Fluoride Concentration Research Articles

Hydrogeochemical characteristics, source distribution, and health risk of high-fluoride groundwater in Swabi, Pakistan.

This paper evaluated fluoride (F-) pollution in drinking groundwater sources, which causes severe fluorosis and other human health concerns in Swabi, Pakistan. We determined F- concentration, prevalence, enrichment, distribution, and health hazards from water ingestion in Swabi, Pakistan. Therefore, 126 groundwater and 18 surface water samples were collected to analyze F- and other geochemical tracers to understand groundwater enrichment and F- mobilization in aquatic systems. The range and mean values of F- in groundwater were 0.02 to 14.2 and 4.0mg/L, and those in surface water were 1.12-0.8 and 1.4mg/L. Most residents used groundwater for drinking purposes. Thus, groundwater results showed that 72.2% of samples had surpassed the WHO guidelines of F- 1.5mg/L. The fluoride pollution index (FPI) declared that 48.73% of samples showed a higher risk, 41.95% medium risk, and 9.32% lower risk. Mineral phases using PHREEQC interactive software determined mineral saturation revealing the dissolution of host rock minerals and unsaturation showed precipitation of minerals within the aquifer. The principal component analysis multilinear regression (PCA-MLR) model showed a five-factor solution: (a) geogenic processes, (b) mixed geogenic and anthropogenic inputs, (c) geochemical processes, (d) agriculture pollution, and (e) industrial effluents which would release F- in the aquifer. The health hazard due to higher F- revealed that children showed high-risk levels compared to adults in endemic areas. The spatial distribution of F- in drinking groundwater increases towards the northern side and decreases in the south to the southeastern side. Therefore, effective water management techniques would be required to safeguard groundwater resources and secure human health from dental and skeletal fluorosis and other associated problems caused by high F- groundwater with varying fluoride concentrations. This study will help the water management authority to safeguard depleted groundwater for drinking demands.

Beyond Fluoride: Exploring Silicon’s Potential for Dental Repair and Caries Prevention

This in vitro study evaluated the protective effect of an Si-containing toothpaste associated with different fluoride concentrations by reducing the depth of the demineralized lesions in dentin after cariogenic pH cycling. Methods: Sixty bovine dentin blocks (4 × 4 × 2 mm) were randomly assigned into five groups (n = twelve/group): RGS1 (Si toothpaste with 1450 ppm F), RGS2 (Si toothpaste with 1100 ppm F), RGS3 (fluoride-free Si toothpaste), negative control (NC) (fluoride-free toothpaste), and positive control (PC) (1450 ppm F toothpaste). The specimens underwent a three-day pH cycling model simulating the oral environment with twice-daily brushing. The mineral loss (ΔF) and lesion depth (ΔFmax) were assessed using quantitative light-induced fluorescence (QLF), and scanning electron microscopy (SEM) provided a morphological analysis. Elemental analyses were performed with an energy-dispersive X-ray spectrometer (EDS). ANOVA and Tukey’s test were used for the data analysis (α = 5%). Results: EDS confirmed the Si in the toothpaste formulations. The groups treated with fluoride silicon toothpastes (RGS1, RGS2) had significantly reduced mineral loss and lesion depth compared to the PC group. The NC group exhibited the greatest mineral loss and lesion depth. SEM images revealed occluded superficial dentin tubules and a protective mineral layer in the groups treated with Si toothpaste, whereas no deposition (NC group) or limited mineral deposition (PC group) was observed in the control groups. Conclusions: The findings suggest that the Si toothpastes favored protection against dentin demineralization, even at a lower concentration or free of fluoride, with dentin tubule occlusion, thus representing a promising oral care product over traditional fluoride toothpastes.

