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.

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.

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 sodium fluoride on myocardial damage by regulating apoptosis through JNK signaling pathway / 环境与职业医学

Background It has been found that fluoride may cause cardiomyocyte damage. c-Jun N-terminal kinases (JNK) signaling pathway plays an important role in apoptosis, but its role in fluorosis-induced cardiomyocyte damage is still unknown yet. Objective To explore the toxic effect of sodium fluoride (NaF) on H9c2 cardiomyocytes of rats and whether NaF affects cardiomyocyte apoptosis through the JNK signaling pathway. Methods According to the concentrations of sodium fluoride and whether sp600125 (JNK inhibitor) was added, cardiomyocytes of rats were divided into six groups, including control group, SP600125 group (SP group), 0.24, 0.48, and 0.96 mmol·L−1 NaF groups, and 0.96 mmol·L−1 NaF+SP600125 group (NaF+SP group). Cardiomyocytes exposed to NaF for 24 h were observed using a fluorescence inverted microscope. The changes of cell viability at 24, 48, and 72 h after the treatment were detected by CCK-8 method. The levels of reactive oxygen species (ROS) at 24 h after the treatment in H9c2 cardiomyocytes were determined by fluorescent probe method. The expression levels of Bcl-2, Bax, Caspase-3, and JNK mRNA at 24 h after the treatment were detected by real-time PCR. The protein expression levels of Bcl-2, Bax, Caspase-3, and p-JNK at 24 h after the treatment were detected by Western blotting. Results Compared with the control group, after being exposed to 0.48 and 0.96 mmol·L−1 NaF for 24 h, the cell growth density decreased. With the increase of NaF concentration, rounded cells and some suspended dead cells appeared. At 24h after exposure to NaF, the cell viability of the 0.48 and 0.96 mmol·L−1 NaF groups decreased compared with the control group (P<0.05). At 48h and 72h after exposure to NaF, the cell viability levels of the NaF treated groups were significantly lower than that of the control group (P<0.05). After NaF exposure for 24 h, compared with the control group, the intracellular ROS levels were increased (P<0.05); the mRNA expression levels of Bcl-2 were decreased to varying degrees, especially in the 0.48 and 0.96 mmol·L−1 NaF groups (P<0.05); the mRNA expression levels of Bax, Caspase-3, and JNK were increased (P<0.05); the protein expression levels of Bcl-2 were reduced (P<0.05); the protein expression levels of Bax, Caspase-3, and p-JNK were elevated (P<0.05). Compared with the 0.96 mmol·L−1 NaF group, the cell viability of the NaF+SP group was increased, the intracellular ROS level was decreased, the mRNA expression levels of Bax, Caspase-3, and JNK were decreased, the protein expression level of Bcl-2 was increased, and the protein expression levels of Bax, Caspase-3, and p-JNK were decreased (P<0.05); the expression level of Bcl-2 mRNA had a rising trend but showed no statistical significance (P>0.05). Conclusion Cardiomyocyte damage after excessive fluoride exposure may result from fluoride inducing excessive ROS production in cardiomyocytes, which may activate the JNK signaling pathway and induce cardiomyocyte apoptosis.

A preliminary study on the mechanism of lung toxicity of sub-chronic exposure to sodium fluoride in rats / 安徽医科大学学报

Objective @#To study the relationship between different doses of subchronic sodium fluoride exposure and lung histopathological changes in rats，and to explore the effect and related mechanism of sodium fluoride induced lung tissue injury in rats．@*Methods@#Thirty-two Wistar male rats were randomly divided into control，low，medium and high dose groups，each group included 8 rats，intragastric administration of sodium fluoride toxin solution 0， 12，24，and 48 mg / (kg · d) ．The experiment lasted for 16 weeks．The incidence of dental fluorosis and weight in each group of rats was recorded，the lung coefficient was calculated，the pathological changes of lung tissue was observed by HE staining，enzyme-linked immunosorbent assay(ELISA) was used to detect the content of superoxide dismutase (SOD) and malondialdehyde (MDA) levels in rats serum，apoptosis level of lung cells was assessed by TUNEL staining，and the Caspase-3 protein expression levels in lung tissues were determined by immunohistochemistry. @*Results@#At the end of exposure，the upper and lower incisors of rats in different dose groups showed different degrees of dental fluorosis．The increase in body weight of the rats in the high-dose group was lower than that in the other three groups (P＜0. 05) ．The coefficient of lung organs and the content of MDA in serum of the rats in the high-dose group were higher than those in the control group (P＜0. 05) ．The rats in the low，medium and high dose groups had different degrees of pulmonary interstitial inflammatory infiltration and alveolar morphological changes．Compared with the control group，the lung cell apoptosis rate and Caspase-3 protein expression of the rats in the low ，middle and high groups significantly increased ，and the differences were statistically significant ( P < 0. 05) ．@*Conclusion @#Subchronic exposure to sodium fluoride can cause the lung tissue damage in rats ，and the mechanism may be related to the apoptosis induced by oxidative stress.

