Fluoruro de estaño en el control de cavidades sin restauración en dientes temporales / Stannous fluoride in nonrestorative cavity control in primary teeth

Introducción: el control de cavidades sin restauración (NRCC, por sus siglas en inglés), es una opción de tratamiento conservador y no invasivo para dentina cariosa, sobre todo en dentición temporal. Una de las estrategias del NRCC es la remineralización. El fluoruro de estaño (FDE) puede considerarse, como una opción viable ya que existe evidencia de su eficacia cariostática. Objetivo: valorar al FDE como remineralizante alternativo en dentina de molares temporales, asociado al NRCC. Material y métodos: se efectuó un estudio clínico, epidemiológico, y descriptivo con preescolares voluntarios de 3 a 5 años de edad con consentimiento firmado de participación en el estudio, y que presentaron molares con ICDAS 5 y 6. La aplicación del FDE a 0.8%, la evaluación de la dureza de la dentina con los criterios de Nyvad, y el diagnóstico del estado pulpar, la efectuó un operador entrenado para esta finalidad. Se aplicó un análisis estadístico descriptivo y uno no paramétrico. Resultados: el efecto cariostático producido por el FDE a 0.8%, sobre dentina afectada de molares temporales de niños mexicanos fue estadísticamente significativo durante cinco meses. Conclusiones: la aplicación de fluoruro de estaño puede considerarse como una alternativa de tratamiento cariostático asociado al NRCC para niños de 3 a 5 años de edad (AU)

Introduction: nonrestorative cavity control (NRCC), is a conservative and non-invasive treatment option for carious dentin, especially in primary dentition. One of the NRCC strategies is remineralization. Stannous Fluoride (SDF) can be considered as a viable option since there is evidence of its cariostatic efficacy. Objective: to evaluate FDE as an alternative remineralizing agent in the dentin of primary molars, associated with NRCC. Material and methods: a clinical, epidemiological, and descriptive study was carried out with preschool volunteers aged 3 to 5 years with signed consent to participate in the study, and who presented molars with ICDAS 5 and 6. The application of FDE at 0.8%, the evaluation of dentin hardness with the Nyvad criteria, and the diagnosis of pulp status, was carried out by an operator trained for this purpose. A descriptive and non-parametric statistical analysis was applied. Results: the cariostatic effect produced by 0.8% FDE on affected dentin of primary molars of Mexican children was statistically significant for five months. Conclusions: the application of stannous fluoride can be considered as an alternative cariostatic treatment associated with NRCC for children 3 to 5 years of age (AU)

Mechanisms of brain damage caused by inorganic fluoride using proteomics-based techniques / 环境与职业医学

Background Chronic excessive exposure to fluoride can cause damage to the central nervous system and a certain degree of learning and memory impairment. However, the associated mechanism is not yet clear and further exploration is needed. Objective Using 4D unlabelled quantitative proteomics techniques to explore differentially expressed proteins and their potential mechanisms of action in chronic excessive fluoride exposure induced brain injury. Methods Twenty-four SPF-grade adult SD rats, half male and half male, were selected and divided into a control group and a fluoride group by random number table method, with 12 rats in each group. Among them, the control group drank tap water (fluorine content<1 mg·L−1), the fluoride group drank sodium fluoride solution (fluorine content 10 mg·L−1), and both groups were fed with ordinary mouse feed (fluoride content<0.6 mg·kg−1). After 180 d of feeding, the SD rats were weighed, and then part of the brain tissue was sampled for pathological examination by hematoxylin-eosin (HE) staining and Nissl staining. The rest of the brain tissue was frozen and stored at −80 ℃. Three brain tissue samples from each group were randomly selected for proteomics detection. Differentially expressed proteins were screened and subcellular localization analysis was performed, followed by Gene Ontology (GO) function analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, cluster analysis, and protein-protein interaction analysis. Finally, Western blotting was used to detect the expression levels of key proteins extracted from the brain tissue samples. Results After 180 d of feeding, the average weight of the rats in the fluoride group was significantly lower than that in the control group (P<0.05). The brain tissue stained with HE showed no significant morphological changes in the cerebral cortex of the fluoride treated rats, and neuron loss, irregular arrangement of neurons, eosinophilic changes, and cell body pyknosis were observed in the hippocampus. The Nissl staining results showed that the staining of neurons in the cerebral cortex and hippocampus of rats exposed to fluoride decreased (Nissl bodies decreased). The proteomics results showed that a total of 6927 proteins were identified. After screening, 206 differentially expressed proteins were obtained between the control group and the fluoride group, including 96 up-regulated proteins and 110 down-regulated proteins. The differential proteins were mainly located in cytoplasm (30.6%), nucleus (27.2%), mitochondria (13.6%), plasma membrane (13.6%), and extracellular domain (11.7%). The GO analysis results showed that differentially expressed proteins mainly participated in biological processes such as iron ion transport, regulation of dopamine neuron differentiation, and negative regulation of respiratory burst in inflammatory response, exercised molecular functions such as ferrous binding, iron oxidase activity, and cytokine activity, and were located in the smooth endoplasmic reticulum membrane, fixed components of the membrane, chloride channel complexes, and other cellular components. The KEGG significantly enriched pathways included biosynthesis of secondary metabolites, carbon metabolism, and microbial metabolism in diverse environments. The results of differential protein-protein interaction analysis showed that the highest connectivity was found in glucose-6-phosphate isomerase (Gpi). The expression level of Gpi in the brain tissue of the rats in the fluoride group was lower than that in the control group by Western blotting (P<0.05). Conclusion Multiple differentially expressed proteins are present in the brain tissue of rats with chronic fluorosis, and their functions are related to biosynthesis of secondary metabolites, carbon metabolism, and microbial metabolism in diverse environments; Gpi may be involved in cerebral neurological damage caused by chronic overdose fluoride exposure.

