Fluoridated Areas Research Articles

WITHDRAWN: Corrigendum to ‘Identification of low fluoride areas using conceptual groundwater flow model and hydrogeochemical system analysis in the aquifer system on the flanks of an active volcano: Mount Meru, Northern Tanzania’

WITHDRAWN: Corrigendum to ‘Identification of low fluoride areas using conceptual groundwater flow model and hydrogeochemical system analysis in the aquifer system on the flanks of an active volcano: Mount Meru, Northern Tanzania’

Association of Dental Fluorosis and Urinary Fluoride with Intelligence among Schoolchildren.

Fluoride is present naturally in water and has been used worldwide for the prevention of caries. Several studies conducted in high water fluoride or endemic fluorosis areas reported that fluoride adversely affected children's cognitive function, but some studies had negative findings. This study aimed to assess the relationship between urinary fluoride, dental fluorosis, and intelligence among schoolchildren living in communities with non-fluoridated drinking water. This cross-sectional study was conducted on 562 children aged 6-12 years in Taichung, Taiwan. Each child's urinary fluoride level was determined by a fluoride-ion-selective electrode, and the dental fluorosis condition was evaluated according to the criteria of Dean's Index. The Raven's Colored Progressive Matrices-Parallel and Standard Progressive Matrices-Parallel were used to assess children's intelligence. The results showed that the mean (±standard deviation) urinary fluoride concentrations were 0.40 ± 0.27 mg/L (0.43 ± 0.23 mg/g creatinine) among participants. The prevalence of dental fluorosis was 23.67%. After extensive evaluation of potential confounders, dental fluorosis and urinary fluoride were not associated with intelligence quotient (IQ) scores or grades in the regression models. In conclusion, dental fluorosis and urinary fluoride levels were not significantly related to the IQ of schoolchildren living in areas with low drinking water fluoride.

Association between low fluoride exposure and children's intelligence: a meta-analysis relevant to community water fluoridation

ObjectivesPrevious meta-analyses have mainly focused on studies conducted in endemic fluorosis areas with relatively high fluoride concentrations. These are impoverished rural communities in China, India, and Iran, and the findings cannot be generalised to developed countries. Therefore, we investigated the association between fluoride concentrations relevant to community water fluoridation and children's cognition measured with IQ scores by synthesising effect sizes reported in observational studies. MethodsA previous meta-analysis and the National Toxicology Program database that included a search of multiple databases and the authors' search of PubMed, Google Scholar, and Mendeley provided the data. Cross-sectional and cohort studies examining the association between fluoride and children's cognition and intelligence scores were selected. Two reviewers abstracted data using standard procedures. We performed three meta-analyses to synthesise the effects using the random effects models. ResultsEight studies of standardized mean difference in IQ scores from non-endemic fluorosis areas found no statistically significant difference between recommended and lower levels of fluoride (standardized mean difference = 0.07; 95% confidence interval: −0.02, 0.17; I2 = 0%), and no significant fluctuation in IQ scores across the differences in fluoride concentrations by non-linear modeling with restricted cubic spline (P = 0.21). Meta-analyses of children's and maternal spot urinary fluoride associated pooled regression coefficients (Betachildren = 0.16; 95% confidence interval: −0.40, 0.73; P = 0.57; I2 = 0%, Betamaternal = −0.92; 95% CI: −3.29, 1.46; P = 0.45; I2 = 72%) were not statistically significant. Further regression analysis by standardizing absolute mean IQ scores from lower fluoride areas did not show a relationship between F concentration and IQ scores (Model Likelihood-ratio test: P-value = 0.34.) ConclusionsThese meta-analyses show that fluoride exposure relevant to community water fluoridation is not associated with lower IQ scores in children. However, the reported association observed at higher fluoride levels in endemic areas requires further investigation.

