Patterns of Fluoride Intake From 6 to 17 Years of Age

The practical significance of this study

This important well-written report from the longitudinal Iowa Fluoride Study confirms what might be assumed that, as children in this age range grow, they ingest a slightly increasing amount of fluoride. However, for their weight, they consume proportionally less fluoride.

For younger children aged 6 to 8 years, during which high daily fluoride intake could contribute to the development of dental fluorosis in late erupting posterior permanent teeth, toothpaste contributes up to 25% of total fluoride intake. A previous publication by the Iowa group showed that a daily average of up to 0.05 mg F/kg body weight (bw) was generally protective against tooth decay and dental fluorosis.¹ For young children in this report, however, there were some who had a higher intake. Approximately 5% of 6-year-olds in this report had a daily fluoride intake ≥0.07 mg F/kg bw (the level indicative of a higher risk for dental fluorosis), with a further 9% having an intake ranging between 0.05 and 0.07 mg F/kg bw. For 7-year-olds, about 10% had an average daily intake ≥0.05 mg F/kg bw; for 8-year-olds, that percentage was about 6%.

The authors noted that the data used for this study were collected between 1998 and 2013, which predates the US Department of Health and Human Services (HHS) 2015 standardization of the recommended community water fluoride concentration to 0.7 mg/L across the US. Hence, future studies conducted after 2015 may find a reduced fluoride intake in children.

To limit the intake of fluoride from toothpaste during the tooth-developing years, HHS in the early 1990s recommended that parents/guardians should supervise toothbrushing with fluoride toothpaste in young children, especially in those with the inability to control the swallowing reflex, using just a smear or pea-sized amount of fluoride toothpaste twice a day. However, this current study indicated that 6- to 8-year-olds are consuming a significant proportion of their total fluoride intake from toothpaste. Reporting on toothpaste and toothbrushing patterns in the US between 2013 and 2016, Thornton-Evans et al found that, among children aged 3 to 6 years, the reported amount of toothpaste varied: 12.4% of children used a smear, 49.2% used a pea-sized amount, 20.6% used a half load, and 17.8% used a full load.²

Clearly, there continues to be a need among clinicians to reinforce the caries-preventive benefits of fluoridated water as well as fluoride toothpaste in young children, while providing guidance on limiting the amount of toothpaste that parents apply on their children’s toothbrushes and encouraging the toothpaste to be spit out rather than swallowed. In some countries, toothpaste manufacturers incorporate a lower fluoride concentration in the toothpaste used by young children, while recognizing the possible reduced caries-preventive effect. For example, in Australia, it is recommended that a low fluoride toothpaste be used from the age of 18 months and regular toothpaste from 6 years.³ This strategy has been part of a successful comprehensive approach for caries prevention while limiting dental fluorosis.

References

1. Warren JJ, Levy SM, Broffitt B, et al. Considerations on Optimal Fluoride Intake Using Dental Fluorosis and Dental Caries Outcomes – A Longitudinal Study. J Public Health Dent. 2009;69(2):111-115. https://onlinelibrary.wiley.com/doi/10.1111/j.1752-7325.2008.00108.x
2. Thornton-Evans G, Junger ML, Lin M, et al. Use of Toothpaste and Toothbrushing Patterns Among Children and Adolescents - United States, 2013-2016. MMWR Morb Mortal Wkly Rep. 2019;68(4):87-90. https://www.cdc.gov/mmwr/volumes/68/wr/mm6804a3.htm?s_cid=mm6804a3_w
3. Do LG, Australian Research Centre for Population Oral Health. Guidelines for use of fluorides in Australia: update 2019. Aust Dent J. 2020;65(1):30-38. https://onlinelibrary.wiley.com/doi/full/10.1111/adj.12742