Topical Fluoride as a Cause of Dental Fluorosis in Children

To the Editor: We write in response to the recent Cochrane for Clinicians review on topical fluoride.¹ We appreciate its discussion of the risks of dental caries and its acknowledgment that dental fluorosis, although undesirable, is mostly cosmetic. However, we are concerned about the concluding recommendation to follow 2014 American Dental Association guidance suggesting toothbrushing with only water in children younger than 2 years, and the conditional phrasing “if [toothpaste is] used….”² This framing may inadvertently convey an unclear message to family physicians. More recent guidance from the American Academy of Pediatrics and American Academy of Pediatric Dentistry recommends using a smear amount (or the size of a grain of rice) of fluoridated toothpaste for children younger than 3 years.^3,4 The Cochrane review also omitted the conclusion from the cited American Dental Association document that supports initiating toothbrushing with a smear of fluoridated toothpaste starting at tooth eruption.²

Fluoridated toothpaste, when used in recommended amounts, effectively prevents caries without meaningfully increasing fluorosis risk. The Cochrane review cites 0.06 mg/kg as a threshold above which fluorosis risk rises. For an average 8-month-old infant (approximately 8 kg), this corresponds to 0.48 mg of fluoride daily.⁵ A smear of toothpaste contains 0.1 mg; therefore, twice-daily brushing yields 0.2 mg, well below this threshold.¹ Even with additional fluoride exposure from water or a supplement, recommended dosing remains within safe limits. The critical factor, as emphasized by the American Dental Association, is caregiver supervision of toothpaste quantity.²

At appropriate doses, fluorosis is uncommon, while the benefits of fluoride in preventing caries are substantial. Consistent with this, the American Dental Association has previously advised against recommending nonfluoride toothpaste for infants and children in its Choosing Wisely guidance.⁶ We agree.

Author Disclosure: Dr. Silk disclosed a relationship with Colgate-Palmolive as a researcher on oral health education in primary care and a relationship with Philips as a consultant on a prenatal oral health education app. All other individuals in a position to control content for this activity have indicated they have no relevant financial relationships to disclose.

In Reply: We appreciate the thoughtful response and the emphasis on clear, evidence-based guidance for primary care clinicians.

We agree that more recent recommendations from the American Academy of Pediatrics and American Academy of Pediatric Dentistry support the use of a smear of fluoridated toothpaste beginning at tooth eruption. Our intent in referencing earlier American Dental Association guidance was to highlight the balance between caries prevention and fluorosis risk. However, we acknowledge that our phrasing may not have reflected the evolution toward more consistent endorsement of early fluoride toothpaste use and should have included the more recent guidelines.`

Importantly, as the letter authors note, available evidence suggests that when used in appropriate amounts under caregiver supervision, fluoridated toothpaste provides substantial protection against dental caries with minimal risk of clinically significant fluorosis. For family physicians, the key practical message is not whether to use fluoride toothpaste, but how to use it safely.

We appreciate the opportunity to clarify this point and reinforce current guidance that supports early initiation of fluoridated toothpaste in young children.