Low Fluoride Concentrations Research Articles

Caries-Preventive Effect of Salt Fluoridation in Preschool Children in The Gambia: A Prospective, Controlled, Interventional Study

The aim of this study was to investigate the anticaries effect of fluoridated salt in a communal feeding program for preschool children. In the Gambian city of Brikama, drinking water had a low fluoride content (0.1 mg F^-/L) and young children did not use toothpaste for oral hygiene. Its 2 preschools served as clusters for the trial. Random allocation of the kindergartens was performed by one person not involved in the study, and the clinical examinations were carried out using the envelope method. Meals were prepared with fluoridated salt (250 mg F^-/kg salt) in the intervention group but not in the control group. According to the inclusion criteria (complete primary dentition and informed consent from legal guardian), 441 children aged 3-5 years were enrolled. The children were examined by calibrated persons according to WHO criteria, allowing the calculation of d₃mft scores. The primary end point was the mean difference in the incidence of caries cavities (Δd_3/4mft) after 12 months. After 12 months, the mean caries incidence per person was 1.29 d_3/4mf teeth (95% CI: 0.96; 1.62) in the test group (n = 304 children) and 3.83 d_3/4mf teeth (95% CI: 2.94; 4.72) in the control group (n = 137 children). Thus, the caries-prevented fraction was 66.3%. No signs of harm due to the intervention were observed. The use of fluoridated salt in a communal feeding program and in an environment with negligible availability of fluoride from other sources yields a considerable caries-preventive effect.

The use of micellar-enhanced ultrafiltration (MEUF) for fluoride removal from aqueous solutions

Abstract Fluorine is a common chemical element. Due to the harmful influence on human health, the World Health Organization determined the permissible level of fluoride in drinking water to be 1.5 mg F−/L. Fluorine can be removed from water solutions by various methods (i.e. ion-exchange, precipitation, adsorption and membrane techniques). One membrane technique that can be effective in fluoride removal is micellar enhanced ultrafiltration (MEUF). This method involves the ability of surfactants to create micelles, which are retained by classic ultrafiltration membranes. In the presented paper, the suitability of the MEUF process for fluoride removal was verified. Polyethersulfone and regenerated cellulose ultrafiltration membranes, as well as two cationic surfactants (cetylpyridinium chloride – CPC, octadecylamine acetate – ODA) were used in the batch experiments. The fluoride content in the model solutions amounted to 10 and 100 mg F−/L, whereas surfactant concentration varied in the range of 1–3 CMC. The MEUF tests were performed under a pressure of 0.2 MPa with and without a salt (NaCl) dosage to the treated solutions. The results obtained showed that for a low fluoride content (10 mg F−/L) and a high CMC value (3CMC), the polyethersulfone membrane allowed F− ions below the permissible level for drinking water to be removed. The presence of NaCl in the model solutions resulted in a significant worsening of fluoride removal efficiency.

Biosorption of fluoride by water lettuce (Pistia stratiotes) from contaminated water

Phytoremediation is a proven low-cost and sustainable method for the removal of toxic pollutants from water. This green technology has been practiced for the past several years all over the world. In the present study, the interaction of fluoride on the surface of the floating aquatic plant water lettuce (Pistia stratiotes) during fluoride removal was investigated. Batch kinetic studies were performed to examine the fluoride uptake capacity of the plant with different initial fluoride concentrations such as 3, 5, 10, and 20 mg/L. The effects of various process parameters on fluoride uptake dynamics such as pH, plant biomass, initial fluoride concentration, and time were examined. Freundlich’s isotherm model was found to (R 2 = 0.957) fit well to the experimental data. The nature of reaction order followed pseudo-first-order kinetics, when the initial fluoride level in the solution was 5 mg/L. The experimental findings showed that the removal mechanism was driven by biosorption phenomenon. High fluoride concentration in the solution reduced the growth ratio of P. stratiotes. The lowest growth ratio of this aquatic macrophyte was found to be 76.80 ± 3.73% at 20 mg/L fluoride concentration. At lower fluoride concentrations such as 3 and 5 mg/L, the growth ratio of the plant was not reduced significantly.