Efficacy of combining soluble calcium and pyrophosphate with sodium fluoride in inhibiting enamel caries progression: an in vitro study

ObjectiveThis study aimed to compare the effects of a combination of sodium fluoride, soluble calcium, and pyrophosphate (FCaP) versus fluoride alone in inhibiting enamel caries progression. DesignDifferent FCaP solutions were prepared, and two were selected for testing (FCaP-1: F = 76mmol/L, Ca = 7.6mmol/L, P = 7.6mmol/L, FCaP-5: F = 76mmol/L, Ca = 23mmol/L, P = 23mmol/L). Fluoride solution (F = 76mmol/L) was used as a control. Fluoride and calcium bioavailability in the solutions were measured, and NMR analysis was used to identify fluorine-containing complexes. Sound bovine enamel samples (n = 24 / group) underwent a 4-day pH cycling protocol followed by an additional 3 days of demineralization. Micro-hardness testing and fluoride concentration measurements were performed. ResultsFCaP-1 and FCaP-5 demonstrated nearly 100% fluoride and calcium bioavailability. NMR analysis confirmed the formation of fluorine-containing complex. Enamel treated with FCaP-5 exhibited significantly less reduction in subsurface hardness after pH cycling and additional demineralization compared to fluoride alone. Interestingly, fluoride concentration and acid resistance on enamel surfaces treated with FCaP-5 was lower than with fluoride alone (Steel’s multiple comparison test, p < 0.05). ConclusionsFCaP effectively inhibits caries progression in subsurface enamel layers under pH cycling conditions by providing bioavailable calcium, indicating that FCaP increases the effectiveness of fluoride in caries management. FCaP may be a valuable addition to clinical practice, particularly for improving the effectiveness of fluoride-containing oral care products in individuals with low salivary calcium levels.

Application of Mont Carlo Simulation and Artificial Neural Network Model to Probabilistic Health Risk Assessment in Fluoride-Endemic Areas

Groundwater contamination with fluoride is a considerable public health concern that affects millions of people worldwide. The rapid growth of urbanization has led to increase in groundwater contamination. The health risk assessment focuses on both acute and chronic health consequences as it investigates the extent and effects of fluoride exposure through contaminated groundwater. Fluoride exposure, especially in endemic locations, has serious health consequences, including dental and skeletal fluorosis. An accurate assessment of these hazards is essential for public health planning and mitigation actions. The present study uses Monte Carlo Simulation (MCS) and an Artificial Neural Network (ANN) model to perform a Probabilistic Health Risk Assessment on populations in fluoride-endemic areas. Analysis of the results of the study reveals that the concentration of fluoride ranged from 0.58 to 3.80 mg/L with an average of 2.30 mg/L across the Kasganj district, which was higher than permissible limits given by BIS and WHO. The highest value of hazard quotient of 3.29 for Children is found to be in the Durga Colony area, while the lowest value of the hazard quotient of 0.31 for adults is found to be in the Nadrai Gate area. The assessment of health risks revealed a high probability of non-carcinogenic disease from the consumption of groundwater containing fluoride. The ANN model has the R2 value of 0.9989 in training and 0.9870 in testing while RMSE value in training and testing was 0.02230 and 0.0267. The findings suggest that before being used, the groundwater in Kasganj, Uttar Pradesh, India, needs to be treated and made drinkable. The results emphasize the critical need for ongoing monitoring, public education initiatives, and implementing feasible mitigating techniques to lower fluoride exposure. The findings show that this hybrid model is excellent at addressing the numerous uncertainties associated with fluoride use, hence improving the reliability of health risk estimates in fluoride-endemic locations. The results offer vital information to help policymakers and local health officials create focused measures to safeguard public health in Kasganj.

Awareness of Fluoride Toothpaste among Parents of Children and Adolescents

This study assessed parental knowledge and utilization patterns of fluoride containing dentifrices in the context of youth oral health promotion. A direct questionnaire was administered to 168 parents of young patients who attended the Pediatric Dental Clinic at Yonsei University Dental Hospital between March and May 2024. The findings indicated that while a significant majority (94.6%) of parents acknowledged the importance of fluoride in adult oral care products, their understanding of the potential adverse effects was limited. The study found that 84.5% of children used fluoride toothpaste and 96.4% of parents considered fluoride toothpaste essential for their children. However, a considerable proportion (40.5%) used low-fluoride formulations and many parents lacked awareness of the fluoride concentration (42.3%) and the appropriate dosage for their children (61.3%). Notably, paternal parents had a higher likelihood of being uninformed about fluoride content (24.7%, &lt;i&gt;p&lt;/i&gt; = 0.003) and the correct quantity of toothpaste (26.2%, &lt;i&gt;p&lt;/i&gt; &lt; 0.05) that children should use. These observations underscore the need for targeted education for fluoride-containing oral care products for parents. Precise guidelines on suitable fluoride toothpaste types and quantities tailored to the developmental stages in children are important for enhancing oral health outcomes in youth.

