Brushing with fluoride toothpaste has been shown to reduce caries incidence in children.14 The National Academies of Sciences, Engineering and Medicine Health and Medicine Division (HMD; formerly the Institute of Medicine, IOM) estimates the amount of fluoride that reduces caries to the greatest extent without causing adverse effects to be 0.05 mg/kg/day (range 0.02 to 0.10 mg/kg/day) for all children older than 6 months.15
Fluorosis may result from excess fluoride ingestion during the period in which permanent teeth are developing.16 Primarily a cosmetic concern, fluorosis can range from mild—in which white flecks or striations appear on the tooth—to severe—which may result in brown spots and/or pitting of the enamel.17
Studies demonstrate that the amount of toothpaste swallowed is directly associated with the age of the child, with younger children swallowing more than older children when the same amount of toothpaste was used.18 And although a study published in 2019 suggested that children in the US commonly use more toothpaste than is recommended,19 a 2018 systematic review and meta-analysis found that the addition of flavoring to toothpaste did not increase ingestion of toothpaste by children.6
The ADA recommends that children use a smear of toothpaste (the size of a grain of rice) from the time the first tooth erupts until age 3 years. After that point, from 3 years to 6 years, children should use a pea-sized amount of paste. According to the ADA, these amounts help limit the exposure of children to fluoride from ingested dentifrice to levels below those suggested by the HMD (0.05 mg/kg/day).15 For example, if a child weighing 15 kg brushed twice per day, using a rice-sized smear of toothpaste (approximately 0.1 gram of toothpaste or 0.1 milligram of fluoride), swallowed the entire smear he or she would ingest 0.2 mg of fluoride, resulting in a dose of 0.013 mg/kg. Under those same conditions, the Association estimates, a child using a pea-sized amount (approximately 0.25 g toothpaste or 0.25 mg fluoride) would ingest 0.5 mg fluoride, resulting in a dose of 0.033 mg/kg.20
In addition to the appropriate amount of toothpaste to be used, the ADA recommends that caregivers supervise children during brushing to ensure that the children spit rather than swallow the paste.20 Educating caregivers on these recommendations is essential as Zohoori et al. found that, on average, caregivers used up to twice the suggested amount of toothpaste.21