Inhibition of the Quorum Sensing System (ComDE Pathway) by Aromatic 1,3-di-m-tolylurea (DMTU): Cariostatic Effect with Fluoride in Wistar Rats.

Dental caries occurs as a result of dysbiosis among commensal and pathogenic bacteria leading to demineralization of enamel within a dental biofilm (plaque) as a consequence of lower pH in the oral cavity. In our previous study, we have reported 1,3-disubstituted ureas particularly, 1,3-di-m-tolylurea (DMTU) could inhibit the biofilm formation along with lower concentrations of fluoride (31.25 ppm) without affecting bacterial growth. In the present study, RT-qPCR analysis showed the target specific molecular mechanism of DMTU. In vivo treatment with DMTU, alone or in combination with fluoride, resulted in inhibition of caries (biofilm development of Streptococcus mutans) using a Wistar rat model for dental caries. The histopathological analysis reported the development of lesions on dentine in infected subjects whereas the dentines of treated rodents were found to be intact and healthy. Reduction in inflammatory markers in rodents' blood and liver samples was observed when treated with DMTU. Collectively, data speculate that DMTU is an effective anti-biofilm and anti-inflammatory agent, which may improve the cariostatic properties of fluoride.

Antibacterial activity against Streptococcus mutans and inhibition of bacterial induced enamel demineralization of propolis, miswak, and chitosan nanoparticles based dental varnishes

Using natural products can be a cost-effective approach for caries prevention especially in low income countries where dental caries is highly prevalent and the resources are limited. Specially prepared dental varnishes containing propolis, miswak, and chitosan nanoparticles (CS-NPs) with or without sodium fluoride (NaF) were assessed for antibacterial effect against Streptococcus mutans (S. mutans) using disk diffusion test. In addition, the protective effect of a single pretreatment of primary teeth enamel specimens against in vitro bacterial induced enamel demineralization was assessed for 3days. All natural products containing varnishes inhibited bacterial growth significantly better than 5% NaF varnish, with NaF loaded CS-NPs (CSF-NPs) showing the highest antibacterial effect, though it didn’t significantly differ than those of other varnishes except miswak ethanolic extract (M) varnish. Greater inhibitory effect was noted with varnish containing freeze dried aqueous miswak extract compared to that containing ethanolic miswak extract, possibly due to concentration of antimicrobial substances by freeze drying. Adding natural products to NaF in a dental varnish showed an additive effect especially compared to fluoride containing varnish. 5% NaF varnish showed the best inhibition of demineralization effect. Fluoride containing miswak varnish (MF) and CSF-NPs varnish inhibited demineralization significantly better than all experimental varnishes, especially during the first 2days, though CSF-NPs varnish had a low fluoride concentration, probably due to better availability of fluoride ions and the smaller size of nanoparticles. Incorporating natural products with fluoride into dental varnishes can be an effective approach for caries prevention, especially miswak and propolis when financial resources are limited.

Fluoride Regulate Osteoblastic Transforming Growth Factor-β1 Signaling by Mediating Recycling of the Type I Receptor ALK5.

This study aimed to preliminary investigate the role of activin receptor-like kinase (ALK) 5 as one of TGF-βR1 subtypes in bone turnover and osteoblastic differentiation induced by fluoride. We analyzed bone mineral density and the expression of genes related with transforming growth factor-β1(TGF-β1) signaling and bone turnover in rats treated by different concentrations of fluoride with or without SB431542 in vivo. Moreover, MTT assay, alkaline phosphatase staining, RT-PCR, immunocytochemical analysis and western blot analysis were used to detect the influence on bone marrow stem cells (BMSC) after stimulating by varying concentration of fluoride with or without SB431542 in vitro. The in vivo study showed SB431542 treatment affected bone density and gene expression of rats, which indicated TGF-β1 and ALK5 might take part in fluoride-induced bone turnover and bone formation. The in vitro study showed low concentration of fluoride improved BMSC cells viability, alkaline phosphatase activity, and osteocalcin protein expression which were inhibited by high concentration of fluoride. The gene expression of Runx2 and ALK5 in cells increased after low concentration fluoride treatment which was also inhibited by high concentration of fluoride. Fluoride treatment inhibited gene and protein expression of Samd3 (except 1 mgF-/L). Compared with fluoride treatment alone, cells differentiation was inhibited with SB431542 treatment. Moreover, the expression of Runx2, ALK5 and Smad3 were influenced by SB431542 treatment. In conclusion, this preliminary study indicated that fluoride regulated osteoblastic TGFβ1 signaling in bone turnover and cells differentiation via ALK5.