Evaluation of Fluoride and Silver Ion Concentrations in e-Silver Diamine Fluoride and Advantage Arrest: An Ion Chromatography and Atomic Absorption Spectrometer Study.

Dentin hypersensitivity (DH) is characterized by sharp shooting pain due to exposed dentin, and the most common method for treating this pain is the occlusion of the dentinal tubules with the help of desensitizing agents. E-silver diamine fluoride (e-SDF) (Kids-e-Dental, Mumbai, India) is a commercially available 38% SDF solution in the Indian market. Despite the fact that its application for caries prevention has been proven, the fluoride (Fl) and silver (Ag) ion concentrations of e-SDF for use in treating DH have yet to be standardized. The aim of this study is to determine and compare the Fl and Ag ion concentrations released from two commercially available 38% silver diamine fluoride (SDF) solutions. The two most common commercially available 38% SDF solution brands, namely Advantage Arrest and e-SDF were used. Two drops of each of these solutions were taken in three beakers and diluted with distilled water. The Fl ion concentration was evaluated using a calibrated ion-specific electrode. The free Ag ion concentration was assessed using an atomic absorption spectrometry (AAS). Release of Ag ions shows that on days 1, 2, 5, 6, and 7, concentration (mg/L) was higher in the Advantage Arrest group but is statistically nonsignificant. On days 3 and 4, it is higher in an e-SDF group with a t-value of 1.085 and 0.243 and is statistically nonsignificant. Release of Fl ion showed that in comparison to the baseline, it was more with Advantage Arrest on days 2, 4, and 7 with a t-value of -3.766, -0.999, and 0.347 and on day 2 was statistically significant. On days 3, 5, and 6 Fl ion release from baseline was more with e-SDF in comparison with Advantage Arrest but statistically insignificant. The AAS analysis as well as the ion chromatography showed that the Ag and Fl ion release respectively on days 1-7 from e-SDF was similar to the one seen in the case of Advantage Arrest. This helps dentists choose among different brands of the same commercially available 38% SDF solutions depending on the cost and availability of the product. Kamath P, Kamath P, P AN, et al. Evaluation of Fluoride and Silver Ion Concentrations in e-Silver Diamine Fluoride and Advantage Arrest: An Ion Chromatography and Atomic Absorption Spectrometer Study. Int J Clin Pediatr Dent 2024;17(10):1141-1145.

Assessing Fluoride Impact in Phosphogypsum: Strength and Leaching Behavior of Cemented Paste Backfill

Phosphogypsum (PG)-based cemented paste backfill (PCPB) is a widely used method for the large-scale disposal of phosphoric acid waste. However, fluoride contaminants in PG pose a significant risk of groundwater pollution. Effective pretreatment methods have been developed to mitigate this issue, but there is limited research on the specific pretreatment standards needed to control fluoride leaching. This study investigates the impact of initial fluoride content (IFC) in PG samples on the strength and leaching behavior of PCPB to establish appropriate pretreatment standards. Pure CaSO4·2H2O and NaF were used to simulate PG samples with varying IFC levels. The findings indicate that lower IFC leads to stronger PCPBs after 28 days of curing. To ensure compliance with Chinese national standards, the initial fluoride concentration must be below 0.0093 wt% to prevent excessive leaching. Microlevel analyses reveal that fluoride influences the hydration reactions of C2S and C3S in cement, affecting the formation of C-S-H and Ca(OH)2. Fluoride is primarily immobilized in PCPB as CaF2, which can either form gypsum crystals within the complex structure or be adsorbed onto hydration products. This research provides crucial insights into the pretreatment standards required for controlling fluoride leaching, offering a foundation for the industrial application of PG.