Prevalence of Dental Fluorosis Amongst School Children in West Bengal, India

Dental fluorosis, a disease, results from excessive fluoride consumption mainly through drinking water during early childhood, which damages tooth-forming cells in children. This study examines the prevalence of dental fluorosis amongst school children in the Puruliya district, located in West Bengal, India. This is because the Puruliya district is one of the worst-affected fluoride areas in India. When compared to the World Health Organization’s 1.5 mg/l permitted limit for fluoride in drinking water, the highest fluoride levels were found to be 8.28 mg/l in the Kashipur block of the district. Therefore, to perform a study to ascertain the prevalence of dental fluorosis among school-going children between the ages of 6 and 14 based on the Dean’s Index, the Kashipur block of the Puruliya District was selected. The fluoride levels of drinking water sources are tested in the public health and Engineering department in the Puruliya district. The average level of fluoride discovered in drinking water ranges from 0.42 mg/l to 5.23 mg/l. The data were analysed with SPSS-20 statistical software, and mapping was done with Arc-GIS 10.5. Linear regression is applied to test the correlation. The findings demonstrate a very strong positive correlation (r = 0.92) between fluoride concentration and the frequency of childhood dental fluorosis. Dental fluorosis was observed to afflict 45.20% of the children in the research area, and it was more common in female children (46%) than in male children (44.40%). There were 226 students with dental fluorosis between the ages of 6 and 15, of whom 16.4% were in Grade I, 13.2% in Grade II, 10.0% in Grade III, and 5.6% in Grade IV.

Prevalence of dental fluorosis in relation to fluoride concentration in two Southern states of India – A comprehensive review

Introduction: Regarding the lack of comprehensive systematic review, efficacy of water fluoridation and prevalence of dental fluorosis in southern Indian states. The aim of the current research was to systematically study the prevalence of dental fluorosis and different levels of water fluoride in the south Indian states of and lay emphasis on the amount of fluoride in drinking water. Aim: To conduct a systematic review of the literature on the prevalence of dental fluorosis and exposure to fluoride in drinking water. Materials and Methods: A systematic search was carried out in the MEDLINE, PubMed, Cochrane databases and Google scholar from 1986 to 2022 using the term the prevalence of dental fluorosis and exposure to fluoride in drinking water. Results and Discussion: The study found highest caries prevalence in low fluoride areas (0.3 ppm) and very high fluoride areas (10.4 ppm). Conclusion: Conc. of fluoride plays an important role in prevalence of dental caries.

Effect of sodium fluoride on germination, seedling growth and biochemical attributes in linseed varieties (Linum usitatissimum L.)

Fluoride is a potential threat to crop plants due to its inherent toxicity and its ability to move within plant tissues. The goal of the current study was to determine how sodium fluoride affected physiological, morphological, and biochemical parameters during the germination and seedling development of the T-397 and Shekhar linseed cultivars. Seeds were exposed to various sodium fluoride (NaF) concentrations (0.1 mM, 0.5 mM, 1.0 mM, 2.5 mM, 5.0 mM, and 10.0 mM) during the experiment. The findings of this investigation unequivocally demonstrated the substantial detrimental effects of sodium fluoride on multiple aspects of linseed growth and development. As the NaF concentration increased, the adverse impacts were magnified, highlighting a concentration-dependent relationship. Notably, the levels of total soluble sugars and proline content exhibited a remarkable fourfold increase as the sodium fluoride concentration escalated. This observation suggests that sodium fluoride may disrupt the normal metabolic processes in linseed, leading to alterations in sugar and proline metabolism. Interestingly, even at the lowest tested concentration of 0.1 mM NaF, linseed displayed susceptibility to fluoride-induced growth inhibition. This suggests that even at very modest levels of contamination, linseed cultivars are susceptible to fluoride stress, which may have an impact on crop yield in fluoridated areas. It is important to remember that this study did not definitively show any differences in the examined cultivars' sensitivity to fluoride stress; therefore more investigation is required to identify which type of linseed is more susceptible to this stress. This study's conclusion emphasizes the substantial harm that sodium fluoride causes to a number of vital indicators of seedling growth and germination of linseed. These results highlight the significance of comprehending the mechanisms underlying plant toxicity to fluoride and the possible ramifications for crop agriculture.

