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.

A simplified protocol to determine total fluoride concentration in NaF/silica-based toothpastes

Aim: To determine total fluoride (TF) concentration in Na2FPO3/Ca-based toothpastes, using fluoride ion selective electrode (F-ISE) by the direct technique, it is necessary to use acid (Ac+) to hydrolyze the FPO32- ion and to dissolve insoluble fluoride salts bound to the abrasive. For NaF/silica-based toothpastes, the use of acid is not necessary (Ac-) and a simplified protocol could be followed. Methods: Thus, we evaluated TF concentration in seven brands of NaF/silica-based toothpastes, following the validated conventional Cury's protocol (Ac+) or a simplification of this protocol (Ac-).Fluoride was analyzed with ISE calibrated with fluoride standard solutions prepared in the same conditions as the samples (Ac+ or Ac-). Results: The mean (±SD; n=21) of TF concentrations (µg F/g) found by Ac+ (971.3±191.2) and Ac- (982.4±201.3) protocols were not statistically different (t test, p=0.22). The TF concentrations found agree with those declared by the manufacturers, except for one toothpaste imported from China. Conclusion: The findings suggest that the determination of fluoride in NaF/silica-based toothpastes can be accurately made using a simplified protocol of analysis

Fluoride concentrations in salt marketed in Managua, Nicaragua

Abstract Nicaraguan legislation has established that fluoride concentrations in salt should be 200-225 mg/kg, but no report describes fluoride concentrations in salt marketed in this country. We evaluated the fluoride concentrations in 33 packages of salt of 11 brands (n = 3 each) purchased in Managua, Nicaragua. According to the package information, 9 of the 11 brands were fluoridated. Six aliquots of each package were weighed (mean 2.5 ± 0.3 g; n = 198) and dissolved in 0.025 g/ml water. Duplicates of 1.0 ml of solutions prepared were buffered (1:1; v/v) with TISAB II. Fluoride concentrations were determined with ion-specific electrode, calibrated with standard solutions (0.25-16.0 μg F/ml) mixed (1:1; v/v) with TISAB II added to 0.025 g (p.a.) NaCl/ml. The mean (± standard deviation, n = 3) fluoride concentrations of two fluoridated brands were in accord with Nicaraguan law (209.8 ± 48.0 and 211.4 ± 26.0 mg F/kg), and those of five brands were below the mandated range (131.0 ± 34.3, 180.6 ± 12.3, 184.6 ± 34.8, 190 ± 47.2, and 199.0 ± 18.9 mg F/kg); two brands contained only traces of fluoride. The two non-fluoridated brands had traces of fluoride. The findings show that the surveillance system for the salt fluoridation program in Nicaragua should be improved, as most salt analyzed violated the requirements of the national legislation.

Fluoride concentration in Peruvian salts determined with specific electrode by the direct method

According to the Peruvian legislation, salt for human consumption should contain 200-250 mg F/kg, but there is limited data showing whether this requirement is being accomplished. Aim: In this pilot study, we evaluated the fluoride concentration in samples of salt marketed in Lima, Peru, using a standardized protocol with ion-specific electrode by direct method (ISE). Methods: Seven 1 kg salt packages of four brands were purchased in two supermarkets of Lima. Six aliquots of each package were weighed and dissolved in the proportion of 0.025 g/mL of water. Duplicates of 1.0 mL of these solutions were mixed with 1.0 mL of TISAB II and fluoride concentration was determined with ISE calibrated with standards fluoride solutions ranging from 0.25 to 16.0 µg F/mL. The ionic strength of the standards was adjusted with p.a NaCL (25 mg/mL). In addition, triplicates of 15 g of each salt package were fractionated in a set of sieves (0.590 to 0.177 mm) to determine the homogeneity of fluoride concentration in salt. Results: In four packages the mean fluoride (mean±SD,n=6) concentration (mg F/kg) was in agreement to the Peruvian regulation (214.5±10.4; 221.8±14.3; 226.9±19.1 and 237.2±52.0 mg F/kg), but in 3 packages it was lower (145.2±7.9; 145.7±23.3 and 158.4±20.6 mg F/kg). Variability in fluoride concentration was observed within the same brand and among brands. Also, the fluoride concentration was not homogeneous in none of the salt samples, ranging from 72.0 to 1449.7 mg F/kg. Conclusion: The findings suggest that the manufacturing and sanitary surveillance of fluoridated salt in Peru should be improved

Comparative Study of Calix-6-arene, 2-Hydroxy Propyl Beta Cyclodextrin and 18-Crown-6 as Ionophores in Potentiometric Ion-Selective Electrodes for Determination of Trigonelline in Trigonella foenum-graecum Seeds Extract and Plasma.

