimated average daily dose (EADD) of F from consuming the crops ranged between 0.004 and 65.17 mg/kg/day where the highest values were from the vegetables. Most of these values were higher than the F reference dose (RfD) of 0.06 mg/kg. The estimated EADD values of several hypothetical meals prepared from the analyzed crops revealed that steamed kale and maize porridge pose the highest health risk of F associated diseases to the local population, whereas boiled cowpeas pose no health risk. Children, due to their higher daily energy requirement and low body weight, were the most vulnerable group at risk of high daily F intake relative to the RfD. These results suggest that consumption of the analyzed food crops in Makueni County may significantly contribute to F related diseases in the local population. This creates a food security issue for the area because of the potential health risks associated with these crops which are highly relied upon in the semi-arid area with a limited selection of food crops available and viable to grow.

Neuro-medical manifestations of fluorosis in populations living in the Main Ethiopian Rift Valley.

Prolonged exposure to higher concentrations of fluoride (> 1.5 mg/L) is associated with dental and skeletal fluorosis. The effects of fluoride on dental and skeletal system have been studied extensively; however, the neurological consequences of fluoride in population-based studies are limited. The study aims to assess the epidemiology of neurological and other manifestations of fluorosis among rural populations living in the Main Ethiopian Rift valley. In this cross-sectional study, we enrolled 316 individuals from 23 rural communities in the Main Ethiopian Rift valley. Fluoride concentration was measured in drinking water samples collected from 23 community wells. Association between fluoride concentrations and clinical features of fluorosis was assessed using student t test, chi square, multivariable regression using adjusted odds ratio (OR). The mean fluoride concentration in the drinking water was 6.8 ± 4.3 mg/L (range: 0.3-15.5 mg/L). At least one clinical sign of skeletal fluorosis was observed in 54.4% (n = 175) of the study participants. Headache and joint pain reported by 67.1% and 56.3% of the participants as the most common neurological manifestation, and skeletal fluorosis symptom, respectively. The mean fluoride level was higher for those individuals who reported paresthesia compared to those with no-paresthesia. Loss of appetite, constipation, and fatigue were reported by 48.0%, 45.6%, and 56.6% of the participants, respectively. Signs of crippling fluorosis were observed in small proportion (1.6%) of the participants. Individuals who reported headache are most likely exposed to higher fluoride concentrations in drinking water compared to those reported no-headache (p < 0.001). The study demonstrates high prevalence of neuro-medical manifestations of fluorosis in population living in the Main Ethiopian Rift valley. Fluoride concentration in drinking water and joint pain were independent predictors of fluorosis.

Epidemiology of Erosive Tooth Wear, Dental Fluorosis and Molar Incisor Hypomineralization in the American Continent.

Non-carious dental lesions such as developmental defects of enamel (DDE) and erosive tooth wear (ETW) are the subject of intensive research. This paper aims to give perspectives on both DDE, including dental fluorosis and molar incisor hypomineralization (MIH), and ETW, presenting epidemiological data from the Americas and associated diagnostic aspects. Besides, it is important to present evidence to guide the clinical assessment process, supporting the clinicians' management decisions towards better oral health of their patients. The overall increase in the worldwide prevalence of non-carious lesions discussed in this this paper may reflect the need of perceptual changes. Although the number of publications related to these conditions has been increasing in the last years, there is still a need for clinical diagnostic and management awareness to include these conditions in routine dental practice. Besides, it is important to provide recommendations for standardized clinical assessment criteria, improving the process and helping clinicians' adherence. In this sense, this paper discusses the most commonly implemented indices for each condition. Thus, despite the wide range of diagnostic indices, BEWE is proposed to be the index recommended for ETW assessment, Dean or Thylstrup & Fejerskov indices for fluorosis and preferably the EAPD criteria (or modified DDE index) for MIH. Overall, non-carious lesions are a growing concern, and it is important to implement preventive measures that control their severity and progression, and accurate diagnosis by the dental clinician.

Associations of low level of fluoride exposure with dental fluorosis among U.S. children and adolescents, NHANES 2015-2016.

