Abstract: In this review, we included eight trials with 1746 participants (four of the trials were new since the 2010 update). Seven trials (1127 participants) contributed to the analyses, and children involved were five to 10 years of age at the start of the trial. Sealant versus fluoride varnish  Resin-based fissure sealants compared with fluoride varnishes  Four trials evaluated this comparison (three of them contributing to the analyses). Compared with fluoride varnish, resin-based sealants prevented more caries in first permanent molars at two-year follow-up (two studies in the meta-analysis with pooled odds ratio (OR) 0.69, 95% confidence interval (CI) 0.50 to 0.94; P value = 0.02; I2 = 0%; 358 children evaluated). We assessed the body of evidence as low quality. The caries-preventive benefit for sealants was maintained at longer follow-up in one trial at high risk of bias: 26.6% of sealant teeth and 55.8% of fluoride-varnished teeth had developed caries when 75 children were evaluated at nine years of follow-up. Glass ionomer-based sealants compared with fluoride varnishes  Three trials evaluated this comparison: one trial with chemically cured glass ionomer and two with resin-modified glass ionomer. Researchers reported similar caries increment between study groups regardless of which glass ionomer material was used in a trial. Study designs were clinically diverse, and meta-analysis could not be conducted. The body of evidence was assessed as of very low quality. Sealant together with fluoride varnish versus fluoride varnish alone  One split-mouth trial analysing 92 children at two-year follow-up found a significant difference in favour of resin-based fissure sealant together with fluoride varnish compared with fluoride varnish only (OR 0.30, 95% CI 0.17 to 0.55). The body of evidence was assessed as low quality. Adverse events  Three trials (two with resin-based sealant material and one with resin-modified glass ionomer) reported that no adverse events resulted from use of sealants or fluoride varnishes. The other five studies did not mention adverse events. 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.

Plain-language summary: This review includes eight studies published from 1984 to 2014, in which 1746 participants were randomly assigned (1127 were included in the analyses) to receive dental sealant (or sealant together with fluoride varnish) or fluoride varnish applications, and the extent of tooth decay was compared. Participants were five to 10 years of age at the start of the trial and represented the general population. Some evidence suggests that applying resin-based sealants to the biting surfaces of permanent back teeth in children may reduce tooth decay in the permanent teeth of children by 3.7% over a two-year period, and by 29% over a nine-year period, when compared with fluoride varnish applications. Applying resin-based sealant together with fluoride varnish to the biting surfaces of the permanent back teeth may reduce tooth decay by 14.4% over a two-year period compared with fluoride varnish alone. Effects of applying glass ionomer sealants may be similar to those seen when fluoride varnish is applied, but evidence showing the similarity between interventions is of very low quality. Three studies reported that there were no associated adverse events from sealants or fluoride varnish applications; the other studies did not mention adverse events. Available evidence is of low to very low quality because of the small number of included studies, and because of problems with the way in which studies were conducted. Further, most studies reported a relatively short follow-up time.