Sensing of fluoride ions in aqueous media using a luminescent coordination polymer and liposome composite.

The synthesis of a luminescent coordination polymer (Tb-BTC) within the confined environment of a liposome allowed for the anisotropic growth of nanosized Tb-BTC crystals. Consequently, the resulting composite Tb-BTC@Lipo exhibited a higher fluorescence sensitivity to fluoride anions in aqueous media compared to the independent Tb-BTC in bulk.

Comparison of Antimicrobial Activity of Child Formula Dentifrices at different Concentrations: An in vitro Study.

AimThe aim of the present in vitro study is to evaluate and compare antimicrobial efficacy of commercially available child’s dental formulas in reduced concentrations containing different forms of fluoride against Streptococcus mutans activity.Materials and methodsThe selected dentifrices were prepared in dilutions of 1:1, 1:2, 1:4, 1:8, and 1:16 using sterile pyrogen-free distilled water. Various dilutions of the selected toothpaste slurries were incubated in the agar plate containing pure strains of S. mutans, and antimicrobial activity of each was assessed by measuring the diameter of zones of inhibition (in mm). Agar well plate diffusion method and minimum inhibitory concentration (MIC) determination were the methods used in this study. The inhibitory circle of each dentifrice was measured and MIC was achieved by considering the value of diameter of the circle.ResultsThe results of the study showed that even at a lower concentration of fluoride, inhibition halos were obtained for all the formulations at different dilutions.ConclusionThe kid’s formulations having lower fluoride concentration show antimicrobial activity even after dilutions. Thus, commercially, the fluoride concentrations can be further lowered down in the dentifrices, thereby reducing the risk associated with fluoride.How to cite this articleMalhotra R, Singla S, Shashikiran ND. Comparison ofAntimicrobial Activity of Child Formula Dentifrices at different Concentrations: An in vitro Study. Int J Clin Pediatr Dent 2017;10(2):131-135.

Insights into the fluoride-resistant regulation mechanism of Acidithiobacillus ferrooxidans ATCC 23270 based on whole genome microarrays.

Acidophilic microorganisms involved in uranium bioleaching are usually suppressed by dissolved fluoride ions, eventually leading to reduced leaching efficiency. However, little is known about the regulation mechanisms of microbial resistance to fluoride. In this study, the resistance of Acidithiobacillus ferrooxidans ATCC 23270 to fluoride was investigated by detecting bacterial growth fluctuations and ferrous or sulfur oxidation. To explore the regulation mechanism, a whole genome microarray was used to profile the genome-wide expression. The fluoride tolerance of A. ferrooxidans cultured in the presence of FeSO4 was better than that cultured with the S(0) substrate. The differentially expressed gene categories closely related to fluoride tolerance included those involved in energy metabolism, cellular processes, protein synthesis, transport, the cell envelope, and binding proteins. This study highlights that the cellular ferrous oxidation ability was enhanced at the lower fluoride concentrations. An overview of the cellular regulation mechanisms of extremophiles to fluoride resistance is discussed.