Drinking water fluoridation was a mid-twentieth century innovation based on the medical hypothesis that consuming low doses of fluoride at the teeth forming years provided protection against dental decays. Numerous studies showed that high level exposure to fluoride could cause dental and skeleton fluorosis. However, there was limited study focusing on the fluorosis effect of low levels of exposure to fluoride. Therefore, our study aimed to examine whether the low level of fluoride exposure (measured in blood plasma and household tap water) was associated with the risk of dental fluorosis based on data of the National Health and Nutrition Examination Survey (NHANES) 2015-2016. We analyzed data in 2098 children and adolescents who had Dean's Index scores, and water and plasma fluoride measures. The Dean's Index score was measured by calibrated dental examiners using the modified Dean's fluorosis classification system. Fluoride was measured in plasma and household tap water. In this study, we found that the rate of fluoride concentration in water above the recommended level of 0.7 mg/L was 25%, but the prevalence of dental fluorosis was 70%. Binary logistic regression adjusted for covariates showed that higher water fluoride concentrations (0.31-0.50, 0.51-0.70, > 0.70 compared 0.00-0.30) were associated with higher odds of dental fluorosis (OR = 1.48, 95% CI: 1.13-1.96, p = 0.005; OR = 1.92, 95% CI: 1.44-2.58, p < 0.001, and OR = 2.30, 95% CI: 1.75-3.07, p < 0.001, respectively). The pattern of regression between plasma fluoride and dental fluorosis was similar. Inclusion, our study showed that even low level of water or plasma fluoride exposure was associated with increased the risk of dental fluorosis. The safety of public health approach of drinking water fluoridation for global dental caries reduction are urgently needed further research.

Progress of Signaling Pathways, Stress Pathways and Epigenetics in the Pathogenesis of Skeletal Fluorosis.

Fluorine is widely dispersed in nature and has multiple physiological functions. Although it is usually regarded as an essential trace element for humans, this view is not held universally. Moreover, chronic fluorosis, mainly characterized by skeletal fluorosis, can be induced by long-term excessive fluoride consumption. High concentrations of fluoride in the environment and drinking water are major causes, and patients with skeletal fluorosis mainly present with symptoms of osteosclerosis, osteochondrosis, osteoporosis, and degenerative changes in joint cartilage. Etiologies for skeletal fluorosis have been established, but the specific pathogenesis is inconclusive. Currently, active osteogenesis and accelerated bone turnover are considered critical processes in the progression of skeletal fluorosis. In recent years, researchers have conducted extensive studies in fields of signaling pathways (Wnt/ß-catenin, Notch, PI3K/Akt/mTOR, Hedgehog, parathyroid hormone, and insulin signaling pathways), stress pathways (oxidative stress and endoplasmic reticulum stress pathways), epigenetics (DNA methylation and non-coding RNAs), and their inter-regulation involved in the pathogenesis of skeletal fluorosis. In this review, we summarised and analyzed relevant findings to provide a basis for comprehensive understandings of the pathogenesis of skeletal fluorosis and hopefully propose more effective prevention and therapeutic strategies.

A review on the potential sources and health implications of fluoride in groundwater of Sub-Saharan Africa.

Groundwater is a major source of drinking water for millions of people around the world. Over 400 million people in Africa depend solely on it as their main source of water supply. Fluoride is a common contaminant in groundwater. In low concentration (0.5-1.0 mg/L), fluoride is needed by humans for healthy development of bones and teeth, however, a concentration >1.5 mg/L has been linked with several fluorosis and non-fluorosis diseases. Dental and skeletal fluorosis are the major fluorosis diseases commonly reported with the consumption of fluoride-rich water. Although fluoride intake through other pathways such as the drinking of tea and eating of vegetables have been reported, the drinking of fluoride-rich water remains the major pathway of fluoride into humans. Cases of high fluoride levels in groundwater have been reported in almost all the sub-Saharan Africa region but it is more prevalent in East African countries, Sudan and South Africa. Although fluoride is present in surface water mostly in the East African Rift Valley across different countries in East Africa, its significant or high levels are usually associated with groundwater. Geogenic sources such as fluorite, apatite, biotite, amphibole, micas, topaz, cryolite, muscovite and fluorspar have been identified as the major sources of fluoride in groundwater. High fluoride levels have been reported across sub Saharan Africa, with generally higher levels in East Africa resulting from the volcanic activities in the rift system. Dental fluorosis has been reported in many sub-Saharan African countries including South Africa, Tanzania, Uganda, Ethiopia, Kenya, Sudan, Niger, Nigeria, Benin, Ghana and Malawi. Geothermal temperature has been regarded as one of the driving forces for high fluoride levels recorded in groundwater from deep aquifers and geothermal springs. The most affected people with the consumption of fluoride-rich water are the poor with low socioeconomic status who live in rural areas. Some of the proposed alternative sources include rainwater and fog water harvesting and blending of water from various sources. Low-cost and sustainable deflouridation technique remains one of the best ways to treat fluoride contaminated water either at communal level or at the point-of-use.

Evaluation of the reliability of human teeth matrix used as a biomarker for fluoride environmental pollution.

