Fluoride varnish for prevention of white spot lesions during orthodontic treatment


A 2019 Cochrane review (Dental Elf – 27th Nov 2019) of the use of topical fluoride to reduce white spot lesions during fixed appliance orthodontic treatment found low certainty evidence for their effectiveness. Cochrane called for more well-conducted studies to improve the quality of the available evidence and since then a number of new trials have been published.

The aim of this review was to evaluate the preventive effect of regular applications of fluoride varnish (FV) on the development of white spot lesions (WSL) during orthodontic treatment.


A protocol was registered with the PROSPERO database. Searches were conducted in the PubMed, Scopus and www.clinicaltrials.gov .  English language peer-reviewed publications of parallel group randomised controlled trials (RCTs) of at least quarterly applications of topical varnish with a minimum follow up period of 12 months were considered. Split mouth studies or those including single or bi-annual varnish applications were excluded. Two reviewers independently selected studies extracted data and assessed risk of bias in accordance with the handbook of Swedish Agency for Health Technology Assessment and Assessment of Social Services. A narrative synthesis and undertaken along with a random effects meta-analysis of comparable data. The certainty of evidence was assessed according to the GRADE working group.


  • 7 RCTs involving a total of 666 patients were included.
  • Studies were conducted in Hong Kong, Iran, Poland, Sweden, and the United States.
  • Three studies involved 5% sodium FV, two a 5% sodium FV with CPP- ACP, one used 0.1 difluorosilane varnish and one 1.5% ammonium FV.
  • 3 studies were considered to be at high risk and 2 at low risk and 2 at moderate risk.
  • All studies tended to favour FV use but only one reached statistical significance at a patient level.
  • Meta-analysis (5 studies) demonstrated a beneficial effect in favour of the FV intervention, risk ratio = 0.64 (95%CI; 0.42 to 0.98).
  • Two studies reported mean values with a standard mean difference = -0.44(95%CI; -0.64 to -0.24).
  • The certainty of evidence was rated as very low.


The authors concluded: –

Regular professional applications of a FV during treatment with fixed orthodontic appliances can prevent the development of WSL adjacent to brackets but the certainty of evidence is very low. Thus, further research is warranted to elucidate the clinical efficiency, health-economic aspects and patients perceived value of FV applications in orthodontic practice.


The authors’ preregistered a protocol on PROSPERO and have followed a typical systematic review methodology.  They have restricted inclusions to studies published in English which may have excluded some relevant studies. In contrast to the 2019 Cochrane review only studies involving fluoride applications at quarterly intervals or more frequently were included. The review also excluded studies using continuous endpoints based on digital technologies. The meta-analysis shows that regular professional application of fluoride varnish can reduce the development of WSL during orthodontic treatment with fixed appliances However, a number of different varnishes were tested and there was significant heterogeneity in the studies, so the certainty of the evidence is very low.  Consequently, as we have noted before well conducted and reported primary studies of appropriate size reported in line with SPIRIT and CONSORT guidelines using core outcomes sets are needed  to provide high quality evidence regarding the use of fluoride varnishes to prevent WSL during fixed appliance orthodontic treatment.


Primary Paper

Sonesson M, Twetman S. Prevention of white spot lesions with fluoride varnish during orthodontic treatment with fixed appliances: a systematic review. Eur J Orthod. 2023 Apr 10:cjad013. doi: 10.1093/ejo/cjad013. Epub ahead of print. PMID: 37032523.

Review protocol in PROSPERO

Other references

Dental Elf – 4th Mar 2022

Enamel demineralisation during multi-bracketed fixed orthodontic treatment

Dental Elf – 27th Nov 2019

White spot lesions: Topical fluoride for prevention during fixed orthodontic treatment

Dental Elf – White spot lesion blogs



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