Fluoruro en el agua subterránea: niveles, origen y control natural en la región de Tenextepango, Morelos, México

El agua subterránea que consume la población en la región de Tenextepango, Morelos, contiene fluoruro en concentración que varía de 0.5 a 1.9 mg/L, causando problema de fluororis dental a la población. El objetivo de este trabajo es conocer los niveles de fluoruro en el agua subterránea, su distribución y su procedencia en la región de Tenexpenango, Morelos, México. Para esto se elaboró el modelo hidrogeológico soportado con análisis químicos del agua obtenida en 17 pozos y cinco manantiales; el pH, alcalinidad, CE y temperatura del agua se registraron en campo. La concentración de cationes, aniones y elementos traza se determinó por ICP-MS. Los resultados indican que la concentración de fluoruro, y temperatura del agua subterránea, son mayores en los pozos que extraen agua sin interrupción y menor en aquéllos que bombean solo nueve horas-día. La variación de estos parámetros sugiere que los primeros extraen agua de un flujo con mayor profundidad de recorrido con respecto al agua de otros pozos, indicando que el incremento en el tiempo de extracción induce un flujo vertical de agua (ascendente) permitiendo que en tales pozos se descargue un sistema de flujo más profundo, cuyo contenido de fluoruro y valor de temperatura son sensiblemente mayores al resto de los demás pozos. Como conclusión, la fuente del fluoruro al agua subterránea en esta región está en las rocas que conforman del relieve que rodea la planicie y principalmente en aquel ubicado fuera de la planicie hacia el noreste (Sierra Nevada). El fluoruro es liberado al agua subterránea por el proceso del intemperismo químico de rocas ígneas intermedias y félsicas.

Comparison of Fluoride Content in Drinking Water and Prevalence of Dental Fluorosis in 6 - 12-Year-Old Students in Mariwan (a Cold Region) and Behbahan (a Warm Region) during the 2013 - 2014 Educational Year

Background: Fluoride plays an important role in preventing dental caries. Low fluoride concentrations cannot prevent dental caries, but ingestion of very high concentrations of fluoride during enamel development and maturation could lead to fluorosis. Fluoridation of drinking water is the most effective and inexpensive method for preventing caries. The mandated concentration of fluoride incorporated into drinking water should consider the mean temperature of each region. Objectives: The aim of the present study was to evaluate the prevalence of fluorosis in children aged 6 - 12 in Mariwan and Behbahan and determine the fluoride content of drinking water in these two towns. Materials andMethods: In the present descriptive and cross-sectional study, 13 water samples were taken from homes in Behbahan, 1 sample from the town’s water reservoir, 10 samples from homes in Mariwan (5 samples for each reservoir) and 1 sample each from the town’s 2 reservoirs. The 26 samples (23 from homes and 3 from reservoirs) were taken in polyethylene containers. The SPANDS colorimetric technique was used to determine fluoride content. Homes that used home-based water purification systems were excluded from the study. In addition, 128 students (62 girls and 66 boys) in Behbahan and 90 students in Mariwan were randomly selected. Dean’s index was used to determine dental fluorosis. The mean yearly temperatures of the two towns were obtained from the metrological bureaus of the two towns. Results: The means fluoride content of water in Behbahan’s reservoir and Mariwan’s reservoirs 1 and 2 were 0.7, 0.24 and 0.036 ppm, respectively. The mean fluoride content of Behbahan’s home waterlines and in the relevant home waterlines of reservoirs 1 and 2 in Mariwan were 0.67, 0.218, and 0.054 ppm, respectively. There were no significant differences between the relevant reservoirs. The prevalence of fluorosis in Behbahan was as follows: 84.4% healthy, 10.9% questionable, 1.6% very mild, 2.3% mild, and 0.8% moderate. In Mariwan, the prevalence in areas related to reservoir 1 was 96.7% healthy and 3.3% questionable; in areas related to reservoir 2 it was 94.4% healthy and 5.6% questionable. Conclusions: The fluoride content of drinking water in reservoirs and at homes was below the optimal level in Mariwan. No differences were observed from the standard levels in Behbahan. There were no differences in fluoride content of water in reservoirs and in home pipelines, indicating no tangible changes in fluoride content from the reservoirs to the homes. In neither of the towns was severe fluorosis observed. There was no significant difference in the prevalence and severity of fluorosis between genders.

