High Fluoride Areas Research Articles

Correlations between bone metabolism biomarkers and fluoride exposure in adults and children

Increased exposure to fluoride, which notably affects bone metabolism, is a global concern. However, the correlations and sensitivity of bone metabolism to fluoride remain controversial. In this cross-sectional study, 549 children (aged 7–12 years) and 504 adults (≥ 18 years old) were recruited in the high-fluoride areas of the Henan Province. Urinary fluoride (UF) level was determined using a fluoride electrode. Fasting venous blood serum was collected to measure bone metabolism biomarkers. The selected bone metabolism biomarkers for children included bone alkaline phosphatase (BALP), serum alkaline phosphatase (ALP), osteocalcin (OCN), calcitonin (CT), parathyroid hormone (PTH), phosphorus (P5+), and calcium (Ca2+). For adults, the biomarkers included ALP, CT, PTH, β-CrossLaps (β-CTX), P5+, and Ca2+. The correlations between UF and bone metabolism biomarkers were analyzed using binary logistic regression, a trend test, a generalized additive model, and threshold effect analysis. Regression analysis indicated a significant correlation between serum OCN, PTH, and UF levels in children aged 7–9 years. Serum OCN, PTH, and BALP contents were significantly correlated with UF in boys (P < 0.05). Furthermore, the interaction between age and UF affected serum P5+ and PTH (P < 0.05). The generalized additive model revealed nonlinear dose–response relationships between P5+, BALP, and UF contents in children (P < 0.05). Serum OCN level was linearly correlated with the UF concentration (P < 0.05). Similarly, a significant correlation was observed between β-CTX and UF levels in adults. In addition, significant correlations were observed between UF–age and serum Ca2+, β-CTX, and PTH contents. There was a non-linear correlation between serum Ca2+, P5+, and β- CTX and UF levels (P < 0.05). Overall, serum OCN, BALP, and P5+ levels can serve as sensitive bone metabolism biomarkers in children, while β-CTX, P5+, and Ca2+ can be considered fluoride-sensitive bone metabolism biomarkers in adults.

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.

Comparing Deterministic and Stochastic Methods in Geospatial Analysis of Groundwater Fluoride Concentration

Dental and skeletal fluorosis caused by consuming high-fluoride groundwater has been reported over several decades globally. Prediction maps to estimate the fluoride contaminated area rely on interpolation methods. This study presents a comparison of the accuracy of nine spatial interpolation methods in predicting the fluoride in groundwater. Leave-one-out cross-validation (LOOCV), hold-out validation and validation with an independent dataset were used to assess the precision of the interpolation methods. This is the first study on fluoride with a large dataset (N = 13,585) applied at the regional level in India. Our findings showed that the inverse distance weighted (IDW) algorithm outperformed other methods in terms of less discrepancy between measured and predicted fluoride. IDW and local polynomial interpolation (LPI) were the only methods to predict contaminated areas (fluoride &gt; 1.5 mg/L). However, the area estimated by the typical assessment of the percentage of unsuitable samples was much higher (6.1%) compared to that estimated by IDW (0.2%) and LPI (0.2%). LOOCV provided viable results than the other two validation methods. Interpolation methods are accompanied with uncertainty which are regulated by the sample size, sample density, sample distribution, minimum and maximum measured concentrations, smoothing and border effects. Drawing a comparison among variegated interpolation methods capturing a wide range of prediction uncertainty is suggested rather than relying on one method exclusively. The high-fluoride areas identified in this study can be used by the Government in planning remediation actions.

Fluorine in shallow groundwater in China: A review of distribution, occurrence and environmental effects

With rapid economic development and the increasing demand for drinking water, a large amount of groundwater is exploited, resulting in a high F− content in groundwater, which is harmful to the environment and human body. In this study, 5,464 data points of fluoride in shallow groundwater were collected, and the F− content distribution, occurrence form and environmental impact of shallow groundwater were discussed. The results showed that 1) the F− content in shallow groundwater in China ranged from 0 to 60 mg/L, with a mean content of 0.90 mg/L; the lowest average F− content in shallow groundwater in Southwest China was 0.36 mg/L; South China (1.20 mg/L), Northeast China (1.25 mg/L) and Northwest China (1.25 mg/L) were considered high-fluoride areas, and North China (0.93 mg/L), East China (0.67 mg/L) and Central China (0.80 mg/L) were considered low-fluoride areas. The mean F− content in groundwater differed between provinces and cities. 2) The F− in shallow groundwater mainly occurred in ionic, complex ionic and organic fluoride molecular states. 3) The influence of a high F− content in shallow groundwater on the environment was mainly manifested in the increase in water F− concentration and soil F− and vegetable F− content. The influence of a high F− content on the human body was mainly manifested in an increase in urinary F− content in children, a high prevalence of dental fluorosis in children, an increase in skeletal fluorosis rate in adults with age, and an influence on cognitive function of older adults. These results provide a basis for F− pollution control and high-fluoride water treatment.

