Fluoride concentration in toothpaste marketed to children in Brazil and Mexico, and discussion on current regulations.

Fluoride toothpastes market to children should contain a minimum concentration of 1000 ppm of fluoride (F), which must be chemically soluble to provide anti-caries effect. Therefore, we determined the concentrations of total fluoride (TF) and total soluble fluoride (TSF) in toothpastes marketed to children in Brazil and Mexico and analyzed the current regulations in force in both countries. Twenty-four brands were found and purchased in Brazil (19 formulated with NaF/SiO2, three with Na2FPO3/CaCO3 and two with Na2FPO3/SiO2) and six in Mexico (all with NaF/SiO2). TF and TSF concentrations were determined after the purchase (fresh samples) but fluoride stability in Na2FPO3/CaCO3-formulations was checked after 18 months. The analyses were performed with an ion-specific electrode and the results expressed in ppm F (mg F/kg). The TF concentrations found ranged from 476.0 to 1385.3 ppm F and they were close the declared by the manufactures (500 to 1450 ppm F). The TF concentrations found were not greater than 1500 ppm F, in accordance with the current regulations of both countries. However, toothpastes presenting TSF concentrations lower than 1000 ppm F were found either in low fluoride toothpaste (500 ppm F) formulated with NaF/SiO2 as in fresh and aged Na2FPO3/CaCO3-toothpastes, originally fabricated with 1000-1100 ppm of TF. In conclusion, although most toothpastes analyzed showed TSF concentration higher than 1000 ppm F, the regulations in force in both countries allow that products not in agreement with the best available evidence are available in the market.

Os dentifrícios fluoretados comercializados para crianças devem conter concentração mínima de 1000 ppm de fluoreto (F), que deve ser quimicamente solúvel para ter efeito anticárie. Portanto, determinamos as concentrações de fluoreto total (FT) e fluoreto solúvel total (FST) em dentifrícios comercializados para crianças no Brasil e no México e analisamos as regulamentações vigentes em ambos os países. Vinte e quatro marcas foram encontradas e adquiridas no Brasil (19 formuladas com NaF/SiO2, três com Na2FPO3/CaCO3 e duas com Na2FPO3/SiO2) e seis no México (todas com NaF/SiO2). As concentrações de FT e FST foram determinadas após a compra (amostras frescas), e a estabilidade do fluoreto nas formulações de Na2FPO3/CaCO3 foi verificada após 18 meses. As análises foram realizadas com eletrodo íon-específico e os resultados expressos em ppm F (mg F/kg). As concentrações de FT encontradas variaram de 476,0 a 1.385,3 ppm F e foram próximas às declaradas pelos fabricantes (500 a 1.450 ppm F). As concentrações de FT encontradas não ultrapassaram 1.500 ppm F, de acordo com as regulamentações vigentes de ambos os países. No entanto, dentifrícios com concentrações de FST inferiores a 1.000 ppm F foram encontrados tanto em dentifrício com baixa concentração (500 ppm F) formulado com NaF/SiO2 como em dentifrícios com Na2FPO3/CaCO3 frescos e envelhecidos, originalmente fabricados com 1.000-1.100 ppm de FT. Em conclusão, embora a maioria dos dentifrícios analisados apresentasse concentração de FST superior a 1.000 ppm F, as regulamentações vigentes em ambos os países permitem que produtos que não estejam de acordo com a melhor evidência disponível estejam presentes no mercado.

Comparative Study: Postmortem Long-Term Stability of Endogenous GHB in Cardiac Blood, Femoral Blood, Vitreous Humor, Cerebrospinal Fluid and Urine with and without Sodium Fluoride Stabilization.

