Dental caries is one of the world’s commonest diseases and for many decades fluoride has been used for caries prevention. While a number of vehicles including water, milk, rinses gels, toothpaste and varnishes have been used to deliver fluoride toothpaste is probably the most commonly used. Regular twice daily toothbrushing with a fluoride toothpaste for 2 minutes is frequently recommended. A typical family toothpaste contains between 1000 to 1500 parts per million (ppm) fluoride but a range of other fluoride concentrations are available.
The aim of this Cochrane review update was to compare the effects of toothpastes of different fluoride concentrations (parts per million (ppm) in preventing dental caries in children, adolescents, and adults.
Methods
Searches were conducted in the Cochrane Oral Health’s Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL). Medline, Embase, the US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform with no restrictions on language or date of publication. Randomised controlled trials (RCTs) comparing toothbrushing with fluoride toothpaste against toothbrushing with a non-fluoride toothpaste or toothpaste of a different fluoride concentration with a minimum follow-up period of 1 year were considered.
Standard Cochrane methodological approaches were followed with independent and duplicate study selection, data abstraction and risk of bias assessment. Mean difference (MD) or standardised mean difference (SMD) in caries increment was the main effect measure. Random effects pairwise or network meta-analysis were carried out where appropriate.
Results
- 96 studies were included with most studies having 36-months follow-up.
- 7 studies (11,356 randomised patients) reported the effects of fluoride toothpaste up to 1500 ppm on the primary dentition;
- 1 study (2500 randomised patients) reported the effects of 1450 ppm fluoride toothpaste on the primary and permanent dentition;
- 85 studies (48,804 randomised patients) reported the effects of toothpaste up to 2400 ppm on the immature permanent dentition; and
- 3 studies (2675 randomised patients) reported the effects of up to 1100 ppm fluoride toothpaste on the mature permanent dentition.
- Only 1 study was considered to be at low risk of bias, 81 at unclear risk of bias and 14 to be at high risk of bias.
- Primary dentition of young children
- 1500 ppm fluoride toothpaste reduces caries increment when compared with non-fluoride toothpaste MD= -1.86 dfs, (95%CI; -2.51 to -1.21) [1 study, 998 patients, moderate-certainty evidence]
- 2 studies (1958 patients) of head-to-head comparison of 1055 ppm versus 550 ppm fluoride toothpaste show similar caries-preventive effects MD= -0.05 dmfs, (95%CI; -0.38 to 0.28)[moderate-certainty evidence].
- Toothbrushing with 1450 ppm fluoride toothpaste slightly reduces decayed, missing, filled teeth (dmft) increment when compared with 440 ppm fluoride toothpaste, MD= – 0.34 dmft (95%CI -0.59 to -0.09) [ 1 study, 2362 patients moderate-certainty evidence.
- Permanent dentition of children and adolescents
- 81 studies were included in the network meta-analysis of D(M)FS increment.
- The network included 21 different comparisons of seven fluoride concentrations.
- The certainty of the evidence was judged to be low with the following exceptions:
- there was high- and moderate-certainty evidence that 1000 to 1250 ppm or 1450 to 1500 ppm fluoride toothpaste reduces caries increments when compared with non-fluoride toothpaste SMD= -0.28 (95%CI; -0.32 to -0.25) 55 studies; and SMD= -0.36 (95%CI; -0.43 to -0.29) 4 studies);
- there was moderate-certainty evidence that 1450 to 1500 ppm fluoride toothpaste slightly reduces caries increments when compared to 1000 to 1250 ppm (SMD -0.08, 95% CI -0.14 to -0.01, 10 studies);
- and moderate-certainty evidence that the caries increments are similar for 1700 to 2200 ppm and 2400 to 2800 ppm fluoride toothpaste when compared to 1450 to 1500 ppm (SMD 0.04, 95% CI -0.07 to 0.15, indirect evidence only; SMD -0.05, 95% CI -0.14 to 0.05, two studies).
- Adult permanent dentition
- 1000 or 1100 ppm fluoride toothpaste reduces DMFS increment when compared with non-fluoride toothpaste in adults of all ages (MD -0.53, 95% CI -1.02 to -0.04; 2162 participants, three studies, moderate-certainty evidence). The evidence for DMFT was low certainty.
- Only a minority of studies assessed adverse effects of toothpaste. When reported, effects such as soft tissue damage and tooth staining were minimal.
Conclusions
The authors concluded: –
This Cochrane Review supports the benefits of using fluoride toothpaste in preventing caries when compared to non-fluoride toothpaste. Evidence for the effects of different fluoride concentrations is more limited, but a dose-response effect was observed for D(M)FS in children and adolescents. For many comparisons of different concentrations the caries-preventive effects and our confidence in these effect estimates are uncertain and could be challenged by further research. The choice of fluoride toothpaste concentration for young children should be balanced against the risk of fluorosis.
Comments
This large detailed Cochrane review and network meta-analysis (NMA) updates the earlier 2010 review (Walsh et al) adding 13 new trials. The previous review was restricted to children and adolescents while this update has been extended to also include adults. Although the age range of the review has been extended the number of adult trials included was limited.
Overall there was good evidence that fluoride toothpaste reduces dental caries with evidence of a dose-effect relationship ( ie a greater reduction of caries with higher fluoride concentrations) with the NMA confirming the existence of a strong dose-response relationship. . The calculated NNT (see table) gives an indication of this.
| Fluoride concentration | Numbers needed to treat (NNT) |
| 440 ppm | 10.40 |
| 1000 ppm | 6.30 |
| 1450 ppm | 5.40 |
| 1700 ppm | 5.10 |
There was limited data available for some comparisons particularly involving higher concentration toothpaste, so the reviewers recommend additions studies comparing lower with higher fluoride concentrations. Data for the primary dentition in young children was scarce as are studies in older adults. Few studies reported adverse effects so future studies should measure and record them. One of the main concerns related to fluoride toothpaste use in younger children in related to dental fluorosis reading the companion Cochrane review by Wong et al provides a good perspective on this.
Links
Primary Paper
Walsh T, Worthington HV, Glenny AM, Marinho VC, Jeroncic A. Fluoride toothpastes of different concentrations for preventing dental caries. Cochrane Database Syst Rev. 2019 Mar 4;3:CD007868. doi: 10.1002/14651858.CD007868.pub3. [Epub ahead of print] Review. PubMed PMID: 30829399.
Other references
Cochrane Oral Health Group Blog – Which strength of fluoride in toothpaste is most effective?
Walsh T, Worthington HV, Glenny AM, Appelbe P, Marinho VC, Shi X. Fluoride toothpastes of different concentrations for preventing dental caries in children and adolescents. Cochrane Database Syst Rev. 2010 Jan 20;(1):CD007868. doi:10.1002/14651858.CD007868.pub2. Review. PubMed PMID: 20091655.
Wong MC, Glenny AM, Tsang BW, Lo EC, Worthington HV, Marinho VC. Topical fluoride as a cause of dental fluorosis in children. Cochrane Database Syst Rev. 2010 Jan 20;(1):CD007693. doi: 10.1002/14651858.CD007693.pub2. Review. PubMed PMID: 20091645.
Kudos for the NNT table!