Prevalence of dental fluorosis and dental caries among people consuming water in urban Vadodara

Introduction: High fluoride concentration in groundwater can result in endemic fluorosis and is a major public health problem in India. Aim: To know the association between prevalence of dental fluorosis and dental caries and fluoride level in the water in urban Vadodara. Methodology: An analytical ecological cross-sectional study was conducted in 4 zones of Vadodara district. Thirty-eight water samples were sent to Gujarat Ecology Society in Vadodara for chemical analysis to test fluoride levels. The data collection was made by house-to-house visit twice during the study involving 2,609 participant interviews. These participants included 449 children belonging to the age group of &lt;15 years. Examination for dental fluorosis and dental caries using Dean's criteria was done. Chi-Square and Mental Hensel Chi-Square were applied for statistical analysis. Results: The prevalence of dental fluorosis was 17.36% in high-fluoride areas and 22.46% in normal-fluoride areas among children (&lt;15 years of age). There was no statistically significant association in dental fluorosis between high-fluoride areas and normal-fluoride areas (P = 0.2533). The prevalence of dental caries was 29.26% in high-fluoride areas and 75.36% in normal-fluoride areas. There was a statistically significant association in dental caries between high-fluoride areas and normal-fluoride areas (P ≤ 0.0001). Conclusions: The risk of dental caries was clearly higher in the areas showing normal-fluoride content compared to places with high fluoride levels in drinking water. The risk of dental fluorosis was higher in area with high-fluoride level but the difference was not statistically significant.

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.

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.

Health‑risk assessment and distribution characteristics of fluoride in groundwater in six basins of Shanxi Province, Middle China.

High-fluoride (F) pollution is an environmental problem that severely affects the growth of human beings, animals and plants. High-fluoride groundwater severely harms the health of Shanxi residents and leads to frequent endemic diseases. This study aims to analyze the differences and possible health risks of fluoride among six basins in Shanxi Province, North China, using 338 groundwater samples collected from wells, infer the main sources of fluoride in the groundwater, and provide valuable suggestions for fluoride contamination in regional groundwater. The results revealed that F in the Yuncheng basin had the highest health risk. In addition to the Changzhi basin, the groundwater at the sampling points in other basins had adverse effects on human health. The main source of fluoride in groundwater is the dissolution of fluoride-containing minerals, which has little to do with human activities. The groundwater in Shanxi Province tends to be alkaline, and the fluorite saturation index is less than 0 in most circumstances, indicating that fluorite is in an unsaturated state, and fluoride will continue to dissolve into groundwater under suitable conditions. Clustering analysis shows that the high-fluoride areas are mainly distributed in the Yuncheng basin and the southern part of the Xinzhou basin. Fluoride-rich groundwater in a basin often exists only in a certain area, and the distribution of confined water and unconfined water in high-fluoride areas is different. Fluoride contamination in the Changzhi basin is not severe. For the high-fluoride areas in the Datong basin, Xinzhou basin, Taiyuan basin and Linfen basin, utilizing water from other areas or exploiting groundwater from other aquifers to diminish the harm of high-fluoride groundwater intake for a long period is suggested. For the Yuncheng basin, adopting membrane-based processes or variable temperature drop fluoride technology to make groundwater contaminated by excessive fluoride potable is recommended.

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.

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.

Chemical characteristics, evolution, and quality of groundwater and processes controlling its fluoride concentration features: case study of a typical high-fluoride areas in the Southwestern Shandong Plain, China.