Unveiling the kinetic predominance of fluoride electrosorption at S-modified defect-rich interface: Microscale disordered reconstruction induced accessible synergistic platform

Excessive hazardous fluoride (F−) have necessitated the advancement of fluoride removal electrode materials to mitigate their environmental impact. Herein, a sulfur-modified Bi-containing mesoporous synergistic platform encapsulated in a carbon shell (BiMCS-P) that provides an open nanostructured framework and high-density defects is reported. The BiMCS-P electrode removes fluoride by electrical double layer (EDL) capacitance and additional reversible redox reactions. Due to the diminished reliance of sluggish diffusion and the reduction of activation energy barrier after appropriate sulfidation, the fluoride can be further captured, as verified with high removal capacity (60.23 mg g−1 at an initial pH of 7) when processed in a 100 mg L−1F− solution, efficient energy utilization (72.8 %), and good applicability (about 80 % capacity retention at weakly acid solution). The BiMCS-P electrode can reduce the fluoride concentration from 5 mg L−1 and 2.5 mg L−1 to below the existing regulatory standards (1.5 mg L−1). The intrinsic defects optimize the electron distribution in an unsaturated coordination environment. The topological defects created during the disordered crystallographic conversion from Bi to Bi2S3 reduce the energy barrier of faradaic conversion and improves the redox activity. Moreover, the unique mesoporous framework achieves more defluoridation sites on the electrode’s surface and enables rapid ion storage behavior dominated by capacitive-controlled process at the solid–liquid interface. This study demonstrates a new strategy to improve the electrosorption performance, offering a promising advancement of defluoridation, particularly for materials that exhibit purely capacitive or purely Faradaic electrochemical characteristics.

To Evaluate Efficacy of Bajra husk and Moringa leaf Powder on Water Defluoridation – A Comparative Study

Introduction: AIM: To evaluate and compare efficacy of naturally available adsorbents Moringa oleifera and Bajra husk in reducing the fluoride content in the high fluoridated drinking water.Methodology: A community with high fluoride content in its water was selected and a sample was taken. The baseline fluoride level was determined using an ion selective electrode. Two naturally occurring adsorbents, powdered moringa leaf and bajra husk, were used. The husk and dried leaves were processed, sieved, and heated to 400 degrees Celsius for 30 minutes in a muffle furnace. The water sample was mixed with biochar and agitated for an hour at 500 rpm. Filter paper was used to filter the water sample and added TISAB. The fluoride content of the water sample was estimated using an ion selective electrode approach.Results: The highest removal of fluoride is significantly done by Moringa leaf biochar (23%) as compared to bajra husk (15%). when 2 grams of this biochar were added in 200ml of water sample separately.Conclusion: Drinking water defluoridation can be effectively achieved by using moringa leaves and bajra husk as adsorbents. On the other hand, Moring leaf powder proved to be more successful.

Health risk modeling and risk factors of fluorosis in the fluoride endemic village of Maharashtra: A cross-sectional study.

Fluorosis, a debilitating disease, causes dental mottling and bone deformities among other adverse health effects. The current epidemiological study focused on the prevalence and risk factors of fluorosis in the fluoride endemic village, Dongargaon, Maharashtra, India. The clinical diagnosis of subjects showed 96.49% prevalence of dental fluorosis, and 63.16% prevalence of skeletal fluorosis. Duration of exposure, age of subjects and physiological symptoms like chronic joint pain were found to be significantly correlated with skeletal fluorosis (p < 0.05). Fluoride in drinking water showed seasonal variation with highest level in winter (6.54 mg/L) and lowest level in monsoon (0.54 mg/L). Consequently, the mean urinary fluoride concentration was also highest in winter (9.37 mg/L) and lowest in monsoon (3.88 mg/L). Multilogit regression analysis demonstrated that subjects excreting urinary fluoride above 4 mg/L had 7.25 times higher odds of developing skeletal fluorosis (p < 0.05). Health risk assessment showed a high value of hazard quotient, indicating a high probability of adverse health effects. The estimated daily ingestion of 8.80 mg F and a predicted bone uptake of 0.19 mg/kg/day raised significant health concerns for the studied population. Exposure and bone F uptake modeling suggested that the predicted mean fluoride concentrations of 4018.77 ± 1762.45 mg/kg bone ash in asymptomatic, and 5535.12 ± 1526.30 mg/kg bone ash in symptomatic subjects were significantly different (p < 0.05). The comprehensive risk evaluation in the study clearly brings out the high risk of fluoride exposure and adverse effects in Dongargaon village for the first time. Further, urinary fluoride was shown to have significant association with the risk of skeletal fluorosis. The study warrants implementation of immediate control measures at the study site.