The present work evaluates the influence of Calix-6-arene, 2-hydroxy propyl β-cyclodextrin and 18-crown-6 as ionophores on the fabrication of trigonelline selective electrodes 1, 2 and 3, respectively. The three proposed sensors showed Nernstian slopes of 59, 60 and 55.75 mV/concentration decades over pH range 4-9 for sensors 1, 2 and 3, respectively. Both sensors 1 and 2 covered the concentration range 10-3 – 10-5 M, while sensor 3 showed linear response over the range 10-2 – 10-4 M. The proposed sensors offer the advantages of fast response and moderate stability time. The selectivity coefficients of the developed sensors indicated excellent selectivity for trigonelline. The proposed electrodes were successfully applied for direct determination of trigonelline in pure form, Trigonella foenum-graecum seeds extract and plasma without prior separation or pretreatment steps. The proposed sensors can be used in quality control labs and in clinical trails for routine analysis of trigonelline in Trigonella foenum-graecum seeds extract and plasma.

Comparative Study of Calix-6-arene, 2-Hydroxy Propyl Beta Cyclodextrin and 18-Crown-6 as Ionophores in Potentiometric Ion-Selective Electrodes for Determination of Trigonelline in Trigonella foenum-graecum Seeds Extract and Plasma.

The present work evaluates the influence of Calix-6-arene, 2-hydroxy propyl β-cyclodextrin and 18-crown-6 as ionophores on the fabrication of trigonelline selective electrodes 1, 2 and 3, respectively. The three proposed sensors showed Nernstian slopes of 59, 60 and 55.75 mV/concentration decades over pH range 4-9 for sensors 1, 2 and 3, respectively. Both sensors 1 and 2 covered the concentration range 10-3 – 10-5 M, while sensor 3 showed linear response over the range 10-2 – 10-4 M. The proposed sensors offer the advantages of fast response and moderate stability time. The selectivity coefficients of the developed sensors indicated excellent selectivity for trigonelline. The proposed electrodes were successfully applied for direct determination of trigonelline in pure form, Trigonella foenum-graecum seeds extract and plasma without prior separation or pretreatment steps. The proposed sensors can be used in quality control labs and in clinical trails for routine analysis of trigonelline in Trigonella foenum-graecum seeds extract and plasma.

Patrón de liberación de flúor in vitro en sellantes fluorados de resina / In vitro fluoride-release profile of fluoridated resin-based sealants

Objetivo: Comparar in vitro la cantidad de fluoruros liberados por los principales sellantes de puntos y fisuras basados en resina comercialmente disponibles en Latinoamérica. Material y Métodos: Se evaluó la liberación de fluoruros in vitro en tres sellantes fluorados de puntos y fisuras: Helioseal F (HF), Fissurit F (FF), Clinpro (CF) y Delton (D), sin flúor como control. Se utilizaron 28 discos de 12 mm de diámetro y 2 mm de espesor (n=7 por grupo). Las muestras fueron almacenadas en 5 ml de agua ultra de-ionizada con pH neutro a 37º C por 93 días. La liberación de fluoruros fue medida mediante un electrodo iónico selectivo a los 1, 2, 3, 8, 15, 28 y 93 días. Los datos fueron analizados con el test ANOVA y Tukey (p<0.05). Resultados: El patrón de liberación de flúor fue similar para los tres sellantes fluorados: una alta liberación durante las primeras 24 horas, que disminuyó bruscamente hacia el segundo día. Luego continuó con una disminución progresiva hasta el día 93. El primer día, FF liberó significativamente más fluoruros que HF. Entre los días 2 y 15 FF y HF liberaron significativamente más fluoruros que CF. Desde el día 28 en adelante, las diferencias de liberación de flúor no fueron significativas. Conclusión: El patrón de liberación de flúor in vitro es similar para los sellantes fluorados, con una elevada liberación durante los primeros dos días y luego, una marcada disminución en todos ellos. Este resultado podría explicar la falta de diferencias en la tasa de caries en pacientes tratados con sellantes de resina fluorados y no-fluorados observada en estudios clínicos.

