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Excessive fluoride intake can cause dental fluorosis during teeth development and growth. However, the mechanisms underlying fluoride-induced enamel damage are still not fully elucidated. Previously, we observed fluoride-induced autophagy in ameloblasts, but the effects of fluoride on autophagy flux in ameloblasts remain unclear. Hence, this study aimed to clarify the effects of fluoride and rapamycin, an autophagy activator, on autophagy flux in ameloblasts. This in vitro study used the murine ameloblast-derived cell line LS8. Cells were treated with different concentrations of sodium fluoride (NaF) to evaluate NaF-induced cytotoxicity. Using transmission electron microscopy, we observed an increase in the number of autophagosomes with increasing fluoride concentrations. Western blot analyses showed increases in microtubule-associated protein 1 light chain 3 (LC3) and SQSTM1 (p62) expression after NaF treatment and an increase in LC3II expression after bafilomycin A1 administration. Together with changes in RFP-GFP-LC3 lentivirus expression, this demonstrated that fluoride impaired autophagy flux. Furthermore, we evaluated whether rapamycin can alleviate fluoride-induced cytotoxicity by restoring autophagy flux. Compared to the NaF-treated group, LS8 cells cotreated with NaF and rapamycin grew considerably better and had significantly decreased p62 expression. Taken together, these data suggest that fluoride-induced impaired autophagosome degradation may damage ameloblasts. This provides experimental in vitro evidence and an explanation for the observed NaF-induced toxicity of ameloblasts. Rapamycin probably alleviates this impairment by decreasing the expression of p62, thereby preventing autophagy defects.

Dentures should have proper fluoride release and physical properties. We evaluated how surface prereacted glass ionomer (S-PRG) nanofillers influenced fluoride release, flexural strength, and surface characteristics of polymethylmethacrylate (PMMA) resin.PMMA resin disc (n = 14) and rectangular (n = 5) specimens containing 0, 20 wt% microparticles, and 20 wt% nanoparticles of S-PRG were prepared. Six-disc specimens were examined for surface roughness; eight-disc specimens were immersed in 5 ml of deionized water for 24 h before analyzing the fluoride levels on days 1-3, 12, and 15. They were recharged with 1000 ppm fluoride solution for 24 h and stored in deionized water for five cycles. Fluoride release was examined. The flexural strength of the rectangular specimens was determined using a three-point bending test. Data were analyzed by two-way repeated-measures ANOVA.S-PRG nanofiller had the highest fluoride exchange rate and did not significantly change the surface roughness compared with the microparticle and control groups; however, the nanofillers agglomerated and reduced the flexural strength to below 65 MPa.Incorporating 20 wt% nanofillers into resin enhanced the fluoride exchange property greater than microfillers at the same content, but diminished the mechanical properties of the resin.Incorporating 20 wt% S-PRG nanofillers in resin denture base can improve the fluoride releasing property without affecting the surface roughness.

OBJECTIVES. To examine variation in the delivery of fluoride varnish during pediatric medical visits by rurality. METHODS. This observational study used private health insurance claims (2016–2018) for children aged 1 to 5 years from Connecticut, Maine, New Hampshire, and Rhode Island linked to the county-level Rural-Urban Continuum codes. County-level Rural-Urban Continuum codes were categorized into three groups: metropolitan, rural, and remote rural. Logistic regression models were used to estimate the odds of a well-child medical visit including fluoride varnish by county rurality, adjusting for other individual and county characteristics. RESULTS. Among 328,661 pediatric well-child visits paid by private insurance, fluoride varnish was included in 4.3% of visits in metropolitan counties, 6.2% of visits in rural counties, and 10.3% of visits in remote rural counties. There were significantly higher odds of a visit including fluoride varnish in rural remote counties (odds ratio [OR]=3.5, 95% confidence interval [CI]=2.3–5.3, P

AIM This prospective cohort study aimed to investigate whether orthodontic appliances removal (OAR) combined with caries-preventive strategies and fluoride varnishes alters salivary physicochemical properties, changes the activity of carbonic anhydrase VI (CA VIACT ) and α-amylase (α-AMLACT ), and favors the regression of active carious lesions (ACL). DESIGN Twenty-two individuals aged between 13 and 24 years old were assessed for the presence of visible biofilm, daily sugar exposure, caries activity, salivary flow rate (SFR), pH, buffering capacity (BC), and CA VIACT and α-AMLACT activity at baseline, and 1, 5 and 13 weeks after OAR. Variables were assessed using repeated-measures analysis of variance, Cochran's Q and McNemar's test, and Pearson's correlation. RESULTS We verified a significant decrease in the number of ACL at the 5-week (29% reduction) and at the 13-week follow-up (58% reduction). At the 5 and 13-week follow-up, the percentage of visible biofilm and sugar exposure decreased, whereas the salivary pH and α-AMLACT activity significantly increased. BC and CA VIACT remained unchanged throughout the follow-up. CONCLUSION OAR combined with caries-preventive strategies and fluoride varnishes favored the regression of active carious lesions and increased salivary pH and α-AMLACT activity, whereas buffering capacity and CA VIACT remained stable.

