Fluoride gels for preventing dental caries in children and adolescents.

Systematic review/meta-analysis of 28 trials in children and adolescents 16 years or younger. Active fluoride-gel arms were compared with placebo, no treatment, or non-fluoride controls across diverse settings, with wide variation in baseline caries risk, background fluoride exposure, application method, and follow-up duration.

Topically applied fluoride gel, most often as acidulated phosphate fluoride (APF) or sodium fluoride, at about 4,500 to 12,300 ppm F. Application schedules varied across trials from once yearly to several times per year, typically using trays or operator application, with some studies using supervised self-application.

Fluoride gels reduced caries in permanent dentition, with pooled D(M)FS prevented fraction 0.28 (95% CI 0.19 to 0.36) across 25 trials. The effect was 0.21 (0.15 to 0.28) in placebo-controlled trials and 0.38 (0.24 to 0.52) in no-treatment trials. Evidence for primary dentition suggested a possible benefit, but it was low quality. Analyses did not show clear effect modification by baseline caries level, background fluoride exposure, application mode, application method, frequency, or fluoride concentration. Safety reporting was limited, so adverse effects from gel ingestion could not be well assessed.

Methodologic quality was variable, and many trials were at risk of bias. The evidence base was heterogeneous, with older study contexts and mixed regimens that may limit current applicability. Safety outcomes were sparsely reported, and subgroup analyses may have been underpowered to detect true effect differences.