Biochemical Analysis of Liver Function in Individuals Affected and Unaffected by Dental Fluorosis in Endemic Fluoride Rural Areas of YSR Kadapa District, AP, India: A Cross-sectional Study

Introduction: Fluoride is known to affect the nervous system, kidneys, liver, and gastrointestinal system, in addition to teeth and bones, when consumed in amounts exceeding 1 ppm per day over a prolonged period. YSR Kadapa district has been identified as one of the districts with endemic fluoride areas in Andhra Pradesh, India, by the Central Groundwater Board of India. Aim: To assess the toxic effects of fluoride on liver function in individuals affected and unaffected by dental fluorosis, who consume high levels of fluoride in water, in the endemic fluoride rural areas of YSR Kadapa district. Materials and Methods: A cross-sectional study was conducted in six villages of YSR Kadapa district, where the drinking water has elevated fluoride content. A total of 320 subjects were selected as study participants. The subjects were divided into two groups based on age and dental fluorosis: Group A, aged between 21 and 40 years, and Group B, aged between 41 and 60 years. Subjects of each group were further sub-grouped according to presence or absence of fluorosis. The selected subjects were screened for dental fluorosis, and Groups A and B were further divided into subgroups based on the presence or absence of dental fluorosis. Blood samples were collected from the participants to assess liver function using serum levels of liver function markers such as total bilirubin (direct and indirect), Serum Glutamic Oxaloacetic Transaminase (SGOT), Serum Glutamate Pyruvate Transaminase (SGPT), and Alkaline Phosphatase (ALP). Water and urine samples were also tested for fluoride levels using a fluoride ion meter. Statistical significance was determined using the t-test. Results: The mean fluoride levels in the water samples from the study areas ranged from 1.55±0.30 mg/L to 4.10±0.20 mg/L, and the urinary fluoride levels in the urine samples ranged from 0.54±0.46 mg/L to 2.13±0.845 mg/L. Among the study subjects, 60.6% (194) were affected by dental fluorosis, with 58.66% (88) belonging to Group A and 62.35% (106) belonging to Group B. There was no statistically significant difference in liver function markers in the serum between subjects with dental fluorosis and those without dental fluorosis in both groups (p>0.05), and the levels were within the normal reference range. Conclusion: This study found no impaired or altered liver function in adults affected by dental fluorosis and adults unaffected by dental fluorosis who consumed water with high levels of fluoride in the YSR Kadapa district.

Evaluation of the effects of dental fluorosis (DF) on the oral health related life quality between 11–14 years school children in Peshawar, Khyber Pakhtoonkhwa

Background: Teenagers' classroom absences were correlated with oral health issues including dental problems. In contrast to severe traumas, gingivitis and periodontal disease have been shown to have a negative effect on Oral Health-related Quality of Life (OHRQoL) in teenagers. Objective: The research's objective was to evaluate how Dental fluorosis affected kids aged 11 to 14 in terms of their quality of life and condition-specific oral influence on daily performance. Methods: This cross-sectional study was conducted Between February 2021 and March 2022, to examine the effects of DF on OHRQoL among students aged 11 to 14 in Peshawar's fluoridated areas. 240 Peshawar-based school children between the ages of 11 and 14 took part in the research. Results: The mean CS OIDP score for high fluoridated areas was 38.84. Additionally, it demonstrates that students struggle most with socialising (7.87), which has the highest mean score, and eating (3.14), which has the lowest mean score. Conclusion: The findings of this research can serve as a warning to dental to conduct demographic research at the town and county level to identify risk variables and determine potential treatments and prevention methods.

Identifying the geochemical evolution and controlling factors of the shallow groundwater in a high fluoride area, Feng County, China.

Understanding how groundwater is formed and evolves is critical for water resource exploitation and utilization. In this study, hydrochemistry and stable isotope tracing techniques were adopted to determine the key factors influencing groundwater chemical evolution in Feng County. A total of fourteen wells and five surface water samples were investigated in November 2021. The δD and δ18O compositions show that both surface water and groundwater are recharged from atmospheric precipitation. The dominating order of cations and anions in groundwater appears to be Na+ > Mg2+ > Ca2+ > K+ and HCO3- > SO42- > Cl- > NO3- > F-, respectively. The groundwater hydrochemical facies are mainly characterized by HCO3-Ca-Mg and SO4-Cl-Na types. The chemical evolution of groundwater is dominated by water-rock interaction and cation exchange reactions. The major ions in groundwater are mainly controlled by various geogenic processes including halite, gypsum, calcite, dolomite, Glauber's salt, feldspar, and fluorite dissolution/precipitation. Furthermore, the abundant fluoride-bearing sediments, together with low Ca2+, promote the formation of high F- groundwater. Approximately 85.7% and 28.6% of groundwater samples exceeded the permissible limit for F- and NO3- respectively. Apart from geogenic F-, human interventions (i.e., industrial fluoride-containing wastewater discharge and agricultural phosphate fertilizer uses) also regulate the F- enrichment in the shallow groundwater. Nitrate pollution of the groundwater may be attributed to domestic waste and animal feces. Our findings could provide valuable information for the sustainable exploitation of groundwater in the study area and the development of effective management strategies by the authorities.

