Objectives: To conduct a systematic review on the relationship between the use of topical fluorides in young children and the risk of developing dental fluorosis. Materials and Methods: Relevant studies were identified through searching electronic databases. Randomised controlled trials (RCTs), quasi-RCTs, cohort studies, case-control studies and cross sectional surveys, in which children under 6 years old who exposed to topical fluorides and later assessed for fluorosis were reviewed. Risk ratios for RCT/cohort studies and odds ratios for casecontrol/cross-sectional studies were extracted. Meta-analyses were performed. Results: 25 studies were included: 2 RCTs, 1 cohort study, 6 case-control studies and 16 crosssectional surveys. These studies, except one RCT, were judged to be at moderate to high risk of bias. Data from observational studies showed a lower risk of fluorosis if brushing of a child's teeth with fluoride toothpaste commenced after 12 months old (OR=0.70, random-effects 95% C.I. 0.57 to 0.88). However, inconsistent statistically significant associations were found between fluorosis and starting using fluoride toothpaste/toothbrushing before or after 24 months old. From the RCTs, use of higher level of fluoride was associated with an increased risk of fluorosis. No significant association between the frequency of toothbrushing or the amount of fluoride toothpaste used and fluorosis was found. Conclusion: Most of the available evidence focused on mild fluorosis. There is weak unreliable evidence that starting the use of fluoride toothpaste in children under 12 months old is associated with an increased risk of fluorosis. The evidence for its use between 12 and 24 months old is equivocal.

Oral presentations: OP-02