Fluoride Products Research Articles

Study on dissociation mechanism and process of regenerated cryolite

Solid waste produced in the process of aluminum electrolysis is a substantial secondary source of fluorine, the fluoride electrolyte in aluminum electrolysis carbon slag accounts for about 75%. Regenerative cryolite, extracted from anode carbon residue through flotation or calcination, possesses a significant potential for fluorine recovery. The fluoride in regenerated cryolite is mainly insoluble, making its efficient dissociation crucial for utilizing the solid waste from aluminum electrolysis. This study uses regenerative cryolite and sodium carbonate to examine how roasting temperature, time, and the reagent-to-cryolite ratio (R/C) affect cryolite dissociation. Dissociation efficiency is measured using indices like baking loss, leaching loss, fluoride ion concentration in the leachate, and fluoride ion conversion rate. Optimal dissociation is achieved at 780-820°, 2.0-2.5 hours roasting time, and an R/C ratio of 1.0-1.2. Orthogonal experimental results highlight the predominant influence of R/C, with roasting temperature being the secondary factor and roasting time having the least impact. Notably, at 780°, 2.0 hours, and an R/C ratio of 1.2:1, the fluoride ion conversion rate reaches a peak of 94.23%. This allows for recycling and production of high-value fluoride products, benefiting both the environment and the economy.

Dentinal Tubule Occlusion and Dentin Permeability Efficacy of Silver Diamine Fluoride Solutions.

This invitro study compared the effect of two commercially available silver diamine fluoride (SDF) products on dentinal tubule (DT) occlusion and dentin permeability. Sixty-six dentin discs (1.0 mm thick) were divided equally into six groups: acid-etched with no treatment (negative control-NC), etched and sealed with nail varnish (positive control-PC), non-etched and treated with Advantage Arrest (AA), non-etched and treated with Topamine (TP), etched and treated with AA, and etched and treated with TP. Eight specimens from each group were tested for permeability using the dye percolation method. The remaining three samples from each group were assessed for dentinal tubule occlusion, depth of SDF penetration, and elemental analysis using a scanning electron microscope coupled with an energy-dispersive X-ray (SEM/EDX) system. One-way ANOVA and Tukey's post hoc test were used to analyze the results. TP exhibited lower (p < 0.05) dye percolation compared to AA. While both SDF materials showed a statistically similar (p > 0.05) penetration depth in the DT, none of them had the ability to completely occlude all the DTs. AA exhibited more silver and fluoride ion deposition on etched dentin than TP, and both materials showed a similar increase in the deposition of Ca and P compared to NC. Whereas the effectiveness of dentin tubule (DT) occlusion varies based on the material used, both tested SDF products exhibit the capability to seal dentinal tubules, decrease dentin permeability, and promote dentin remineralization. These findings suggest their potential advantage in managing dentin hypersensitivity.

Efficacy of silver diamine fluoride (SDF) in arresting dentin caries against inter-kingdom biofilms of Streptococcus mutans and Candida albicans.