Preparation of β-AlF3 from fluorine-containing wastes: Leaching with fluorosilicic acid and crystallization

Numerous fluorine-containing hazardous solid wastes from the electrolytic aluminum process pose a serious threat to the ecosystem and human health. Currently, in the study of leaching on these wastes, Al and F are usually recovered by adjusting the pH of the leaching solution to precipitate aluminium hydroxyfluoride hydrate, which can be used to produce aluminum fluoride by roasting. However, aluminium hydroxyfluoride hydrate is often mingled with cryolite and other impurities when precipitating, which ultimately affects the purity of obtained aluminum fluoride by calcination. Interestingly, herein, the aluminium hydroxyfluoride hydrate residue was digested by fluorosilicic acid to effectively remove impurities and obtain a pure aluminum fluoride solution, from which the β-AlF3 product was produced by crystallization at a high-temperature. The results show that under the conditions of a temperature of 60 °C, time of 35 min, initial fluorine-aluminum molar ratio of 3:1 and initial concentration of fluorosilicic acid of 18 %, the gross yield of fluorine is 86.2 %, and the recovery of silicon in the form of SiO2 is 95.2 %. During crystallization, the product changes from AlF3·3H2O to β-AlF3 with the increase of temperature. Under the conditions of a crystallization temperature of 150 °C, an initial concentration of aluminum fluoride of 191.10 g/L and a stirring speed of 200 rpm, β-AlF3 of an average particle size of 43.22 μm was obtained by adding 5 % seed. The contents of Al and F in β-AlF3 products are 32.57 % and 61.49 % respectively, which meet the requirements of GB/T 4292–2017 (AF-0) about National Standards of China. According to DFT calculation, the β-AlF3 tends to adsorb two or three water molecules in its cavity structure, which explains why the crystallized β-AlF3 contains water of 5.10 % at 180 °C.

Efficacy and safety of TiF4 varnish in preventing erosive tooth wear in a rat animal model

An animal model was applied to develop erosive tooth wear (ETW) and to evaluate the efficacy and safety of titanium tetrafluoride (TiF4) in preventing ETW. Forty-eight male Wistar rats were divided into three groups (n = 16): TiF4 (2.45% F−), NaF (2.45% F−) and placebo varnishes. Eight from each group were subjected to erosive challenges (Sprite Zero) and the other received tap water, both ad libitum. After twenty-eight days, the mandibles were resected for histopathological gingival analysis, clinical and microscopic tooth evaluation by 3D confocal laser microscopy, scanning electron microscopy (SEM-EDX) and micro-Raman spectroscopy (MRS). Organs were evaluated with respect to fluoride content. No significant difference was found in F content in tissues. No histopathological damage was seen in gingiva. ETW was clinically more aggressive in rats from placebo group consuming Sprite compared to water (Q²=12.6, p < 0.01), in accordance with confocal images. TiF4 was superior in reducing cross-section area loss (0.036 ± 0.01µm2) compared to NaF and placebo, respectively (0.044 ± 0.01/0.063 ± 0.01µm2, ANOVA, p < 0.0001). Dentin exposure was detected by SEM in rats belonging to placebo consuming Sprite. Peaks compatible with typical apatite bands were visible. TiF4 reduces the progression of ETW without causing any relevant side-effect and the rats’ model was able to simulate ETW in vivo.