Environmental contamination by heavy metals has been a matter of great concern in many countries for several decades. Human exposure to such elements may cause adverse health effects and young children are particularly at risk. Many matrixes have been used for determination of metal exposure levels. Hard tissues such as teeth and bones have some advantages compared to other matrix. Dental tissues are considered to be suitable for long-term metal exposure due to their stability, resistance to physical and chemical degradation and their good preservation over time. Several studies have analyzed the teeth of animals for assessment the relationship between increased fluoride exposure and dental fluorosis, however few studies have been conducted on human teeth. Thus, the aim of the present study was to assess the reliability of human teeth matrix used as a biomarker for fluoride environmental pollution in Tunisia, and to evaluate the relationship with place of residence, age, dental caries and sex. Teeth samples (n=123) were collected from individuals living in Gafsa (fluoride-polluted area which inhabitants are to a great extent exposed to heavy metals) and Tunis (non polluted area). Samples were analyzed using a potentiometric method. The fluoride concentration was found to be significantly higher in teeth from Gafsa samples than those from Tunis. Their control levels were respectively 6793.1µg/g and 1068.8µg/g. The results indicate that there is a clear relation between fluoride concentration and residence of living. An increased level of dental fluorosis in fluoridated communities has been used to evaluate historical chronic exposure to fluoride in these communities, despite constant fluoride levels in the drinking-water. The fluoride concentration was also observed to be significantly increased in polluted area with age and in carious teeth whereas, no significant difference was observed for sex. Our study confirms well that human teeth used as a bioindicator for environmental pollution provide good chronological information on exposure, and highlighted the risks incurred by consumers living in such polluted area.

DENTAL FLUOROSIS PREVALENCE, SEVERITY AND ASSOCIATED RISK FACTORS IN PRE-SCHOOL AGED CHILDREN RESIDING IN FLUORIDE DEFICIENT REGIONS OF GEORGIA.

The aim of study was to assess prevalence, severity, and associated risk-factors for Dental Fluorosis in Pre-School children (1-6 years) in Fluoride deficient regions (1) Tbilisi (F=0.08-0.22 mg/l) and (2) Akhaltsikhe, (F<0.4 mg/l) Georgia, having different geographic location and socio-economic conditions. A cross-sectional study was carried out on 570 pre-school aged children (1-6 years) attending public kindergartens of Tbilisi and Akhaltsikhe region. Descriptive analysis was performed for Dental Fluorosis prevalence and severity using Thylstrup-Fejerskov Index (TFI). Correlative analysis was done to assess information about possible acquired risk-factors through questionnaire including biological and social variables. To differentiate genuine Dental fluorosis from other non-carious resembling defects ECEL method was introduced. For Fluoride concentration determination in potable water (2) ISO 10359-1:1992 Electrochemical probe as ion-selective electrode method was used. Information about F concentration in Tbilisi tap water (1) was obtained by GWP. (Georgian Water and Power, 2019). The overall Prevalence of Dental Fluorosis in study group was 6.3% (36 Children) (95% CI;(4.3 - 8.3)). There was no statistically significant difference in the level of Dental Fluorosis prevalence between rural and urban residents (P>0.05). Dental Fluorosis prevalence was similar in both gender groups. 6.0% of girls had dental fluorosis (95% CI 2.2% - 8.8%), whereas DF prevalence in boys was 6.5% (95% CI3.7% - 9.3%), respectively. Regular brushing and dentifrices ingestion were not effecting DF prevalence and severity (p>0.05). Indoor coal-burning environment increasing airborne Fluoride absorption during pregnancy was recognized as a risk-factor for dental fluorosis occurrence in children (OR=5.8 (95% CI; 2.1-15.9)). High tea consumption (≥2 cups/day) was increasing Odds of DF occurrence (OR=17.3 (95% CI; 7.4-40.7)). Exposure to diverse fluoride sources like indoor coal-burning and high tea consumption in non-fluoridated areas is a risk-factor of Dental Fluorosis in study community.

The pathogenesis of endemic fluorosis: Research progress in the last 5 years.

Fluorine is one of the trace elements necessary for health. It has many physiological functions, and participates in normal metabolism. However, fluorine has paradoxical effects on the body. Many studies have shown that tissues and organs of humans and animals appear to suffer different degrees of damage after long-term direct or indirect exposure to more fluoride than required to meet the physiological demand. Although the aetiology of endemic fluorosis is clear, its specific pathogenesis is inconclusive. In the past 5 years, many researchers have conducted in-depth studies into the pathogenesis of endemic fluorosis. Research in the areas of fluoride-induced stress pathways, signalling pathways and apoptosis has provided further extensive knowledge at the molecular and genetic level. In this article, we summarize the main results.