To compare, in vitro, the efficacy of three proprietary silver diamine fluoride (SDF) products in mitigating progression of dentinal caries induced by an inter-kingdom, dual-species, bacterial-yeast biofilm. Human dentin blocks were demineralized to create artificial caries lesions and randomized into three SDF test groups: Saforide, Topamine, T-SDF, and an aqueous control (n = 26 per group). After application of foregoing SDF variants, the blocks were incubated with Streptococcus mutans and Candida albicans for 24 h for biofilm development, and subsequently subjected to a microbe-induced, pH-cycling process for 7 days, to mimic the oral eco-system. The biofilm cell viability and surface topography were assessed by colony-forming units (CFUs) and scanning electron microscopy respectively. The lesion depth and mineral density were evaluated by micro-computer tomography. SDF precipitate and matrix-to-mineral ratio were evaluated by X-ray diffraction and Fourier transform infrared spectroscopy, respectively. Standard, accepted methodology was used for all these evaluations and procedures. After pH cycling, the SDF groups demonstrated comparable inhibition of the biofilm relative to the control. the log CFU of S. mutans for Saforide, Topamine, T-SDF, and control were 6.69±0.73, 6.48±0.56, 6.63±0.66, and 8.01±0.45, respectively. For C. albicans, the log CFU were 4.86±0.44, 4.72±0.53, 4.92±0.29, and 5.60±0.27, respectively. The log CFU of S. mutans and C. albicans in the SDF groups were significantly lower than the control group (p<0.001). Further, the lesion depth decreased by approximately 14.79±7.00% in the SDF groups, while it increased by 11.07±8.61% in the control (p<0.001), and the mineral density increased by 16.36±4.58% in the SDF group, as opposed to a 5.59±2.64% reduction in the control (p<0.001) implying their caries mitigating effect. These findings were corroborated by SEM images of the lesions. SDF significantly mitigated dentin caries due to an assault by a polymicrobial plaque biofilm whilst arresting mineral loss and lesion growth. There was no difference in the caries-arresting efficacy of the compared SDF variants.

Dental Erosion in Competitive Swimmers and Preventive Treatments: An In Vitro Study.

The aim of this in vitro study was to evaluate the effectiveness of highly concentrated fluoride products and remineralizing products (F-APC) in preventing erosive dental lesions in competitive swimming patients. A total of 48 teeth were extracted, preserved in saline solution and divided into three groups. In G1 (control group), each tooth was half-immersed in chlorinated pool water; in G2 (fluoride-treated group), after being totally immersed in chlorinated water, each tooth had half of its surface treated with a highly concentrated fluoride product once a week; in G3 (remineralization product-treated group), each tooth was totally immersed in chlorinated water and half of its surface was treated with a remineralizing product after each immersion. The study was conducted over a 4-week period, immersing the teeth for 4 h per day. In G1, statistically significant differences were observed in submerged versus non-submerged tooth surfaces at week 3 (T3) (p = 0.019) and week 4 (T4) (p = 0.0007), with four and eight surfaces showing erosive tooth wear (ETW), respectively. In G2, a difference was observed between fluoride-treated and non-fluoride-treated surfaces at T4 (p = 0.039), with three surfaces with ETW among the non-treated ones. In G3, the difference was observed between portions treated with F-APC and those not treated at T4 (p = 0.019), with four surfaces with ETW among the untreated ones. Chlorinated pool water is a potential erosive agent for teeth if water pH values reach a critical value. Treating the teeth surface with highly concentrated fluoride products, once a week for 5 min, and F-APC are effective in protecting teeth against tooth erosion.

Comparative Perceptions of Fluoride Toxicity in Oral Hygiene Products: Insights from the General Population and Healthcare Professionals.

The safety of oral hygiene products is a growing concern, particularly regarding the toxicity of specific ingredients used in their formulations. The purpose of this study was to evaluate the knowledge and attitudes of dentists, physicians, pharmacists, and the general public regarding ingredients in oral hygiene products, especially fluoride. Additionally, this study aimed to identify which ingredients may exhibit potential toxicity based on historical records of any adverse effects being induced by a material/component. A self-administered questionnaire was used in an online cross-sectional observational study to collect data on sociodemographic characteristics, knowledge of fluoride in dental medicine, fluoride usage practices in oral hygiene products, opinions on ingredient toxicity in oral hygiene products, and personal experiences of adverse reactions to products and their components. The collected data underwent descriptive and regression analyses to reveal patterns and relationships within the dataset. The study found a moderate overall knowledge level regarding fluoride usage in dentistry among participants (Md = 5.00, IQR 2.50-7.00). Healthcare professionals exhibited significantly higher knowledge scores compared to the general population (p ≤ 0.001), with dental professionals displaying the highest scores. Regarding concerns about the usage of fluoride, the majority of respondents (77.0%) did not express any concerns. Minor concerns included the risk of ingestion (6.0%) and dental fluorosis (4.6%). Among the other ingredients in oral hygiene products, respondents named alcohol as the most toxic ingredient (70.3%), followed by artificial colors (53.1%), artificial sweeteners (50.4%), and parabens (50.1%). It is noteworthy that the majority of participants (61.6%) stated that they had never experienced any side effects associated with the use of oral hygiene products. This study underscores disparities in fluoride knowledge between healthcare professionals and the general population in Croatia, with dental experts exhibiting a superior understanding. Despite lingering misconceptions about fluoride content and potential toxicity, the majority of participants acknowledge its oral health benefits and use fluoride products regularly.