The interpretation of postmortem γ-hydroxybutyric acid (GHB) concentrations is challenging due to endogenous existence and postmortem GHB production in body tissues and fluids. As an additional complication, formation of GHB was also described in stored postmortem samples. We examined cardiac blood, femoral blood, vitreous humor, cerebrospinal fluid and urine of eight different corpses (male/female 5/3, aged 33-92 years, postmortem interval 1-6 days) where no intake of GHB or one of its precursors was assumed. All samples were collected during autopsy and divided into two aliquots. To one of the aliquots, sodium fluoride (NaF, 1% w/v) was added. Both aliquots were vortexed, further divided into seven aliquots and stored at -20°C. GHB concentrations were measured immediately and subsequently 1 day, 7 days, 2 weeks, 4 weeks, 3 months and 6 months, after sample collection using trimethylsilyl derivatization and gas chromatography, coupled to single quadrupole mass spectrometry. Similar progression curves of GHB concentrations were obtained for the different matrices in the individual corpses. Femoral and cardiac blood GHB concentrations were always found to be higher than in vitreous humor, cerebrospinal fluid, and urine irrespective of stabilization and storage time. None of the obtained GHB concentrations exceed the cutoff values for postmortem matrices commonly used for the identification of an exogenous GHB intake (urine, venous blood and cerebrospinal fluid: 30 mg/L, cardiac blood and vitreous humor 50 mg/L). No significant differences were found for the GHB concentrations measured immediately and 6 months after autopsy. However, we found a significant increase for the GHB concentrations 4 weeks as well as 3 months after sample collection, which was followed by a decrease nearly to initial values. There were no significant differences between samples with and without NaF addition. The data presented are useful for the interpretation of GHB concentrations in upcoming death cases, with special attention to storage conditions and different postmortem matrices.

Gold nanozyme as an excellent co-catalyst for enhancing the performance of a colorimetric and photothermal bioassay.

Advanced oxidation processes (AOPs) have recently proposed for advancing colorimetric sensing applications, owing to their excellent performance of sensitive color readout that generated from the oxidation of chromogenic substrates like 3,3',5,5'-tetramethylbenzidine (TMB) by reactive oxygen species (ROS) of AOPs such as ·OH and ·O2- radicals. However, the efficiency of ROS generation and the related H2O2 decomposition in most AOPs is quite low especially at neutral pH, which greatly hampered the practical sensing applications of the AOPs. We herein communicated that ß-cyclodextrin (ß-CD)-capped gold nanoparticles (ß-CD@AuNPs) can promote catalysis at neutral pH for AOP as an excellent co-catalyst. In this strategy, inorganic pyrophosphate (PPi) ions was first used to coordinate with Cu2+ and form Cu2+-PPi complex. In the presence of hydrogen peroxide, target inorganic pyrophosphatase (PPase) can hydrolyze PPi into inorganic phosphate (Pi) and release free Cu2+ simultaneously, resulting in a Cu2+-triggered Fenton-like AOP reaction. The introduced ß-CD@AuNPs acts as a co-catalyst, analogous to mediators in the most co-catalyzed system, to enhance the rate-limiting step of Cu2+/Cu+ conversion in Cu2+/H2O2 Fenton-like AOP and resulting in an efficient generation of ·OH and ·O2- radicals, which further producing an intense blue color by oxidizing TMB into its oxidation product (TMBox) within a short time. Finally, this reaction system was used to simply detecting target PPase with the colorimetric and photothermal readout based on the in-situ generated TMBox indicator. More significantly, we successfully demonstrated nanozyme can serve as a co-catalyst to promote the AOP catalysis at neutral pH, and inspire other strategies to overcome the pH limitation in the AOP catalysis and expand its colorimetric and photothermometric application.

Accurate and Real-Time Temperature Monitoring during MR Imaging Guided PTT.

Photothermal therapy (PTT) is an efficient approach for cancer treatment. However, accurately monitoring the spatial distribution of photothermal transducing agents (PTAs) and mapping the real-time temperature change in tumor and peritumoral normal tissue remain a huge challenge. Here, we propose an innovative strategy to integrate T1-MRI for precisely tracking PTAs with magnetic resonance temperature imaging (MRTI) for real-time monitoring temperature change in vivo during PTT. NaBiF4: Gd@PDA@PEG nanomaterials were synthesized with favorable T1-weighted performance to target tumor and localize PTAs. The extremely weak susceptibility (1.04 × 10-6 emu g-1 Oe1-) of NaBiF4: Gd@PDA@PEG interferes with the local phase marginally, which maintains the capability of MRTI to dynamically record real-time temperature change in tumor and peritumoral normal tissue. The time resolution is 19 s per frame, and the detection precision of temperature change is approximately 0.1 K. The approach achieving PTT guided by multimode MRI holds significant potential for the clinical application.

Fluoride content in children's dentifrices marketed in Lima, Peru.