Aim: To compare in vitro the amount of fluoride released from the main pit and fissure sealant resin-based on commercially available in Latin America. Materials and Methods: Twenty-eight samples of 12 x 2 mm were made from three commercial fluoridated resin-based sealants: Helioseal F (HF), Fissurit F (FF), Clinpro (CF) and without fluoride Delton (D), as a control. Samples were stored in 5 ml of deionized water at 37° C and neutral pH. Fluoride releases were measured at 1, 2, 3, 8, 15, 28 and 93 days with an ion-selective electrode. Data were analyzed using ANOVA and one-way and Tukey (p<0.05). Results: Fluoride-release profiles were similar for the three fluoridated sealants: a high release rates during the first 24 hrs and then a drastic drop. Afterward, they continued with a progressive decrease until day 93. The first day, FF release significantly more fluoride than HF. Between days 2 and 15, CF release significantly less fluoride than FF and HF, and later, there was no significant differences between sealants (p>0.05). Conclusion: The fluoride-release profile is similar for the fluoridated resin-based sealants under study: a high release during the first two days and afterwards, a very slow release. These results can explain the lack of differences in caries rate between fluoridated and non-fluoridated resin-based sealants observed in clinical trials.

Polymeric Matrix Membrane Sensors for Stability-Indicating Potentiometric Determination of Bambuterol Hydrochloride and Its Metabolite Terbutaline.

The construction and electrochemical response characteristics of polyvinyl chloride (PVC) membrane sensors for determination of bambuterol hydrochloride (BH) in presence of its degradation products are described. The sensors are based on the ion association complexes of BH cation with sodium tetraphenyl borate (BH-TPB) [sensor 1] or ammonium reineckate (BHRNC) [sensor 2] counter anions as ion exchange sites in PVC matrix. Fast and stable Nernstian responses in the range 10-5-10-2 M for BH over the pH range 5–8 revealed the performance characteristics of these electrodes, which were evaluated according to International Union of Pure and Applied Chemistry recommendations. The two proposed sensors are used for determination of BH, in pure form, in presence of its degradation product and in pharmaceutical formulations. Validation of the method according to the quality assurance standards showed suitability of the proposed electrodes for use in the quality control assessment of BH. The recoveries for determination of BH by the two proposed selective electrodes were 100.07 ± 1.008, 99.93 ± 0.920, for sensor 1 and sensor 2, respectively. Statistical comparison between the results obtained by this method and the official non-a method of BH was done, and no significant difference was found.

Effect of three tropical fluoride solutions on fluoride level in plaque / Efeito de três soluções tópicas de fluor no nível de fluor do biofilme dentário

Objective: To examine process inside plaque after application of three topical fluoride solutions: 1% TiF4, 1% NaF and Aminfluorid solution. Efficiency of three of these was estimated through concentrations of fluoride ions. Methods: Fluoride ions concentrations were measured and demonstrated as potential of fluoride electrode. 60 adult volunteers, divided in three groups (20 volunteers for each group, one agent per one group) have participated in the research. Subjects refrained of oral hygiene for 48 hours before the experiment. Plaque samples were taken before the application of fluoride solutions, and again after 5, 30, 60 and 120 minutes following the treatment. Results: Fluoride concentrations in plaque were not significantly different for three tested solutions. Conclusion: There isn't clinically significant difference in efficacy of three used topical fluoride agents, despite their pH values differences. Only one statistically significant difference appeared after 60 minutes between sodium fluoride and titanium tetra fluoride, but it disappeared after 120 minutes.

Objetivo: Avaliar a ação no biofilme dental após a aplicação de três soluções de flúor tópico: 1% TIF4, NaF 1% e solução de Aminfluorid. A eficiência das três soluções foi estimada através da concentração de íons de flúor. Método: As concentrações de íons de flúor foram medidas com um eletrodo para flúor. 60 voluntários adultos, divididos em três grupos (20 voluntários para cada grupo, uma substância por um grupo) participaram da pesquisa. Os sujeitos permaneceram sem higiene oral por 48 horas antes do experimento. Amostras do biofilme dentário foram tomadas antes da aplicação das soluções de flúor, e novamente depois de 5, 30, 60 e 120 minutos após o tratamento. Resultados: A concentração de flúor no biofilme dental não foi estatisticamente diferente para as três soluções testadas. Conclusão: Não houve diferença clinicamente significativa na eficácia nas três soluções tópicas de flúor utilizadas, apesar das diferenças nos valores do pH. Apenas uma diferença estatisticamente significante foi observada após 60 minutos entre o fluoreto de sódio e o tetrafluoreto de titânio, mas ela desapareceu após 120 minutos.

