Satish Kumar DDS, MDSc
There is weak evidence that starting the use of fluoride toothpastes (FT) in children under 12 months of age is associated with an increased risk of fluorosis.
Evidence from 2 RCT’s of which only one was classified as having low risk of bias, suggests that the use of toothpastes with a fluoride concentration of 1000 ppm or greater in children from 1 – 6 years may be associated with an increased risk of mostly mild fluorosis.
Is the use of topical fluoride in young children associated with fluorosis?
The authors searched seven electronic databases through March 2009. They considered different studies in which FT, mouthrinses, gels, foams, paint-on solutions, and varnishes were compared to an alternative fluoride treatment, placebo or no intervention. They evaluated the increased risk of developing dental fluorosis in children with varied exposures to systemic fluoride (such as water or salt fluoridation). The authors’ primary outcome measure was the percentage person (not tooth or surface) prevalence of fluorosis in the permanent dentition. They performed separate meta-analyses to analyze different factors related to use of fluoride toothpaste and combined data according to study designs.
The authors included 25 studies published between 1988 and 2006. The studies included two randomized controlled trials (RCT), one cohort study, six case-control studies and 16 cross-sectional surveys. The percentage person prevalence of fluorosis using different fluorosis indices and case definitions ranged from 10 percent to 72 percent. All the included studies related to use of FT. The authors analyzed several variables concerning fluoride exposure from FT, including (1) age of starting toothbrushing/use of FT, (2) frequency of toothbrushing, (3) amount of toothpaste used and (4) fluoride concentration in the toothpaste. Combining data from five cross-sectional surveys, the authors reported decreased risk of fluorosis when children started toothbrushing/FT use after 12/14 months compared to those who began earlier (odds ratio: 0.70; 95% CI: 0.57 – 0.88). Based on a meta-analysis of data from four cross-sectional surveys, the authors reported no statistically significant association between fluorosis and either the frequency of toothbrushing or the amount of FT used. The authors determined the effect of fluoride concentration in toothpastes based on results from 2 RCT’s. One RCT compared a FT containing 550 ppm fluoride with another containing 1000 ppm fluoride; the second study compared a FT containing 440 ppm fluoride with that containing 1450 ppm fluoride. The two RCTS found that a higher concentration of fluoride in FT was associated with an increased risk of mild fluorosis (relative risk [RR] = 0.75; 95 percent CI, 0.57 to 0.99) and (RR = 0.59, 95 percent CI, 0.44 to 0.79), respectively.
There is weak evidence that starting the use of FT use in infants younger than 12 months is associated with an increased risk of fluorosis.
Source of Funding:
School of Dentistry, The University of Manchester, UK; Department of Health Cochrane Review Incentive Scheme 2008, UK; National Institute for Health Research (NIHR), UK.
Importance and Context:
There is strong evidence that FT prevents caries in both children and adults. (1) However, young children who ingest excessive fluoride may develop fluorosis in their permanent dentition. Previous nonsystematic reviews have suggested that the use of FT in children may be associated with fluorosis. This is the first systematic, quantitative review to study this association.
Strengths and Weaknesses of the Systematic Review:
In this systematic review, the authors used standard methods to identify, select and analyze qualified studies published in all languages. The authors did not include one pending study, which is being translated for their review. The review also excluded several studies (on the basis that they had used the Fluorosis Risk Index) that appeared relevant and could have provided additional information.
Strengths and Weaknesses of the Evidence:
Though 25 studies qualified for the review, only two were RCT’s, of which one had a low risk of bias. All other studies had a moderate to high risk of bias mainly from an inherent bias in observational studies and a lack of information [of the 25 studies, more than half (13) had missing or limited data that were not in a useable form]. Hence, the conclusions in this review should be interpreted with caution. All the studies included for meta-analysis focused on FT intervention and did not include any other means of applying topical fluorides. Since different topical fluorides are used at different concentrations and with varying frequency and duration of use/exposure, extrapolation of results from toothpastes to other topical modalities is difficult. A total of four studies evaluated the use of mouthrinses or professional application of fluoride. However, the authors did not include these studies in the meta-analysis because the data were unclear regarding the ages at which the subjects were exposed to the topical fluorides. In addition, studies that evaluated the amount of fluoride toothpaste used subjective categorizations such as small versus medium or large.
Implications for Dental Practice:
Limited evidence suggests that starting the use of FT in children under 12 months of age or using toothpastes with fluoride concentrations at 1000 ppm or greater in children aged between 12 months and 6 years is associated with an increased risk of dental fluorosis. In making recommendations to patients, clinicians should weigh the benefits of caries prevention and the risk of fluorosis when prescribing FT. If fluorosis is a concern, the total fluoride ingested form toothpastes can be controlled by either lowering the concentration of fluoride in the toothpaste or lowering the amount of toothpaste used. There is evidence from four RCT’s that the use of toothpastes with fluoride concentration at or above 1000 ppm is effective for caries prevention in the deciduous dentition, but there is insufficient evidence for a caries preventive benefit from toothpastes with lower fluoride concentrations. (1) Thus, lowering the concentration may or may not provide the desired preventive benefit. While this review did not show a statistically significant difference between small versus medium or large amounts of FT use and the risk of developing fluorosis, lack of a statistical difference cannot be interpreted as equivalent effectiveness. Thus, using lesser toothpaste may be a reasonable approach to mitigate risk of fluorosis while deriving the caries preventive benefit. The European Academy of Pediatric Dentistry recommends using 500 ppm of FT for children between 6 months and 2 years and toothpaste with 1000 ppm for those aged 2 – 6 years. The amount recommended is 'pea-sized'. (2) The American Academy of Pediatric Dentistry recommends using a ‘smear’ of fluoridated toothpaste for children less than 2 years of age and a pea-size amount for children aged 2-5 years to decrease risk of fluorosis. (3)
(1) Walsh T et al. Fluoride toothpastes of different concentrations for preventing dental caries in children and adolescents. Cochrane Database Syst Rev. 2010 Jan 20;(1):CD007868.
(2) European Academy of Paediatric Dentistry. EAPD guidelines on early childhood caries (ECC). www.eapd.gr 2009. http://www.eapd.gr/Guidelines/Vol_10_2_June_F_Guide.pdf.
Accessed Online 04/15/2010.
(3) American Academy of Pediatric Dentistry. Guideline on Fluoride Therapy. http://www.aapd.org/media/Policies_Guidelines/G_FluorideTherapy.pdf Accessed Online 05/09/10.