Diagnostic Efficacy of 68Ga-Labeled Prostate-Specific Membrane Antigen and 18F-Labeled Sodium Fluoride PET/CT in Prostate Cancer With Bone Metastasis / 中国医学科学院学报

Objective To compare the efficiency of 68Ga-labeled prostate-specific membrane antigen (68Ga-PSMA-11) and 18F-labeled sodium fluoride (18F-NaF) PET/CT in the diagnosis of bone metastasis in the patients with prostate cancer.Methods The prostate cancer patients suspected of bone metastasis who underwent 68Ga-PSMA-11 PET/CT and 18F-NaF PET/CT from January 2018 to January 2021 were included in this study.The number of lesions,maximum standardized uptake value (SUVmax),and tumor-to-background (T/B) ratio were compared between the two methods.Results 18F-NaF PET/CT detected more metastases than 68Ga-PSMA-11 PET/CT (310 vs.264,P<0.001).The median SUVmax[23.2 (16.4,33.4) vs.4.1 (2.5,5.6)] and median T/B ratio[7.0 (4.9,9.9) vs.6.7 (3.7,9.6)] of 18F-NaF PET/CT were higher than those of 68Ga-PSMA-11 PET/CT (all P<0.001).With the number of lesions as the indicator,the sensitivity,specificity,accuracy,positive predictive value,and negative predictive value of 18F-NaF PET/CT were 100.0%,92.0%,92.0%,98.7%,and 100.0% respectively,and those of 68Ga-PSMA-11 PET/CT were 85.2%,94.0%,79.2%,98.9%,and 50.5%,respectively.Conclusion 18F-NaF PET/CT is superior to 68Ga-PSMA-11 PET/CT in the detection of bone metastases of prostate cancer.

Evaluation of the remineralizing capacity of silver diamine fluoride on demineralized dentin under pH-cycling conditions

Abstract Objective (1) to determine the effects of the silver diamine fluoride (SDF) and sodium fluoride (NaF) in demineralized dentin exposed to an acid challenge by pH-cycling, (2) to evaluate the remineralizing capacity of SDF/NaF products based on the physicochemical and mechanical properties of the treated dentin surfaces. Methodology In total, 57 human molars were evaluated in different stages of the experimental period: sound dentin - negative control (Stage 1), demineralized dentin - positive control (Stage 2), and dentin treated with SDF/NaF products + pH-c (Stage 3). Several commercial products were used for the SDF treatment: Saforide, RivaStar, and Cariestop. The mineral composition and crystalline and morphological characteristics of the dentin samples from each experimental stage were evaluated by infrared spectroscopy (ATR-FTIR), X-ray diffraction, and electron microscopy (SEM-EDX) analytical techniques. Moreover, the mechanical response of the samples was analyzed by means of the three-point bending test. Statistics were estimated for ATR-FTIR variables by Wilcoxon test, while the mechanical data analyses were performed using Kruskal-Wallis and Mann Whitney U tests. Results Regarding the chemical composition, we observed a higher mineral/organic content in the SDF/NaF treated dentin + pH-c groups (Stage 3) than in the positive control groups (Saforide p=0.03; Cariestop p=0.008; RivaStar p=0.013; NaF p=0.04). The XRD results showed that the crystallite size of hydroxyapatite increased in the SDF/NaF treated dentin + pH-c groups (between +63% in RivaStar to +108% in Saforide), regarding the positive control. SEM images showed that after application of the SDF/NaF products a crystalline precipitate formed on the dentin surface and partially filled the dentin tubules. The flexural strength (MPa) values were higher in the dentin treated with SDF/NaF + pH-c (Stage 3) compared to the positive control groups (Saforide p=0.002; Cariestop p=0.04; RivaStar p=0.04; NaF p=0.02). Conclusions The application of SDF/NaF affected the physicochemical and mechanical properties of demineralized dentin. According to the results, the use of SFD/NaF had a remineralizing effect on the dentin surface even under acid challenge.

Evaluation of three different remineralizing agents on artificially demineralized enamel lesions Using scanning electron microscopy-energy dispersive X-ray and magic-angle spinning nuclear magnetic resonance - An in vitro study

Aim: Demineralization can be arrested or reversed when remineralization agents are applied to incipient carious or noncavitated carious lesions. A large number of therapeutic agents, including nonfluoridated products, have been developed to promote enamel remineralization. This study aims to evaluate the efficacy of different remineralizing agents on artificially demineralized enamel lesions. Materials and Methods: The present in vitro study was conducted on 75 sound premolars divided into three groups of normal, demineralized (n = 15 each), and remineralized teeth (n = 45). The remineralized teeth were further subdivided into three groups (n = 15) as remineralized with 2% sodium fluoride (NaF), 2% NaF, and Psoralea corylifolia (bakuchi) and white mineral trioxide aggregate. Specimens of each group were treated with the above-mentioned remineralizing agents and then subjected to Vickers hardness number (VHN), scanning electron microscopy–energy dispersive X-ray (SEM-EDX), and magic-angle spinning nuclear magnetic resonance (MAS-NMR) for further evaluation. Results: The test results showed significantly the highest VHN and the emission peak of elements under the EDX test, such as calcium, phosphorous, oxygen, and fluorine with remineralized with NaF + bakuchi. MAS-NMR spectra showed fluorine and phosphorous peak in a group with NaF + bakuchi indicative of the increase in remineralization. NaF + bakuchi showed effective results in VHN, SEM-EDX, and MAS-NMR with no antagonist interaction. Conclusion: Thus, P. Corylifolia presents an advantage in enhancing remineralization and inhibiting demineralization for early carious lesions and can be used as a herbal extract for effective reduction in pathogenic bacteria.

