Background: This article critically appraises an 18-month, double-blind, randomized controlled trial (RCT) investigating caries arrest rates in three different groups utilizing topical application of 30% silver diamine fluoride (SDF) or 5% fluoride (NaF) varnish at varying intervals.
Clinical question: Is there a difference in the caries arrest rates among preschool children receiving annual application of 30% SDF, weekly application of 30% SDF for 3 weeks, or weekly application of 5% NaF varnish for 3 weeks?
Summary of methods: This RCT was conducted with 16 kindergartens in Hong Kong, a community with fluoridated drinking water. Carious lesions were assessed by visual and tactile detection. The study participants were randomly assigned to three parallel groups with no negative control group: group 1, an application of 30% SDF at baseline and repeated at 12 months; group 2, a weekly application of 30% SDF for 3 weeks; or group 3, a weekly application of 5% NaF varnish for 3 weeks. Follow-up examinations were conducted at 6, 12, and 18 months.
Critical appraisal: Based on an evaluation using the Critical Appraisal Skills Programme (CASP) tool, this study met all criteria for a credible RCT. The strength of the findings was low to moderate, given selective outcome reporting and subsequent potential for reporting bias.
Practical implications: The results showed that SDF had a faster rate of arresting dental caries than NaF varnish. These findings are of importance, as they are consistent with a growing body of evidence.