Combinatorial Effects of Aromatic 1,3-Disubstituted Ureas and Fluoride on In vitro Inhibition of Streptococcus mutans Biofilm Formation

Dental caries occur as a result of disequilibrium between acid producing pathogenic bacteria and alkali generating commensal bacteria within a dental biofilm (dental plaque). Streptococcus mutans has been reported as a primary cariogenic pathogen associated with dental caries. Emergence of multidrug resistant as well as fluoride resistant strains of S. mutans due to over use of various antibiotics are a rising problem and prompted the researchers worldwide to search for alternative therapies. In this perspective, the present study was aimed to screen selective inhibitors against ComA, a bacteriocin associated ABC transporter, involved in the quorum sensing of S. mutans. In light of our present in silico findings, 1,3-disubstituted urea derivatives which had better affinity to ComA were chemically synthesized in the present study for in vitro evaluation of S. mutans biofilm inhibition. The results revealed that 1,3-disubstituted urea derivatives showed good biofilm inhibition. In addition, synthesized compounds exhibited potent synergy with a very low concentration of fluoride (31.25–62.5 ppm) in inhibiting the biofilm formation of S. mutans without affecting the bacterial growth. Further, the results were supported by confocal laser scanning microscopy. On the whole, from our experimental results we conclude that the combinatorial application of fluoride and disubstituted ureas has a potential synergistic effect which has a promising approach in combating multidrug resistant and fluoride resistant S. mutans in dental caries management.

Fluoride levels in UK infant milks.

AimTo provide a comprehensive report of fluoride concentration in UK infant milks and estimate their contribution to daily fluoride intake.MethodsA total of 60 formula milk products available commercially or within a hospital environment were analysed, along with eight pasteurised cow’s milk samples. Formula milk products requiring preparation were reconstituted with fresh Leeds tap water (0.02 ppmF). Fluoride concentration was measured for all products directly using an ion selective electrode after addition of low-level total ionic strength adjustment buffer.ResultsThe overall median fluoride concentration for the 68 infant milks was 0.025 ppmF, with a wide range of 0.002–0.282 ppmF. Analysis revealed variation between composition and manufacturer, in addition to differences between measured and labeled fluoride concentration. Although all products contained low fluoride concentration, the fluoride concentrations for formula milks used within the hospital setting (0.029 ppmF) were statistically higher in comparison to the commercial formula milk (0.016 ppmF) and cow’s milk (0.017 ppmF) products. The daily fluoride contribution from infant milks was low; 0.0034 mgF/kg body weight per day was estimated between birth and 6 months of age, further decreasing as intake of infant milk decreased with age.ConclusionsFluoride concentration of the analysed infant milks is low, providing minimal contribution towards total daily F intake and alone are unlikely to pose a threat for the development of dental fluorosis.

Development of a nanosphere adsorbent for the removal of fluoride from water

A new uniform-sized CeCO3OH nanosphere adsorbent was developed, and tested to establish its efficiency, using kinetic and thermodynamic studies, for fluoride removal. The results demonstrated that the CeCO3OH nanospheres exhibited much high adsorption capacities for fluoride anions due to electrostatic interactions and exchange of the carbonate and hydroxyl groups on the adsorbent surface with fluoride anions. Adsorption kinetics was fitted well by the pseudo-second-order model as compared to a pseudo-first-order rate expression, and adsorption isotherm data were well described by Langmuir model with max adsorption capacity of 45mg/g at pH 7.0. Thermodynamic examination demonstrated that fluoride adsorption on the CeCO3OH nanospheres was reasonably endothermic and spontaneous. Moreover, the CeCO3OH nanospheres have less influence on adsorption of F− by pH and co-exiting ions, such as SO42−, Cl−, HCO3−, CO32−, NO3− and PO43−, and the adsorption efficiency is very high at the low initial fluoride concentrations in the basis of the equilibrium adsorption capacities. This study indicated that the CeCO3OH nanospheres could be developed into a very viable technology for highly effective removal of fluoride from drinking water.