Cytocompatibility of electrospun polyvinylidene fluoride piezoelectric bionic periosteum / 中国组织工程研究

BACKGROUND:Polyvinylidene fluoride(PVDF)with piezoelectric properties,good biocompatibility and nontoxicity make it a suitable candidate for periosteal repair. OBJECTIVE:To evaluate the cytotoxicity of PVDF bionic periosteum by electrospinning with zinc and magnesium ions in vitro. METHODS:Pure PVDF,zinc-doped PVDF,magnesium-doped PVDF and Zinc-magnesium ion PVDF piezoelectric bionic periosteum were prepared by electrospinning technology,respectively.They were named PVDF,PVDF-Zn,PVDF-Mg and PVDF-Zn-Mg,in which the mass fraction of zinc and magnesium ions were all 1%.Osteoblasts and vascular endothelial cells were co-cultured with four groups of bionic periosteum.Cell compatibility of bionic periosteum was determined by alkaline phosphatase staining,CD31 immunofluorescence staining,and scanning electron microscopy. RESULTS AND CONCLUSION:(1)Osteoblasts:Alkaline phosphatase staining after 7 days of culture showed that the PVDF-Zn group secreted more alkaline phosphatase than the other three groups.Under a scanning electron microscopy,after 1 day of culture,the cells had a certain spread on the surface of PVDF-Mg and PVDF-Zn-Mg bionic periosteum,and the pseudopod extended to all sides.On day 3,the cell edge of each group extended pseudopods to the material.By days 5 and 7,the cells were fully spread,well grown and firmly covered the surface of the fibers,and the cellular pseudopods extended around and into the interstitial space of the fibers.CCK-8 assay showed that the cell proliferation on the bionic periosteum of each group showed an increasing trend over time and the relative proliferation rate of cells at 1,3,5,and 7 days was≥75%,and the cytotoxicity was≤grade 1.(2)Vascular endothelial cells:CD31 immunofluorescence staining for 3 days showed that the cells adhered and spread well on the bionic periosteum of each group and connected with each other,and the number of cells in the PVDF-Zn-Mg group was more than that in the other three groups.Under scanning electron microscope,the cells began to adhere to the surface of each group of fibers after 1 and 3 days of culture.On day 5,the cells were well spread on the surface of the fibers and extended obvious pseudopods.On day 7,the cells on the PVDF-Mg and PVDF-Zn-Mg bionic periosteum grew in multiple layers and extended the pseudopod into the fibrous void.CCK-8 assay showed that the cell proliferation on the bionic periosteum of each group showed a downward trend over time,and the relative proliferation rate of cells at 1,3,5 and 7 days was≥125%,and the cytotoxicity was grade 0.(3)The results showed that Zn-Mg electrospun PVDF piezoelectric bionic periosteum had good cytocompatibility.

Screening and analysis of differentially expressed genes for calcium homeostasis in ameloblasts with high fluoride intervention / 中国组织工程研究

BACKGROUND:Fluorosis is a disorder of enamel development caused by long-term intake of large amounts of fluoride during enamel development. OBJECTIVE:To further explore the molecular mechanism of dental fluorosis formation by screening the differentially expressed genes associated with calcium homeostasis in ameloblasts by transcriptome sequencing technology. METHODS:LS8 cells were treated with 0,0.4,0.8,1.6,3.2 and 6.4 mmol/L sodium fluoride(NaF)for 24,48 and 72 hours to observe the effects of different concentrations of NaF on the morphology,cell activity and intracellular Ca2+ concentration of LS8 cells.The differentially expressed genes were screened by transcriptome sequencing and validated. RESULTS AND CONCLUSION:After 24 hours of treatment,the cells treated with 0,0.4,and 0.8 mmol/L NaF were in good growth condition,with increased cell number and clear cell outline.When the NaF concentration was≥1.6 mmol/L,the cells were gradually shrunken and became smaller and the number of cells decreased with the increase of NaF concentration.After 48 and 72 hours of treatment,the number of cells increased in the 0,0.4 mmol/L NaF groups,while gradually decreased in the 0.8,1.6,3.2 mmol/L NaF groups,with rounded and smaller cell morphology.The cells in the 6.4 mmol/L NaF group were shrunken,rounded and suspended in the medium,with almost no adherent cells.When treated with the same concentration of NaF,LS8 cells were in optimal growth after 24 hours of treatment.Results from cell counting kit-8 assay showed that when treated with the same concentration of NaF,the cell activity decreased with the increase of treatment time;when the treatment time was the same,the cell activity decreased with the increase of NaF concentration.After 24 hours of treatment,the intracellular Ca2+ concentration increased with the increase of NaF concentration.Transcriptome sequencing analysis identified genes involved in the regulation of cellular calcium homeostasis:Hsp90b1,Canx,Calr,and Hspa5 that were significantly upregulated(P＜0.05)and Cacna1a that was significantly downregulated(P＜0.05).To conclude,the inhibitory effect of NaF on LS8 cell proliferation may be related to the abnormal increase in intracellular Ca2+ concentration,and the mechanism may be caused by the upregulation of the expression of protein processing and synthesis pathways Hsp90b1,Canx,Calr,and Hspa5 and the downregulation of the expression of calcium signaling pathway Cacna1a.

Preparation and osteoinductivity of piezoelectric polyvinylidene fluoride foam-based scaffold / 中国组织工程研究