Fluoruros en agua de consumo al norte y occidente de México / Fluorides in water for consumption in northern and western Mexico

La cantidad de fluoruros en el agua en algunas regiones de México representa un problema de salud pública. El objetivo de este trabajo fue realizar una revisión sistemática de estudios originales que reportaran niveles de fluoruros en agua corriente y embotellada de la región norte y occidente de México. Esta revisión sistemática se elaboró utilizando el sistema PRISMA en las bases de datos de PubMed, Scopus, Medigraphic y Scielo. Se implementaron las palabras clave de fluoride OR fluorosis AND water AND Mexico, y se incluyeron y excluyeron registros de acuerdo con los criterios previamente establecidos. Fueron revisados aquellos artículos publicados entre el 1 de enero del 2010 y el 30 de marzo del 2021. Se identificaron 36 registros en total. La mayoría mostraban datos encontrados en la región occidente del país (n = 23) mientras que los restantes fueron realizados al norte. Ambas regiones se mostraron con rangos máximos y medias muestrales por encima de lo sugerido por la Organización Mundial de la Salud y los organismos reguladores nacionales. De acuerdo con los estudios aquí analizados en México, las regiones Norte y Occidente del país muestran una situación preocupante por los elevados niveles de fluoruros que reportan los autores en agua corriente y embotellada, los niveles se encuentran casi en su totalidad por encima de los recomendados a nivel nacional e internacional lo cual significa un problema de salud pública que requiere de atención.

The amount of fluoride in water in some regions of Mexico represents a public health problem. The aim of this study was to conduct a systematic review of original studies that report fluoride levels in tap and bottled water from the northern and western regions of Mexico. A systematic review was conducted using the PRISMA method in PubMed, Scopus, Medigraphic and Scielo databases. The keywords fluoride OR fluorosis AND water AND Mexico were used for the search and the records found were included and excluded according to the previous established criteria. We reviewed data in articles published between January 1st, 2010 and March 30th, 2021. We identified a total of 36 records. Most showed data found in the western region (n = 23), while the rest reported data found in the north. Both regions reported maximum and mean sample ranges above those suggested by the World Health Organization and national regulations. According to the analyzed data, in Mexico, the northern and western regions of the country show a concerning situation due to the high levels of fluoride reported by many authors in tap and bottled water. Almost all authors reported data above those recommended for national and international regulations, which represent an important public health problem that requires attention.

SODIUM FLUORIDE DISTRESSES CHROMATOPHORE INTEGRITY AND BEHAVIOUR OF GUPPY, POECILIA RETICULATA PETERS

The present study was undertaken to investigate the toxicological effect of ?uoride (as NaF) on chromatophores in skin of larvivorous fish, Poecilia reticulata Peters after chronic exposure. Guppy is supposed to be amongst the most colourpolymorphic vertebrates in the animal kingdom. Fish were exposed to three sub-lethal concentrations of Sodium fluoride viz. lowest (5.75 ppm), lower intermediate (7.18 ppm) and higher intermediate (9.58 ppm), which were selected on the basis of 96 hrs. LC value of 115 ppm. 50 Anomalous behavioral alterations observed in NaF intoxicated fish were restlessness, erratic swimming movement, periodic surface to bottom movement, recurrent surfacing activity, loss of equilibrium, amplified gulping and increased opercular activity were pragmatically seen. Significant variation in colouration was observed in all the experimental groups as compared to control. The melanophores showed notable pigment aggregation state and/or pigment dispersion state. Structurally, melanophores were distinguished into three types viz., reticulate, stellate and punctuate. The severity in distortion of structure and number of chromatophore increased with increasing concentrations of fluoride. Several distortions in morphology and even functional integrity of chromatophores when compared with the control group were observed, for instance, rupture of pigment cells accompanied by breakage in dendritic processes, conversion of one type of chromatophore into another type, augmentation and detachment between adjacent chromatophores, variation in number with complete loss of cellular activity. The derangement in structural integrity was observed to be dose dependent and increased with increasing concentrations of Sodium fluoride, thus making the fish unfit for survival. The attractive pigmentation of the male Guppy fish was abridged making them less attractive for their mate thus affecting reproductive potential of the fish.

Acute toxicity of fluoride and aluminium on the freshwater fish, Cyprinus carpio L

Fluoride is a trace element which has beneficial effect at lower concentration but detrimental at higher concentration. The fluoride contamination in ground water is a major global problem. Similarly, aluminium is the most abundant metal of the earth, highly toxic to all organisms. In the present study, we investigated the acute toxicity of fluoride and aluminium on three month old fingerlings of Cyprinus carpio L. in hard water (Hardness 125 mg/L of CaCO3) under static renewal bioassay. The 96 h LC50 value of the fluoride and aluminium were 675.615 and 224.214 mg/L, respectively. There was a significant correlation (P <0.01) between mortality rate of C. carpio with all concentrations of fluoride as well as aluminium. The exposure time (24, 48, 72 and 96 h) and different concentration of fluoride (680, 684, 686 and 692 mg/L) and aluminium (228, 229, 231 and 232 mg/L) was also significantly correlated (P <0.05). The different abnormal behaviour displayed by the fluoride and aluminium exposed fishes were erratic swimming movements, rapid opercular activity and excessive secretion of mucous. The safe level of concentrations of fluoride and aluminium were 6.75 and 2.24 µg/L, respectively. The LC50 values of fluoride and aluminium of the present study may be useful in deriving water quality standards in West Bengal.