This study aimed to determine caries prevalence, oral health practices/behaviours and dental anxiety levels amongst dental hygiene students.A self-administered questionnaire was used to determine students' oral hygiene practices/behaviours. The students were subjected to oral examinations to determine their decayed, missing, filled teeth (DMFT) scores according to the WHO criteria. In addition, the Corah's Dental Anxiety Scale (CDAS) was used to measure the students' dental anxiety levels.A total of 280 students (mean age: 20.8 years) participated in this study. Amongst the students, 52.8% brush their teeth twice a day, and 17.48% and 15.17% use floss and mouthwash daily, respectively. Moreover, the defined smoking rate was 22.85%. The mean DMFT scores of the preclinical and clinical students were 3.39 ± 3.22 and 3.55 ± 3.19, respectively. Most of the students (82.6%) preferred fluoride toothpaste, and the DMFT scores of those who use and do not use fluoride toothpaste significantly differed (p = 0.031). Furthermore, junk-food consumption affected the scores for decayed teeth (p = 0.048) and missing teeth (p = 0.039). Most students had low or moderate CDAS scores (CDAS13), and anxiety scores were lower amongst the clinical students than amongst the preclinical students.Although the students demonstrated favourable oral health behaviours/practices and low caries prevalence, their adherence to oral hygiene instructions and to healthy dietary and lifestyle habits should improve. The importance of this topic should be strongly emphasized in the undergraduate curriculum. For this purpose, professional behavioural control methods that suit students' individual capacities, motivations and therapeutic needs may be employed. The principal findings of similar studies should be evaluated by lecturers to help students adopt optimal oral health practices/behaviours, reducing their dental anxiety levels and improving their professional competencies.

The aim of this study was to assess the ability of self-assembling peptide (P11-4) diffusion, assembly, and remineralization to effect artificial secondary caries-like lesions in human primary teeth in vitro. Enamel-dentin blocks obtained from extracted human primary molars were embedded into epoxy resin blocks. Cavities (approximately 1 × 1 × 2 mm) were prepared on the surface using a high-speed diamond bur under constant water cooling and filled with composite restorative material (Filtek Z250; 3 M ESPE). The samples were immersed in demineralizing solution (20 ml) for 96 h to produce secondary caries lesions and divided into two groups according to the testing materials: fluoride varnish (Duraphat; Colgate, UK) and P11-4 (Curodont Repair; Credentis, Switzerland). Except for the control areas, all samples were remineralized for 3-5 min using the remineralizing agents, and then all the sections were placed in a pH-cycling system for 5 days at 35°C. The pH cycling procedure was followed by micro-CT analysis for the qualitative evaluation of surface changes. The Mann-Whitney U test was used to compare two independent groups. In the comparison of more than two dependent groups, Bonferroni smoothed pairwise analyses were used to determine the source of the Kruskal-Wallis H test difference. The results of the study revealed that the remineralization depths of the peptide group were higher than those of the fluoride group (p .01). There was a statistically significant difference in remineralization effects between the fluoride and peptide groups. P11-4 can be considered as an effective remineralizing agent for secondary caries lesions.

Fluoride has been shown to be shown to be an effective agent in the prevention of caries during orthodontic treatment. Resin modified glass ionomer cements possess therapeutic anticariogenic properties acting as a fluoride reservoir and releasing fluoride into the environment, particularly at low pH where there is a threat of enamel demineralisation and white spot lesions (WSL's). Patient compliance to instructions in standard oral hygiene measures limits the success of caries prevention and the routine use of glass-ionomer cements can mitigate the lack of compliance, although RMGIC's are not a panacea against WSL's. The adhesion of GIC's to the enamel surface is a physico-chemical bond rather than a mechanical bond which reduces the risk of iatrogenic damage to the enamel when bonding and debonding attachments. RMGIC's can be recommended as a bonding adhesive for all attachments but one needs to be selective when bonding molar attachments to avoid occlusal interferences as masticatory forces can be high in these areas.

OBJECTIVES To determine whether children participating in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) had more caregiver-reported preventive dental care visits (PDCVs) and preventive dental services (PDS) than nonparticipating children. METHODS A secondary data analysis was performed utilizing the National Survey of Children's Health 2017 and 2018 combined datasets. The analytic sample included 10,356 children aged 1-4 years. It was further stratified into three groups by WIC eligibility and participation to include WIC participation, income-eligible nonparticipants, and higher-income nonparticipants. The independent variables included child-level characteristics (age, sex, race/ethnicity, and insurance) and caregiver-level characteristics (age of mother and the highest level of education in the household). The dependent variable was the report of PDCV and PDS (dental cleaning, toothbrushing instructions, and fluoride treatment) in the past 12 months. RESULTS Of the 10,356 children aged 1-4 years, 3025 were eligible for WIC and nearly half of those eligible (49.5%) reported participating in the WIC program. Caregivers of WIC-participating children had a higher reported prevalence of PDCV for their children than those of income-eligible nonparticipants (57.6% vs. 49.6%, respectively) (p

Thrombosis is an important factor that causes the failure of artificial biological valves in addition to calcification and immune rejection. A hydrophobic antifouling surface can improve blood compatibility by reducing the absorption of protein. In this study, porcine pericardium was cross-linked with glycidyl methacrylate, and carbon-carbon double bonds were introduced. Then, fluoride monomer was added so that the pericardial surface would become hydrophobic and antifouling. Fluoride modification changed the hydrophilicity of the pericardium surface, and the surface water contact angle increased from 84° to 143°. Compared with unmodified pericardium, the adsorption of bovine serum albumin and fibrinogen decreased by 93.1% and 85%, respectively, and the anti-thrombogenicity was greatly enhanced.

BACKGROUND Water-soluble fluoride (WS-F) can be absorbed directly by tea plants from soil and comprises a major source of dietary F in tea consumers. To reveal the WS-F accumulation in tea leaves and assess WS-F health risks, 70 sets of samples including tea leaves at three maturity stages and corresponding topsoil were collected from Xinyang, China. The WS-F contents in tea samples and pH values in soil samples were determined. RESULTS The contents of WS-F in tea leaves exhibited a positive correlation with leaf maturity. The contents of WS-F in tea leaves showed a positive correlation with WS-F contents in the soil as the soil pH value exceeds 5. All the bud with two leaves samples, 84.29% of the third to sixth leaves samples, and 78.57% mature leaves samples in 5-min infusion tend to be no health threat. The leaching characteristics of WS-F from tea leaves were influenced by the leaf maturity and soaking time. CONCLUSION Taking measures to control pH and WS-F concentration of plantations soil, as well as drinking tea infusion made from young leaves or reducing soaking time could decrease the WS-F health risk. © 2021 Society of Chemical Industry.