BACKGROUND:Bone is a remarkable natural material possessing piezoelectric properties.By harnessing the biomimetic piezoelectric effect,tissue engineering materials can be employed to effectively address bone tissue defects and facilitate their repair. OBJECTIVE:Using a solid-phase force chemistry technique,a piezoelectric scaffold with inherent osteogenic properties was meticulously fabricated.This unique scaffold was then assessed for its impact on osteoblast adhesion,proliferation,and osteogenic differentiation. METHODS:Polyvinylidene fluoride(PVDF)powders,along with commercially available NaCl(mass ratios are 60:40,50:50,40:60,and 30:70,respectively),were subjected to solid-phase shear milling technology,resulting in a homogenous mixture.Through a melting process,a substantial material was formed,and subsequent treatment with a pure water solution effectively eliminated the NaCl.Consequently,PVDF piezoelectric foam scaffolds with varying pore sizes were successfully prepared.These materials were categorized as PVDF-40,PVDF-50,PVDF-60,and PVDF-70,denoting the respective mass percentages of NaCl during preparation.The surface morphology,crystal phase composition,thermodynamic behavior,mechanical properties,and piezoelectric properties of each group were meticulously characterized.The four kinds of piezoelectric foam scaffolds were co-cultured with the MG63 osteoblast cell line to evaluate its biocompatibility and potential to promote bone differentiation. RESULTS AND CONCLUSION:(1)The scanning electron microscopy,four groups of scaffolds had multi-level pores.As the NaCl mass fraction in the mixed powder increased,the porosity of the scaffolds increased.X-ray energy dispersion spectrum,X-ray diffraction,Fourier transform infrared spectroscopy,and thermogravimetric analysis collectively revealed the scaffold predominantly comprised the α phase,which inherently lacked piezoelectric properties.However,the application of solid-phase force chemistry successfully stimulated the formation of the β phase,thereby enhancing the scaffold's piezoelectric properties.Notably,the PVDF-60 group exhibited the highest proportion of the β phase among all the tested groups.The results of cyclic compression testing and piezoelectric performance assessment demonstrated that the PVDF-60 group exhibited superior compressive strength and piezoelectric performance compared to the other groups.(2)The findings from scanning electron microscopy and laser confocal microscopy exhibited that MG63 cells adhered well to the surface of the four groups of scaffolds,with good morphology,extended more pseudopods,and secreted a large amount of extracellular matrix.CCK-8 assay revealed that the proliferative absorbance of PVDF-60 cells cultured for 4 days was higher than that of the other three groups(P<0.000 1).Alkaline phosphatase staining and alizarin red staining showed that the expression of alkaline phosphatase and the number of calcified nodules in the PVDF-60 group were higher than those in the other three groups(P<0.01,P<0.000 1).(3)The piezoelectric PVDF foam-based scaffolds demonstrated favorable cytocompatibility.Notably,the PVDF-60 group showed superior mechanical properties,piezoelectric performance,and bone-inducing capabilities.

Two directions that cannot be ignored in the study of endemic fluorosis and endemic arsenicosis in China: long-term exposure to low-dose fluoride and arsenic, and non-target organ damage / 中华地方病学杂志

With the comprehensive implementation of prevention and control measures for endemic fluorosis and endemic arsenicosis in China, and in accordance with the World Health Organization (WHO) recommended drinking water standards and the Chinese standards of allowable daily fluoride intake and limit values of arsenic content in drinking water, Chinese residents have entered the era of low-dose fluoride and arsenic exposure. However, there have been few studies focused on the long-term health effects of exposure to low-dose fluoride and arsenic both domestically and internationally. Further more, study on non-target organs of fluoride and arsenic has been neglected. The conclusions are also inconsistent, and there is an urgent need for systematic study to clarify them. Accordingly, this paper proposes to establish a cohort of people exposed to low-dose fluoride and arsenic, systematically carry out study on the long-term health effects and mechanisms of low-dose fluoride and arsenic exposure, and promote China's prevention and control experience to the "the Belt and Road" countries, in order to provide a scientific basis for the formulation of prevention and control strategies and measures for endemic fluorosis and endemic arsenicosis under the new situation in China.

Research progress on the effect of fluoride on bone marrow mesenchymal stem cells / 中华地方病学杂志

Fluorine is an important element widely present in nature, and moderate intake can prevent dental caries and promote bone development. However, long-term excessive intake can lead to fluorosis, damaging tissues or organs such as teeth, bones, heart muscle, and blood vessels. Bone marrow mesenchymal stem cells (BMSCs) play an important role in the repair process of bone injury due to their excellent multi-directional differentiation potential. Therefore, studying BMSCs is of great value in the treatment of fluorosis caused by fluoride poisoning. This article summarize the progress on the effect of fluoride on BMSCs, providing new ideas for the study of the pathogenesis and clinical treatment of fluorosis.

Renal impairment in mice induced by environmental high concentration of polyionized drinking water and high temperature exposure / 环境与职业医学

Background The burden of chronic kidney diseases (CKD) is continuously increasing in the globe. Environmental factors are one of the trigger factors for chronic kidney diseases of unknown etiology (CKDu). However, the current toxicological evidence on the renal effects induced by environmental high concentrations of multiple ions in drinking water and high temperature exposure is very limited. Objective To preliminary investigate the renal effects of exposure to drinking water with environmental high concentrations of fluoride, calcium, sodium, and bromide ions alone or in combination with high temperature in mice. Methods A mouse drinking water exposure model was established using ICR male mouse (8 weeks old) with exposure to 3 mg·L−1 fluoride ions, 250 mg·L−1 calcium ions, 400 mg·L−1 sodium ions, and 1 mg·L−1 bromide ions (to mimic the high concentration of ions in the groundwater in the areas with a high prevalence rate of CKDu in Sri Lanka) and high temperature of 32 ℃. ICR male mice were randomly divided into a mixed fluoride-calcium-sodium-bromide ion and high temperature exposure group, exposure groups of each ion and high temperature alone, a fluoride-calcium-sodium ion exposure group, and a fluoride-calcium-sodium-bromide ion exposure group. In the control group, the animals were given normal purified water at room temperature of (23±2) ℃. After 12 consecutive weeks of exposure, body weights and liver (kidney) organ coefficients were determined. Assessment of renal histopathologic damage was performed by hematoxylin-eosin staining and pathology scoring. At the end of the 12-week exposure period, 24 h urine samples were collected for the measurements of creatinine (UCr), albumin (ALB), neutrophil gelatinase-associated lipocalin (NGAL), and β2-microglobulin (β2-MG) levels. Cell apoptosis was assessed by TUNEL assay. Results The mice in the mixed exposure group showed a significant decrease in body weight and marked increases in the scores of renal histopathological injuries and the urinary levels of β2-MG compared to those of the control mice (P<0.05). Compared with the control group, the differences in body weight and urinary renal injury indexes of the mice in the fluoride-calcium-sodium and the fluoride-calcium-sodium-bromide ion groups (except for the decrease of the β2-MG levels in urinary in the latter group) were not statistically significant (P>0.05), but the renal histopathological injury scores were significantly increased (P<0.05). By contrast, body weights, liver (kidney) organ coefficient, and renal histopathological injury scores were comparable in the control mice and the mice fed with drinking water containing high levels of a single ion alone or housed at high temperature alone (P>0.05). Furthermore, the renal histopathological injury score showed no significant differences between the fluoride-calcium-sodium ion exposure group and the fluoride-calcium-sodium-bromide ion exposure group (P>0.05). The interaction between bromide ions and fluoride-calcium-sodium ions on renal tissue pathological damage was not statistically significant (P>0.05). Results from the TUNEL assay showed a significant increase in renal cell apoptosis in the fluoride-calcium-sodium ion exposure group (P<0.05). Conclusions Environmental high levels of mixed fluoride, calcium, and sodium ions in drinking water induce renal pathological damage in mice, which are exacerbated in combination with high temperature environment. High temperature exposure alone does not affect the pathological damage of renal tissue,

