Occlusal caries prevention: Seal or varnish?

shutterstock_34500700 - caries sign

Dental Caries remains a common problem and the occlusal surfaces of the first permanent molar accounts for much of the affected tooth surfaces in adults and adolescents.  Two interventions, pit and fissure sealants and fluoride varnish that can be targeted at these surfaces have good evidence supporting their effectiveness. However, there is little evidence of their comparative effectiveness.

The aim of this trial was to compare the clinical effectiveness of pit and fissure sealant (FS) and fluoride varnish (FV)


6-7yr old children from primary schools in areas of social and economic deprivation were randomised to receive either FS or FV. Examinations and treatments took place in mobile dental clinics as part of the Welsh national oral health improvement programme, Designed to Smile.  Standard protocols were used for the applications of FS and FV.

Caries status was assessed at baseline and 12, 24, and 36 months by trained and calibrated dentists at the d1/D1 to d6/D6 level per ICDAS criteria (International Caries Detection and Assessment System;).

The primary outcome was the proportion of children developing new caries (D4-6MFT) on any surface of up to 4 treated first permanent molars (FPMs). Secondary outcomes were; the number of FPMs remaining free of caries into dentine per child for those FPMs included, caries status of treated or untreated caries on FPM surfaces and the binary outcome of caries occurrence on occlusal versus non-occlusal surfaces of each FPM.


  1. 1015 children were randomised (FS=514; FV=501)
  2. 78.6% of children lived in the bottom 2 quintiles of deprivation.
  3. 835 (82.2%) children underwent a final clinical examination at 36 months (FS =418 FV=417).
  4. The proportion of children with dentine caries (D4-6MFT) on at least 1 FPM at 36 months was 19.6% in the FS arm and 17.5% in the FV arm.
  5. The odds of developing caries in the FV arm was 0.84 (95% CI, 0.59 to 1.21) in the adjusted model, an non-statistically significant difference


The authors concluded

The findings of this trial demonstrate that in community oral health programs targeted at children at high caries risk, the application of FV as a caries-preventive measure will result in caries prevention that is not significantly different from that obtained by applying and maintaining FS after 36 months.


This large, well-conducted study in a primary care setting found a small but not statistically significant difference between fissure sealants and fluoride varnish for the prevention of caries in first permanent molars.  Two Cochrane reviews  (Ahovuo-Saloranta et al. 2013 and  Marinho et al. have previously confirmed the effectiveness of both fissure sealants and fluoride varnish in preventing caries. However a 2016 Cochrane review by Ahovuo-Saloranta et al comparing sealants with fluoride varnish concluded:-

Currently, scarce and clinically diverse data are available on the comparison of sealants and fluoride varnish applications; therefore it is not possible to draw clear conclusions about possible differences in effectiveness for preventing or controlling dental caries on occlusal surfaces of permanent molars. The conclusions of this updated review remain the same as those of the last update (in 2010). We found some low-quality evidence suggesting the superiority of resin-based fissure sealants over fluoride varnish applications for preventing occlusal caries in permanent molars, and other low-quality evidence for benefits of resin-based sealant and fluoride varnish over fluoride varnish alone. Regarding glass ionomer sealant versus fluoride varnish comparisons, we assessed the quality of the evidence as very low and could draw no conclusions.

This new primary care based trial adds to the research in this area and would suggest that there may be little difference in the effectiveness of the two approaches. This and the marked difference in the cost of the applications between sealants and varnish (Neidell et al 2016) would favour the use of fluoride varnish. While having better comparative data between the two agents it would also be useful to know whether a combination of the two approaches would lead to a further reduction in caries?


Primary paper

Chestnutt IG, Playle R, Hutchings S, Morgan-Trimmer S, Fitzsimmons D, Aawar N, Angel L, Derrick S, Drew C, Hoddell C, Hood K, Humphreys I, Kirby N, Lau TM,Lisles C, Morgan MZ, Murphy S, Nuttall J, Onishchenko K, Phillips C, Pickles T, Scoble C, Townson J, Withers B, Chadwick BL. Fissure Seal or Fluoride Varnish? A Randomized Trial of Relative Effectiveness. J Dent Res. 2017 Mar 1:22034517702094. doi: 10.1177/0022034517702094. [Epub ahead of print] PubMed PMID: 28394709.

Other references

Ahovuo-Saloranta A, Forss H, Walsh T, Hiiri A, Nordblad A, Mäkelä M, Worthington HV. Sealants for preventing dental decay in the permanent teeth. Cochrane Database of Systematic Reviews 2013, Issue 3. Art. No.: CD001830. DOI:

Marinho VCC, Worthington HV, Walsh T, Clarkson JE. Fluoride varnishes for preventing dental caries in children and adolescents. Cochrane Database of Systematic Reviews 2013, Issue 7. Art. No.: CD002279. DOI: 10.1002/14651858.CD002279.pub2.

Ahovuo-Saloranta A, Forss H, Hiiri A, Nordblad A, Mäkelä M. Pit and fissure sealants versus fluoride varnishes for preventing dental decay in the permanent teeth of children and adolescents. Cochrane Database of Systematic Reviews 2016, Issue 1. Art. No.: CD003067. DOI: 10.1002/14651858.CD003067.pub4.

Neidell M, Shearer B, Lamster IB. Cost-Effectiveness Analysis of Dental Sealants versus Fluoride Varnish in a School-Based Setting. Caries Res. 2016;50 Suppl 1:78-82. doi: 10.1159/000439091. Epub 2016 Apr 22. PubMed PMID: 27100884.



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Derek Richards

Derek Richards is a specialist in dental public health, Director of the Centre for Evidence-Based Dentistry and Specialist Advisor to the Scottish Dental Clinical Effectiveness Programme (SDCEP) Development Team. A former editor of the Evidence-Based Dentistry Journal and chief blogger for the Dental Elf website until December 2023. Derek has been involved with a wide range of evidence-based initiatives both nationally and internationally since 1994. Derek retired from the NHS in 2019 remaining as a part-time senior lecturer at Dundee Dental School until the end of 2023.

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