OBJECTIVES This cluster-randomized controlled community trial aimed to assess the efficacy and costs of fluoride varnish (FV) application for caries prevention in a high-risk population in South Africa. METHODS 513 children aged 4-8 years from two schools in a township in South Africa were randomly allocated by class to the FV or Control (CO) groups. In addition to supervised toothbrushing with fluoridated toothpaste in both groups, FV was applied in 3-month intervals by trained local non-professional assistants. Intraoral examinations were conducted at baseline, 12, 21 and 24 months. Primary outcome was the increment of teeth with cavitated lesions (i.e. newly developed or progressed, formerly non-cavitated lesions), requiring restoration or extraction over the study period. Additionally, treatment and re-treatment costs were analyzed. RESULTS 513 children (d1-4 mft 5.9 ± 4.3 (mean ± SD)) were randomly allocated to FV (n = 287) or CO (n = 226). 10.2% FV and CO teeth received or required a restoration; 3.9% FV and 4.1% CO teeth were extracted, without significant differences between groups. While FV generated high initial costs, follow-up costs were comparable in both groups, resulting in FV being significantly more expensive than CO (1667 ± 1055 ZAR vs. 950 ± 943 ZAR, p

Total syntheses of (+)-cinereain and (-)-janoxepin, two fungal cyclotripeptides featuring a complex heterocyclic core and interesting phytotoxic and antimalarial activities, have been achieved in a convergent manner. A key step in this synthesis is a one-pot cascade initiated by the cyclocondensation of two fragments-a hindered 2-vinylcyclopropane-1-acyl fluoride and an electron-deficient cyclic amidine-to release a reactive spiro[2-vinylcyclopropane-1,5'-pyrimidine-4',6'-dione]. This intermediate underwent a spontaneous retro-Claisen rearrangement that was rationalized by DFT calculations. The cascade directly afforded a 2,5-dihydrooxepin-fused heterotricyclic product, and the challenging oxepin ring was finally forged by the palladium-catalyzed β-hydride elimination of an allylic fluoride intermediate.

Singlet oxygen can be generated by thermal cycloreversion of aromatic endoperoxides. However, for any practical potential of chemically generated singlet oxygen within a therapeutic context, the time and place of the release of this cytotoxic species must be tightly regulated. We now show that using a bimodular design with a hypoxia responsive unit and fluoride-triggered endoperoxide unit, a bioorthogonal metabolic shunt can be established, where an enzymatically generated submicromolar fluoride signal plays a crucial role. Thus, cellular nitroreductase is repurposed in a bioorthogonal enzymatic activity, where it releases fluoride ions upon the reduction of a targeted compound. The fluoride ions released in the initial reaction remove the silyl stopper, yielding a highly accelerated release of singlet oxygen. The result is a remarkable difference in cytotoxicity between hypoxic and normoxic conditions as evidenced by microscopy, viability assays and the use of control compounds.

OBJECTIVE To determine the impact of water fluoridation on the prevalence and severity of dental caries and fluorosis in individuals aged 17-20 years exposed to fluoride toothpaste. METHODS The study population consisted of 660 students from public schools, residents of areas supplied with fluoridated water (exposed group) or not (not exposed group). Students from both groups had access to fluoride toothpaste throughout life. A questionnaire about socioeconomic demographic aspects, conditions related to access and exposure to fluoridated water, and habits related to oral health was applied. Dental caries was measured by the DMFT index and dental fluorosis by the TF index. The chi-square test, t test, and subsequently logistic regression were applied for data analysis. RESULTS Caries experience (DMFT≠0) was significantly higher in students from areas not exposed to fluoridated water, after adjustments to clinical conditions, demographic socioeconomic profile, and hygiene habits. The DMFT mean (±SD) was significantly higher in students from areas not exposed to fluoridated water than exposed (3.83 [±3.28] and 2.48 [±2.71] respectively). The prevalence of very mild/mild and moderate fluorosis was 41.1% and 21% for students either exposed to fluoridated water or not, respectively. CONCLUSION Exposure to fluoridated water was associated with a lower prevalence and severity of tooth decay, in spite of the use of fluoridated toothpaste. The prevalence of dental fluorosis at all levels was higher in fluoridated areas, however, in both groups, there were few cases with esthetic implications.

Background Globally, has been an increase in the use of silver fluoride products to arrest carious lesions and a variety of products are available. Objectives To examine differences in caries arrest and lesion colour of primary tooth carious lesions. Material and methods A four-armed, parallel-design cluster-randomised controlled trial which investigated four protocols for caries arrest at 6m and 12m. Children in Group 1 and Group 2 received Rivastar Silver Diammine Fluoride (SDF), and children in Group 3 and Group 4 received a stabilised aqueous silver fluoride solution (AgF). Children in Group 2 and Group 4 received an additional application of KI immediately after the fluoride. Differences in caries arrest and lesion appearance were examined at 6m and 12m using two level logistic regression modelling. Results The arrest rate varied by group membership; group 1 and group 3 had higher arrest rates (77.3% and 75.3% respectively) than group 2 and group 4 (65.4% and 51.2% respectively). The use of KI was also associated with lower odds of arrest (12m OR 0.25; CI 0.19, 0.34) and higher odds of avoiding black discolouration (12m OR 6.08; 2.36, 15.67). Conclusions Globally, has been an increase in the use of silver fluoride products to arrest carious lesions and a variety of products are available. This study demonstrated that both AgF and SDF can effectively arrest carious lesions on primary teeth. The use of KI is associated with poorer caries control but better aesthetic outcomes.