In this study, the groundwater (GW) in the high-fluorine area of the Southwestern Shandong Plain was divided according to the characteristics of high Na% (> 75%), and its water chemistry characteristics and causes were discussed separately, and the hydrochemical process of the formation of high-fluorine GW was determined. Finally, the GW quality of the study area was evaluated. The results proved that silicate hydrolysis can significantly promote the release of F- in fluorine-containing minerals; high %Na can be used as one of the early-warning conditions for judging high-fluoride areas. To this end, 132 GW samples were collected from 66 wells during the dry and wet seasons. The study area was found to have weakly alkaline GW (pH 7.1-8.9) and could be divided into high %Na areas (HNA) and non-HNA. GW exhibited different hydrochemical characteristics between HNA and non-HNA. In non-HNA, total hardness (TH) exceeded 200mg/L, and total dissolved solids (TDS) ranged from 514.1 to 5246.1mg/L; in HNA, TH was less than 200mg/L, TDS ranged from 552.8 to 1298.3mg/L, and Na+ increased with TDS, whereas Ca2+ and Mg2+ contents were low. The main water type in HNA was HCO3-Na and in non-HNA was SO4·Cl-Ca·Mg and SO4·Cl-Na. The study area is experiencing serious fluoride pollution. GW in HNA is mostly controlled by carbonate and silicate hydrolysis and evaporation, whereas GW in non-HNA is controlled by dolomite dissolution and cation exchange in the main. Moreover, GW in HNA has significantly been altered by albite hydrolysis, which produces Na+ and HCO3- and triggers various reactions promoting the release of F- from fluorine-containing minerals (FCM). Regarding the water quality for irrigation, GW in HNA was found to be less suitable than that in non-HNA. Nevertheless, in terms of the water quality index (WQI), GW is moderate for drinking and poor for irrigation. Therefore, extensive attention should be paid to the exploitation and management of high-sodium GW in the plain area.

Preliminary screening of fluorine-stained osteoblastic apoptosis-related microRNA.

Endemic fluorosis is a chronic systemic disease that seriously endangers human health. In high fluoride areas, people consume excessive fluoride for a long time through drinking water or food, which leads to chronic cumulative fluorosis in the body. Fluorosis can cause changes in the expression of some miRNA in cells, and the miRNA can participate in fluoride-induced osteoblast activation through various signal pathways. To observe the differential expression of apoptosis-related microRNA (miRNA) in mouse osteoblasts under the action of excessive fluoride. Primary cultured mouse osteoblasts, identified by osteocalcin (OC) and alkaline phosphatase (ALP) staining, were treated with 20 mg/L sodium fluoride and 40 mg/L sodium fluoride for 12/24 hr, respectively, to establish the fluoride staining model for comparing and analyzing the sequence of miRNA among groups by bioinformatics methods; four miRNA chains were verified by fluorescence quantitative PCR. After treatment with 20 mg/L sodium fluoride for 12 hr and 24 hr, 128 miRNA expressions were up-regulated while 36 miRNA expressions were down-regulated. In Group 40 mg/L, 130 miRNA expressions were up-regulated while 29 miRNA expressions were down-regulated after 12 hr and 24 hr; 72 miRNA were up-regulated and 2 miRNA were down-regulated at the two time points. 10 up-regulated miRNA and 2 down-regulated miRNA with higher scores in Bioinformatics software were analyzed the target genes. Fluorescence quantitative PCR verified that the expressions of four miRNA were up-regulated. Target gene analysis of the 10 selected mouse osteoblastic apoptosis-related miRNA reveals their involvement of the functions of inhibiting or promoting apoptosis, which has certain theoretical significance for early identification of skeletal fluorosis. The involved signaling pathways include the Wnt signaling pathway, ubiquitin-regulated proteolysis, Toll signaling pathway, TNF signaling pathway, pluripotent stem cell signaling pathway, MAPK signaling pathway, phosphatidylinositide metabolism, FoxO signaling pathway, ErbB signaling pathway, autophagy, and so forth.

Formation and In Situ Treatment of High Fluoride Concentrations in Shallow Groundwater of a Semi-Arid Region: Jiaolai Basin, China.

Fluorine is an essential nutrient, and excessive or deficient fluoride contents in water can be harmful to human health. The shallow groundwater of the Jiaolai Basin, China has a high fluoride content. This study aimed to (1) investigate the processes responsible for the formation of shallow high-fluoride groundwater (SHFGW); (2) identify appropriate methods for in situ treatment of SHFGW. A field investigation into the formation of SHFGW was conducted, and the results of experiments using soils from high-fluoride areas were examined to investigate the leaching and migration of fluoride. The results showed that the formation of SHFGW in the Jiaolai Basin is due to long-term geological and evaporation processes in the region. Stratums around and inside the basin act as the source of fluoride whereas the terrain promotes groundwater convergence. The hydrodynamic and hydrochemical conditions resulting from slow groundwater flow along with high evaporation and low rainfall all contribute to the enrichment of fluoride in groundwater. In situ treatment of SHFGW may be an effective approach to manage high SHFGW in the Jiaolai Basin. Since soil fluoride in high-fluoride areas can leach into groundwater and migrate with runoff, the construction of ditches can shorten the runoff of shallow groundwater and accelerate groundwater loss, resulting in the loss of SHFGW from high-fluoride areas through river outflow. The groundwater level will be reduced, thereby lowering the influence of evaporation on fluoride enrichment in shallow groundwater. The results of this study can act a reference for further research on in situ treatment for high-fluoride groundwater.