The aim of the present study was to determine the concentration of total fluoride (TF) and total soluble fluoride (TSF) in children's dentifrices marketed in the city of Lima, Peru. Three samples of 23 dentifrices (4 without fluoride and 19 with fluoride) were purchased in different pharmacies in Lima, Peru. The TF and TSF concentrations found in the dentifrices were determined by ion-selective electrode, expressed in ppm F (µg F/g of dentifrice). The TF concentration in the majority of the fluoride toothpastes matched that shown on the label, except for one declared as 1450 ppm F by the manufacturer, whereas only 515.1 ppm F was found. The concentration of TSF found in the fluoride toothpastes ranged from 457.5 to 1134.8 ppm F. All the dentifrices were formulated with silica, but one also presented calcium carbonate. In conclusion, 83% of the children's dentifrices marketed in Lima, Peru, were fluoridated, but only 53% contained a TSF concentration greater than 1000 ppm F, the minimum concentration required to provide an anticaries effect.

Molecular Imaging of Vascular Calcification with 18F-Sodium-Fluoride in Patients Infected with Human Immunodeficiency Virus.

18F-Sodium Fluoride (NaF) accumulates in areas of active hydroxyapatite deposition and potentially unstable atherosclerotic plaques. We assessed the presence of atherosclerotic plaques in 50 adult patients with HIV (HIV+) who had undergone two cardiac computed tomography scans to measure coronary artery calcium (CAC) progression. CAC and its progression are predictive of an unfavorable prognosis. Tracer uptake was quantified in six arterial territories: aortic arch, innominate carotid artery, right and left internal carotid arteries, left coronary (anterior descending and circumflex) and right coronary artery. Thirty-one patients showed CAC progression and 19 did not. At least one territory with high NaF uptake was observed in 150 (50%) of 300 arterial territories. High NaF uptake was detected more often in non-calcified than calcified areas (68% vs. 32%), and in patients without than in those with prior CAC progression (68% vs. 32%). There was no correlation between clinical and demographic variables and NaF uptake. In clinically stable HIV+ patients, half of the arterial territories showed a high NaF uptake, often in the absence of macroscopic calcification. NaF uptake at one time point did not correlate with prior progression of CAC. Prospective studies will demonstrate the prognostic significance of high NaF uptake in HIV+ patients.

Hybrid PET/MR Kernelised Expectation Maximisation Reconstruction for Improved Image-Derived Estimation of the Input Function from the Aorta of Rabbits.

Positron emission tomography (PET) provides simple noninvasive imaging biomarkers for multiple human diseases which can be used to produce quantitative information from single static images or to monitor dynamic processes. Such kinetic studies often require the tracer input function (IF) to be measured but, in contrast to direct blood sampling, the image-derived input function (IDIF) provides a noninvasive alternative technique to estimate the IF. Accurate estimation can, in general, be challenging due to the partial volume effect (PVE), which is particularly important in preclinical work on small animals. The recently proposed hybrid kernelised ordered subsets expectation maximisation (HKEM) method has been shown to improve accuracy and contrast across a range of different datasets and count levels and can be used on PET/MR or PET/CT data. In this work, we apply the method with the purpose of providing accurate estimates of the aorta IDIF for rabbit PET studies. In addition, we proposed a method for the extraction of the aorta region of interest (ROI) using the MR and the HKEM image, to minimise the PVE within the rabbit aortic region-a method which can be directly transferred to the clinical setting. A realistic simulation study was performed with ten independent noise realisations while two, real data, rabbit datasets, acquired with the Biograph Siemens mMR PET/MR scanner, were also considered. For reference and comparison, the data were reconstructed using OSEM, OSEM with Gaussian postfilter and KEM, as well as HKEM. The results across the simulated datasets and different time frames show reduced PVE and accurate IDIF values for the proposed method, with 5% average bias (0.8% minimum and 16% maximum bias). Consistent results were obtained with the real datasets. The results of this study demonstrate that HKEM can be used to accurately estimate the IDIF in preclinical PET/MR studies, such as rabbit mMR data, as well as in clinical human studies. The proposed algorithm is made available as part of an open software library, and it can be used equally successfully on human or animal data acquired from a variety of PET/MR or PET/CT scanners.