Fluoride is a persistent environmental pollutant, and its excessive intake contributes to skeletal and dental fluorosis. The mechanisms underlying fluoride-induced abnormal osteoblast proliferation and activation, which are related to skeletal fluorosis, have not yet been fully clarified. As important epigenetic regulators, microRNAs (miRNAs) participate in bone metabolism. On the basis of our previous miRNA-seq results and bioinformatics analysis, this study investigated the role and specific molecular mechanism of miR-486-3p in fluoride-induced osteoblast proliferation and activation via CyclinD1. Herein, in the fluoride-challenged population, we observed that miR-486-3p expression decreased while CyclinD1 and transforming growth factor (TGF)-β1 increased, and miR-486-3p level correlated negatively with the expression of CyclinD1 and TGF-β1 genes. Further, we verified that sodium fluoride (NaF) decreases miR-486-3p expression in human osteoblasts and overexpression of miR-486-3p reduces fluoride-induced osteoblast proliferation and activation. Meanwhile, we demonstrated that miR-486-3p regulates NaF-induced upregulation of CyclinD1 by directly targeting its 3'-untranslated region (3'-UTR). In addition, we observed that NaF activates the TGF-β1/Smad2/3/CyclinD1 axis and miR-486-3p mediates transcriptional regulation of CyclinD1 by TGF-β1/Smad2/3 signaling pathway via targeting TGF-β1 3'-UTR in vitro. This study, thus, contributes significantly in revealing the mechanism of miR-486-3p-mediated CyclinD1 upregulation in skeletal fluorosis and sheds new light on endemic fluorosis treatment.

Pentafluorosulfanyl (SF

Herein, a water-accelerated, N-heterocyclic carbene (NHC)-catalyzed aza-Michael addition reaction was reported to access β-aminosulfonyl fluorides, which are key hubs of the sulfur(VI) fluoride exchange (SuFEx) reaction. As a crucial reaction medium, water considerably enhanced the reaction rate with excellent chemo- and site-selectivity (up to99 : 1) compared to conventional solvents. In addition, the late-stage ligation of bioactive molecules with the aliphatic β-amino SuFEx hub was demonstrated. Mechanistic studies on experimental, analytical, and computational approaches support noncovalent activation over NHC catalysis "on-water".

Monofluoroalkanes are important in many pharmaceuticals, agrochemicals and functional materials. However, the lack of easily available and transformable monofluoroalkylating reagents that facilitate a broad array of transformations has hampered the application of monofluoroalkylation. Herein, we report a general and efficient method of preparing diverse aliphatic monofluorides with monofluoroalkyl triflate as the synthetic scaffold. Using both nickel-catalyzed hydromonofluoroalkylation of unactivated alkenes and copper-catalyzed C-C bond formation, the general diversification of the monofluoroalkylating scaffold has been exhibited. The broad utility of this monofluoroalkylating reagent is shown by concise conversion into various conventional fluoroalkylating reagents and construction of monofluoro-alkoxy, -alkylamino motifs with commercially available heteroatom-based coupling partners.

International audience; Carbamoyl fluoride is a fluorinated group which, to this date, remains underexplored, probably due to the lack of data concerning their properties. In this paper, a study of carbamoyl fluoride is proposed. Stability studies, in particular under physiological conditions, and lipophilicity measurement have been performed. A new easy, safe, inexpensive and metal-free synthesis method has also been described. Finally, a potential use in radiochemistry through a 18 F/ 19 F isotopic exchange has been demonstrated.

The propensity of organic fluorine acting as a weak hydrogen bond acceptor (HBA) in intermolecular and intramolecular interactions has been the subject of many experimental and theoretical studies often reaching different conclusions. Over the last few years new and stronger evidences have emerged for the direct involvement of fluorine in weak hydrogen bond (HB) formation. However, not all the fluorine atom types can act as weak HBA. In this work we have analyzed the differential HBA propensity of various types of fluorine atoms with a particular emphasis for the different types of alkyl fluorides. This is carried out by evaluating ab initio computed parameters, experimental 19 F NMR chemical shifts and small molecule crystallographic structures (extracted from the CSD database). According to this analysis, shielded (with reference to the 19 F NMR chemical shift) mono-fluorinated alkyl motifs display the highest HBA propensity in agreement with solution studies. Although much weaker than other well characterized HB complexes, the fragile HBs formed by these fluorinated motifs have important implications for the chemical-physical and structural properties of the molecules, chemical reactions and protein/ligand recognition.

Aim To assess the clinical effectiveness of 38% silver diamine fluoride (SDF) in arresting dental caries when compared to combination of fluoride-containing glass ionomer cement (GIC) and fluoride varnish(FV) (5%) among intellectually disabled (ID) individuals. Methodology A randomized controlled trial was conducted among ID (n = 82) individuals, in permanent posterior teeth with Nyvad score 2 and 3 (active caries) of dental caries, randomly allocated to experimental arm (38% SDF) (n = 41) and control arm (GIC along with FV) (n = 41). The caries arrest rate and caries preventive fraction was observed at 6-months among both groups. Results The caries arrest rate was 94.5% with SDF and 90.1% with GIC and FV (p = 0.405).The caries preventive fraction of SDF over GIC with FV was 45%, with hazard ratio (-0.588) at 6 months (p = 0.292). The binary logistic regression revealed that the Odds of arresting caries in SDF group is two times when compared to GIC group with p value = 0.218 which is not significant. Conclusion The present study concluded that the SDF is as clinically effective as combination of GIC and fluoride varnish in arresting caries. Further research and longer follow-up required for more conclusive results.

