Background: Early childhood caries is a public health problem that continues to affect babies and preschool children worldwide. This untreated caries process results in progressive destruction of the crowns of the teeth, often accompanied by severe pain and suffering, affecting the quality of life. Fluoride varnish which is one of the most important materials to prevent ECC is easy to apply and well tolerated by children. This study aimed to evaluate the scientific evidence regardingthe role of fluoride varnish in preventing early childhood caries. Materials and Methods: Records were searched from various databases such as PubMed/Medline, Cochrane, and EMBASE. Articles published over the past 36 years (1979-2015) were identified using the key search terms. A total of 190 records were identified by title/abstracts/full text articles and were retrieved. Potentially relevant reports identified from the reference lists of relevant studies, review articles and chapters were hand-searched, which yielded an additional 10 articles. The main outcome of our investigation was prevention of early childhood caries following application of fluoride varnish and unavoidable fluoride exposure. Out of 190 articles originally identified, 30 records were considered potentially eligible and sought for further assessment. 17 articles met the inclusion criteria and these studies were assessed independently for methodology and performance. Results: Analysis of literature revealed that basically two concentrations of fluoride varnishes have been used: 1% and 5%, with a caries preventive fraction ranges of 6.4-30% and 5-63%, respectively. Conclusion: The results showed that fluoride varnishes have been used at concentrations of 1% and 5% in the prevention of ECC. The preventive fraction was influenced by the frequency of application, the duration of study and sample size. The evidence level of the studies was of moderate to limited value.

Background: The objective of this study was to systematically review prevalence of dental caries at different water fluoride levels and emphasize fluoride concentration of drinking water and prevalence of dental caries. Materials and Methods: A comprehensive study was conducted using PubMed database. Inclusion criteria were predefined and some articles fulfilled these criteria. Study validity was assessed by some checklists. Surveys were conducted to determine prevalence of dental caries among individuals. Results: The heterogeneity in the group of children with deciduous teeth in terms of the amount of fluoride in drinking water and social class was significant, and the results of the studies in all the subgroups could not be pooled. However, the heterogeneity of group 2 for subjects with permanent teeth in terms of the fluoride level in drinking water and social class was not significant, and the results of the studies in each subgroup could be pooled together. Conclusion: The meta-regression showed that tooth type and social class had a significant association with the difference in the prevalence of dental caries. Therefore, these variables were the sources of heterogeneity, and the studies must be grouped and subgrouped based on these variables.