Adsorptive processes applied to the defluorination of groundwater for human consumption

Contamination of groundwater by fluoride ions can occur through both natural and anthropogenic activities, such as the discharge of industrial waste containing this compound. Thus, effective fluoride removal from groundwater is essential to ensure safe drinking water. This study evaluated the performance of adsorption techniques for defluoridating groundwater in Rio Grande do Sul, Brazil. Preliminary tests were conducted using synthetic solutions with a fluoride concentration of 5 mg.L−1, applying several adsorbents. Additionally, an ultrasonic process was used to synthesize an adsorbent from activated alumina pre-treated with carbon (AACP) and modified with ZnCl₂ (AA-ZnCl₂). The AACP and AA-ZnCl2 were characterized through BET, EDS, scanning electron microscopy, X-ray diffraction (XRD), and FT-IR analysis. A Central Composite Design and response surface methodology were applied to optimize adsorption efficiency, focusing these factors: pH and adsorbent dosage. Kinetic and isotherm adsorption tests were conducted for both AACP and AA-ZnCl₂. The results showed that AACP achieved fluoride removal efficiencies of 65.4 % in synthetic solutions and 38.6 % in groundwater. The AA-ZnCl₂ demonstrated superior performance, removing over 98 % of fluoride in synthetic solutions and 55.4 % in groundwater, across a pH range of 4 to 10, with an optimal solid dosage of 3 g.L−1. For an initial fluoride concentration of 5 mg.L−1, a removal efficiency of 97.4 % was achieved within 5 min of contact time. The kinetic adsorption data were best described by the pseudo-second-order model, while the Freundlich isotherm model provided the best fit for the adsorption isotherm data. The findings in this work indicate hat ZnCl₂-modified activated alumina, synthesized with ultrasonic assistance, is highly effective for defluoridating groundwater for safe human consumption being an alternative method to be implemented in an industrial scale.

Seasonal Variation of Physicochemical Properties in the Lower River Benue, Nigeria

The study investigates the impact of seasonal changes on water quality in the River Benue, Nigeria. Conducted over eighteen months from January 2020 to June 2021, the research focuses on three locations: Ibi, Lau, and Mayo-Ranewo. Key physicochemical parameters such as temperature, pH, turbidity, conductivity, Biochemical Oxygen Demand (BOD), hardness, dissolved oxygen (DO), fluoride, and nitrate were measured to assess water quality. The findings reveal significant seasonal variations in these parameters, influenced by rainfall patterns, land use, and anthropogenic activities. Temperature ranged from 25.56°C to 30.70°C, remaining within acceptable limits for tropical waters, supporting stable biological processes. However, turbidity levels exceeded recommended values, indicating the presence of suspended solids that could impair water quality and harm aquatic life. Total dissolved solids (TDS) and conductivity showed potential contamination risks, likely due to agricultural runoff and urban discharges. Dissolved oxygen (DO) levels were generally adequate, especially during the wet season, enhancing oxygen content through increased photosynthetic activity and water inflows. However, BOD spiked with rainfall, signalling organic pollution and potential eutrophication risks. Seasonal shifts in pH and water hardness reflected changes in runoff and photosynthesis, with values largely within acceptable ranges for aquatic life. Fluoride and nitrate concentrations increased in the wet season, primarily due to agricultural runoff, highlighting the influence of land-based activities on water quality.

