Fluoride content of toothpastes marketed for children in Thailand: an analytical study

Abstract

To evaluate the total fluoride and total soluble fluoride concentrations in children’s toothpaste products available in Thailand, and to compare measured values with labeled fluoride concentrations. Twenty-one brands of children’s toothpaste were purchased from supermarkets in Bangkok in 2024. Three samples from different manufacturing lots were collected for each brand. Total fluoride and total soluble fluoride concentrations were determined using a fluoride ion-selective electrode after appropriate acid hydrolysis, neutralization, and buffering. Measured fluoride concentrations were compared with labeled values using one-sample t-tests, with statistical significance set at p < 0.05. Twenty-one toothpaste brands were analyzed, 14 (66.67%) exhibited total fluoride concentrations consistent with their labeled fluoride values, while seven (33.33%) demonstrated significant discrepancies. Three brands (14.28%) contained total fluoride levels significantly lower than declared, whereas four brands (19.05%) demonstrated higher total fluoride concentrations than stated on their labels. For total soluble fluoride, 14 brands (66.67%) showed concentrations consistent with labeled claims. In contrast, six brands (28.57%) exhibited significantly lower total soluble fluoride levels than declared, and one brand (4.76%) showed a significantly higher total soluble fluoride concentration. Notably, several toothpaste products demonstrated adequate total fluoride levels but reduced total soluble fluoride concentrations, indicating limited fluoride bioavailability. The findings indicate that labeled fluoride concentrations in children’s toothpaste do not always reflect the amount of bioavailable fluoride. Although most products complied with declared total fluoride values, reduced total soluble fluoride levels were observed in several brands, potentially compromising their anticariogenic efficacy. Ongoing market surveillance focusing on both total and bioavailable fluoride is recommended to ensure the efficacy and safety of children’s toothpaste products in Thailand.