Anti-erosive profile of an experimental 5% SnCl₂ varnish containing different concentrations of NaF

Abstract This in vitro study evaluated the anti-erosive effect of an experimental varnish containing 5% stannous chloride (SnCl₂) associated with different concentrations of NaF (NaF-free, 2.5% NaF, or 5.2% NaF) on bovine enamel and root dentin. One hundred samples were pre-eroded (0.3% citric acid, pH 2.6, 10 min) and randomized into five groups (n=10 for each substrate): Negative control - milli-Q water; NaF-free - Experimental varnish SnCl₂-free and NaF-free; 2.5 NaF - Experimental varnish 5% SnCl₂ associated with 2.5% NaF; 5.2 NaF: Experimental varnish 5% SnCl₂ associated with 5.2% NaF and positive control - Commercial varnish containing 5% NaF (Duraphat). After the varnishes were applied, the erosive and abrasive challenges were carried out for five days. Loss of tooth structure (TSL) was determined by optical profilometry, and the loss of calcium (ΔCa2+) using atomic absorption spectroscopy. Dentin analysis was also performed by SEM. A one-way ANOVA/Bonferroni test was performed to analyze the data (α=0.05). The experimental 2.5 NaF and 5.2 NaF groups showed greater effectiveness in preventing TSL when compared to the other groups (p <0.05), regardless of the substrate. In addition, these groups showed lower loss in Ca2+ content when compared to the other groups (p <0.05), for enamel and dentin. Dentin showed greater TSL and ΔCa2+ loss when compared to enamel in all treatments (p <0.05). The 5.2% and 2.5% NaF-containing experimental varnishes showed promising results in both, the prevention of TSL and the loss of Ca2+, regardless of the substrate studied.

Resumo Este estudo in vitro avaliou o efeito anti-erosivo de um verniz experimental contendo 5% de cloreto estanoso (SnCl₂) associado a diferentes concentrações de NaF (sem NaF, 2,5% NaF ou 5,2% NaF) sobre esmalte e dentina radicular bovinos. Cem amostras foram pré-erodidas (ácido cítrico 0,3%, pH 2,6, 10 min) e randomizadas em cinco grupos (n=10 para cada substrato): Controle negativo - água milli-Q; Sem NaF - Verniz experimental sem SnCl2 e sem NaF; 2,5 NaF - Verniz experimental 5% SnCl2 associado a 2,5% NaF; 5,2 NaF: Verniz experimental 5% SnCl2 associado a 5,2% NaF e controle positivo - Verniz comercial contendo 5% NaF (Duraphat). Após a aplicação dos vernizes, os desafios erosivos e abrasivos foram realizados por cinco dias. A perda de estrutura dentária (PED) foi determinada por perfilometria óptica e a perda de cálcio (ΔCa2+) por espectroscopia de absorção atômica. A análise da dentina também foi realizada por MEV. Um teste ANOVA/Bonferroni de uma via foi realizado para analisar os dados (α=0,05). Os grupos experimentais 2,5 NaF e 5,2 NaF apresentaram maior eficácia na prevenção de PED quando comparados aos demais grupos (p<0,05), independentemente do substrato. Além disso, esses grupos apresentaram menor perda no teor de Ca2+ quando comparados aos demais grupos (p<0,05), para esmalte e dentina. A dentina apresentou maior PED e de ΔCa2+ quando comparada ao esmalte em todos os tratamentos (p<0,05). Os vernizes experimentais contendo NaF 5,2% e 2,5% apresentaram resultados promissores tanto na prevenção de PED quanto na perda de Ca2+, independente do substrato estudado.

Effect of Different Preparations of Fluoride Gel on Salivary pH of Albino Rats

Abstract Objective: To evaluate the effect of different preparations of fluoride gels on the salivary pH of albino rats. Material and Methods: This experimental study consisted of 40 Albino rats randomly divided into four equal groups. Group A was the control group and received no intervention. Experimental group B received a topical application of 0.2% sodium fluoride gel. Experimental group C received topical application of stannous fluoride gel 0.4%. Experimental group D received topical application of APF gel (1.23% acidulated phosphate fluoride gel). The different preparations of the gels were applied once daily for 4 minutes on the occlusal surface of the right maxillary molars for 14 days. Salivary pH values were recorded immediately after the application of gels with the help of pH paper on day 1 and day 14. Results: There was a significant difference in the pH level of groups B, C and D after 14 days of fluoride application (p < 0.05). The non-parametric Kruskal Wallis test was applied for the comparison between the groups. Conclusion: This study concluded that all the fluoride gels after administration caused the acidic pH of saliva with the most acidic effect produced by APF gel (AU).