Comparative assessment of enamel surface remineralisation with three different dentifrices: An energy dispersion x-ray spectroscopy analysis

Comparative assessment of remineralisation of enamel surface when treated with three different dentifrices. Sixty-six extracted upper right first premolars were demineralized to form artificial white spot lesions. The samples were divided into 3 groups: Group 1-Biomin F, Group 2- Clinpro ToothCreme, Group 3- Amflor. They were treated with three different dentifrices (22/ group) for 14 days in simulated oral conditions. Energy dispersion X-Ray Spectroscopy was done pre and post remineralistaion. The primary evaluation parameter for this study was the Ca/P ratio. As per the results, the maximum increase in Ca/P ratio was seen in Group1, followed by Group 3 and 2 respectively. The results were found to be statistically significant. (p=0.045 i.e. p&amp;#60;0.05) The secondary evaluation parameter for this study was the change in Fluoride content. As per the results, the maximum increase in Fluoride content was seen in Group 2 which was followed by Group 3 which is equivalent to Group 1. However, the results were found to be statistically non-significant. (p=0.219 i.e. p&amp;#62;0.05) Biomin F has the highest remineralisation efficiency when compared to the other 2 dentifrices. Biomin F contains an optimum combination of fluoride (600 ppm), phosphate and calcium ions, incorporated within the structure of the glass itself. The glass gradually dissolves over up to 12 hours neutralizing acids in the mouth and deposit fluorapatite. Thus, it can be used in patients undergoing orthodontic treatment to prevent or reduce the formation of white spot lesions.

INFLUENCE OF FLUORIDE ON PUBLIC HEALTH AND WORKER’S HEALTH – LITERATURE REVIEW

Dental caries is a multifactorial disease that affects a large part of the world's population. Can be prevented by various means and methods, including the use of fluoridated mouthwashes, topical fluoride, fluoridated toothpaste and fluoridation of public water supplies for human consumption. Fluoride has been shown to be a therapeutic agent that modulates dental caries. Frequent contact between patients and small concentrations of fluoride hinders demineralization and activates remineralization, in addition to inhibiting cariogenic microorganisms. The oral health of workers is directly related to the health of the population, since they are part of this context and suffer from the same problems that occur in the environment in which they live. Since workers are the agents who convert work activity into profits for the employer, a detailed and complete vision addressing prevention is extremely important, as this is a way to reduce absenteeism and keep workers in their jobs, achieving better performance of their activities. This bibliographic review aims to analyze fluoride in its various forms and evaluate its anti-cariogenic power for workers, with the aim of preventing cavities and providing well-being, quality of life and greater productivity to them. Based on the data analyzed, it is concluded that fluoride is an effective and inexpensive measure to prevent the appearance of cavities and that due to the large size of Brazil and its socioeconomic difficulties, fluoridated toothpaste associated with assisted brushing, with topical fluoride applications, prove to be the best measures to prevent cavities and absenteeism, consequently improving public health indices. This is one of the most relevant public policies, which is in fact underestimated and which can change the reality of Brazil, reducing high government costs and promoting the quality of life of the population, which suffers from oral problems, which can affect the entire organism, causing a series of other ailments, which should be avoided by adopting preventive measures on a permanent basis.

Hydrochemical processes and fluoride enrichment patterns in high-fluoride geothermal water in the Weihe Basin, China

The enrichment of fluoride in the deep geothermal water of the Lantian – Bahe Formation in parts of the Weihe Basin in China is a potential health hazard for the millions of inhabitants of this region. We conducted hydrochemical and hydrogeological analyses of water samples from 31 geothermal wells in the Weihe Basin, with the aims of determining the distribution characteristics, enrichment patterns, hydrochemical processes, and the factors influencing the geochemistry of deep geothermal fluids. We also evaluated the potential health hazards of fluoride ions in these fluids. Our results show that geothermal fluids with high fluoride content are widely distributed in the deep aquifers of the Weihe Basin. The principal hydrochemical types are: HCO3–Na and SO4⋅HCO3⋅Cl–Na. We used hydrodynamic simulation and regression analysis to show that the high proportion of HCO3– in the geothermal water facilitates the precipitation of Ca2+ and the dissolution of fluorine-bearing minerals. The high temperature, alkaline environment, cation exchange reactions, and dissolution and precipitation processes lead to Ca2+ depletion, which facilitates the release of fluoride ions from the surrounding rocks into the geothermal fluids. A human health risk assessment shows that the hazard quotient (HQ) values of geothermal water for adult males, adult females, children, and infants are: 3.96 – 14.41 (median 6.55), 3.32 – 12.08 (median 4.50), 4.63 – 16.84 (median 5.50), and 7.48 – 27.22 (median 9.00), respectively. Infants are the most susceptible to the effects of high fluoride in groundwater due to their physiological characteristics. while the potential health risks of F− for children and adult women/men are relatively low. Therefore, in the process of developing deep geothermal water, it is necessary to prevent it from mixing into shallow drinking water as much as possible. If the fluoride ion content in the shallow water exceeds the standard, it may have an impact on the local environment and residents' health. These findings provide a scientific foundation for the effective management of high fluoride groundwater in the Weihe Basin and analogous regions elsewhere.