The Modular Synthesis of Sulfondiimidoyl Fluorides and their Application to Sulfondiimidamide and Sulfondiimine Synthesis.

A modular synthesis of sulfondiimidoyl fluorides-the double aza-analogues of sulfonyl fluorides-allowing variation of the carbon and both nitrogen-substituents is reported. The chemistry uses readily available organometallic reagents, commercial sulfinylamines, simple electrophiles, and N-fluorobenzenesulfonimide (NFSI), as the starting materials. The reactions are broad in scope, efficient, and scalable. We show that the sulfondiimidoyl fluoride products can be combined with amines to provide sulfondiimidamides, and with organolithium reagents to provide sulfondiimines, and that reactivity in these transformations can be modulated by variation of the N-substituents.

The Role of Sodium Fluoride Mouthwash in Regulating FGF-2 and TGF-β Expression in Human Gingival Fibroblasts.

Sodium fluoride (NaF) is a fluoride application recommended by the World Health Organization for its efficacy and safety in preventing dental caries. Gingival fibroblasts that constitute the majority of connective tissue cells play a major role in wound healing via the expression of growth factors, including fibroblast growth factor-2 (FGF-2) and transforming growth factor-beta (TGF-β). This study examined the effect of NaF mouthwash on FGF-2 and TGF-β expression in human gingival fibroblasts (HGnFs). Fibroblasts were exposed to a medium with 225 ppmF NaF for 1 min, then switched to either 15 ppmF NaF for continuous stimulation or no NaF for transient stimulation. Continuous NaF stimulation significantly increased the gene and protein expression of FGF-2 and TGF-β in HGnFs compared to controls, suggesting NaF's potential role in modulating periodontal tissue wound healing. Signaling pathway investigations showed the involvement of heterotrimeric GTP-binding proteins, calcium/calmodulin-dependent kinase II (CaMKII), and extracellular signal-regulated kinase (ERK) phosphorylation. Inhibiting CaMKII reduced NaF-induced FGF-2 and TGF-β expression, while ERK phosphorylation increased after NaF stimulation. These results highlight NaF mouthwash's potential in promoting wound healing in extraction sockets, particularly during the mixed dentition period. Understanding NaF's effects is clinically relevant due to the common use of fluoride products.

Prevalence and socioeconomic factors associated with non-utilization of dental care in Lebanon: A nationwide cross-sectional survey.

To assess the prevalence of non-utilization of dental care in Lebanon and associated socioeconomic factors and self-care behaviours. A nationwide, quantitative, survey-based study was conducted by trained interviewers with Lebanese residents aged ≥18 years between July and September 2019. Univariate analyses were performed using Pearson Chi Square test or the Fisher's exact test followed by a binary logistic regression using the SPSS Version 25. Of the 1070 participants, 247 (23.1%) did not utilise any type of healthcare and 144/247 (58.3%) did not utilise dental care. The prevalence of non-utilization of dental care was estimated at 13.5%. Only 4.7% of the respondents consulted their dentist in the past year, among which 53% cited pain/emergencies as the reason for their consultation. Socioeconomic factors associated with the non-utilization of dental care were lack of social medical insurance (OR, 0.49 [95% CI, 0.31 to 0.79]) and long waiting time/patient time restriction (OR, 2.05 [95% CI, 1.26 to 3.35]). On the other hand, facilitators for utilization of dental care included ethical standards/personal qualities of the dentist (OR, 0.53 [95% CI, 0.32 to 0.88]) and convenient cost with respect to the individual's economic status (OR, 0.28 [95% CI, 0.18 to 0.43]). This study suggests that dental care practices in Lebanon, including the non-utilization of dental care, are suboptimal. Measures such as reducing sugar and tobacco consumption, providing information on oral hygiene, and using fluoride products are inexpensive; however, implementing these measures may take substantial time and input by multiple stakeholders.