Effect of low concentration of sodium fluoride on osteogenic/odontogenic differentiation of human dental pulp cells / 口腔疾病防治

Objective@#To study the effect of low concentrations of sodium fluoride on the osteogenic/odontogenic differentiation of human dental pulp cells (hDPCs) in vitro.@*Methods@#This study was reviewed and approved by the Ethics Committee. hDPCs were cultured using a modified tissue explant technique in vitro. The effects of different concentrations of sodium fluoride on the proliferation of hDPCs were measured by methylthiazol tetrazolium (MTT) assay. Appropriate concentrations were added to the osteogenic/odontogenic differentiation induction medium, and the cells were induced in vitro. Alizarin red S staining was used to detect the osteoblastic/odontogenic differentiation ability of the cells, and the mRNA expression of the key differentiation factors was detected by RT-qPCR. Moreover, the expression of key molecules of endoplasmic reticulum stress (ERS) was detected by RT-qPCR and Western blot. The data were analyzed with the SPSS 18.0 software package.@*Results@#Low concentration of NaF (0.1 mmol/L) could stimulate cell proliferation in vitro, while a high concentration (5-10 mmol/L) could inhibit cell proliferation (P<0.05). According to the literature and the experimental data, 0.1 mmol/L NaF was selected as the following experimental concentration. The levels of alizarin red S staining were increased after NaF induction of mixed osteogenic/odontogenic differentiation in vitro. The mRNA expression levels of key molecules for osteogenic/odontogenic differentiation, dentin sialophosphoprotein (DSPP), bone sialoprotein (BSP) and osteocalcin (OCN), were increased (P<0.05). The mRNA levels of ERS markers (splicing x-box binding protein-1 (sXBP1), glucose-regulated protein 78 (GRP78) and activating transcription Factor 4 (ATF4) were increased in NaF-treated cells. The protein expression levels of key ER stress molecules (phosphorylated RNA-activated protein kinase-like ER-resident kinase (p-PERK), phosphorylated eukaryotic initiation factor-2α (p-eIF2α) and ATF4) were higher in NaF-treated cells.@*Conclusion@#A low concentration of NaF promotes the osteogenic/odontogenic differentiation of hDPCs and increases the level of ER stress.

Effect of artesunate on NaF-induced apoptosis and mitophagy in osteocytes MLO-Y4 / 中国药理学与毒理学杂志

OBJECTIVE To investigate the protective effect of artesunate(Art)against apoptosis and mitophagy induced by NaF in osteocytes MLO-Y4,and to explore the molecular mechanism.METHODS MLO-Y4 cells were treated with NaF(2 mmol·L-1)for 48 h to establish an in vitro model of osteocytes injuries,and the cells were divided into the cell control group,NaF(2 mmol·L-1)group and NaF+Art 0.25,0.50 and 1.00 μmol·L-1 groups.The cells were pretreated for 2 h and NaF was added for 48 h.The cell survival of MLO-Y4 cells was detected by MTT assay.The cell viability of MLO-Y4 cells was measured by Calcein-AM staining.The lactate dehydrogenase(LDH)content in the supernatant was examined by the LDH detection kit.The level of intracellular reactive oxygen species(ROS)was examined by DCFH-DA staining.The malondialdehyde(MDA)content and superoxide dismutase(SOD)activity were detected by chemical colorimetry.Apoptosis was measured by Hoechst33342 staining and Annexin-V/PI staining.The level of mitochondrial membrane potential(MMP)was measured by JC-1 staining.The formation of autophagic vacuoles and morphological mitochondrial changes were observed via Lyso-tracker staining and Mito-Tracker staining.The ATP content was detected with the luciferase method.The expression of microtubule-associated protein light chain 3(LC-3)in mitochon-dria was examined by immunofluorescence staining.Protein expressions of LC-3,P62,E3 ubiquitin-ligase(Parkin)and PTEN-induced putative kinase 1(PINK1)were detected by Western blotting.RESULTS Compared with the cell control group,the cell survival rate and cell viability were significantly reduced in the NaF group(P<0.01),LDH content in the supernatant,the level of intracellular ROS,the MDA content,apoptosis rate and autophagic vesicle formation were remarkably increased(P<0.01),protein levels of Parkin and PINK1,and the conversion of LC-3Ⅱ from LC-3Ⅰ were markedly upregulated along with the elevation of LC-3 in damaged mitochondria(P<0.01),while P62 levels,SOD activity,MMP and ATP contents were reduced in NaF cells(P<0.05,P<0.01).Compared with NaF group,the cell viability and survival rate of MLO-Y4 cells in NaF+Art 0.25,0.50 and 1.00 μmol·L-1 groups were significantly increased(P<0.01);the content of LDH in supernatants was decreased obviously(P<0.01);the levels of intracellular ROS and MDA content were markedly reduced(P<0.05,P<0.01);the apoptosis rate and autophagic vesicle formation were remarkably decreased(P<0.05,P<0.01);protein levels of Parkin and PINK1,and the conversion of LC-3Ⅱ from LC-3Ⅰ were markedly down-regulated along with the accumulation of LC-3 in damaged mitochondria(P<0.01);MMP and ATP content were also reduced(P<0.05,P<0.01);while SOD activityand P62 levelwere significantly increased(P<0.05,P<0.01).CONCLU-SION Art has a protective effect against oxidative damage induced by NaF in MLO-Y4 cells,which might be related to the inhibition of apoptosis and mitophagy.

