Topical fluoride as a cause of dental fluorosis in children

Background This is an update of a review first published in 2010. Use of topical fluoride has become more common over time. Excessive fluoride consumption from topical fluorides in young children could potentially lead to dental fluorosis in permanent teeth. Objectives To describe the relationship between the use of topical fluorides in young children and the risk of developing dental fluorosis in permanent teeth. Search methods We carried out electronic searches of the Cochrane Oral Health Trials Register, CENTRAL, MEDLINE, Embase, three other databases, and two trials registers. We searched the reference lists of relevant articles. The latest search date was 28 July 2022. Selection criteria We included randomized controlled trials (RCTs), quasi‐RCTs, cohort studies, case‐control studies, and cross‐sectional surveys comparing fluoride toothpaste, mouth rinses, gels, foams, paint‐on solutions, and varnishes to a different fluoride therapy, placebo, or no intervention. Upon the introduction of topical fluorides, the target population was children under six years of age. Data collection and analysis We used standard methodological procedures expected by Cochrane and used GRADE to assess the certainty of the evidence. The primary outcome measure was the percentage prevalence of fluorosis in the permanent teeth. Two authors extracted data from all included studies. In cases where both adjusted and unadjusted risk ratios or odds ratios were reported, we used the adjusted value in the meta‐analysis. Main results We included 43 studies: three RCTs, four cohort studies, 10 case‐control studies, and 26 cross‐sectional surveys. We judged all three RCTs, one cohort study, one case‐control study, and six cross‐sectional studies to have some concerns for risk of bias. We judged all other observational studies to be at high risk of bias. We grouped the studies into five comparisons. Comparison 1. Age at which children started toothbrushing with fluoride toothpaste Two cohort studies (260 children) provided very uncertain evidence regarding the association between children starting to use fluoride toothpaste for brushing at or before 12 months versus after 12 months and the development of fluorosis (risk ratio (RR) 0.98, 95% confidence interval (CI) 0.81 to 1.18; very low‐certainty evidence). Similarly, evidence from one cohort study (3939 children) and two cross‐sectional studies (1484 children) provided very uncertain evidence regarding the association between children