The Modular Synthesis of Sulfondiimidoyl Fluorides and their Application to Sulfondiimidamide and Sulfondiimine Synthesis

A modular synthesis of sulfondiimidoyl fluorides ‐ the double aza‐analogues of sulfonyl fluorides ‐ allowing variation of the carbon and both nitrogen‐substituents is reported. The chemistry uses readily available organometallic reagents, commercial sulfinylamines, simple electrophiles, and N‐fluorobenzenesulfonimide (NFSI), as the starting materials. The reactions are broad in scope, efficient, and scalable. We show that the sulfondiimidoyl fluoride products can be combined with amines to provide sulfondiimidamides, and with organolithium reagents to provide sulfondiimines, and that reactivity in these transformations can be modulated by variation of the N‐substituents.

Radical Ring-Opening Fluorosulfonylation of Methylenecyclobutanols via Electron Donor-Acceptor Photoactivation.

A visible-light-mediated catalyst- and additive-free method for radical ring-opening fluorosulfonylation of methylenecyclobutanols is reported. Sulfuryl chlorofluoride acts as a FSO2 radical precursor as well as an electron acceptor to form electron donor-acceptor complexes with various methylenecyclobutanol substrates. This method shows fully regioselective and (E)-stereoselective ring-opening processes, providing a variety of FSO2-functionalized γ,δ-unsaturated carbonyls in 38-77% yields. A selection of product diversifications has been studied to demonstrate the versatility of these sulfonyl fluoride products.

Explorations of the chemical constitution and aqueous solution status of caries-arresting silver(I)-diammine fluoride and silver(I)-fluoride products using high-resolution 19F NMR analysis. Spectroscopic and SEM investigations of their interactions with human saliva: evidence for the in vivo salivary-catalysed autoconstruction of Ag/AgCl-based nanoparticles (IV-SCAN)-part I.

Silver(I)-diammine fluoride (SDF) and silver(I)-fluoride (SF) complexes have been successfully employed for the arrest of dental caries for many years. However, to date there are very few studies available reporting on the molecular structural compositional and solution status of these agents [typically applied as highly-concentrated 38% (w/v) solutions]. Here, we explored the solution status and chemical constitution of commercially-available SDF and SF products, and secondly investigated the multicomponent interplay of these products with biomolecules present in intact human whole-mouth salivary supernatants (WMSSs) in vitro. High-resolution 19F NMR analysis was employed to explore SDF and SF product solutions, and to determine WMSS fluoride (F-) concentrations, whereas ammonia (NH3) release form SDF was tracked by 1H NMR spectroscopy. SEM and thin-film FTIR-ATR analyses were employed to explore the atomic and molecular compositions of sequentially-generated AgCl deposits and chromophoric Ag/AgCl nanoparticles (CSNPs); the time-dependent generation of the latter was followed spectrophotometrically. 19F NMR spectra of aqueous SF solutions contained a very broad F- signal (Δv1/2 70 Hz), demonstrating that much of its solvated F- content was rapidly exchanging with Ag(I) on the NMR timescale, but those of SDF had a much sharper resonance, similar to that of "free" F- (4 Hz). Moreover, further NMR results revealed that a popular SDF product contained high molar excesses of both F- and NH3. Treatment of WMSSs with SDF and SF generated an off-white precipitate, which slowly developed into CSNPs at 23°C; SEM demonstrated high contents of both silver and chloride in this material (ca.1:1 atomic content ratio). FTIR-ATR analysis found that the CSNPs formed contained a range of salivary biomolecules, which appear to encapsulate the Ag/AgCl core (significant thiocyanate contents were also found). In conclusion, NMR results acquired demonstrated that SF, but not SDF, product solutions feature rapidly-exchanging F - between its "free" and Ag(I)-bound forms, and that SDF contains large excesses of both F- and its NH3 ligands. Characterised AgCl deposits and CSNPs were sequentially produced from the interactions of these complexes with WMSS biomolecules. In view of their well-known microbicidal and cariostatic properties, the observed autobioconstruction of CSNPs involving salivary catalysis is of much therapeutic significance.

