Fluoride stability in dentifrices stored in schools in a town of northern Brazil

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

Resumo 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.

Fluoride in toothpaste - is the expressed total fluoride content meaningful for caries prevention?

In today's global market, there is a very wide range of fluoride toothpastes varying in formulation, fluoride concentration, quality control of ingredients and manufacture, and some products are transported, stored and sold to consumers in countries far removed from where they are made. The competitiveness of the toothpaste market has driven the major manufacturers to offer an increasing and frequently changing variety of formulations to support claims of caries prevention, tooth whitening, sensitivity prevention, gum health and total oral health. However, the focus of this article is to consider how variations in formulation and the fluoride content of toothpastes might affect clinical efficacy for caries prevention. On the basis of presently available evidence, it would appear that the most reliable indicator of the effective fluoride content for a toothpaste formulation is the ionic fluoride concentration (F^-) as parts per million (ppm) available immediately on brushing. However, as the recent international workshop on testing methods concluded, the clinical validation, acceptance and agreement of standardised testing methods by both manufacturers and international bodies would be required. If these technical difficulties can be overcome and all manufacturers standardised on this form of expression and did not declare the total, soluble or free ionic fluoride as calculated on a theoretical basis, then it would provide a more meaningful indicator that dental professionals, pharmacies and indeed the consumer could rely upon.