Toothpaste Studies

Topic Summary

By Center for Fluoride Research Analysis / Fluoride Science Editorial Board
Last updated: September 16, 2016

The use of toothpaste during tooth brushing is a practice that dates back centuries. However, the ingredients used in toothpaste have evolved over time, as have toothpaste studies and research. The addition of fluoride to toothpaste began to be commonplace in the US in the 1960s, and by the 1990s, fluoride toothpaste accounted for more than 90% of the market in the United States and other developed countries.1

The active ingredient in the US for most fluoride toothpaste is sodium fluoride, at a concentration of 1000 to 1100 parts per million fluoride ion (ppm), which is equivalent to 1000 to 1100 milligrams of fluoride per gram(mg/g). The benefits of using a standard concentration (1000-1100 ppm) fluoride toothpaste in preventing caries both in permanent and primary dentitions in children are confirmed through several systematic reviews and meta-analyses of toothpaste studies.2-6 The use of fluoride toothpaste by young children with developing teeth, however, has been the topic of controversy because they tend to swallow toothpaste while brushing.  This can increase the risk for mild enamel fluorosis. Evidence on the inception of brushing with fluoride toothpaste and the risk of fluorosis, however, is limited and conflicting and also lacks critical information such as the amount of toothpaste used by young children to fully determine the risk for fluorosis.4,6 The most recent systematic review conducted by Wright and colleagues found that ingesting pea-sized amounts or more of fluoride toothpaste can lead to mild fluorosis, while postponing brushing with fluoride toothpaste may decrease the odds of having enamel fluorosis compared with initiating the use before 24 months of age (OR=0.66, 95%CI=0.48-0.90).6

The US Food and Drug Administration labels currently recommend consultation with a dentist when considering the use of fluoride toothpaste by children younger than 2 years of age. Recommending fluoride therapy (i.e. professionally applied fluoride treatment) for children is indeed typically tied to a dentist’s assessment of individual patients’ caries risk, with fluoride therapies recommended for those who are at high risk of developing caries.While caries risk assessment is a cornerstone for developing a personalized prevention plan, currently available caries risk assessment tools still heavily rely on the presence or history of caries to predict future development of caries and have limited validity for use in young children, especially those with no clinically detectable caries.7 Caries on primary teeth progresses more rapidly because of their thinner enamel compared to that of permanent teeth, and children with caries in their primary teeth are three times more likely to develop caries in their permanent teeth.5,8 Nearly one in four children younger than 6 years of age have caries experience today in the US.9

Considering the best available evidence from studies of toothpaste, and the continued burden of early childhood caries, the American Dental Association Council on Scientific Affairs updated recommendations on fluoride toothpaste use for young children in 2014 as follows:7

  • For children younger than 3 years, caregivers should begin brushing children’s teeth as soon as they begin to come into the mouth by using fluoride toothpaste in an amount no more than a smear or the size of a grain of rice (approximately 0.1 milligram of fluoride). Brush teeth thoroughly twice per day or as directed by a dentist or physician. Supervise children’s brushing to ensure that they use the appropriate amount of toothpaste.
  • For children 3-6 years of age, caregivers should dispense no more than a pea-sized amount of fluoride toothpaste (approximately 0.25 mg of fluoride). Brush teeth thoroughly twice per day or as directed by a dentist or physician. Supervise children’s brushing to minimize swallowing of toothpaste.
  • It is especially critical that dentists provide counseling to caregivers that involve the use of oral description, visual aids and actual demonstration to help ensure that the appropriate amount of toothpaste is used.
Amount recommended based on toothpaste studies reviewed by the American Dental Association
ADA’s Council on Scientific Affairs’ 2014 recommendation for amount of fluoride toothpaste appropriate for different ages of young children, based on a systematic review of studies of fluoride toothpaste. Full recommendation is available at

Fluoride added to toothpaste is proven to help preventing dental caries in children, and the combined use with fluoridated water offers protection above either used alone.1 To prevent mild fluorosis in children with developing teeth an age-appropriate amount should be used under parental supervision in children of any age. The following section summarizes the findings from the most recent systematic reviews of toothpaste studies.