Снижение экологической нагрузки на регион за счет рационального способа утилизации фторангидрита

The article considers the chemical industry technologies contaminating the environment with sulfate-calcium waste in three regions of the former Soviet Union, i.e., the Tomsk region (SHK LLC, Seversk), the Perm territory (Galopolimer JSC, Perm), and East Kazakhstan region (UMZ JSC, Ust-Kamenogorsk). The differences and similarities of technological processes of anhydrous calcium sulfate production in the above-mentioned regions have been considered. Some properties of sulfate calcium (acid fluoride) that until recently was the main environmental contaminator used in the technology of hydrogen fluoride production have been specified. The objective of the study is to provide generalized positive results obtained by the authors of the article in the field of optimization of sulfuric decomposition of fluorspar not changing the production conditions and the quality of the main product — hydrogen fluoride. As a result of the process, the solid waste of hydrogen fluoride production is transformed into a target product, i.e., a technogenic anhydrite binder that can be an alternative to Portland cement and gypsum binders in the construction industry. Therefore, acid fluoride waste is removed from the hydrogen fluoride technology, and the environmental contamination with sulfate-calcium waste is prevented. In addition, a new trend in the construction industry is set, which is the industry production of anhydrite materials and products. The list of pilot-industrial and semi-industrial tests of the production of various anhydrite products has been provided (as an image listing the fields of use of acid fluoride in the industry of construction materials). In conclusion, the amount of environmental damage caused by the acid fluoride waste has been specified. In the Ob basin of the West Siberian region, it was 270 million rubles for 2023.

Tooth Discoloration from 2 Silver Fluorides Used in Adults with Special Needs: A Randomized Trial.

Discoloration of carious lesions after application of silver diamine fluoride lowers patient acceptance and limits its wider use for caries arrest. To assess lesion and tooth color changes from 2 novel silver fluoride (AgF) products and its relationship to caries activity (clinical visuo-tactile scores) and bacterial load (using laser fluorescence with the DIAGNOdent). A split-mouth design was followed, with matched smooth surface carious lesions in the same arch in adults with special needs randomized for 1-min treatments with AgF/potassium iodide (KI) (Riva Star Aqua, SDI) and AgF/stannous fluoride (SnF2) (Caries Status Disclosing Solution; Whiteley). Standardized images taken at baseline, immediately postoperatively, and at 3-mo review were subjected to digital image analysis to calculate delta-E and to track changes in luminosity of carious lesions. Twelve participants were recruited in the study. A total of 56 teeth (28 pairs) were included. Significantly greater changes were seen in treated lesions than in the adjacent noncarious natural tooth structure, both immediately after treatment and at the 3-mo review (P < 0.0001). Color change and caries activity were not affected by tooth type, tooth location, plaque status, salivary status, or special needs condition. AgF/SnF2 caused transitory darkening immediately on application, while AgF/KI caused the immediate formation of yellow deposits (silver iodide). Both products caused significant darkening of treated lesions at 3 mo (P = 0.0009; P = 0.0361), with no differences between them (P = 0.506). Responding lesions showed larger and more perceptible color changes immediately after either AgF application (P = 0.002; P = 0.024). Both AgF products were highly effective for caries arrest in this patient population. Despite minor differences in the appearance of treated lesions at the time of application, both products lead to similar darkening of treated sites at 3 mo. This study shows the usefulness of silver fluoride used in conjunction with potassium iodide or stannous fluoride for achieving caries arrest in smooth surface lesions in adults with special needs. Patients need to be informed that long-term staining of the lesion occurs with both, similar to silver diamine fluoride.

