This study aimed to investigate the effectiveness of the semi-annual application of 38% silver diamine fluoride (SDF) and that of 5% sodium fluoride (NaF) varnish in preventing occlusal cavitated caries in the primary molars of preschool children over a 30-mo period. This was a parallel 3-arm, double-blind, randomized controlled trial. Generally healthy children around 3 y old were randomly allocated to 1 of the 3 study groups: group 1: 38% SDF solution; group 2: 5% NaF varnish; and group 3: tonic water (placebo). The noncavitated occlusal surfaces of all primary molars received semi-annual topical application of the agent according to group assignment. The outcome was caries development at the cavitation level. An intention-to-treat analysis was adopted. A generalized estimating equation and a multilevel grouped proportional hazards model were used to evaluate the differences in caries development rates at the tooth level. A total of 791 children with 5,909 primary molars were included. At the 30-mo follow-up, the caries incidence rates were 25.5%, 24.4%, and 30.1% at the child level and 7.5%, 7.6%, and 9.1% at the tooth level in groups 1, 2, and 3, respectively. The odds of having cavitated caries in the study primary molars in both the SDF and NaF groups were significantly lower than that of the placebo group (aOR SDF = 0.67, aOR NaF = 0.58, P = 0.027). The effectiveness of SDF and NaF varnish in preventing occlusal cavitated caries was not significantly different (hazard ratio = 0.97, 95% credible interval = 0.57, 1.63). Baseline oral hygiene status, caries experience, occlusal surface status, tooth type and location, and snack-taking frequency significantly influenced the incidence of occlusal caries. Compared with placebo control, both semi-annual application of 38% SDF and semi-annual application of 5% NaF varnish are effective in preventing occlusal cavitated caries in primary molars, and their effectiveness is not significantly different.
He et al. (2025) studied this question.