The safe generation of F2 gas at room temperature by using simple cell configurations has been the "holy grail" of fluorine research for centuries. Thus, to address this issue, we report generation of F2 gas through the electrolysis of CuF2 in a CsF-2.45HF molten salt without the evolution of H2 gas. The CuF2 is selected through a series of thermodynamic and kinetic assessments of possible metal fluorides. Anode assessments on graphite and glass-like carbon demonstrate the effect of the absence of the anode during generation of F2 gas owing to stabilized operations at room temperature. Although the Ni anode dissolves during electrolysis in the conventional medium-temperature cell, herein, it facilitates stable electrolysis over 100 h, achieving an F2 gas purity of over 99 % with the potential to operate using one-compartment electrolysis. This work presents a safe and propitious method for the generation of high-purity F2 gas for small-scale lab and industrial applications.

Objectives\ud To determine the prevalence of dental fluorosis, and factors associated with its occurrence in two cohorts of children exposed to different fluoride concentrations in the Malaysian water supply.\ud \ud Methods\ud A cross‐sectional study was conducted among lifelong residents (n = 1,155) aged 9 and 12 years old living in fluoridated and nonfluoridated areas. Malaysian children aged 12 years were born when the level of fluoride in the public water supply was 0.7 ppm while those aged 9 years were born after the level was reduced to 0.5 ppm. Fluorosis was blind scored using standardized photographs of maxillary central incisors using Dean's criteria. Fluoride exposures and other factors were assessed by parental questionnaire. Data were analyzed using descriptive statistics, Chi‐squared analyses, and logistic regression.\ud \ud Results\ud Fluorosis prevalence was lower (31.9 percent) among the younger children born after the reduction of fluoride concentration in the water, compared to a prevalence of 38.4 percent in the older cohort. Early tooth brushing practices and fluoridated toothpaste were not statistically associated with fluorosis status. However, the prevalence of fluorosis was significantly associated with parents' education level, parents' income, fluoridated water, type of infant feeding method, age breast feeding ceased, use of formula milk, duration of formula milk intake, and type of water used to reconstitute formula milk via simple logistic regression. Fluoridated water remained a significant risk factor for fluorosis in multiple logistic regression.\ud \ud Conclusions\ud Fluorosis was lower among children born after the adjustment of fluoride concentration in the water. Fluoridated water remained as a strong risk factor for fluorosis after downward adjustment of its fluoride concentration.

Early childhood caries (ECC) is a global problem, disproportionately affecting disadvantaged populations. The aim of this study was to evaluate systematically the available scientific evidence on the effectiveness of methods for ECC prevention. Six electronic databases were searched. Two independent reviewers selected the publications and analysed the quality of the included systematic reviews. Thirteen studies were included. Overall, eight reviews were classified with methodological quality critically low using the AMSTAR 2, whereas five reviews achieved a high risk of bias using the ROBIS tool. The methods identified that were positively related to the prevention of ECC were as follows: preventive dental programmes for pregnant women; advice on diet and feeding; prenatal oral health care; integration of maternal and children's oral health promotion into nursing practice; maternal oral health programmes undertaken by non-dental health professionals; dental health education in combination with the use of fluoride for children; early preventive dental visits; and the use of fluoride varnish and toothpastes with more than 1000 ppm of fluoride. The currently available evidence supporting the effectiveness of methods for prevention of ECC, although suggesting some methods of greater potential, is still lacking due to the methodological quality of the systematic reviews and the included primary studies.

Reinforced glass ionomer cements have been widely used in pediatric dentistry to prevent dental caries. However, the influence of biomaterial light-curing and its anti-cariogenic effects remain unclear. This study evaluates the influence of the light-curing time on fluoride release, surface topography, and bacterial adhesion in two types of resin-modified glass ionomer cements (RMGICs). One hundred disks were made, and samples were divided into two groups (n = 50 per group), according to each dental material (Vitremer™ and Ketac™ N100), and also divided into different light-cured times (10, 20, 30, 40, and 60 s). They were placed in phosphate-buffered saline solution (PBS) to measure the fluoride release. Subsequently, an independent sample of RMGICs per group was examined using atomic force microscopy (AFM). Four disks per group were incubated in a brain heart infusion (BHI) medium that was inoculated with Streptococcus mutans GS5 to evaluate the bacterial adhesion by 3-4, [5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide cell viability assay (MTT assay). The fluoride release was related to the light-curing time and gradually decreased as the light-curing time increased in both materials. Surface topography in Vitremer™ presents more irregular surfaces than Ketac™ N100. For S. mutans adhesion, the smallest number of cells per milliliter (cell/ml) was found at 40 s for Vitremer™ and at 30 s for Ketac™ N100. Thus, the shorter light-curing times allowed for major fluoride release in both materials. However, the RMGICs showed different patterns of bacterial adhesion according to the brand and light-curing time.

Biological and medical researchers often collect count data in clusters at multiple time points. The data can exhibit excessive zeros and a wide range of dispersion levels. In particular, our research was motivated by a dental dataset with such complex data features: the Iowa Fluoride Study (IFS). The study was designed to investigate the effects of various dietary and nondietary factors on the caries development of a cohort of Iowa school children at the ages of 5, 9, and 13. To analyze the multiyear IFS data, we propose a novel longitudinal method of a generalized estimating equations based marginal regression model. We use a zero-inflated model with a Conway-Maxwell-Poisson (CMP) distribution, which has the flexibility to account for all levels of dispersion. The parameters of interest are estimated through a modified expectation-solution algorithm to account for the clustered and temporal correlation structure. We fit the proposed zero-inflated CMP model and perform a comprehensive secondary analysis of the IFS dataset. It resulted in a number of notable conclusions that also make clinical sense. Additionally, we demonstrated the superiority of this modeling approach over two other popular competing models: the zero-inflated Poisson and negative binomial models. In the simulation studies, we further evaluate the performance of our point estimators, the variance estimators, and that of the large sample confidence intervals for the parameters of interest. It is also demonstrated that our longitudinal CMP model can correctly identify the time-varying dispersion patterns.