A global survey of national oral health policies and its coverage for young children.

There is no accessible information on countries with oral health policies. The purpose of this study was to identify World Dental Federation (FDI) member countries with oral health policies and their scope and extent of coverage of oral health care for young children. This international survey recruited chief dental officers, oral health advisors to national ministries of health, and other key informants of the 158 FDI member countries between December 2020 and December 2021. The survey tool was administered online to the study participants. Key questions explored the following outcome measures: countries with oral health policies; the thrusts of the oral health policies; policy thrusts targeting young children; and dental care plans as a component of a universal health care plan. Descriptive statistics were conducted to determine the number of countries with any of the study outcome measures and coverage per country. Sixty (38%) of the 158 FDI member-countries responded to the survey. Forty-eight (55.2%) of the 60 countries had a national oral health policy document or position statement on oral health; 54 (62.1%) countries had plans on universal health care, and 42 (48.3%) included dental care within their universal health care plan. The most common policy thrusts addressing the oral health needs of children were the promotion of oral hygiene (71.7%), provision of fluoride products for children (53.3%), collaboration with primary care providers (35%), and prenatal oral health education (50%). There were differences in the scope of oral health care coverage and the coverage for young children between continents as well as between countries. Europe had many countries with children-friendly oral health policy coverage. About half of the surveyed countries had a national oral health policy. There were variations in the scope of oral health care coverage, particularly for young children, both between continents and among individual countries. These findings underscore the importance of understanding the landscape of oral health policies globally. Such insights can help inform targeted interventions to enhance oral health policies, thereby contributing to improved oral health outcomes on a global level.

Engineering non-haem iron enzymes for enantioselective C(sp3)-F bond formation via radical fluorine transfer.

In recent years there has been a surge in the development of methods for the synthesis of organofluorine compounds. However, enzymatic methods for C-F bond formation have been limited to nucleophilic fluoride substitution. Here, we report the incorporation of iron-catalysed radical fluorine transfer, a reaction mechanism that is not used in naturally occurring enzymes, into enzymatic catalysis for the development of biocatalytic enantioselective C(sp 3)-F bond formation. Using this strategy, we repurposed (S)-2-hydroxypropylphosphonate epoxidase from Streptomyces viridochromogenes (SvHppE) to catalyse an N-fluoroamide directed C(sp 3)-H fluorination. Directed evolution has enabled SvHppE to be optimized, forming diverse chiral benzylic fluoride products with turnover numbers of up to 180 and with excellent enantiocontrol (up to 94% e.e.). Mechanistic investigations showed that the N-F bond activation is the rate-determining step, and the strong preference for fluorination in the presence of excess NaN3 can be attributed to the spatial proximity of the carbon-centered radical to the iron-bound fluoride.

Structural stability and proton beam irradiation effects on simulated metal fluoride waste–loaded iron phosphate glass

AbstractNext‐generation nuclear reactor technologies such as the molten salt reactor utilize alkali metal fluoride salts as both fuel and coolant. In the present study, the suitability of iron phosphate glass (IPG) as a vitrification matrix for alkali metal fluoride (NaF, CaF2) and simulated fission product loaded fluoride (NdF3, CeF3, SmF3) waste has been explored. The structural change in the metal fluoride–loaded IPG has been analyzed thoroughly using Raman and fourier transform infrared (FTIR) spectroscopy. Thermal analysis showed that the stability and glass forming ability of IPG improved upon loading the same with various mixed metal fluorides. Mössbauer data and X‐ray absorption spectroscopy at Fe K‐edge explored the minute changes in the local structure. The effect of radiation emanating from radioactive wastes in the fluoride‐loaded IPG has been scrutinized via 4.5 MeV proton beam irradiation. Our study firmly establishes the applicability of IPG as suitable vitrification matrix for radioactive metal fluoride–loaded nuclear wastes.