The purpose of this systematic review was to assess the efficacy and safety of fluoride toothpaste use in children younger than 6 years. Authors reviewed 17 toothpaste studies including 14 clinical trials and one systematic review that were published before April 2012. Despite the limited quantity and quality of available evidence, authors reported the following:

  • Brushing with fluoridated toothpaste resulted in significantly fewer mean dmfs (-0.25 [95% CI -0.36, -0.14]) and dmft (-0.19 [95%CI -0.32, -0.06]) in high risk populations.
  • Toothpaste with a fluoride concentration of 500ppm or above had a greater effect on caries reduction compared with toothpastes below this concentration.
  • While authors found the inception of brushing with fluoride toothpaste after 24 months of age decreased the odds of dental fluorosis compared with the initiation before 24 months of age (odds ratio or OR=0.66, 95% CI=0.48-0.90), inconsistent evidence was found with regard to independent risk of fluoride concentration in the toothpaste, frequency of brushing, and amount of toothpaste used for fluorosis development.

Eight clinical trials published before March 2012 were eligible for meta-analyses to assess the effects of fluoride (F) toothpastes on the prevention of dental caries in the primary dentition of preschool children. When standard F toothpastes (1000-1500ppm) were compared to placebo or no intervention, significant caries reduction was observed in all dmft (prevented fraction or PF=16%; 95%CI=8-5; 2555 participants in one study), dmfs (PF=31%; 95%CI=18-43; 2644 participants in five studies), and the proportion of children developing dental caries in the primary dentition (relative risk or RR=0.86; 95%CI=0.81-0.93; 2806 participants in two studies). Low F toothpastes (<600ppm) were effective only at the surface level (PF=40%; 95%CI=5-75; 561 participants in two toothpaste studies). Authors commented that equivocal evidence on the effectiveness of low F toothpastes on the prevention of dental caries may be due to the different concentrations compared.


Twenty-five studies of fluoride toothpaste, published between 1988 and 2006, including 2 randomized control trials, 1 cohort, 6 case-control, and 16 cross-sectional studies, were included in quantitative synthesis to determine 1) the relative effectiveness of fluoride toothpastes of different concentrations in preventing dental caries in children and adolescents; and 2) the relationship between the use of topical fluorides in young children and their risk of developing dental fluorosis.

  • A statistically significant benefit of using 1000ppm fluoride or more toothpaste was found relative to 250ppm fluoride toothpaste for caries prevention in the mixed/permanent dentition (DMFS PF=14%, 95% CI=1-26%). The relative caries-preventive effects of fluoride toothpastes of different concentrations increase with higher fluoride concentration.
  • No significant association was found between the frequency of toothbrushing, the amount of fluoride toothpaste used, and fluorosis.
  • Using toothpaste with a higher level of fluoride was significantly associated with an increase in fluorosis across the toothpaste studies examined. There is also weak, unreliable evidence that starting the use of fluoride toothpaste in children under 12 months of age may be associated with an increased risk of fluorosis.
  1. Adair SM, Bowen WH, Burt BA et al. Recommendations for using fluoride to prevent and control dental caries in the United States. MMWR. 2001/50(RR14);1-42
  2. Marinho VC, Higgins JP, Sheiham A, Logan S. Fluoride toothpastes for preventing dental caries in children and adolescents. Cochrane Database Syst Rev. 2003;(1):CD002278
  3. Twetman S, Axelsson S, Dohlgren H et al. Caries-preventive effect of fluoride toothpaste: a systematic review. Acta Odontol Scand. 2003;61(6):347-55
  4. Wong MCM, Clarkson J, Glenny AM et al. Cochrane Reviews on the benefits/risks of fluoride toothpastes. J Dent Res. 2011;90(5):573-9
  5. Santos APP, Nadanovsky P, Oliveira BH. A systematic review and meta-analysis of the effects of fluoride toothpastes on the prevention of dental caries in the primary dentition of preschool children. Community Dent Oral Epidemiol. 2013;41:1-12
  6. Wright JT, Hanson N, Ristic H et al. Fluoride toothpaste efficacy and safety in children younger than 6 years. JADA 2014;145(2):182-9
  7. ADA Council on Scientific Affairs. Fluoride toothpaste use for young children. JADA. 145(2):190-1
  8. Li Y, Wang W. Predicting caries in permanent teeth from caries in primary teeth: an eight-year cohort study. J Dent Res. 2002;81:561-6
  9. Dye BA, Thornton-Evans G, Li X, Iafolla TJ. Dental caries and sealant prevalence in children and adolescents in the United States, 2011-12. NCHS Data Brief. No. 191. March 2015
Public resources from partner Fluoride Exposed

Why you shouldn’t use fluoride free toothpaste

Fluoride in toothpaste history & toothpaste ads