Influence of calcium lactate and sodium fluoride solution mouthwashes on enamel microhardness and dentin permeability during in-office bleaching / Influência das soluções enxaguatórias de lactato de cálcio e fluoreto de sódio na microdureza do esmalte e permeabilidade dentinária durante o clareamento em consultório

Objective: This study evaluated the influence of calcium lactate and sodium fluoride mouthwashes on enamel microhardness and dentin permeability during in-office bleaching. Material and Methods: For the microhardness evaluation, enamel blocks were randomly submitted to different treatments associated with in-office bleaching agent using 40% hydrogen peroxide (Opalescence Boost PF 40%/ Ultradent; 3 sessions x 40-minute each) (n = 10): 1) Control: application of bleaching agent; 2) Calcium lactate: 1-minute immersion before bleaching treatment; 3) Sodium fluoride: immersion for 1 minute before bleaching treatment; 4) Calcium lactate + sodium fluoride: 1 minute immersion in calcium lactate solution, followed by 1 minute immersion in sodium fluoride before bleaching treatment. Dentin discs received the same treatment protocols (n = 10) to evaluate permeability. Knoop microhardness and dentin permeability assessments were performed twice (at baseline and 48 hours after the end of bleaching treatment). Results: The generalized linear model considering the design of repeated measures over time showed that there was no significant difference between treatments (p = 0.9577) and between assessments (p = 0.3267) regarding Knoop microhardness. Kruskal Wallis and Dunn tests showed that calcium lactate immersion before bleaching treatment provided higher dentin permeability than other groups (p = 0.0009). Conclusion: The use of sodium fluoride solution and calcium lactate in association with in-office bleaching treatment did not influence the microhardness of tooth enamel, although calcium lactate may increase dentin permeability. (AU)

Objetivo: Este estudo avaliou a influência dos enxaguatórios bucais com lactato de cálcio e fluoreto de sódio na microdureza do esmalte e na permeabilidade da dentina durante o clareamento em consultório. Material e Métodos: Para avaliação da microdureza, blocos de esmalte foram submetidos aleatoriamente a diferentes tratamentos associados a agente clareador em consultório com peróxido de hidrogênio 40% (Opalescence Boost PF 40% / Ultradent; 3 sessões x 40 minutos cada) (n = 10): 1) Controle: aplicação de agente clareador; 2) Lactato de cálcio: imersão de 1 minuto antes do tratamento clareador; 3) Fluoreto de sódio: imersão por 1 minuto antes do tratamento clareador; 4) Lactato de cálcio + fluoreto de sódio: 1 minuto de imersão em solução de lactato de cálcio, seguido de 1 minuto de imersão em fluoreto de sódio antes do tratamento clareador. Os discos de dentina receberam os mesmos protocolos de tratamento (n = 10) para avaliar a permeabilidade. As avaliações da microdureza Knoop e da permeabilidade dentinária foram realizadas duas vezes (no início do estudo e 48 horas após o término do tratamento clareador). Resultados: O modelo linear generalizado considerando o delineamento de medidas repetidas ao longo do tempo mostrou que não houve diferença significativa entre os tratamentos (p = 0,9577) e entre as avaliações (p = 0,3267) em relação à microdureza Knoop. Os testes de Kruskal Wallis e Dunn mostraram que a imersão de lactato de cálcio antes do tratamento clareador proporcionou maior permeabilidade dentinária do que os outros grupos (p = 0,0009). Conclusão: O uso de fluoreto de sódio e lactato de cálcio associado ao clareamento em consultório não influenciou a microdureza do esmalte dentário, embora o lactato de cálcio possa aumentar a permeabilidade dentinária (AU)

Chemically soluble fluoride in toothpastes marketed in Colombia / Fluoruro químicamente soluble en cremas dentales distribuidas en Colombia / Fluoreto químico solúvel em cremos dentários distribuídos na Colômbia

Abstract Introduction and objective: Toothpastes should contain chemically soluble fluoride to have anti-caries efficacy. This study aimed at determining how much of the total fluoride (TF) concentration in the five top-selling children/family Colombian-toothpaste brands corresponds to total chemically soluble fluoride (TSF). Materials and methods: a convenience sample of three tubes of each of the following five toothpaste brands were obtained from three different chain stores, one-per-store, in five Colombian cities (n=3/brand/city): Colgate-Smiles-6+, Kolynos-Super-Blanco, Fortident-Cuatriacción, Colgate-Triple-Acción, Fluocardent. TF (sum of all toothpaste's fluoride) and TSF (toothpaste's chemically soluble fluoride) concentrations were determined in each fresh toothpaste sample (before expiry date) using a standardized ion-specific electrode direct-technique protocol. TF concentration was compared with the manufacturers' declared concentration. The difference between TF and TSF's concentrations purchased in different cities was compared with a one-way ANOVA (5%). Results: Most toothpastes' TF concentration complied with what was declared in the label. One toothpaste had a non-compatible fluoride/abrasive fluoride formulation and TSF < TF; however, it still complied with the minimum TSF requirement to exert a caries-preventive effect (>1000 ppm). Toothpastes' TF and TSF concentrations did not differ between cities (p>0.05). Conclusion: Fresh samples of highly distributed toothpaste brands sold in five Colombian-cities contain chemically available fluoride concentrations with the potential to control and prevent dental caries.