Objectives To compare the efficacy of calcium sodium phosphosilicate (CSPS) and arginine dentifrices on dentin permeability and acid tolerance. Material and Methods Sixty dentin discs were randomly assigned into 3 groups, then brushed for 1 min with CSPS, arginine, or fluoride (control) dentifrices. To test acid tolerance, each disc was soaked in 6% citric acid for 1 min. Dentin permeability was measured before, following brushing, and acid challenge. Ten discs per group were similarly treated and evaluated for tubule occlusion following a single dentifrice application, while other five discs per group were employed in an acid tolerance assay. Results The percentage reduction in dentin permeability was 39.26%, 32.27%, and 21.71% in the arginine, CSPS, and control groups, respectively. The differences in dentin permeability reduction between the arginine and CSPS groups following brushing and acid challenge were not significant (p = 0.398 and p = 0.211, respectively). The arginine dentifrice demonstrated a significant reduction in permeability compared with the control (p = 0.011). In addition, the occlusion exhibited by the arginine and CSPS dentifrices was more resistant to acid challenge compared with that of the control (p

An efficient hydrazine substitution of p-nitro-aryl fluorides with hydrazine hydrates catalyzed by FeO(OH)@C nanoparticles is described. This hydrazine substitutions of p-nitro-aryl fluorides bearing electron-withdrawing groups proceeded efficiently with high yield and selectivity. Similarly, hydrogenations of p-nitro-aryl fluorides containing electron-donating groups also smoothly proceeded under mild conditions. Furthermore, with these prepared aryl hydrazines, some phthalazinones, interesting as potential structures for pharmaceuticals, have successfully been synthesized in high yields.

Phosphotyrosine residues are essential functional switches in health and disease. Thus, phosphotyrosine biomimetics are crucial for the development of chemical tools and drug molecules. We report here the discovery and investigation of pentafluorophosphato amino acids as novel phosphotyrosine biomimetics. A mild acidic pentafluorination protocol was developed and two PF5-amino acids were prepared and employed in peptide synthesis. Their structures, reactivities, and fluorine-specific interactions were studied by NMR and IR spectroscopy, X-ray diffraction, and in bioactivity assays. The mono-anionic PF5 motif displayed an amphiphilic character binding to hydrophobic surfaces, to water molecules, and to protein-binding sites, exploiting charge and H−F-bonding interactions. The novel motifs bind 25- to 30-fold stronger to the phosphotyrosine binding site of the protein tyrosine phosphatase PTP1B than the best current biomimetics, as rationalized by computational methods, including molecular dynamics simulations.

Fluorine is a critical element for the design of bioactive compounds, driving advances in selective and sustainable fluorination. However, stereogenic tertiary fluorides pose a synthetic challenge and are thus present in only a few approved drugs (fluticasone, solithromycin, and sofosbuvir). The aldol reaction of fluorinated donors provides an atom-economical approach to asymmetric C-F motifs via C-C bond formation. We report that the type II pyruvate aldolase HpcH and engineered variants perform addition of β-fluoro-α-ketoacids (including fluoropyruvate, β-fluoro-α-ketobutyrate, and β-fluoro-α-ketovalerate) to diverse aldehydes. The reactivity of HpcH towards these fluoro-donors grants access to enantiopure secondary or tertiary fluorides. In addition to representing the first synthesis of tertiary fluorides via biocatalytic carboligation, the afforded products could improve the diversity of fluorinated building blocks and enable the synthesis of fluorinated drug analogs.

Here, we show that gastrodin, which is extracted from Gastrodia and has anti‐cell death, antiapoptosis and antioxidative activities, can reverse fluoride‐induced bone injury and apoptosis in a dose‐dependent way. This protective effect of gastrodin is likely to be exerted via inhibiting oxidative stress. Therefore, gastrodin may have potential for future development into a possible treatment for fluorosis., Fluorosis is a common disease characterized by disruptions in bone metabolism and enamel development. The production of reactive oxygen species is thought to play an important role in fluorosis. Gastrodin (4‐hydroxybenzylalcohol4‐O‐beta‐d‐glucopyranoside) has been reported to have antioxidative activity, and so here we examined whether gastrodin has protective effects against oxidative stress and bone tissue toxicity in rats with fluorosis. Wistar rats were given different doses of gastrodin 1 month after fluoride administration, and samples of blood, bone and teeth were collected after 2, 3 and 4 months; glutathione peroxidase glu, CAT and SOD levels in the fluorosis group were lower than those in the control group. Gastrodin treatment in rats ameliorated oxidative stress and fluoride accumulation that were induced by fluoride; treatment with 400 mg·kg−1 gastrodin protected trabecular bone structure and reduced femur and alveolar bone injury in rats with fluorosis. Enhanced expression of cysteinyl aspartate‐specific proteinase (caspase) 3, caspase‐9 and Bax and decreased expression of Bcl‐2 induced by fluoride were also reversed by gastrodin. In summary, the present data suggest that gastrodin, and in particular a dose of 400 mg·kg−1, can improve the antioxidative capacity of rats, reduce concentration of fluoride in tissues, alleviate bone damage and modulate expression of Bcl‐2, Bax, caspase‐3 and caspase‐9.