Fluoride in drinking groundwater and prevalence of fluorosis in children and adolescents: A systematic review / Fluoruro en el agua subterránea potable y prevalencia de fluorosis en niños y adolescentes: Una revisión sistemática

ABSTRACT Fluorosis is a worldwide public health problem. One of the factors related to it is the type of water consumed, such as groundwater. High fluoride concentration in groundwater may be explained by contamination from local industries. Since fluoride and arsenic are the main pollutants of groundwater, some studies correlate groundwater consumption with high prevalence of fluorosis Aim The aim of this study was to conduct a systematic review to determine whether children's risk of fluorosis is related to drinking groundwater Materials and Method The protocol for this systematic review was registered at the National Institute of Health Research Database (CRD42021227298). A comprehensive search was conducted to identify potentially relevant studies by exploring a range of electronic databases (Medline via PubMed, Scopus, Cochrane Library, Science Direct, Web of Science Core Collection, Medline via Ovid, Lilacs, Embase, and grey literature) Results A total 2189 articles were found. After reading titles and abstracts, 63 were selected for screening, and the final data was extracted from 15 articles Conclusion A relationship was identified between drinking fluoridated water from wells and the prevalence of fluorosis in individuals up to 18 years old. This is the first study to assess the issue systematically worldwide.

RESUMEN La fluorosis es un problema de salud pública a nivel mundial y el tipo de agua consumida es uno de los factores relacionados con ella, como el consumo de aguas subterráneas. La alta concentración de fluoruro en estas aguas puede justificarse por la contaminación por industrias locales y las características del suelo, donde algunos estudios correlacionan el consumo de aguas subterráneas con una alta prevalencia de fluorosis, ya que el fluoruro, junto con el arsénico, se consideran los principales contaminantes de estas aguas Objetivo El objetivo es realizar una revisión sistemática que relacione el riesgo de fluorosis en niños expuestos al consumo de agua procedente de pozos Materiales y Método El protocolo de esta revisión sistemática fue registrado en el National Institute of Health Research Database (CRD42021227298). Se realizó una búsqueda bibliográfica de estudios primarios explorando diversas bases de datos electrónicas (Medline vía PubMed, Scopus, Cochrane Library, Science Direct, Web of Science Core Collection, Medline vía Ovid, Lilacs, Embase y literatura gris) Resultados Se encontraron 2189 artículos, tras la lectura de títulos y resúmenes se seleccionaron 63 referencias para examinar y, finalmente, se extrajeron los datos de 15 artículos Conclusiones Se identificó una relación entre el consumo de agua fluorada de pozo y la prevalencia de fluorosis en individuos de hasta 18 años, siendo este estudio el primero en evaluarlo sistemáticamente a nivel mundial.

Determination of bioavailable fluoride in toothpastes marketed in Medellín, Colombia, through capillary electrophoresis / Fluoruro biodisponible en cremas dentales comercializadas en Medellín ­ Colombia mediante electroforesis capilar

Currently, the FDI recommendation (World Dental Federation) for fluoride concen­tration in toothpastes is that the total fluoride content declared by manufacturers be between 1,000 and 1,500 ppm, and of this amount, at least 800 ppm should be bioavai­lable fluoride. The aim of this study was to describe the market of toothpastes marketed in Medellín and to measure the concentration of bioavailable fluoride by capillary elec­trophoresis to verify their compliance with the FDI recommendation for the prevention of dental caries. After sampling the toothpastes available for sale in the 16 communes of the city of Medellin, a single operator measured in triplicate the concentration of bioavailable fluoride in 36 samples of previously blinded toothpastes using the capi­llary electrophoresis (EC) technique. Most of the evaluated toothpastes that declared a content of 1,000­1,500 ppm fluoride met the recommendation of presenting at least 800 ppm bioavailable fluoride. Measurement of bioavailable fluoride in toothpastes with MFP (sodium monofluorophosphate) is recommended, as it is known that binding to the abrasive can decrease its concentration over time.

Actualmente la recomendación de la FDI (Federación Dental Internacional) sobre la concentración de fluoruro en cremas dentales es que el contenido de fluoruro total de­clarado por los fabricantes sea entre 1.000 y 1.500 ppm, y que de esta cantidad al menos 800 ppm sea fluoruro biodisponible. El objetivo de este estudio fue describir el mercado de las cremas dentales comercializadas en Medellín y medir en estas la concentración de fluoruro biodisponible por electroforesis capilar para verificar su cumplimiento de la recomendación de la FDI para la prevención de la caries dental. Luego de realizar un mues­treo en las 16 comunas de la ciudad de Medellín sobre las cremas dentales disponibles a la venta, un solo operador midió por triplicado la concentración de fluoruro biodisponible en 36 muestras de cremas dentales previamente cegadas, mediante la técnica de electroforesis capilar (EC). La mayoría de las cremas dentales evaluadas que declaraban contenido de 1.000 a 1.500 ppm de fluoruro, cumplieron la recomendación de presentar al menos 800 ppm de fluoruro biodisponible. Se recomienda realizar la medición del fluoruro biodisponible en las cremas con MFP, ya que se conoce que la unión al abrasivo puede disminuir su concentración en el tiempo.