Resumen Introducción y objetivo: las cremas dentales requieren de la disponibilidad de fluoruro químicamente soluble para tener efecto anticaries. Este estudio tuvo como objetivo determinar qué parte de la concentración total de fluoruro (FT) en las cinco marcas de pastas dentales colombianas para niños/familias más vendidas corresponde al fluoruro total químicamente soluble (FTS). Materiales y métodos: se recolectaron tres tubos de cinco marcas diferentes en tres supermercados de cadena; una por tienda, en cinco ciudades colombianas (n=3/marca/ciudad): Colgate-Smiles-6+, Kolynos-Super-Blanco, Fortident-Cuatriacción, Colgate-Triple-Acción, Fluocardent. Las concentraciones de FT y FST se determinaron en cada una de las muestras frescas utilizando técnica directa con electrodo específico y un protocolo estandarizado. La concentración de FT se comparó con la concentración declarada por el fabricante. Se compararon las diferencias entre las concentraciones de FT y FST de la misma marca compradas en diferentes ciudades a con un análisis ANOVA (α=5%). Resultados: La mayoría de las cremas dentales cumplió con la concentración de FT declarada en la etiqueta. Una de las cremas dentale tenía una formulación de fluoruro/abrasivo no compatible y TSF <TF; sin embargo, aún cumplía con el requisito mínimo de TSF para ejercer un efecto preventivo de caries (> 1000 ppm). Las concentraciones de TF y TSF de las pastas de dientes no difirieron entre las ciudades (p> 0.05). Conclusión: Las muestras frescas de cremas dentales de las marcas más vendidas en cinco ciudades colombianas contienen concentraciones de fluoruro químicamente disponibles con el potencial de controlar y prevenir la caries dental.

Resumo Introdução e objetivo: os cremes dentais requerem a disponibilidade de fluoreto quimicamente solúvel para ter um efeito anticárie. O presente estudo determinou a proporção de fluoreto total (FT) que corresponde ao fluoreto total quimicamente solúvel (FST) em cinco marcas de creme dental amplamente distribuídas na Colômbia. Materiais e métodos: três tubos de cinco marcas diferentes foram coletados em três supermercados da rede; uma por loja, em cinco cidades colombianas (n = 3 / marca / cidade): Colgate-Smiles-6 +, Kolynos-Super-Blanco, Fortident-Quad, Colgate-Triple-Action, Fluocardent. As concentrações de FT e FST foram determinadas em cada uma das amostras frescas, utilizando a técnica direta com eletrodo específico e um protocolo padronizado. A concentração de FT foi comparada com a concentração declarada pelo fabricante. As diferenças entre as concentrações de FT e FST da mesma marca comprada em diferentes cidades foram comparadas com a análise ANOVA (α = 5%). Resultados: a maioria das marcas possui concentrações de flúor que atendem à concentração declarada pelo fabricante. Uma marca contém uma formulação de sal abrasivo e fluoreto quimicamente não compatível e FST menor que FT; no entanto, as amostras frescas atenderam à concentração necessária para exercer um efeito anticárie (> 1000 ppm). As concentrações de FT e TSF não foram significativamente diferentes entre amostras da mesma marca compradas em diferentes cidades (p> 0,05). Conclusão: as amostras frescas (analisadas antes do prazo de validade) das cinco marcas de creme dental com maior distribuição na Colômbia contêm concentrações de fluoreto quimicamente solúvel, com potencial para controlar e prevenir a cárie dentária.

Effect of preconditioning the fractured coronal fragments with remineralizing agents on fracture resistance of re-attached teeth

Background: Fragment re-attachment has been considered as one of the treatment modalities for the management of fractured anterior teeth. Hydration of fractured fragments aids in inhibiting the loss of ions and maintains vitality and esthetics. Aim: The study aimed to evaluate the effect of preconditioning the fractured fragments with remineralizing agents on fracture resistance of re-attached teeth. Settings and Design: This was an in vitro study. Materials and Methods: Sixty freshly extracted noncarious human permanent maxillary central and lateral incisors were randomly allocated into three Groups of 20 each: Group 1: 2% sodium fluoride (2%NaF), Group 2: casein phosphopeptide–amorphous calcium phosphate (CPP-ACP), and Group 3: self-assembling peptide P11-4 (SAP). These were further divided into two subgroups of 10 teeth each, based on contact time with remineralizing agents, i.e., 30 min and 2 h. Fractured fragments were treated with remineralizing agents for a specified contact time and then re-attached with flowable composite resin. Force required to fracture the re-attached tooth was recorded in Newtons using universal testing machine. Statistical Analysis: Unpaired t-test, one-way analysis of variance test, and post hoc Tukey test were used for the statistical analysis. Results: A higher fracture resistance was noticed in fragments treated with 2% NaF (30 min- 215.6 N, 2 h- 188.5 N) compared to CPP-ACP (30 min- 141.3 N, 2 h- 111.1 N) and SAP (30 min- 134.8 N, 2 h- 149.5 N). At 30 min interval, it was found to be more in 2% NaF and CPP-ACP groups compared to 2 h. However, it increased with time in the SAP group. A statistically significant difference was found between the groups at both time intervals (P = 0.007 and 0.017). Conclusion: Preconditioning of fractured coronal fragments with 2% NaF showed higher fracture resistance compared to CPP-ACP and self-assembling peptide P11-4. Samples treated with SAP P11-4 exhibited good fracture resistance at 2 h contact time.