Relationship between COVID-19 severity and fluoride levels of drinking water among children in Karnataka state, India: An epidemiological study

Background: The severity and susceptibility to COVID-19 infection are the two main epidemiological factors influenced by the host and environmental factors. Environmental factors like drinking water fluoride levels have a direct role in depleting Vitamin D and serum calcium level in the body which were found to have a positive effect on the recovery from COVID-19.Aim and Objective: To find out if there is any association between the severity of COVID-19 and ground water fluoride level among children and young adults in Karnataka.Settings and Design: Ecological/Correlational study designMethods: Ground water fluoride levels of districts of Karnataka was obtained from the Government of India Central Ground Water Board’s Ministry of Water Resources River Development and Ganga Rejuvenation Year Book 2016-17 and 2018-19 and data on COVID-19 mortality under the age group of 20 years was obtained from the media bulletin of The Ministry of Health and Family Welfare, Government of Karnataka.Statistical analysis: Descriptive analysis was performed and Pearson’s correlation was used to find out the linear association between the variables.Results: The higher percentage of death due to COVID-19 was observed among males (65.8%) of age 16-20 (52.6%) years and around 71.8% of COVID-19 associated death among children and young adults were not associated with any co-morbidity. The ground water fluoride levels exhibit statistically significant linear strong positive (r=+0.734; P=0.024) correlation with the Case Fatality Rate (CFR).Conclusion: The severity of COVID-19 was observed to be severe in the high concentration of ground water fluoride areas in Karnataka.

Prospective Role of Calcium Supplementation in Prevention of Fluorosis: A Study in Some North Indian Villages

More than a hundred million people from almost twenty-five countries, including India, are affected by fluorosis. An assessment of fluoride in water, a prospective study of dental fluorosis and the role of calcium in preventing or ameliorating dental fluorosis through a long-term community study in endemic high fluoride area in Northern India was done. Water survey from different areas was done to identify high fluoride area in Unnao district of Uttar Pradesh, India. House to house survey of a population of almost 5000 people was done. Biochemical tests were performed in 50 dental fluorotic and 50 non-fluorotic randomized subjects. Clinical and biochemical status was recorded after six months of calcium supplementation. Our results have shown that 28.64% population had dental fluorosis (total fluorosis: 43%), the highest in 13-15 years age group. After six months of calcium supplementation, 44% of cases showed reversal of dental fluorosis, whereas in 40% of them disease did not progress further. An increase in serum calcium and a significant decrease in urinary fluoride was observed post supplementation. In this first large-scale prospective community study of its kind, it is demonstrated that long-term administration of calcium can reverse dental fluorosis especially in children with early grades of fluorosis. Calcium may protect tooth against damage from high fluoride intake and reduces dental fluorosis. With the increase in the prevalence of dental fluorosis, calcium can prove a cheap and effective method for the prevention and treatment of dental fluorosis.

Effect of smoking and dental fluorosis as environmental risk factors in periodontal disease — An observational study

To assess the periodontal status of smokers and non-smokers in dental fluorosis subjects from endemic water fluoride areas of Davangere district, Karnataka. A stratified random sample study (n=338) was performed to obtain an equal number of subjects in tobacco and non-tobacco users. Participants had similar perceived oral health status (including self-reports of bleeding gums, loose teeth, and receding gums) low to medium socioeconomic status, and education. The sample for the present study on the tobacco effect consisted of 338 subjects aged 15-74 years. The periodontal status was assessed by clinical parameters Oral Hygiene Index — Simplified (OHI-S), Jackson’s Fluorosis Index (JFI), Community Periodontal Index Treatment Needs (CPITN). Overall, periodontitis is significantly higher among smokers as compared to non-smokers. Although dental fluorosis is a risk factor compared in relation to age, sex was statistically not significant. OHI-S, JFI, and CPITN show statistical significance among smokers and tobacco chewers. The risk determinants such as age, sex followed by risk factors such as smoking and oral hygiene status for periodontal disease would make no difference from high to low fluoride areas but the current study concept on tobacco use in dental fluorosis subjects is thought-provoking and has to be considered in further studies.