¿Cómo Intervenir el Proceso de Caries en Personas Mayores? Adaptación del Consenso de ORCA/EFCD/DGZ / How to Intervene the Caries Process in Older Persons? Adaptation of the ORCA/EFCD/DGZ Consensus

Los cambios demográficos y epidemiológicos actuales determinarán un aumento en la prevalencia e incidencia de caries, específicamente lesiones de caries radicular (RCLs, por sus siglas en inglés) en personas mayores, por lo que la necesidad de tratamiento de mayor cobertura y efectividad será también cada vez mayor. Este artículo resume en español la evidencia actual disponible acerca de las recomendaciones clínicas para las intervenciones preventivas, no invasivas, micro o mínimamente invasivas e invasivas para el manejo de la caries dental en personas mayores, con especial énfasis en RCLs. La presente publicación se basa en un taller de consenso, seguido de un proceso de consenso e-Delphi, realizado por un panel de expertos nominados por la Organización Europea para la Investigación en Caries (ORCA), la Federación Europea de Odontología Conservadora (EFCD) y la Federación Alemana de Odontología Conservadora (DGZ). El propósito de este artículo es presentar las principales conclusiones alcanzadas en el consenso de ORCA/EFCD/DGZ para permitir una mejor difusión del conocimiento y la aplicación de estos conceptos en la práctica clínica, orientando la correcta toma de decisiones en el manejo de la enfermedad y RCLs en las personas mayores.

Current demographic and epidemiological changes will condition increased caries prevalence and incidence, specifically root caries lesions (RCLs) in the elderly. There will be a need, therefore, for therapeutic approaches with greater coverage and effectiveness. This article summarizes, in Spanish, the current available evidence leading to clinical recommendations for preventive, non-invasive, micro or minimally invasive and invasive interventions for the management of dental caries in older people, with special emphasis on RCLs. This publication is based on a consensus workshop, followed by an e-Delphi consensus process, conducted by a panel of experts nominated by the European Organization for Caries Research (ORCA), the European Federation of Conservative Dentistry (EFCD) and the German Federation of Conservative Dentistry (DGZ). The purpose of this article is to present the main conclusions reached in the ORCA/EFCD/DGZ consensus to allow a better dissemination of knowledge and the application of these concepts in clinical practice, guiding the correct decision-making for the disease management and the RCLs in the elderly.

Fluorosis dental en adolescentes de instituciones educativas de Lima, Perú / Dental fluorosis in adolescents from Educational Institutions in Lima, Peru

Introducción: La fluorosis dental es una patología endémica causada por la ingestión excesiva de fluoruros que pueden producir una alteración durante el desarrollo del esmalte, y es considerado un importante problema de salud pública porque afecta la salud bucal y sistémica de la población. Objetivo: Este estudio tuvo como idea principal determinar la frecuencia y los niveles de fluorosis dental en escolares de 12 a 15 años pertenecientes a dos instituciones educativas de Lima - Perú. Método: Se realizó un estudio descriptivo de tipo transversal, la muestra estuvo conformada por 252 estudiantes, entre 12 y 15 años de dos centros educativos de Lima. El muestreo fue por selección sistemática de elementos muestrales. La fluorosis dental se evalúo mediante el Índice de Dean. Para determinar la frecuencia y los niveles de fluorosis dental, se realizó un examen clínico bucal y se desarrolló un cuestionario validado previamente. Resultados: La frecuencia de fluorosis dental fue de 44,8% (n=113) afectando más a los varones en un 27,39% (n=69) y a los adolescentes de 13 años (15,1%). En relación con los niveles de fluorosis, predominó el tipo "muy leve" (34,9%). También se encontró una asociación entre la presencia y el nivel de fluorosis con el número de aplicaciones de flúor (p<0,05). Además, se dijo que el índice comunitario de fluorosis de Dean fue de 0,43. Conclusiones: En la población escolar evaluada, la frecuencia de fluorosis fue de 44,8% y el nivel predominante de fluorosis fue muy leve. Además, el índice comunitario fue de 0,43, el cual mostró un nivel límite de importancia para la salud pública. Por lo que se puede considerar que el número de aplicaciones tópicas de flúor recibido por la población sin una planificación adecuada se podría convertir en un factor de riesgo para causar fluorosis dental.

Introduction: Dental fluorosis is an endemic pathology caused by the excessive ingestion of fluorides that can produce an alteration during the development of the enamel and is considered an important public health problema because it affects the oral and systemic health of the population. Objective: The objective of this study was to determine the frequency and levels of dental fluorosis in school children between 12 and 15 years of age belonging to two educational institutions in Lima, Peru. Method: A descriptive cross-sectional study was carried out, the sample consisted of 252 students between 12 and 15 years of age from two educational centers in Lima. Sampling was by systematic selection of sample elements. Dental fluorosis was evaluated using the Dean Index. To determine the frequency and levels of dental fluorosis a clinical oral examination was carried out and a previously validated questionnaire was developed. Results: The frequency of dental fluorosis was 44.8% (n=113) affecting more males by 27.39% (n=69) and adolescents aged 13 years (15.1%). In relation to the levels of fluorosis, the "very mild" type predominated (34.9%). An association was also found between the presence and level of fluorosis with the number of fluoride applications (p<0.05). In addition, Dean's community fluorosis index was reported to be 0.43. Conclusions: In the school population evaluated, the frequency of fluorosis was 44.8% and the predominant level of fluorosis was very mild. In addition, the community index was 0.43, which indicated a borderline level of public health importance. Therefore, it can be considered that the number of topical fluoride applications received by the population without adequate planning could become a risk factor for causing dental fluorosis.