Fluoride content in children's dentifrices marketed in Lima, Peru

Abstract The aim of the present study was to determine the concentration of total fluoride (TF) and total soluble fluoride (TSF) in children's dentifrices marketed in the city of Lima, Peru. Three samples of 23 dentifrices (4 without fluoride and 19 with fluoride) were purchased in different pharmacies in Lima, Peru. The TF and TSF concentrations found in the dentifrices were determined by ion-selective electrode, expressed in ppm F (μg F/g of dentifrice). The TF concentration in the majority of the fluoride toothpastes matched that shown on the label, except for one declared as 1450 ppm F by the manufacturer, whereas only 515.1 ppm F was found. The concentration of TSF found in the fluoride toothpastes ranged from 457.5 to 1134.8 ppm F. All the dentifrices were formulated with silica, but one also presented calcium carbonate. In conclusion, 83% of the children's dentifrices marketed in Lima, Peru, were fluoridated, but only 53% contained a TSF concentration greater than 1000 ppm F, the minimum concentration required to provide an anticaries effect.

Chronic Exposure to Fluoride During Gestation and Lactation Increases Mandibular Bone Volume of Suckling Rats.

We aimed to investigate the effect of maternal exposure to NaF on mandibular bone microarchitecture and phosphocalcic plasma parameters of the offspring. For this purpose, 10-, 15-, and 21-day-old pups (n = 6-8 per group) from two groups of mothers, control and NaF 50mg/L treated dams, were used. Plasma calcium (Ca) and phosphorus (P) levels and alkaline phosphatase activity (ALP) were measured. Fluoride concentration (F-) in bone and in stomach content was measured using potentiometry after isothermal distillation. Morphometric, histological, and histomorphometric analyses of the jaw bones were performed. Plasma Ca and P levels and ALP activity increased in 10-day and decreased in 21-day-old pups from NaF-treated mothers. Fluoride concentration in stomach content samples of 15- and 21-day-old nursing pups from mothers exposed to NaF in their drinking water was higher compared to that observed in control dam offspring. Mandibular F- content was higher in 21-day-old pups born to F--exposed dams compared to those observed in age-matched control pups. Mandibular area increased in 21-day-old pups born to treated mothers as compared to controls. Mandibular bone volume BV/TV (%) was higher in offspring from NaF-exposed dams than in controls at all the studied times. The increase in bone volume after exposure to F- was concomitant with the increase in trabecular thickness and the decrease in trabecular separation. Altogether, our results showed that exposure to NaF during gestation and lactation increased mandibular area and bone volume of pups, with concomitant changes in phosphocalcic parameters associated with the bone modeling process.

[18F]NaF PET/CT scan as an early marker of heterotopic ossification in fibrodysplasia ossificans progressiva.

Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disease with a progressive course characterized by episodically local flare-ups, which often but not always leads to heterotopic bone formation (HO). Recently, we showed that [18F]NaF PET/CT may be the first tool to monitor progression of a posttraumatic flare-up leading to new HO, which was demonstrated in a patient with FOP who underwent a maxillofacial surgery. This paper evaluates [18F]NaF PET/CT as a marker of FOP disease activity, comparing its use with other imaging modalities known in literature. In addition, the follow-up of a spontaneous flare-up in a 19-year old patient is presented showing high muscle [18F]NaF uptake in one defined part within the flare-up area after three weeks. During follow-up [18F]NaF PET /CT scan revealed newly formed heterotopic bone but only in this previously active [18F]NaF region. In conclusion, increased muscle [18F]NaF uptake may predict future HO development in FOP patients. At present [18F]NaF PET/CT appears to be a sensitive imaging modality to serve as a noninvasive marker for bone formation and to monitor disease activity during flare-ups in FOP.

Novel weight-based dose threshold for 18F-NaF PET-CT imaging using advanced PET-CT systems: a potential tool for reducing radiation burden.