Effect of Dental Fluorosis on Oral Health-Related Quality of Life and Daily Performances Among 12- and 15-year-old School-going Children Residing in High- and Low-Fluoridated Areas of Meerut District

Introduction: Dental fluorosis is a clinical situation that leads to changes in esthetic appearance in teeth. Oral health problems can cause problems in performing daily activities and social well-being, which may affect individual's quality of life (QOL). Aim: To assess the effect of dental fluorosis on oral health-related QOL and condition-specific oral impact on daily performance (CS-OIDP) among 12- and 15-year-old children residing in high and low fluoridated areas of Meerut district, UP. Methodology: A cross-sectional study was conducted among 200 12- and 15-year-old school-going children residing in high- and low--fluoridated areas of Meerut district. Dean's fluorosis index was used to evaluate dental fluorosis. A pretested questionnaire, CS-OIDP index, was used to assess the dental fluorosis effect on the oral health-related QOL and daily performances. Results: The mean CS-OIDP score among high-fluoridated area was 39.85 and a significant correlation was found between dental fluorosis, CS-OIDP, and oral health-related QOL (P < 0.005). Conclusion: The results of the present study can act as an alarm for dentists to carry out epidemiological investigation at village and district level to evaluate the risk factors and possible treatment and preventive measures.

Effectiveness of Fluoride Varnish in Prevention of Early Childhood Caries in 3-4 Years Old Children - A 36 Month Prospective Community Based Randomized Controlled Trial.

Evidence for the benefit of applying Fluoride Varnish FV to permanent teeth is generally very positive. However, the caries-inhibiting effect of FVs on primary teeth is still debatable. To assess the effectiveness of fluoride varnish in prevention of early childhood caries in children over the period of 3 years in high fluoride areas. A double-blind cluster-randomized controlled trial was undertaken amongst 3-4 years old children. The varnish application was done at three points in the intervention group. Experimental group showed significantly lesser increment in mean ICDAS score than control group at both 12 month and 36 months. Preventive fraction was 72.4% at 12 months and 18.2% at 36 months. Multiple linear regression showed that at 12 months, intervention was the significant predictor with varnish group having 0.140 (95% CI 0.175-0.230) lower net caries increment. At 36 months, baseline ICDAS score and intervention were the significant predictors. This study suggests that fluoride varnish is an effective and a safe mode of prevention of early childhood caries in children residing in high fluoride zone. However, the overall effect is influenced by the baseline caries status.

Soil Culturable Bacteria Increase the Water-Soluble Fluoride Content in the Soil

To evaluate the effects of soil bacteria on the contents of water-soluble fluoride in the soil in high fluoride area, a total of 225 isolates were firstly obtained from the soil collected from Xianghuangqi County in Inner Mongolia, an typical high fluoride area in China. These isolates were grouped into 10 operational taxonomic units according to their 16SrRNA gene sequences using 97% sequence identity threshold. An isolate was randomly selected from each group as the representative strain to study their mineral weathering potentials, calcium precipitating potentials, and their effect on the content of water-soluble fluoride in the soil. Most of the representative strains showed the silicate mineral weathering capacities and all showed the calcium precipitating capacities. The results of the soil column experiment showed the concentration of water-soluble fluoride in majority of the bacteria-inoculated soils (8 out of 10) increased compared to abiotic control after two weeks’ incubation. The increases in the fluoride content were closely correlated with a reduction of water-soluble calcium contents and/or an increase of pH, suggesting that calcium precipitation by these bacteria could be an important factor to elevate the content of water-soluble fluoride content in soil. This work would deepen our understanding of the microbial contribution to the formation of high fluoride groundwater.

Impact of water fluoridation on dental caries decline across racial and income subgroups of Brazilian adolescents.