An Investigation of the Knowledge and Preferences of Parents About Dental Preventive Practices

Objective: Dental caries poses a significant health concern affecting, 60%-90% of children globally. While fluoride is widely utilized to prevent and eliminate dental caries, recent negative media coverage and concerns about irresponsible fluoride use have prompted a shift in parental perspectives. This study explores parental knowledge, preferences, and attitudes regarding preventive measures, with a focus on fluoride and potential natural or herbal alternatives. Methods: Our research was designed as a survey study. A survey form consisting of 11 questions was delivered to parents of children aged 6–14 years and presented to the Erciyes University Department of Pediatric Dentistry for examination or treatment were included in the study. A total of 300 parents participated in the study. Data was recorded as numbers and percentages. Results: Of the parents, 69% (207) reported that if they were offered natural herbal compounds instead of fluorinated varnish, they would prefer natural alternatives. A statistically significant relationship was found between the responses received from the parents about the effects of fluoride and the educational level of the parents (p&lt;0.05). Only 4 (1.3%) university graduate parents stated that fluoride had harmful effects. We found that 80.95% of the fathers and 68.39% of the mothers stated that they would prefer natural or herbal alternatives for their children instead of fluorinated varnish, and this was a statistically significant result (p&lt;0.05). Conclusion: Parents do not have sufficient knowledge and attitudes about preventive practices in oral dental health, and some parents still avoid the use of fluoride products. Therefore, there is a need to increase fluoride intake and its effects on children's health by educating parents or informing dentists.

Mortality and cancer incidence in perfluorooctanesulfonyl fluoride production workers.

Exposure to per- and polyfluoroalkyl substances (PFAS) has been associated with several health outcomes, though few occupationally-exposed populations have been studied. We evaluated mortality and cancer incidence in a cohort of perfluorooctanesulfonyl fluoride-based specialty chemical manufacturing workers. The cohort included any employee who ever worked at the facility from 1961 to 2010 (N = 4045), with a primary interest in those who had 365 cumulative days of employment (N = 2659). Vital status and mortality records were obtained through 2014 and the cohort was linked to state cancer registries to obtain incident cancer cases from 1995 to 2014. Cumulative exposure was derived from a comprehensive exposure reconstruction that estimated job-specific perfluorooctanesulfonate (PFOS)-equivalents (mg/m3 ) exposure. Overall and exposure-specific standardized mortality ratios (SMR) were estimated in reference to the US population. Hazard ratios (HRs) and 95% confidence interval (CI) for cumulative PFOS-equivalent exposure (log2 transformed) were estimated within the cohort for specific causes of death and incident cancers using a time-dependent Cox model. Death rates were lower than expected except for cerebrovascular disease (SMR = 2.42, 95% CI = 1.25-4.22) and bladder cancer (SMR = 3.91, 95% CI = 1.07-10.02) in the highest exposure quartile. Within the cohort, the incidence of bladder, colorectal, and pancreatic cancer were positively associated with exposure, however except for lung cancer (HR = 1.05, 95% CI = 1.00-1.11) the CIs did not exclude an HR of 1. This study provides some evidence that occupational exposure to PFOS is associated with bladder and lung cancers and with cerebrovascular disease.

Fluoride and caries prevention: a scoping review of public health policies.