Biomarkers for the Assessment of Fluoride Exposure in Children

Due to practical difficulties in quantifying fluoride exposure, the ability of various biomarkers to predict exposure has been investigated previously. However, the results are inadequate for validation of their application and usefulness. This study aimed to investigate the association between contemporary/recent biomarkers of fluoride exposure and total daily fluoride intake (TDFI) of children with large differences in fluoride exposure through drinking water. TDFI was assessed in 61 healthy 4- to 5-year-old children who provided at least 1 biomarker sample; 32 lived in a low-fluoride area (0.04 mg F/L) and 29 lived in a high-fluoride area (3.05 mg F/L). Validated questionnaires were administered to evaluate fluoride intake from diets (including water) and toothpaste ingestion. Daily urinary fluoride excretion (UFE) and fluoride concentrations in plasma, fasting whole saliva, hair, and nails (toenails/fingernails) were evaluated and related to total fluoride exposure. TDFI, UFE, and fluoride concentrations of biomarkers were statistically significantly higher in the high-fluoride area than in the low-fluoride area. There was a strong statistically significant positive correlation between TDFI and UFE (ρ = 0.756, p < 0.001); plasma fluoride concentration (ρ = 0.770, p < 0.001); and toenail fluoride concentration (ρ = 0.604, p < 0.001). The statistically significant positive correlation between TDFI and fingernail fluoride concentration (ρ = 470, p < 0.001) as well as between TDFI and fasting whole saliva fluoride concentration (ρ = 0.453, p = 0.001) was moderate, whereas it was weak between TDFI and hair fluoride concentration (ρ = 0.306, p = 0.027). In conclusion, the current study confirmed the suitability of 24-h urine samples for estimating fluoride exposure in children. The strong correlations between TDFI and fluoride in plasma and toenails also suggest these biomarkers may be considered for health risk assessments of fluoride in children who are susceptible to development of dental fluorosis.

Magnitude of fluorosis and various interventions to reduce fluorosis in Gujarat, India

Background: Gujarat is one of the endemic states for the prevalence of fluorosis due to high fluoride levels in water of many villages in the state. Aim and Objectives: To determine the prevalence of dental fluorosis and skeletal fluorosis in Vadodara district, Gujarat, India, and to document various interventions conducted by Government to reduce the prevalence of fluorosis in Gujarat. Materials and Methods: A cross sectional survey was carried out in 11 villages (6 with high fluoride level and 5 with normal fluoride level) by house to house visits. Various interventions like capacity building of faculties, diagnostic, treatment and counseling for fluorosis and alternate water supply facilities were provided. Results: The prevalence of dental fluorosis and skeletal fluorosis was 59.31% and 18.65% in high fluoride areas, while it was 39.21% and 12.54% in normal fluoride areas, respectively. After estimation of this problem, and other research studies carried in Gujarat, the Government of Gujarat provided a fluorine meter to measure the fluoride level in water and urine in all government medical colleges of the state. Capacity building of faculties from various departments was done regarding the epidemiology, diagnosis, treatment, and counseling of fluorosis patients. Early diagnosis and treatment were provided to all fluorosis patients visiting tertiary care hospitals. Alternate drinking water supply was also provided by the government. Conclusion: Both dental and skeletal fluorosis was high in Gujarat and field level diagnostic facilities are inadequate. A coordinated training program helped to identify the problem and suggest remedial measures. An integrated and comprehensive approach is required to reduce the problem of fluorosis in Gujarat.

Awareness of the Benefits and Risks Related to Using Fluoridated Toothpaste Among Doctors: A Population-Based Study.