Aim This study determined the prevalence of molar-incisor hypomineralization (MIH) and its association with dental fluorosis and caries in children living in rural areas in north-eastern Brazil who are exposed to residual fluoride (F) levels in the drinking water. Design A census was carried out with 610 schoolchildren aged 6 to 12 years. The European Academy of Paediatric Dentistry criteria, Thysltrup and Fejerskov index, and World Health Organization index were used for diagnosis of MIH, dental fluorosis, and caries detection, respectively. The association between the outcome and exposure variables was determined by robust Poisson regression (P Results Water F-levels varied from 0.06 to 1.98 ppm. MIH was not related to fluoride levels in the drinking water, but it showed an inverse and direct correlation with dental caries and fluorosis, respectively. Children with MIH had a higher DMFT, and severe MIH cases were most frequent in children with dental fluorosis. Conclusion Drinking water F-levels were not directly related to the occurrence of MIH in schoolchildren. The severity of MIH, however, was likely to be associated with dental fluorosis in areas with moderate to high fluoride levels in the drinking water.

O-Sulfation is an important chemical code widely existing in bioactive molecules, but the scalable and facile synthesis of complex bioactive molecules carrying O-sulfation remains challenging. Herein, we report a general approach to O-sulfation via the Sulfur (VI) Fluoride Exchange (SuFEx) reaction between aryl fluorosulfates and silylated hydroxyl groups. Efficient sulfate diester formation was achieved through systematic optimization of the electronic properties of aryl fluorosulfates. The versatility of this O-sulfation strategy was demonstrated in the scalable syntheses of a variety of complex molecules carrying sulfate diesters at various positions, including monosaccharides, disaccharides, amino acid, and steroid. Selective hydrolytic and hydrogenolytic removal of the aryl masking groups from sulfate diesters yielded the corresponding O-sulfated products in excellent yields. This strategy provides a powerful tool for the synthesis of O-sulfated bioactive compounds.

Tea is the one of the most popular non-alcoholic caffeinated beverages in the world. Tea is produced from the tea plant (Camellia sinensis (L.) O. Kuntze), which is known to accumulate fluoride. This article systematically analyzes the literature concerning fluoride absorption, transportation and fluoride tolerance mechanisms in tea plants. Fluoride bioavailability and exposure levels in tea infusions are also reviewed. The circulation of fluoride within the tea plantation ecosystems is in a positive equilibrium, with greater amounts of fluoride introduced to tea orchards than removed. Water extractable fluoride and magnesium chloride (MgCl2 ) extractable fluoride in plantation soil are the main sources of absorption by tea plant root via active trans-membrane transport and anion channels. Most fluoride is readily transported through the xylem as F- /F-Al complexes to leaf cell walls and vacuole. The findings indicate that tea plants employ cell wall accumulation, vacuole compartmentalization, and F-Al complexes to co-detoxify fluoride and aluminum, a possible tolerance mechanism through which tea tolerates higher levels of fluoride than most plants. Furthermore, dietary and endogenous factors influence fluoride bioavailability and should be considered when exposure levels of fluoride in commercially available dried tea leaves are interpreted. The relevant current challenges and future perspectives are also discussed. © 2020 Society of Chemical Industry.

A new synthetic route for the synthesis of WF5 utilizing a mercury photosensitized reduction of tungsten hexafluoride with H2 is described. Crystals of WF5 were studied using single-crystal X-ray diffraction, resulting in the first-reported crystal structure of WF5. Powder X-ray diffraction studied at room-temperature showed the compound was phase-pure. The IR spectrum of WF5 was reinvestigated and interpreted with the use of solid-state quantum-chemical calculations using the DFT-PBE0 density functional method. The compound synthesized herein was free of HF and moisture but may have contained minute amounts of WOF4, that were only observed in the IR spectrum.

We correct the crystal structure of MnF 3, of which the space group was reported as monoclinic C2/c (no. 15) with a = 8.9202, b = 5.0472, c = 13.4748 Å, β = 92.64°, V = 606.02 ų, Z = 12, mS48, T not given, likely 298 K. In the structure model proposed here, we use a unit cell of one third of the former volume. The ruby red crystals of MnF 3 were synthesized by a high-pressure/high-temperature method, where MnF 4 was used as a starting material. As determined on a single crystal, MnF 3 crystallizes in the monoclinic space group I2/a (no. 15) with a = 5.4964(11), b = 5.0084(10), c = 7.2411(14) Å, β = 93.00(3)°, V = 199.06(7) Å 3, Z = 4, mS16, T = 183(2) K. The crystal structure of MnF 3 is related by a direct group-subgroup transition to the VF 3 structure-type. We performed quantum chemical calculations on the crystal structure to allow the assignment of bands of the obtained vibrational spectra.

Excessive fluoride exposure contributes to neurotoxic effects. Emodin exhibits antioxidative functions in the central nervous system (CNS); however, its neuroprotective mechanism against fluoride remains to be elucidated. Our aim was to explore the neuroprotective efficacy and the possible mechanisms of emodin. In our study, synaptic proteins and oxidative stress damage were examined after human neuroblastoma SH-SY5Y cells were treated with high doses of NaF for 24 hours. Moreover, pretreatment with emodin was used to shed light on the neuroprotective effects in NaF-induced toxicity in SH-SY5Y cells. We found that NaF significantly lowered the protein expressions of SNAP 25, synaptophysin and PSD 95 in SH-SY5Y cells. In addition, NaF exposure increased the protein expression of p-ERK1/2 and decreased the protein expressions of Nrf2 and HO-1, as well as facilitated increasing ROS, 4-hydroxynonenal (4-HNE), and 8-Hydroxy-2'-deoxyguanosine (8-OHdG). Pretreatment with emodin significantly recovered these alterations caused by NaF. These data implied that the neuroprotective effects of emodin and pointed to the promising utilization for protecting against neurotoxicity induced by fluoride.