Anticaries potential of a fluoride foam

Abstract Foam has been used worldwide as a vehicle for the professional application of fluoride and hypothetically should have the same anticaries potential as conventional fluoride gel (F-gel) in terms of the formation of reaction products with enamel. Thus, the ability of Flúor Care® foam (FGM, Joinville, SC, Brazil, 12,300 ppm F, acidulated) to react with enamel was evaluated in comparison with Flúor gel® (DFL, Rio de Janeiro, RJ, Brazil, 12,300 ppm F, acidulated). Slabs (n=10/group) of sound enamel and with caries lesion were used, in which the concentrations of total fluoride (TF), and loosely (CaF2-like) and firmly (FAp) bound types were determined. The importance of agitation during application was previously tested. The determinations were made with fluoride ion-specific electrode and the results were expressed in μg F/cm² of the treated enamel area. ANOVA and Tukey tests were used to analyze the difference among treatments, independently for sound and carious enamel. The agitation of the products during application significantly increased the reactivity of the foam (p<0.05), but not that of the gel (p>0.05). The foam did not differ from F-gel (p>0.05) concerning the formation of TF and CaF2-like in sound or carious enamel. Regarding FAp, the foam did not differ from F-gel (p>0.05) in the carious enamel, but the concentration in the sound was lower (p<0.05). The results show that this commercial fluoride foam tested needs to be agitated during application to improve its reactivity with enamel, which raises a question about other brands.

Resumo A espuma tem sido utilizada mundialmente como veículo para aplicação profissional de fluoreto e hipoteticamente deveria ter o mesmo potencial anticárie que o gel fluoretado convencional (F-gel) em termos de formação de produtos de reação com o esmalte. Assim, a capacidade da espuma Flúor Care® (FGM, Joinville, SC, Brasil, 12.300 ppm F, acidulada) de reagir com o esmalte foi avaliada em comparação com o Flúor gel® (DFL, Rio de Janeiro, RJ, Brasil 12.300 ppm F, acidulado). Foram utilizados blocos (n=10/grupo) de esmalte hígido e com lesão de cárie, nos quais foram determinadas as concentrações de flúor total (FT), e os tipos de flúor fracamente (tipo-CaF2) e firmemente (FAp) ligados ao esmalte. A importância da agitação durante a aplicação foi previamente testada. As determinações foram feitas com eletrodo íon específico para fluoreto e os resultados foram expressos em μg F/cm² da área tratada do esmalte. A diferença entre os tratamentos foi analisada por ANOVA e Tukey (α=5%), independentemente para esmalte hígido e cariado. A agitação dos produtos durante a aplicação aumentou significativamente a reatividade da espuma (p<0,05), mas não a do gel (p>0,05). A espuma não diferiu do F-gel (p>0,05) quanto à formação de FT e tipo-CaF2 no esmalte hígido ou cariado. Em relação à FAp, a espuma não diferiu do F-gel (p>0,05) no esmalte cariado, mas a concentração no hígido foi menor (p<0,05). Os resultados mostram que esta espuma fluoretada comercial testada precisa ser agitada durante a aplicação para melhorar sua reatividade com o esmalte, o que levanta questão sobre outras marcas.

Effect of aluminum-fluoride interactions on overall cognitive function of aluminum plant workers / 环境与职业医学

Background Aluminum and fluoride are neurotoxic, and aluminum exposure alone is closely related to the overall cognitive function of operational workers. It is unclear about the effect of aluminum and fluoride interactions on cognitive function. Objective To evaluate a potential interaction effect of blood aluminum and urinary fluoride on the overall cognitive function of workers working in an aluminum plant. Methods Using cluster sampling, 230 workers in the electrolysis workshop of an aluminum group company in Shanxi Province were selected, and plasma aluminum concentrations were determined by inductively coupled plasma mass spectrometry (ICP-MS) and urinary fluoride by ion-selective electrode. The study participants were divided into a low blood aluminum group and a high blood aluminum group according to the median (M) of blood aluminum concentration, and a low urinary fluoride group and a high urinary fluoride group by a predetermined cutoff point (2.160 mg·L−1). The Montreal Cognitive Assessment-Beijing (MoCA-BJ) was used to assess overall cognitive function of the workers. Logistic regression model was used to analyze the relationship between blood aluminum, urinary fluoride, and mild cognitive impairment (MCI), including multiplicative interaction analysis and correlation analysis; R language was used to fit an additive interaction model of blood aluminum and urinary fluoride on MCI and to calculate synergy index (S), relative excess risk due to interaction (RERI), and attributable proportion due to interaction (API). Results Among the 230 operational workers, the median blood aluminum concentration (P25, P75) was 40.11 (25.16, 58.89) µg·L−1, and there were 104 cases of abnormal urinary fluoride, with an abnormality rate of 45.2%. There was a multiplicative interaction (OR=7.783, 95%CI: 1.377, 43.991) and no additive interaction (RERI=0.030, 95%CI: −0.498, 0.559; API=0.018, 95%CI: −0.279, 0.316; S=1.049, 95%CI: 0.519, 2.118) for the effect between blood aluminum and urinary fluoride on overall cognitive function of the workers. The logistic regression analysis showed that the risk of MCI was 12.105 (95%CI: 2.802, 52.287) times higher in workers with both high blood aluminum and high urinary fluoride than in those with low blood aluminum and low urinary fluoride, after adjusting for selected influencing factors. Conclusion Occupational exposure related high blood aluminum and high urinary fluoride are risk factors for cognitive dysfunction, and the coexistence of both indicators increases the risk of MCI in workers with occupational aluminum exposure, with a multiplicative interaction.

Health risk assessment of water fluoride in rural schools in drinking-water fluorosis areas in Shaanxi Province / 公共卫生与预防医学

Objective To assess the health risks of fluoride in drinking water in rural schools in drinking-water fluorosis areas in Shaanxi Province, and to provide a scientific basis for formulating measures to prevent fluoride and improve water quality. Methods The drinking water of rural schools in Guanzhong and northern Shaanxi Province was monitored from 2017 to 2020. The fluoride concentration was evaluated in accordance with the “Sanitary Standards for Drinking Water” (GB5749-2006). The health risk assessment method recommended by USEPA was used to assess the health risk of rural students exposed to fluoride through drinking water in the two regions. Results A total of 2 826 water samples were monitored from 2017 to 2020. The overall compliance rate of fluoride in water quality was 92.29%, with an average concentration of 0.500 mg/L. The non-carcinogenic health risk of fluoride in drinking water in rural schools in drinking-water fluorosis areas was 0.05). In the same age group, the non-carcinogenic health risk of fluoride in groundwater was higher than that in surface water (P sedimentation filtration > conventional treatment > untreated (P < 0.05). Conclusion The non-carcinogenic risk of oral intake of fluoride in drinking water from rural schools in drinking-water fluorosis areas in Shaanxi Province is still at an acceptable level. In the future, it is necessary to continue to promote comprehensive prevention and treatment measures focusing on water improvement and fluoride reduction.