BACKGROUND: Fluorine-18-sodium fluoride (F-NaF) PET/CT is an important tool for detecting and evaluating metastatic bone cancer. Besides traditional dose metrics, recent methods such as real-time dose mapping, dose calculation from DICOM information, and their relevance to entrance skin exposure are currently in use to reduce the radiation burden. In this study, we have analyzed the data of 1062 patients retrospectively to evaluate patterns of absorbed dose for institutional weight-based dose protocol as compared with fixed dose method guidelines of Society of Nuclear Medicine and Molecular Imaging (SNMMI). PATIENTS AND METHODS: The effective dose imparted by F-NaF (internal exposure) was calculated by using coefficient 0.089 mrem/mCi (0.024 mSv/MBq) according to ICRP publication 106. To estimate the effective dose from whole-body CT scan (external exposure), volume CT dose index (mGy) and dose length product (mGy cm) were directly obtained from the display screen of CT workstation. Effective dose was calculated by multiplying DLP (mGy cm) with ICRP conversion coefficient 'k' 0.015 (mSv/mGy cm). RESULTS: Of the total 1062 patients, there were metastases in 44% (464), probable malignancy in 9% (96), negative findings in 40.5% (433), equivocal findings in 3% (32), and probable benignancy in 3.5% (37). All patients were injected with an institutional agreed protocol of 2.22 MBq/kg (0.06 mCi/kg). The mean injected activity for entire population came out to be 4.79±0.99 mCi. The mean effective absorbed doses were 3.37±0.70 and 5.5±1.35 mSv for F-NaF alone and CT alone, respectively. The mean cumulative effective dose of combined F-NaF PET and CT scan was calculated to be 8.8±1.8 mSv. The minimum absorbed dose for our method was as follows: 1.37 mSv for Kuwait Cancer Control Center vs. 4.44 mSv for SNMMI. Absorbed dose for maximum injected activity was as follows: 5.7 mSv for Kuwait Cancer Control Center vs. 8.88 mSv for SNMMI. Our weight-based doses were also lower when compared with minimum and maximum absorbed doses of technetium-99m-methylene diphosphonate as per SNMMI guidelines (i.e. 4.21 and 6.32 mSv, respectively). CONCLUSION: Our weight-based dose protocol showed a significant reduction in absorbed doses (i.e. 69.14% for F-NaF and 67.45% for technetium-99m-methylene diphosphonate) when compared with fixed dose method guidelines of SNMMI. It is suggested that further prospective studies may be performed in adult population, to evaluate dosimetry efficacy of F-NaF at a low dose of 0.06 mCi/kg as inferred in our current study.

The value of quantitative analysis in 18F-NaF PET/CT / El valor del análisis cuantitativo en la PET/TC con 18F-FNa

Aim. To evaluate the ability of SUVmax to differentiate bone metastases from degenerative lesions, blastic from lytic metastases, as well as to determine the correlation between SUVmax with 18F-NaF and with 18F-FDG. Material and methods. A review was performed on 115 18F-NaF PET/CT studies. Of the 64 patients with bone metastases, 49 (39 women, 10 men, 61±12 years (16-81)), in whom the PET/CT supported the diagnosis of bone metastases, were selected for analysis. A record was made of the SUVmax of a maximum of ten metastases in each patient (total 172: 141 blastic, 31 lytic), as well as four degenerative lesions (total 188) with the greatest 18F-NaF uptake intensity. Of the 49 patients analyzed, 43 also had a 18F-FDG PET/CT performed in which a record was made of the SUVmax values for 18F-FDG calculated in the locations corresponding to the bone metastases observed in the 18F-NaF PET/CT: 128 metastases (106 blastic, 22 lytic). Results. The mean of the SUVmax values was significantly higher in metastases than in degenerative lesions, 26.8±17.3 vs. 15.3±6.3 (P<0.001) and in blastic than in lytic metastases, 27.9±18.3 vs. 22.1±11.3 (P=0.03). A SUVmax value above 42 always represented metastases, with all values above 49 representing blastic metastases. Using the SUVmax values, it was possible to predict the occurrence of metastases (AUC=0.723; P<0.001; 95% CI=0.671-0.776). The mean of the SUVmax with 18F-NaF was significantly higher in blastic metastases (27.9±18.3 vs. 22.1±11.3, P=0.03), whereas with 18F-FDG it was significantly higher in lytic ones (3.9±3.4 vs. 9.6±3.3; P<0.01). Conclusions. SUVmax can contribute to the differentiation of metastases from degenerative lesions, and blastic from lytic metastases (AU)