Dental caries is the most common infectious disease, affecting approximately 60 to 90% of the world population, especially young children, and disadvantaged communities. Due to the extremely high prevalence and the significant negative impact on general health, well-being, and quality of life it is considered a global public health problem. Despite the improvement of policies to promote oral health care in the past decades, dental caries is still a healthcare challenge, characterized by increasing disparities among different social groups between and within countries. Fluoride-based prevention of dental caries is a cost-effective approach, that has been implemented since 1940's. It includes systemic and topical administrations, through community-based or individual programs. Preventive interventions should be tailored to individual and community caries risk assessment and estimate of cumulative fluoride intake, in order to maximize the preventive effect and avoid the risk of potential adverse effects associated with excessive fluoride exposure. Regulation of public health policies plays a major role in this context. Scoping review. The aim of this scoping review was to report an overview of current guidelines regarding fluoride-based preventive strategies for dental caries and relevant policies on the matter, as well as to address current issues related to public health aspects of dental caries prevention. We searched for the relevant literature on the matter, focusing on policy documents, such as recommendations, position papers and guidelines, issued from the major scientific and regulatory institutions involved in oral health promotion and on publications concerning relevant aspects of public health law. Prevention of dental caries through fluoride can rely on topical fluorides for home-use (toothpastes and mouthrinses), professionally applied topical fluorides (gels, varnishes, silver diamine fluoride, fluoride-releasing restorative materials and sealants), fluoride supplements (tablets and drops), and community-based strategies (community water fluoridation, fluoridated salt and milk). Current relevant guidelines for all these preventive aids are outlined in the paper. A significantly greater preventive effect of topical fluorides has been widely established in the recent past, as compared to systemic effects. Furthermore, increasing concerns have emerged on potential adverse effects on general health associated with early and excessive systemic exposure to fluoride, especially for children, supported by recent meta-analyses. Also, community water fluoridation has raised significant aspects of relevance for health law and policies. In a public health perspective, healthcare policymakers should tackle social iniquities by promoting information and oral health literacy, through community and school-based programs, ensuring access to early dental visits and basic dental care and improving availability and affordability of fluoride topical products. Conclusions. Fluoride-based prevention can provide a simple and cost-effective approach to reduce the incidence of dental caries and the associated social burden. Among fluoride-based preventive strategies, systemic community-based administration of fluoride should be considered with great caution, due to the unfavorable risk-benefit ratio currently established. Topical fluoridated pro-ducts are generally preferred, given the optimal risk-benefit ratio. Further efforts must be made to identify and tackle the barriers to dental caries prevention and related social iniquities from a public health perspective. Policies and laws on oral health should promote access to caries prevention with targeted comprehensive strategies.

Cu(II)-Mediated direct 18F-dehydrofluorination of phosphine oxides in high molar activity

BackgroundThe 18F/19F-isotope exchange method employing P(V)-centered prosthetic groups demonstrates advantages in addressing mild one-step aqueous 18F-labeling of peptides and proteins. However, the molar activity (Am) achieved through isotope exchange remains relatively low, unless employing a high initial activity of [18F]F−. To overcome this drawback, our work introduces a novel approach through a Cu-mediated direct 18F-dehydrofluorination of phosphine oxides. This method leverages the straightforward separation of the 18F-labeled product from the phosphine oxide precursors, aiming to primarily increase Am.ResultsThrough a 19F-dehydrofluorination efficiency test, Cu(OAc)2 was identified as the optimal oxidative metal salt, exhibiting a remarkable 100% conversion within one hour. Leveraging the straightforward separation of phosphine oxide precursors and phosphinic fluoride products, the Am of an activated ester, [18F]4, sees an impressive nearly 15-fold increase compared to the 18F/19F-isotope exchange, with the same initial activity of [18F]F−. Furthermore, this Cu(II)-mediated 18F-dehydrofluorination approach demonstrates tolerance up to 20% solvent water content, which enables the practical radiosynthesis of 18F-labeled water-soluble molecules under non-drying conditions.ConclusionsThe direct 18F-dehydrofluorination of phosphine oxide prosthetic groups has been successfully accomplished, achieving a high Am via Cu(II)-mediated oxidative addition and reductive elimination.