Effects of sodium fluoride on growth and development and serum oxidative stress of offspring rats / 中华地方病学杂志

Objective:To investigate the effects of sodium fluoride on growth and development and serum oxidative stress of offspring rats.Methods:Twenty-four clean female SD rats and 24 clean male SD rats were selected, weighting 180 - 220 g, and mating in the same cage for 10 d according to 1 ∶ 1 for male and female. According to body weight by random number table method, the female rats were divided into control group, low-dose fluoride group, and high-dose fluoride group, 8 rats in each group. They were drunk 0, 100 and 200 mg/L sodium fluoride solution prepared with purified water, respectively, and they all ate standard feed. The female rats were exposed to fluoride from the 0th day of pregnancy to the 3rd week after the offspring rats were born (before weaning). After weaning, 10 female offspring rats were selected from each group and continued to be exposed to fluoride in the same amount and manner until the 12th week after birth. The body weight, body length and hind limb length of the offspring rats were measured every week before weaning and every two weeks after weaning. After 12th week of exposure to fluoride, blood samples were taken from abdominal aortas to detect the levels of serum superoxide dismutase (SOD), malondialdehyde (MDA), inducible nitric oxide synthase (iNOS), glutathione peroxidase (GSH-Px) and total antioxidant capacity (T-AOC).Results:At the 2nd week after birth, the body weight [(24.87 ± 3.36) g], body length [(6.37 ± 0.52) cm] and hind limb length [(2.27 ± 0.13) cm] of the offspring rats in high-dose fluoride group were lower than those in control group [(29.23 ± 4.19) g, (6.92 ± 0.47), (2.44 ± 0.16) cm, P < 0.05], but there was no statistically significant difference between low-dose fluoride group and control group and high-dose fluoride group ( P > 0.05). At 3rd to 12th weeks after birth, the body weight, body length and hind limb length of the offspring rats in high-dose fluoride group were lower than those in low-dose fluoride group and control group ( P < 0.05), the low-dose fluoride group were lower than those in control group ( P < 0.05). Serum SOD, GSH-Px and T-AOC levels in control group [(176.51 ± 29.55), (985.23 ± 164.80) U/ml, (0.864 ± 0.167) mmol/L] were higher than those in low-dose fluoride group [(127.98 ± 24.41), (776.53 ± 107.85) U/ml, (0.639 ± 0.110) mmol/L] and high-dose fluoride group [(99.75 ± 14.56), (425.14 ± 78.67) U/ml, (0.441 ± 0.072) mmol/L], the levels of MDA and iNOS [(3.37 ± 0.73) nmol/ml, (189.00 ± 44.67) pg/ml] were lower than those in low-dose fluoride group [(8.22 ± 1.38) nmol/ml, (305.60 ± 73.41) pg/ml] and high-dose fluoride group [(14.81 ± 1.81) nmol/ml, (431.00 ± 91.19) pg/ml], the differences were statistically significant ( P < 0.05); the levels of serum SOD, GSH-Px and T-AOC in high-dose fluoride group were lower than those in low-dose fluoride group, and the levels of MDA and iNOS were higher than those in low-dose fluoride group ( P < 0.05). Conclusion:Excessive fluoride can increase the serum oxidative stress level of offspring rats, which may affect the growth and development of offspring rats.

Inhibitory effects of sodium butyrate on microglial activation and expression of inflammatory factors induced by fluorosis / 中国组织工程研究

BACKGROUND: In the diseases process of the central nervous system, pathogenic factors stimulate microglia cells to over-activate and secrete inflammatory factors, which lead to further injury of neurons. Whether the deacetylase inhibitor sodium butyrate can reduce the over-activation and inflammatory effects of microglia cells caused by fluorosis is worthy of further study. OBJECTIVE: To investigate the effects of sodium butyrate on fluorine-induced over-activation of microglia in the brain and the expression of inflammatory factors interleukin-1β, interleukin-6 and tumor necrosis factor-α. METHODS: Microglia cells (BV-2) were routinely cultured in F12/DMEM medium containing 10% fetal bovine serum. CCK-8 method was used to observe the effects of sodium fluoride, sodium butyrate and their combination on the viability of BV-2 cells in logarithmic growth phase. The morphology of BV-2 cells after treatment with sodium fluoride, sodium butyrate and their combination, mRNA and protein expressions of interleukin-1β, interleukin-6 and tumor necrosis factor-α were observed by inverted microscope, RT-qPCR and western blot assay. RESULTS AND CONCLUSION: (1) CCK8 results showed that 25×10-6 sodium fluoride could reduce the viability of BV-2 cells, and 0.25 mmol/L sodium butyrate could increase the viability of BV-2 cells. Sodium butyrate 0.25 mmol/L could reverse the decreased viability of 25×10-6 sodium fluoride on BV-2 cells. (2) RT-qPCR and western blot assay results showed that 0.25 mmol/L sodium butyrate could antagonize the over-expression of interleukin-1β, interleukin-6 and tumor necrosis factor-α induced by 25×10-6 sodium fluoride. (3) It indicates that sodium butyrate, in a certain dose, can reduce the inflammatory response mediated by fluorium-induced microglia cells.