Objetivo. Evaluar la capacidad del SUVmax para diferenciar metástasis óseas de lesiones degenerativas, metástasis blásticas de líticas, así como la relación del SUVmax con 18F-FNa y con 18F-FDG. Material y métodos. Revisamos 115 exploraciones de PET/TC con 18F-FNa. De 64 pacientes con metástasis óseas, se seleccionaron 49 en los que la TC de la PET/TC apoyaba el diagnóstico de metástasis óseas: 39 mujeres y 10 hombres, 61±12 años (16-81). En cada paciente se calculó el SUVmax en un máximo de 10 metástasis (total 172: 141 blásticas, 31 líticas) y 4 lesiones degenerativas (total 188) que presentaban la mayor captación de 18F-FNa. De los 49 pacientes analizados, en 43 también se había realizado una exploración PET/TC con 18F-FDG y se calculó el valor de SUVmax para la 18F-FDG en las localizaciones correspondientes a las metástasis óseas observadas en la PET/TC con 18F-FNa: 128 metástasis (106 blásticas, 22 líticas). Resultados. El SUVmax promedio fue más elevado en las metástasis que en las lesiones degenerativas, 26,8±17,3 vs. 15,3±6,3 (p<0,001), y más elevado también en las metástasis blásticas que en las líticas: 27,9±18,3 vs. 22,1±11,3 (p=0,03). Todas las metástasis presentaron un valor de SUVmax>42 y las blásticas>49. La utilización del SUVmax permitió predecir la presencia de metástasis (AUC=0,723; p<0,001; IC95%=0,671-0,776). El valor medio de SUVmax con 18F-FNa fue significativamente más alto en las metástasis blásticas (27,9±18,3 vs. 22,1±11,3; p=0,03), mientras que el de 18F-FDG fue significativamente más alto en las líticas (3,9±3,4 vs. 9,6±3,3; p<0,01). Conclusiones. El SUVmax puede ayudar a diferenciar metástasis de lesiones degenerativas y metástasis blásticas de líticas (AU)

Influence of bioadhesive polymers on the protective effect of fluoride against erosion.

OBJECTIVE: This study investigated if the incorporation of the bioadhesive polymers Carbopol 980, Carboxymethyl cellulose (CMC), and Aristoflex AVC in a fluoridated solution (NaF-900ppm) would increase the solution's protective effect against enamel erosion. METHODS: Enamel specimens were submitted to a 5-day de-remineralization cycling model, consisting of 2min immersions in 0.3% citric acid (6x/day), 1min treatments with the polymers (associated or not with fluoride), and 60min storage in artificial saliva. Ultrapure water was used as the negative control and a 900ppm fluoride solution as positive control. The initial Knoop microhardness (KHN1) was used to randomize the samples into groups. Another two microhardness assessments were performed after the first (KHN2) and second (KHN3) acid immersions, to determine initial erosion in the first day. The formula: %KHNalt=[(KHN3-KHN2)/KHN2]*100 was used to define the protective effect of the treatments. After the 5-day cycling, surface loss (SL, in µm) was evaluated with profilometry. Data were analyzed with 2-way ANOVA and Tukey's tests (p<0.05). RESULTS: For %KHNalt, the polymers alone did not reduce enamel demineralization when compared to the negative control, but Carbopol associated with NaF significantly improved its protective effect. The profilometric analysis showed that Carbopol, associated or not with NaF, exhibited the lowest SL, while CMC and Aristoflex did not exhibit a protective effect, nor were they able to improve the protection of NaF. CONCLUSIONS: It is concluded that Carbopol enhanced NaF's protection against initial erosion. Carbopol alone or associated with NaF was able to reduce SL after several erosive challenges. CLINICAL SIGNIFICANCE: Carbopol by itself was able to reduce the erosive wear magnitude to the same extent as the sodium fluoride, therefore, is a promising agent to prevent or control enamel erosion.

Protective Effect of Whole and Fat-Free Fluoridated Milk, Applied before or after Acid Challenge, against Dental Erosion.

This study analysed in vitro the effect of milk against dental erosion, considering three factors: the type of milk (bovine whole/fat-free), the presence of different fluoride concentrations and the time of application (before/after erosive challenge). Bovine enamel (n = 15/group) and root dentine (n = 12/group) specimens were submitted to the following treatments: after the first erosive challenge - 0.9% NaCl solution (negative control), whole milk with 0, 2.5, 5.0 and 10.0 ppm F, fat-free milk with 0, 2.5, 5.0 and 10.0 ppm F, and 0.05% NaF solution (positive control); before the first erosive challenge - whole milk with 0, 2.5, 5.0 and 10.0 ppm F, fat-free milk with 0, 2.5, 5.0 and 10.0 ppm F, and 0.05% NaF solution (positive control). Specimens were submitted to demineralisation-remineralisation regimes 4 times/day for 5 days. The response variables were enamel and dentine loss (in micrometres). Data were analysed using Kruskal-Wallis/Dunn's test (p < 0.05). For enamel, whole milk containing 10 ppm F, applied before the erosive challenge, was the most protective treatment, but with no significant difference compared with the same treatment carried out after the erosive challenge. For dentine, whole fluoridated milk (all concentrations, after), fat-free 10 ppm F milk (after, before) and whole milk with or without F (except 2.5 ppm F, all before) significantly reduced dentine erosion. It seems that the presence of fluoride, especially at 10 ppm, is the most important factor in reducing dental erosion.