Synthesis of bagasse-derived magnetic biochar for the removal of fluoride from water solution

ABSTRACT Fluoride levels in drinking water pose a significant environmental threat, and adsorption is a common technique. However, many adsorbent materials have drawbacks such as poor adsorption capabilities, extended contact times, high pH levels, and large dosages. A biochar-based magnetic composite adsorbent has been developed for water defluoridation using a chemical co-precipitation process to immobilize iron particles on the biochar surface. X-ray diffraction analysis, Fourier transformed infrared spectroscopy, Brunauer–Emmett–Teller, and scanning electron microscopy were used to analyse the composite. The central composite design was used to design laboratory tests, which included four input variables: solution pH, dosage, contact time, and initial concentration. The adsorbent dosage was 5.92 g/L, the aqueous pH was 5.79, the contact time was 66.48 min, and the initial fluoride concentration was 12.38 mg/L. The removal efficiency was predicted to be 98.61%, with a 98.55% removal efficiency at optimum conditions. The study concluded that the composite adsorbent can be a reliable and sustainable solution for fluoride removal from water.

Feed Monocalcium Phosphate Derived from Wet-process Phosphoric Acid and Calcium-based Raw Materials

In this study, granulated feed-grade monocalcium phosphate was produced using highly purified wet-process phosphoric acid (WPA) and finely milled limestone (99.5% CaCO3). The WPA was desulfated to 0.09–0.14% SO₃, defluorinated to 0.18–0.20% F, and concentrated to 50.55% P₂O₅. Under controlled conditions—achieving a 95% reaction rate and a 15-minute decomposition time—a high-quality product was obtained. The final composition included 50.45% digestible P₂O₅, 38.02% water-soluble P₂O₅, 21.14% total CaO, and 14.39% water-soluble CaO, with a fluoride content of 0.16%. The granules achieved 2.13 MPa in strength, with over 85% in the optimal 2-3 mm size range, meeting GOST 23999-80 standards. This phosphate supplement offers high bioavailability for livestock, poultry, and aquaculture.

Effect of Chronic Consumption of Fluoridated Water on Sciatic Nerve Conduction Velocity in Male Wistar Rats.

The long-term effect of fluoridated water consumption during development on the velocity of nerve impulse conduction in the sciatic nerve of rats was assessed. Thirty male Wistar rats, 21 days old, were randomly assigned to five groups. Three groups were given fluoridated water ad libitum (as the only source) at different concentrations (10, 100, and 150 ppm), designated as groups F10, F100, and F150, respectively. The study included a control group (C) that received fluoridated water at the maximum level established by the World Health Organization (1.5 ppm of fluorides) and another group that received deionized water (DW). The animals were treated until they reached 90 days of age. Electrophysiological recordings were performed on the rats' sciatic nerves to determine nerve conduction velocity, and blood plasma was extracted for fluoride concentration analysis. The study found that the F150 group had a lower nerve impulse conduction velocity in the sciatic nerve compared to the C group (P = 0.0015). Additionally, there was a negative correlation between the concentration of fluorides in plasma and the nerve conduction velocity (r = -0.5132, P = 0.0037). These findings indicate that chronic consumption of high concentrations of fluoride leads to a decrease in nerve conduction velocity. This, in conjunction with potential alterations in the central nervous system, may explain the deficits in learning and memory tests that have been documented in numerous studies evaluating individuals exposed to fluoride consumption. These results provide valuable information for understanding the effects and action mechanisms of fluoride in exposed individuals.