Hydrogeochemical appraisal of fluoride in groundwater of Langtang area, Plateau State, Nigeria

Consumption of high fluoride in groundwater of Langtang area, manifest in the inhabitants of the area in form of dental fluorosis and skeletal fluorosis in older group. The aim of this study was to appraise the hydrogeochemistry of fluoride in the groundwaters of Langtang area. Thirty seven surface and groundwater samples and nine rock samples were collected in Langtang area for geochemical analysis. The Inductively Coupled Plasma Emission Spectrometry (ICPOES) was used to detect cations. The anions (Cl - , SO 4 = and Br - ) were determine by Ion Chromatography method. Fluoride was determined by the Specific Ion Electrode and bicarbonate was determined by titration. Major oxides, trace elements and rare earth elements for the rock samples were determined by the XRF method and fluorine by the Fusion method. Polished thin sections for rocks were prepared and studied. Geochemical results from analysis of the samples (rock and water) show that four major rock units make up the geology of the area; coarse porphyritic biotite granite, migmatite, rhyolite and riebeckite granites, the minor ones are pegmatite, trachyte, aplite and fine to medium grained biotite granites. The rhyolite, the riebeckite granites and trachyte have the highest level of fluorine content in the area (1,470, 1000, 900 and 800 ppm) respectively. The fluorine mineral (Fluorite) crystallized in the late stage of the magma as replacement of Fe/Mg mineral probably hornblende or biotite. Fluorine is leached into the groundwater from the rhyolite under the slightly alkaline (Ca-Mg-HCO 3 evolving Na-HCO 3 ) water in the area. The two major groundwater types (Ca-Mg-HCO 3 and Na-HCO 3 ) in the area have good relationship with content of fluoride in water. Although, the riebeckite granites have high fluorine content, contribution of fluoride from them is towards the southern portion of the map, owing to the groundwater flow direction. The different water sources in the area do not show variation in content of fluoride in water. However, groundwater barriers (dykes) may be responsible for some area having low fluoride (<1.5 mg/l) content. The consumption of high content of fluoride in the area has resulted in severe dental fluorosis in both children and youths and bowing of legs ( Genu Valgum ) in children with no discrimination between the sexes. Keywords: Fluoride, Fluorite, Fluorine, Fluorosis, Riebeckite Granite, Groundwater

Effectiveness of a toothpaste with low fluoride content combined with trimetaphosphate on dental biofilm and enamel demineralization in situ

Effectiveness of a toothpaste with low fluoride content combined with trimetaphosphate on dental biofilm and enamel demineralization in situ

Hygienic aspects of dental caries and its prevention

This review summarizes fluoride content in surface water sources of various Russian regions and its relationship with the prevalence of caries in the population. Low Fluoride content in almost all water sources of Russia highlights the importance of individual prevention of dental caries above all by the use of fluorinated toothpaste. From the standpoint of evidence-based medicine the tooth brushing with fluorinated paste twice daily has the highest level of efficiency of caries reduction.

A facile method to effectively combine plasmon enhanced fluorescence (PEF) and fluoride-Lewis acid based reactions to detect low concentrations of fluoride in solution

Synergizing the Purcell-effect of silver nanoparticles and fluoride-Lewis acid based reactions to enhance the sensitivity and detection limit of a fluoride ion chemodosimeter.

Correction: A facile method to effectively combine plasmon enhanced fluorescence (PEF) and fluoride-Lewis acid based reactions to detect low concentrations of fluoride in solution

Correction for ‘A facile method to effectively combine plasmon enhanced fluorescence (PEF) and fluoride-Lewis acid based reactions to detect low concentrations of fluoride in solution’ by Richard Appiah-Ntiamoah et al., RSC Adv., 2016, 6, 78918–78929.

STRUCTURE AND TRANSPORT PROPERTIES OF Ba0.8-0.5хLa1.2In2O5.6-хFx

In this article through joint cationic and anionic doping brawnmillerite Ba2In2O5 compounds obtained from the homogeneity range Ba0.8-0.5хLa1.2In2O5.6-хFx (0 ≤ х ≤ 0.2). It is established that structures are characterized by cubic symmetry (space group Pm3m) by the method of the full-profile analysis of Rietveld. It is proved these phases are capable to high-temperature protonic conductivity. It was found that mixed anion effect comprising the growth of electrical conductivity at low concentrations of fluoride observed for the Ba0.8-0.5хLa1.2In2O5.6-хFx.