Influence of topical fluoride on shear bond strength of orthodontic brackets and enamel white spot lesions formation / Influência do flúor tópico na resistência ao cisalhamento de braquetes ortodônticos e na formação de lesões de manchas brancas no esmalte

Introduction Fluoride is considered a key element in the remineralization process of tooth enamel. Objective To evaluate the influence of a topical solution of sodium fluoride (NaF) on the shear bond strength of orthodontic brackets and white spot lesions formation. Material and method Sixty bovine teeth were divided into three groups (n=20). Group 1 (Control): shear bond strength; Group 2: shear bond strength after pH cycling; Group 3: shear bond strength after pH cycling and treatment with 0.04% NaF solution. Groups 2 and 3 underwent pH cycling with demineralizing (6hs) and remineralizing (17hs) solutions at pH of 4.3 and 7.0 respectively for 15 days. The specimens were submitted to the shear bond strength and the Adhesive Remnant Index was verified (ARI). The specimens of each group (n=3) were qualitatively analyzed by means of Scanning Electron Microscopy (SEM). Kruskal-Wallis test assessed the shear bond strength and Fisher's exact test evaluated ARI, with significance level of 5%. Result There was no significant difference among the three groups in shear bond strength (p=0.2679). Significant difference was found in ARI (p=0.0199). The frequency of ARI 1 was 55% in group 1, 90% in group 2, and 80% in group 3. SEM showed difference between the enamel and bonding. Group 2 showed structural change of the enamel surface, adjacent to the bond area; and group 3 showed enamel with characteristics similar to those of group 1. Conclusion It was concluded that there was no NaF influence on the bracket shear bond strength and even in low concentrations it prevented the development of areas of demineralization of white spot lesions.

Introdução O flúor é considerado um elemento chave no processo de remineralização do esmalte dentário. Objetivo Este estudo teve como objetivo avaliar a influência da solução tópica de fluoreto de sódio (NaF) na resistência ao cisalhamento da colagem de barquetes ortodônticos durante a formação de lesões de manchas brancas. Material e método Sessenta dentes bovinos foram divididos em três grupos (n=20). Grupo 1 (Controle) - Cisalhamento imediato; Grupo 2 - Cisalhamento após ciclagem de pH; Grupo 3 - Cisalhamento após ciclagem de pH e tratamento com solução de 0,4% de NaF (Ortho Gard, Colgate-Palmolive®). Os Grupos 2 e 3 sofreram ciclagem de pH com soluções de desmineralização e remineralização em pH de 4,3 e 7,0 respectivamente, com ciclos de desmineralização (6 horas) e remineralização (17 horas), durante 15 dias. Os corpos de prova foram submetidos ao teste de resistência de união ao cisalhamento e remanescente adesivo (IRA). Espécimes de cada grupo (n=3) foram analisados qualitativamente por microscopia eletrônica de varredura (MEV). O teste de Kruskal-Wallis foi utilizado para avaliar a resistência ao cisalhamento e o teste exato de Fisher para avaliação do IRA, adotando nível de significância de 5%. Resultado Os resultados não encontraram diferença significativa entre os três grupos quanto à força de cisalhamento (p=0,2679). Diferença significativa foi encontrada no IRA (p = 0,0199). A frequência de IRA 1 foi de 55% no grupo 1, 90% no grupo 2 e 80% no grupo 3. A análise em MEV mostrou diferença entre o esmalte e a área de colagem submetida ao cisalhamento. Grupo 2 apresentou alteração estrutural na superfície do esmalte adjacente à área de colagem, e o Grupo 3 apresentou esmalte com característica semelhante ao do Grupo 1 na área que foi submetida à ciclagem de pH e NaF. Conclusão Concluiu-se que não houve influência do flúor na resistência ao cisalhamento de braquetes. O uso de soluções fluoretadas, ainda que em baixa concentração, preveniu o aparecimento de áreas desmineralizadas e lesões de manchas brancas.

Fluoride concentration in mouth rinses marketed in Chile and Brazil, and a discussion regarding their legislations

Abstract For fluoride to be effective in controlling caries, it should be bioavailable in commercial products, so that it can be released into the mouth in the products it contains. We chemically determined the available fluoride and pH in nine mouth rinses marketed in Chile, and eleven, in Brazil, and then discussed the legislation in force in both countries, regarding the anticaries potential of these oral hygiene products. The fluoride was analyzed with an ion-selective electrode (F-ISE), using the direct technique. The determinations were made in duplicate, and the results were expressed in ppm F (μg F/mL). The total fluoride concentration found in all the mouth rinses evaluated ranged from 94.7 to 233.5 ppm F, and closely matched what was declared by the manufacturers (100.0 to 226.2 ppm F). However, some mouth rinses showed lower fluoride concentrations (90 and 180 ppm F) in both countries. A Na2FPO3-formulated mouth rinse was found only in Chile, with 216.8 ppm F as the FPO32- ion, and 4.9 ppm F as the F-. The findings show that fluoride was potentially bioavailable in all the mouth rinses evaluated. Regarding the national legislations, although the mouthwashes sold in Brazil comply with the Brazilian legislation, discrepancies were found for Chile. However, neither country had a legislation matching the best available evidence on fluoride mouthwash efficacy for caries control. Thus, some products with low fluoride concentrations (below 226 ppm F), or manufactured with a fluoride salt other than NaF (Na2FPO3) are being sold in the Brazilian and Chilean markets.