pH-dependent modulation of intracellular free magnesium ions with ionselective electrodes in papillary muscle of guinea pig

A change in pH can alter the intracellular concentration of electrolytes such as intracellular Ca2+ and Na+ ([Na+]i) that are important for the cardiac function. For the determination of the role of pH in the cardiac magnesium homeostasis, the intracellular Mg2+ concentration ([Mg2+]i), membrane potential and contraction in the papillary muscle of guinea pigs using ion-selective electrodes changing extracellular pH ([pH]o) or intracellular pH ([pH]i) were measured in this study. A high CO2-induced low [pH]o causes a significant increase in the [Mg2+]i and [Na+]i, which was accompanied by a decrease in the membrane potential and twitch force. The high [pH]o had the opposite effect. These effects were reversible in both the beating and quiescent muscles. The low [pH]o-induced increase in [Mg2+]i occurred in the absence of [Mg2+]o. The [Mg2+]i was increased by the low [pH]i induced by propionate. The [Mg2+]i was increased by the low [pH]i induced by NH4Cl-prepulse and decreased by the recovery of [pH]i induced by the removal of NH4Cl. These results suggest that the pH can modulate [Mg2+]i with a reverse relationship in heart, probably by affecting the intracellular Mg2+ homeostasis, but not by Mg2+ transport across the sarcolemma.

Validación del método Potenciométrico por Ión Selectivo para la determinación de Flúor en sal, agua y orina

Objetivo: Validar el método potenciómetro por ión selectivo en la determinación de fluoruro. Materiales y métodos: Se analizaron 3 tipos de muestras (sal, agua, y orina), trabajándose con 3 analistas para el agua y sal, y 2 para la orina. La validación se realizó en 2 días, realizándose 10 ensayos por día. Se calculó la precisión (en condiciones de repetibilidad y reproducibilidad) y exactitud del método (en términos de recuperación del analito adicionado a la muestra). Resultados: Se obtuvo una desviación estándar relativa (RSD) de 2.68%, 3.29% y 2.52% en sal, agua y orina, respectivamente, y se logró recuperar 98.20%, 99.42% y 98.11 % del analito en las mismas muestras de sal, agua y orina, respectivamente. Conclusión: El método potenciómetro, por ión selectivo, realizado en condiciones óptimas y apropiadas, puede aplicarse para la determinación de flúor en muestras de sal, agua y orina.

Objective: To validate the ion?selective potentiometric method for fluorine determination. Materials and methods: Three different samples (salt, water and urine) were analyzed; 3 analysts took part in the water and salt determination and 2 in the urine's. The validation was done in 2 days, having performed 10 trials/day. The accuracy, in terms of reproducibility and repeatability, and the precision of the method (in terms of recovery of the analyte added to the sample) were determined. Results: A Relative Standard Deviation (RSD) of 2.68%, 3.29% and 2.52% in salt, water and urine was obtained, and it was also possible to recover 98.20%, 99.42% and 98.11% of the analito for the same salt, water and urine samples. Conclusion: The ion?selective potentiometric method, if used in optimal and appropriate conditions, can be useful to determine fluorine in salt, water and urine samples.

Development of a F~--ion sensitive field transistor microelectrode and its preliminary application / 实用口腔医学杂志

Objective:To develop a new type of microelectrode used to measure free fluoride in minim solution. Methods:F--ion sensitive field transistor( F--ISFET) microelectrode was developed based on H+-ISFET combined with an Ag/AgCl referential electrode of microtube. The F--ISFET was used to determine the free fluoride ions in saliva and dental plaque fluid in microliter. And its property was investigated. Results:The test limit of F--ISFET was 10 -6 mol/L-10 -1mol/L, the linear test limit was 10 -6mol/L-10 -4mol/L, the sensitivity was 30-55 mV/pF, the responding time was less than 30 seconds, r2 was 0.97, the reclamation was 94%-104%. Conclusion:F--ISFET can be used to measure free fluoride ions in dental plaque.