Although the anti-caries effects of standard fluoride (F) toothpastes are well established, their use by preschoolers (2- to 5-year-olds) has given rise to concerns regarding the development of dental fluorosis. Thus, a widespread support of low F toothpastes has been observed. The aim of this study was to assess the effects of low (<600 ppm) and standard (1,000-1,500 ppm) F toothpastes on the prevention of caries in the primary dentition and aesthetically objectionable (moderate to severe) fluorosis in the permanent dentition. A systematic review of clinical trials and meta-analyses were carried out. Two examiners independently screened 1,932 records and read 159 potentially eligible full-text articles. Data regarding characteristics of participants, interventions, outcomes, length of follow-up and potential of bias were independently extracted by two examiners and disagreements were solved by consensus after consulting a third examiner. In order to assess the effects of low and standard F toothpastes on the proportion of children developing caries and fluorosis, pooled relative risks (RR) and associated 95% confidence intervals were estimated using a fixed and a random-effects model, respectively. Five clinical trials fulfilled the inclusion criteria. Low F toothpastes significantly increased the risk of caries in primary teeth [RR = 1.13 (1.07-1.20); 4,634 participants in three studies] and did not significantly decrease the risk of aesthetically objectionable fluorosis in the upper anterior permanent teeth [RR = 0.32 (0.03-2.97); 1,968 participants in two studies]. There is no evidence to support the use of low F toothpastes by preschoolers regarding caries and fluorosis prevention.

The aim of this study was to assess the effectiveness of fluoride varnish (FV) in reducing dentine caries at the patient, tooth, and surface levels as well as caries-related hospitalizations in preschoolers. We performed a systematic review of clinical trials of FV, alone or associated with an oral health program, compared with placebo, usual care, or no intervention. Bibliographical search included electronic searches of seven databases, registers of ongoing trials, and meeting abstracts, as well as hand searching. We performed random-effects meta-analyses and calculated confidence and prediction intervals. The search yielded 2,441 records; 20 trials were included in the review and 17 in at least one meta-analysis. Only one study had low risk of bias in all domains. We found no study reporting on caries-related hospitalizations. At the individual level, the pooled relative risk was 0.88 (95% confidence interval [CI] 0.81, 0.95); this means that in a population of preschool children with 50% caries incidence, we need to apply fluoride varnish in 17 children to avoid new caries in one child. At the tooth level, the pooled weighted mean difference was –0.30 (95% CI –0.69, 0.09) and at the surface level –0.77 (95% CI –1.23, –0.31). Considering the prediction intervals, none of the pooled estimates were statistically significant. We conclude that FV showed a modest and uncertain anticaries effect in preschoolers. Cost-effectiveness analyses are needed to assess whether FV should be adopted or abandoned by dental services.