OBJECTIVESThe aim of this study was to assess the impact of community water fluoridation (CWF) on differences in dental caries decline across racial and socioeconomic subgroups of Brazilian adolescents.METHODSTwo nationwide Brazilian population-based oral health surveys were used (Brazilian Oral Health Survey 2003 and 2010). In total, 7,198 adolescents from 15 years to 19 years old living in 50 cities investigated in both surveys were included. The mean numbers of untreated decayed teeth (DT) according to racial (Whites vs. Browns/Blacks) and socioeconomic subgroups (at or above the minimum wage per capita vs. under) were analysed. Difference-in-differences negative binomial regressions were adjusted by schooling, age, and sex. Decayed, missing, and filled teeth and DT prevalence, calculated as a categorical variable, were used in sensitivity analyses.RESULTSThe adjusted difference of reduction in DT was similar across socioeconomic subgroups (β=-0.05; 95% confidence interval [CI], -0.45 to 0.35) and favoured, but not to a significant degree, Whites (β=-0.34; 95% CI, -0.74 to 0.04) compared to Brown/Blacks in fluoridated areas. In non-fluoridated areas, significant differences were observed in the mean number of DT, favouring the higher socioeconomic subgroup (β=-0.26; 95% CI, -0.53 to -0.01) and Whites (β=-0.40; 95% CI, -0.69 to -0.11) in relation to their counterparts. The sensitivity analyses confirmed the findings.CONCLUSIONSThe similar reduction in DT across income subgroups suggests that CWF has had a beneficial effect on tackling income inequalities in dental caries within a 7-year timeframe.

Estimation of fluoride uptake in soil and staple food crops produced in highly fluoridated and non-fluoridated regions of Raichur District, Karnataka.

A staple food crops have varied role in diet of people living in particular regions of world; hence, it is critical to recognize their productivity. Therefore, the purpose of this study was to estimate fluoride concentration in staple food crops grown in highly fluoridated and non-fluoridated regions and its correlation with soil. Total 36 samples were collected of which 18 samples consisting of each three samples of rice, redgram and jowar were selected. Likewise 18 corresponding soil samples from both areas were collected. All samples were ashed for 4-6 hours at 550°C in muffle furnace. The samples were allowed to cool, after which 10 ml distilled water was added to each sample and fluoride concentration was determined using ion selective electrode method, before each sample analysis the instrument was standardized using fluoride containing TISAB (III) buffer solution. The data was tabulated and subjected to cross-sectional observational statistical analysis using SPSS software applying unpaired t-test and Pearson's test. The mean fluoride concentration in crops and soils were rice (0.79 ppm), redgram (4.26 ppm), jowar (8.8 ppm) and in soil of rice (1.23 ppm), redgram (1.23 ppm) and jowar (1.21 ppm) respectively in fluoridated area. Where as in non-fluoridated area rice (0.07 ppm), redgram (0.81 ppm), jowar (0.81 ppm) and in soil of rice (0.61 ppm), redgram (0.07 ppm) and jowar (0.52 ppm) respectively. The resultant correlation between staple food crops with their corresponding soils were found highly significant in both regions with P value <0.005; hence, crops in fluoridated region exhibited increased fluoride retention, whereas crops in non-fluoridated region had optimal fluoride levels. Fluoride concentration in food crops has strong correlation with their respective soils and water irrigation properties.

Prevalence of dental fluorosis and dental caries in fluoride endemic areas of Rohtak district, Haryana.

This study investigates the estimation of the fluoride concentration in drinking water in Rohtak district, Haryana, and quantifies its effect on the prevalence of dental fluorosis and dental caries. A cross-sectional survey was conducted among 1262 school children in endemic fluoride areas of Haryana. Using simple random sampling, thirty villages from five blocks of Rohtak districts were selected, and children 6-12 years of age were examined. A questionnaire survey form was filled out to record the demographic details of the samples. Dental caries was recorded according to DMFT (D = Decayed, M = Missing due to caries only, F = Filled, T = Teeth)/deft index (d = decayed, e = extracted due to caries, f = filled, t = teeth). Assessment of Dental Fluorosis was done according to Dean's Fluorosis index, modified in 1942. The data were analyzed using SPSS version 19, and nonparametric tests were used to assess the significance. The study participants included 615 males and 647 females among which Mean DMFT in the area of study ranged from 0.32 to 1.90. Mean deft in the area of study ranged from 0.34 to 1.91. The fluoride concentrations in groundwater are in the range of 0.532-8.802. Out of 1262 children examined, 655 (51.90%) children were having dental fluorosis. 607 (48.10%) of the subjects were free from fluorosis. 16.09%, 13.39%, 9.11%, and 8.16% and 5.15% were having questionable, very mild, mild, moderate, and severe form of fluorosis, respectively. It can be concluded that in Rohtak district, the fluoride levels in drinking water and the prevalence of dental fluorosis are high, so requiring an urgent need to improve the quality of water and institute de-fluoridation of drinking water in affected areas to lower the burden of dental fluorosis in the community.