BackgroundThis study aimed to assess the awareness of dentists and non-dental doctors regarding the benefits and risks of using fluoridated toothpaste.Material/MethodsA self-administered questionnaire was used to collect information in this study. Multistage cluster sampling method was used to enroll doctors in 5 districts or counties in Chongqing, China. A total of 403 doctors (160 dentists and 243 non-dental doctors) completed the questionnaire.ResultsThe awareness of the anti-caries efficacy and the usage of fluoridated toothpaste in dentists was significantly higher than those of non-dental doctors (P<0.001). Most (about 60%) dentists and non-dental doctors had concerns about fluoridated toothpaste. Only 31.3% of dentists and 25.9% of non-dental doctors had a good understanding of the benefits and risks of use of fluoridated toothpaste in children under 3 years of age to 49.4% of dentists and 73.3% of non-dental doctors did not understand the benefits and risks in children 3~6 years old, and 40.0% of dentists and 67.5% of non-dental doctors did not understand the risks and benefits in individuals living in high-fluoride areas. Most dentists (76.3%) and non-dental doctors (87.3%) did not understand the benefits and risks in pregnant women.ConclusionsDentists and non-dental doctors were concerned about the potential risks of use of fluoridated toothpaste, and they lacked adequate knowledge about the benefits and risks of use of fluoridated toothpaste. Health education is needed to improve doctors’ knowledge about use of fluoridated toothpaste.

Fluorite Dissolution by a Phosphate-Solubilizing Bacterium Isolated from Groundwater of Xianghuangqi County, Inner Mongolia, China

Xianghuangqi County of Inner Mongolia is a typical high-fluoride area in China. Present work discussed a possible role of phosphate-solubilizing bacteria (PSBs) in the formation of high-fluoride groundwater in this area. An indigenous PSB was isolated from the local groundwater. Analysis of 16S rDNA sequence indicates that the bacterium belongs to the Pseudomonas genus. This bacterium caused acidification of the culture media under phosphate-limited conditions. HPLC analysis detected several metabolites that are likely to acidify the cultural media. Fluorite dissolution experiment with this bacterium in minimum medium containing 2 mg/L, 20 mg/L, and 200 mg/L glucose showed that the initial concentration of glucose has a large effect on pH of the culture medium and the fluorite dissolution rate. The pH of bacterial cell-free medium remained constant throughout the experiment. Introduction of the PSB caused an initial decrease in pH, followed by an increase. The measured pH minima were 4.8, 5.8, and 6.0 for culture media amended with 200 mg/L, 20 mg/L, and 2 mg/L glucose, respectively. A slow increase of the fluoride concentration in bacterial cell-free medium was observed, and inoculation of the PSB increased the rate of fluoride release causing the concentration of fluoride in bacterial-inoculated medium to markedly exceed that found in control medium. The highest fluorite dissolution rate was observed in culture medium amended with 200 mg/L glucose, while the rates observed in culture medium amended with 20 mg/L and 2 mg/L glucose were comparable. Given the ubiquity of PSBs in natural environment, these findings show PSBs could be important contributors to fluoride mobilization in high fluoride area.

Geochemical and geostatistical appraisal of fluoride contamination: An insight into the Quaternary aquifer

Fluoride (F−) in groundwater poses a severe public health threat in the Dwarka River Basin (DRB) of West Bengal, India, where many cases of fluorosis have been reported. This research evaluates the spatial distribution patterns of major cations and anions, delineates zones of high F− concentrations within alluvial sediments of the DRB, and identifies both the sources and the geochemical processes responsible for the release of F− to groundwater. A total of 607 groundwater samples were collected from shallow and deep tube wells located within the DRB, encompassing an area of 435 km2 and including 211 villages. Fluoride levels range from 0.01 to 10.6 mg/L, and high concentrations (>1.5 mg/L) are restricted to isolated areas within the basin (occurring within nine of the villages and comprising 4.3% of the samples collected). The high-fluoride areas are characterized by mostly Na-HCO3 type groundwater, where the abundance of cations and anions are Na+ > Ca2+ > Mg2+ > K+ and HCO3– > Cl− > SO42− > F− > NO3− > Br−, respectively. Analyses of the groundwater geochemistry and sediment mineralogy suggest that fluoride is released to groundwater primarily through the hydrolysis of albite and biotite; however, the resulting alkaline conditions are also favorable for release of fluoride from weathered biotite and clay minerals through anion exchange (OH– in groundwater replacing F− within the mineral structure). Multiple linear regression models show that fluoride concentrations can be predicted from the measures of other dissolved constituents with a high degree of accuracy (R2 = 0.96 for high fluoride samples and R2 = 0.8 for low fluoride samples).

Oral Hygiene Habits and Dental Treatment Needs of Children with Dental Fluorosis and Those Without Dental Fluorosis Aged 12-15 Years In in a High Fluoride Area in North Kajiado Kenya

Oral Hygiene Habits and Dental Treatment Needs of Children with Dental Fluorosis and Those Without Dental Fluorosis Aged 12-15 Years In in a High Fluoride Area in North Kajiado Kenya