Influence of the Amount of Dentifrice and Fluoride Concentrations on Salivary Fluoride Levels in Children.

PURPOSE: This study evaluated fluoride (F) concentrations in saliva of children after brushing with dentifrices containing different F concentrations (zero, 550, and 1,100 ppm F) in different quantities (full bristles, transversal technique, and pea-sized). METHODS: Eight- to 10-year-old volunteers (N=24) were randomly assigned into nine experimental groups (dentifrice type versus amounts) following a double-blind, crossover protocol. After a one-week washout period (use of placebo toothpaste), stimulated saliva was collected prior to toothbrushing (baseline) and at five, 15, 30, 60, and 120 minutes after toothbrushing with one of the possible combinations. Centrifuged saliva was used for F analysis after buffering with TISAB III. Data were submitted to repeated-measures ANOVA followed by Student-Newman-Keuls' test (P<0.05). RESULTS: Salivary F peaked at five minutes after brushing, decreasing exponentially afterward. A clear dose-response relationship was seen between F concentration/amount of dentifrice applied and the mean area under the curve (AUC) of salivary F concentrations (P<0.001). The low-fluoride toothpaste applied using transversal technique or full bristles led to a significantly higher AUC than the conventional toothpaste using a pea-sized amount. CONCLUSIONS: Brushing with a low-fluoride toothpaste applied using the transversal technique delivers more fluoride to saliva compared to a conventional toothpaste in a pea-sized amount.

Necessity to review the Brazilian regulation about fluoride toothpastes.

The aim of this study was to evaluate the adequacy of the Brazilian legislation about fluoride toothpaste. A search was conducted in LILACS, Medline and SciELO databases about the fluoride concentration found in Brazilians toothpastes, using descriptors on health. Publications since 1981 have shown that some Brazilian toothpastes are not able to maintain, during their expiration time, a minimum of 1,000 ppm F of soluble fluoride in the formulation. However, the Brazilian regulation (ANVISA, Resolution 79, August 28, 2000) only sets the maximum total fluoride (0.15%; 1,500 ppm F) that a toothpaste may contain but not the minimum concentration of soluble fluoride that it should contain to have anticaries potential, which according to systematic reviews should be 1,000 ppm F. Therefore, the Brazilian regulation on fluoride toothpastes needs to be revised to assure the efficacy of those products for caries control.

Salivary fluoride levels after use of high-fluoride dentifrice.

The aim of the study was to evaluate salivary fluoride (F) availability after toothbrushing with a high-F dentifrice. Twelve adult volunteers took part in this crossover and blind study. F concentration in saliva was determined after brushing with a high-F dentifrice (5000 µg F/g) or with a conventional F concentration dentifrice (1100 µg F/g) followed by a 15 mL distilled water rinse. Samples of nonstimulated saliva were collected on the following times: before (baseline), and immediately after spit (time = 0) and after 1, 2, 3, 4, 5, 10, 15, 20, 30, 45, 60, 90, and 120 min. F analysis was performed with a fluoride-sensitive electrode and the area under curve of F salivary concentration × time (µg F/mL × min(-1)) was calculated. At baseline, no significant difference was found among dentifrices (P > 0.05). After brushing, both dentifrices caused an elevated fluoride level in saliva; however salivary F concentration was significantly higher at all times, when high-F dentifrice was used (P < 0.01). Even after 120 min, salivary F concentration was still higher than the baseline values for both dentifrices (P < 0.001). High-F dentifrice enhanced the bioavailability of salivary F, being an option for caries management in patients with high caries risk.

On the relationship between the rate of salivary flow and salivary fluoride clearance.

