Chemically Soluble Fluoride in Na₂FPO₃/CaCO₃-Based Toothpaste as an Indicator of Fluoride Bioavailability in Saliva during and after Toothbrushing

Abstract

The relationship between the concentration of chemically soluble fluoride found in toothpaste and that present in saliva, during and after brushing, was evaluated as an indicator of potentially bioavailable fluoride in toothpaste. Ten adult participants brushed their teeth with the assigned toothpastes: group I: fresh sample of a fluoride toothpaste: Na 2 F-PO 3 /CaCO 3 , 1,378 µg F/g of total soluble fluoride (TSF); groups II-IV: aged samples of toothpaste presenting TSF concentrations of 1,160, 900, and 597 µg F/g, respectively; group V: non-F placebo toothpaste. The volunteers brushed their teeth for 1 min with 0.7 g of the toothpaste, all toothbrushing residues (TR) produced were collected, the mouth was rinsed with water, and saliva samples were collected up to 120 min. Total fluoride (TF) and TSF concentrations were determined in TR and in saliva samples using a fluoride ionselective electrode. TSF concentration (µg F/mL) in TR was determined as an indicator of fluoride bioavailability during toothbrushing and the areas under curves of saliva fluoride concentration versus time (area under the curve, AUC = µg F/mL × min) were calculated as an indicator of fluoride bioavailability after toothbrushing. A significant correlation was found between the TSF concentrations in the toothpastes and the variables TR (r = 0.850; p = 0.0001) and AUC (r = 0.445; p = 0.004). For TF no significant correlation was found for TR (r =-0.099; p = 0.542) and AUC (r =-0.018; p = 0.912). The findings suggest that TSF concentration chemically found in Na 2 FPO 3 /CaCO 3-based toothpaste could estimate how much fluoride would be bioavailable in saliva when the teeth are brushed.

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

“…Furthermore, our data showed that fluoride was found in a chemically soluble form in all the mouth rinses evaluated. Unlike toothpaste, 22 all fluoride in mouth rinses is potentially bioavailable when released in the oral cavity during rinsing. Nevertheless, it is known that some substances, such as detergents used in mouthwash formulations, may interfere with the effect of fluoride.…”

Concentração do fluoreto em dentifrícios distribuídos pelo serviço público em Salvador, Bahia

“…Em seguida, lavaram a boca com água purificada e as amostras foram novamente colhidas. Amostras de saliva não estimuladas foram coletadas antes e após a escovação em diferentes intervalos de tempo (3,6,9,15,30,45, 60 e 120 minutos), concluindo-se que o fluoreto capaz de se manter biodisponível na saliva para exercer ação anticárie é o flúor solúvel. Além disso, após a etapa de envelhecimento das amostras, para obter diferentes concentrações de flúor para análise, o valor do flúor total encontrado não sofreu alteração em nenhum momento 6 .…”

“…O uso do creme dental fluoretado é considerado o método mais racional de uso do fluoreto, uma vez que, em conjunto com a escovação, promove a desorganização do biofilme, ao mesmo tempo em que expõe as superfícies dentárias ao íon flúor, o qual se mantém presente no biofilme remanescente pós-escovação não eficiente e na saliva e, desta forma, mantém o equilíbrio desmineralização-remineralização tecidual. O fluoreto liberado na cavidade bucal serve tanto como efeito preventivo, para reduzir o desenvolvimento de lesões de cárie, quanto como efeito terapêutico, agindo na reparação das lesões iniciais já existentes [6][7][8][9] .…”

“…No entanto, essa legislação não informa a concentração mínima de flúor solúvel (potencialmente ativo contra cárie) que um dentifrício deveria conter e manter ao longo do prazo de validade do produto. A concentração mínima de FST, forma em que o flúor se encontra biodisponível para exercer o seu potencial anticárie, é de 1.000 ppm F 6,16,17 .…”

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

“…The protocol of fluoride determination in toothpastes with F-ISE by the direct technique and used since 1980 in Laboratory of Oral Biochemistry from FOP-UNICAMP 3,5,7-20 is considered chemically valid, reliable, and feasible 1 . In addition, it is able to estimate how much of the total fluoride presents in Na 2 FPO 3 /CaCO 3 -based toothpaste is bioavailable to be released in the oral cavity during toothbrushing 21 . However, this protocol could be simplified to determine fluoride in Ca-free toothpaste formulations, which contains ionic fluoride salts, such as NaF.…”