Identification of low fluoride areas using conceptual groundwater flow model and hydrogeochemical system analysis in the aquifer system on the flanks of an active volcano: Mount Meru, Northern Tanzania

This study investigates the localities of low and high F− groundwaters in the aquifer system on the flanks of Mount Meru to come up with guidelines to provide groundwater that can be used for drinking water supply without health impacts on the population. Our study focuses on parts of the flanks which were only partially or not at all covered by previous research. Results show that the groundwater chemistry of F−-rich NaHCO3 alkaline groundwater in the area is controlled by dissolution of weathering aluminosilicate minerals, dissolution of F−-bearing minerals, the precipitation of carbonate minerals as secondary products and the dissolution of magmatic gases. The low F− groundwaters which can be used for drinking water supply without health impacts under the WHO limit (1.5 mg/L) are the low-fluoride springs from the high altitude recharge areas on the eastern and north-western flanks of Mount Meru inside Arusha National Park, whereas on the western flank the groundwater meets the Tanzanian limit (4.0 mg/L). On the south-western flank, the shallow aquifer composed of alluvium deposits at lower elevations, shows F− values that meet the Tanzanian limit. One of the three investigated deep boreholes on this flank also meets the Tanzanian limit, suggesting a possibility of finding relatively low F− groundwaters in the deep aquifer. Yet, in general, the deposits at lower elevations are found to contain high to very high F− values, whereas the deposits at high elevations contain groundwater of low F− values. Thus, the internal texture and grain size of geological formations, the burial depth of these formations and the water residence times are the factors determining the groundwater mineralisation and F− concentrations in the area. The study identified that the deep hydrothermal system has influence on the high F− groundwaters on the eastern and north-eastern flanks of Mount Meru.

Effectiveness of water fluoridation in an upper-middle-income country: A systematic review and meta-analysis.

To summarize the information on the effectiveness of community water fluoridation (CWF) on the reduction of dental caries in the context of the wide use of fluoridated toothpaste in Brazil. A systematic review was conducted regarding the effect of CWF based on studies with Brazilian population groups using the following electronic databases: MEDLINE/PubMed, LILACS, SciELO, and SCOPUS. The literature search was conducted up to August 2019. Studies that compared caries experience in at least two areas, one fluoridated and the other non-fluoridated, by mean dmft/DMFT (decayed, missing, and filled teeth) index or caries prevalence (caries vs. caries-free) were included. Considering the beginning of widespread use of fluoride dentifrice and the time for producing dental caries decline, studies published before 1995 were excluded. Descriptive analysis and meta-analyses were carried out. The effect size was measured by mean difference for dmft and DMFT±SD and odds ratios on a logarithmic scale for caries prevalence. Of the 574 studies retrieved, 16 and 10 were included in the qualitative and quantitative analysis, respectively. Fluoridated areas exhibited lower mean dmft/DMFT than non-fluoridated areas did. The mean difference in the dmft between non-fluoridated and fluoridated areas was -2.28 (95% CI -3.26; -1.30) for children aged 5-8years and -1.12 (95% CI -1.93; -0.32) for those aged 3-12years; the mean difference in the DMFT was -0.61 (95% CI -0.80; -0.42) for the children aged between 7 and 12years. The caries prevalence was 1.4 times and 57% lower, respectively, at primary and permanent dentition in fluoridated areas. Heterogeneity was observed in all age groups, ranging from 77.6% to 98.2%. Community water fluoridation remains effective in preventing dental caries in children younger than 13years, even with the widespread use of fluoridated toothpaste.