The amount of fluoride retained in the mouth following the application of dentifrices, mouthwashes, etc. may be important in determining their anticaries efficacy. In this study we investigated the relationship between the salivary flow rate and salivary fluoride clearance. Ten adults tested six mouthrinses, consisting of aqueous sodium fluoride solutions (0.013, 0.026 mol/l) with and without added sodium chloride (1.28 mol/l) or sucrose (0.44 mol/l), in a randomised order. Prior to each test, subjects swallowed, rinsed for 2 min with 2 ml water and then expectorated into a preweighed container to obtain a measure of initial saliva flow rate. Next, the procedure was repeated using one of the test rinses. Finally, samples of unstimulated whole saliva were collected for up to 3 h after each mouthrinse application and analysed for fluoride. Salivary fluoride concentrations were significantly lower after application of mouthrinses that contained either sucrose or NaCl, both of which compounds markedly enhanced salivary flow, than after the use of corresponding mouthrinses without any additive. Area under the salivary fluoride clearance curve (AUC) values were inversely correlated with salivary flow rate on an individual basis (p < 0.01). The observed behaviour could not be completely attributed to treatment dilution by saliva at the time of application.

High concentration aqueous sodium fluoride certified reference materials for forensic use certified by complexometric titration.

Sodium fluoride in concentrations of 1 to 2 % is used to prevent the formation of ethanol in blood and urine samples that are to be analysed for ethanol content. The majority of such samples form part of forensic investigations into alleged drunken driving. In South Africa, the laboratory performing the tests is required to prove that the sodium fluoride concentration in the blood samples is above 1 g/100 ml on receipt. This is done by using a fluoride ion-selective electrode calibrated with external aqueous solutions of sodium fluoride. The National Metrology Institute of South Africa (NMISA) prepares sodium fluoride solutions in concentrations from 0.3 to 3.0 g/100 ml. No other certified sodium fluoride reference solutions in these concentrations are available commercially. The sodium fluoride is certified by precipitation of the fluoride as lead chlorofluoride (PbClF) through the addition of a known excess of lead nitrate. The excess lead is back-titrated with ethylenediamine tetraacetic acid (EDTA) using a photometric electrode to detect the endpoint. Aqueous sodium fluoride solutions are prepared and the concentrations verified by the precipitation/back-titration method. This paper shows the application of a classical complexometric method to the certification of reference materials and describes the procedures for the preparation of the sodium fluoride solutions, verification of the concentrations, homogeneity and stability by primary titrimetry. It also briefly covers the calculation of uncertainty, the establishment of traceability and the quality control measures applied to ensure the quality of the certified reference materials (CRMs).

Necessity to review the Brazilian regulation about fluoride toothpastes / Necessidade de revisão da regulamentação brasileira sobre dentifrícios fluoretados

The aim of this study was to evaluate the adequacy of the Brazilian legislation about fluoride toothpaste. A search was conducted in LILACS, Medline and SciELO databases about the fluoride concentration found in Brazilians toothpastes, using descriptors on health. Publications since 1981 have shown that some Brazilian toothpastes are not able to maintain, during their expiration time, a minimum of 1,000 ppm F of soluble fluoride in the formulation. However, the Brazilian regulation (ANVISA, Resolution 79, August 28, 2000) only sets the maximum total fluoride (0.15%; 1,500 ppm F) that a toothpaste may contain but not the minimum concentration of soluble fluoride that it should contain to have anticaries potential, which according to systematic reviews should be 1,000 ppm F. Therefore, the Brazilian regulation on fluoride toothpastes needs to be revised to assure the efficacy of those products for caries control.

O presente estudo analisou a adequação da regulamentação brasileira vigente sobre dentifrícios fluoretados. Foi realizada busca da literatura sobre a concentração de flúor nos dentifrícios brasileiros, tendo como fontes Lilacs, Medline e SciELO, com uso de descritores em saúde. Publicações sobre a composição de dentifrícios fluoretados brasileiros têm mostrado desde 1981 que nem todos os dentifrícios são capazes de manter durante o prazo de validade uma concentração mínima de 1.000 ppm F. Esse problema ocorre não só com dentifrícios adquiridos no mercado como com aqueles distribuídos por serviços públicos de saúde. Entretanto, a legislação brasileira (Resolução 79, Anvisa, 28/8/2000) apenas estabelece que um dentifrício não pode conter mais que 0,15% (1.500 ppm F) de flúor total, sem estabelecer o mínimo de flúor solúvel que ele deveria conter para ter potencial anticárie, a qual de acordo com revisões sistemáticas deve ser igual ou maior que 1.000 ppm F. Concluiu-se que a regulamentação brasileira sobre dentifrícios fluoretados necessita ser revisada, garantindo a eficácia desses produtos para o controle da cárie.