Human exposure to fluoride in drink water at a level above 1.5 mg/L causes a lot of health problems. The present study was carried out to assess the fluoride biosorption capability of Padina sp. alga as biosorbent material using conventional one-factor-at-a-time (OFAT) and Box-Behnken design to optimize the process. By OFAT, fluoride uptake was significantly affected by pH, time, fluoride concentration, and biosorbent dose (p-value < 0.05) and the highest fluoride biosorption (85.95%) was recorded at pH 7, time 60 min, fluoride concentration 2 g/L, and an adsorbent dose 30 g/L. Based on the Box-Behnken design, the quadratic model was developed to correlate the variables to the response. By Analysis of Variance (ANOVA), the model was statistically significant (p-value < 0.05). It was suggested that optimal values of pH, time, fluoride concentration, and biosorbent dose were 5, 90 min, 3 mg/L, and 30 g/L, respectively, and fluoride removal at these optimum conditions was 94.57%. For application, Padina sp. was removed from 67.79% to 78.78% of fluoride in collected groundwater samples. It was concluded that the Padina sp. could be used as eco-friendly biosorbent for fluoride and response surface methodology was more applicable and effective in optimization to obtain the highest removal efficiency of fluoride by Padina sp. PRACTITIONER POINTS: The fluoride biosorption was studied using Padina sp. alga as an eco-friendly biosorbent. By one-factor-at-a-time (OFAT), the highest fluoride biosorption rate was 85.95%. Response surface methodology was suggested that maximum Fluoride removal at optimum condition was 94.57%. Statistical response surface methodology was more applicable, effective in optimization and considered the interaction between factors.

Chronic fluoride exposure from drinking water may result in endemic fluorosis. To better understand the mechanisms by which some people are resistant to fluorosis, here we investigated the effect of treatment with NaF (sodium fluoride) on production of reactive oxygen species (ROS), morphological changes in mitochondria, the mRNA expression of Fas ligand (Fas‐L), and the protein expression of cleaved caspase‐3 in regular L‐929 cells and fluoride‐resistant (FR) L‐929 cells. While morphological changes indicative of apoptosis and a network of fragmented mitochondria were observed in regular L‐929 cells after NaF treatment, there were no morphological changes in FR L‐929 cells after NaF treatment. Treatment with 10 mm NaF induced a significant difference in the production of ROS, triggered the expression of cleaved caspase‐3, and upregulated the mRNA expression of Fas‐L in regular L‐929 cells. However, there was no significant production of ROS in FR L‐929 cells. Additionally, cleaved caspase‐3 and upregulated Fas‐L were not detected in FR L‐929 cells. These results suggest that FR fibroblasts are resistant to oxidative stress and apoptosis induced by fluoride., To better understand the mechanisms by which some people are resistant to fluorosis, here we compared reactive oxygen species production, apoptosis, and morphological changes in mitochondria between regular and fluoride‐resistant (FR) cells after NaF treatment. We report that FR cells were resistant to oxidative stress and apoptosis induced by fluoride.

Fluoride use is the cornerstone of dental caries prevention. There are numerous sources of fluoride which might have different balance of risks and benefits. The first National Guidelines for Use of Fluorides in Australia were developed at a national Workshop in 2005, and updated in 2012. Since then, more evidence on the balance of risks and benefits of fluoride has become available. A third national Workshop was convened in 2019 to update the Guidelines for Use of Fluorides in Australia.

The present work proposes the synthesis of robust biochar from Gracilaria Rhodophyta red weeds for sequential removal of Al(III) and fluoride from wastewater. The sorption experiments have been modeled by preliminary optimization of operational parameters using 24 factorial statistical modeling. The model has estimated an optimum sequential synergetic removal of 44.5 mg/g of Al(III) and 2.1 mg/g of fluoride onto the biochar. FESEM, BET, XRD, EDX, and FTIR established the potentiality of biochar toward synergetic sorption of Al(III) and fluoride. The thermodynamic analysis projected that the adsorption is physisorption in nature. The adsorption of Al(III) and fluoride follows the Langmuir and Freundlich isotherm models, respectively, and the kinetic analysis established the pseudo-second-order deposition of Al(III) and fluoride ions. The synthesized adsorbent is regenerative enough and could achieve synergetic removal of Al(III) and fluoride ions from industrial- and groundwater-contaminated water bodies. PRACTITIONER POINTS: Biochar from seaweeds is explored in the sequential removal of Al(III) and F- ions. Statistical model is developed for % adsorption and tested for reliability by ANOVA. GRBC sorbed 44.5 and 2.1 mg/g of Al(III) and F- ions, respectively, at optimum levels. FESEM, EDX, XRD, and FTIR characterization confirm the potentiality of the GRBC. GRBC sorbed ⁓90% of Al(III) and F- ions from wastewater and is regenerative.

Environmental exposure to arsenic (As) and fluoride (F) in the recent year has been increased because of excessive use of naturally contaminated ground water. Surface water is also regularly contaminated with these elements in various industrial areas. Arsenicosis and fluorosis upon individual exposure of As and F are reported in many studies. A syndrome of endemic As poisoning and fluorosis occurs during concurrent exposure of As and F. Previous reports showed synergistic, antagonistic and independent effects of these two compounds, although few recent reports also revealed antagonistic effects after co-exposure. Interaction during intestinal absorption and influence of F on As metabolism might be the cause of antagonism. The synergism/antagonism is thought to depend on the dose and duration of the co-exposure. However, the detailed mechanism is still not fully understood and needs further studies. Removal technologies of As and F from contaminated water is available but removal of such contaminants from food is yet to be developed. Antioxidants are useful to mitigate the toxic effects of As and F. This review focused on the effect of co-exposure, amelioration as well as removal techniques of As and F.