Mechanism of Learning and Memory Impairment in Rats Exposed to Arsenic and/or Fluoride Based on Microbiome and Metabolome / 生物医学与环境科学（英文）

OBJECTIVE@#Arsenic (As) and fluoride (F) are two of the most common elements contaminating groundwater resources. A growing number of studies have found that As and F can cause neurotoxicity in infants and children, leading to cognitive, learning, and memory impairments. However, early biomarkers of learning and memory impairment induced by As and/or F remain unclear. In the present study, the mechanisms by which As and/or F cause learning memory impairment are explored at the multi-omics level (microbiome and metabolome).@*METHODS@#We stablished an SD rats model exposed to arsenic and/or fluoride from intrauterine to adult period.@*RESULTS@#Arsenic and/fluoride exposed groups showed reduced neurobehavioral performance and lesions in the hippocampal CA1 region. 16S rRNA gene sequencing revealed that As and/or F exposure significantly altered the composition and diversity of the gut microbiome，featuring the Lachnospiraceae_NK4A136_group, Ruminococcus_1, Prevotellaceae_NK3B31_group, [Eubacterium]_xylanophilum_group. Metabolome analysis showed that As and/or F-induced learning and memory impairment may be related to tryptophan, lipoic acid, glutamate, gamma-aminobutyric acidergic (GABAergic) synapse, and arachidonic acid (AA) metabolism. The gut microbiota, metabolites, and learning memory indicators were significantly correlated.@*CONCLUSION@#Learning memory impairment triggered by As and/or F exposure may be mediated by different gut microbes and their associated metabolites.

Correlation analysis and benchmark dose study on bone metabolic biochemical index of low doses of exposed hydrogen fluoride workers / 中华劳动卫生职业病杂志

Objective: To analyze correlation of occupational hydrogen fluoride exposure to low doses of bone metabolism index through occupational epidemiological investigation and benchmark dose calculation. Methods: In May 2021, using cluster sampling method, 237 workers exposed to hydrogen fluoride in a company were selected as the contact group, and 83 workers not exposed to hydrogen fluoride in an electronics production company were selected as the control group. The external exposure dose and urinary fluoride concentration, blood and urine biochemical indicators of the workers was measured.The relationship between external dose and internal dose of hydrogen fluoride was analyzed. The external dose, urinary fluoride was used as exposure biomarkers, while serum osteocalcin (BGP), serum alkaline phosphatase (AKP) and urinary hydroxyproline (HYP) were used as effect biomarkers for bone metabolism of hydrogen fluoride exposure. The benchmark dose calculation software (BMDS1.3.2) was used to calculate benchmark dose (BMD) . Results: Urine fluoride concentration in the contact group was correlated with creatinine-adjusted urine fluoride concentration (r=0.69, P=0.001). There was no significant correlation between the external dose of hydrogen fluoride and urine fluoride in the contact group (r=0.03, P=0.132). The concentrations of urine fluoride in the contact group and the control group were (0.81±0.61) and (0.45±0.14) mg/L, respectively, and the difference between the two groups was statistically significant (t=5.01, P=0.025). Using BGP, AKP and HYP as effect indexes, the urinary BMDL-05 values were 1.28, 1.47 and 1.08 mg/L, respectively. Conclusion: Urinary fluoride can sensitively reflect the changes in the effect indexes of biochemical indexes of bone metabolism. BGP and HYP can be used as early sensitive effect indexes of occupational hydrogen fluoride exposure.

Analysis of monitoring results of skeletal fluorosis in coal-burning type endemic fluorosis areas in Guizhou Province / 中华地方病学杂志

Objective:To analyze the monitoring results of skeletal fluorosis in coal-burning type endemic fluorosis areas in Guizhou Province, and evaluate the effectiveness of comprehensive treatment of coal-burning type endemic fluorosis in the affected areas.Methods:In 2009, 2014, and 2019, monitoring of skeletal fluorosis was carried out in six counties (cities, districts) of Renhuai City, Qixingguan District, Dafang County, Qianxi City, Puding County, and Pu'an County in Guizhou Province. Age stratification was conducted in each county (city, district) for permanent residents aged 25 and above, and survey subjects were selected for X-ray examination of skeletal fluorosis.Results:The detection rates of skeletal fluorosis in 2009, 2014, and 2019 were 51.48% (798/1 550), 34.88% (308/883), and 6.51% (60/922), respectively, showing a decreasing trend year by year (χ 2trend = 505.83, P < 0.001), decreased by 44.97 percentage points from 2009 to 2019. The age distribution of patients with skeletal fluorosis was mainly in the age group of 55 years and older, with annual proportions of 53.88% (430/798), 56.49% (174/308), and 78.33% (47/60), all higher than 50%. In 2009, 2014, and 2019, 483, 222 and 21 cases of mild skeletal fluorosis were detected, and 315, 86, and 39 cases of moderate to severe skeletal fluorosis were detected. There was a statistically significant difference in disease grading among different years(χ 2 = 32.63, P < 0.001). Among them, there were statistically significant differences in the grading of skeletal fluorosis in Qixingguan District, Qianxi City, Puding County, and Pu'an County(χ 2 = 14.56, 12.24, 35.01, 23.35, P < 0.05). Conclusions:The detection rate of skeletal fluorosis in Guizhou Province decreases year by year, and the prevention and control effect is significant. Patients with skeletal fluorosis are mainly in the age group of 55 years and older, and the proportion of patients with moderate to severe skeletal fluorosis is increasing. We should continue to monitor and manage the treatment of current patients with skeletal fluorosis.