School-based caries prevention using silver diamine fluoride: A pragmatic randomized trial in low-income rural children

Abstract Background Dental caries is the world’s most prevalent noncommunicable disease, disproportionately affecting children from low-income families and rural geographic areas. Methods The CariedAway 3.0 study was a cluster-randomized pragmatic non-inferiority trial comparing silver diamine fluoride (SDF) to sealants and atraumatic restorations (ART) for the prevention and control of dental caries. All participants also received fluoride varnish. Analysis consisted of mixed-effects logistic regression for caries prevalence and weighted least squares and mixed-effects negative binomial regression for caries incidence. A non-inferiority margin of 10% for the difference between groups was used. Dental caries was defined as an ICDAS score of four or greater. Results A total of 3345 children were enrolled across 35 schools; however there was a large proportion of children who were noncompliant and received external dental care over the course of the trial. In adjusted analyses of compliant participants (n=1083; 543 in the SDF group and 540 in the sealant and ART group), there was no difference in the weighted risk difference between treatment groups (B=0.003, 95% CI = -0.0001, 0.0008). The odds of caries prevalence was elevated in the SDF group in longitudinal analyses (OR = 1.35, 95% CI = 0.86, 2.11) but was not significant and was below the non-inferiority margin. There were no significant differences between groups for caries incidence in adjusted models (IRR = 1.19, 95% CI = 0.81, 1.74). Results for intent to treat analyses were similar to that of per-protocol. Discussion In this school-based clinical trial, the prevalence of dental caries in children treated with SDF and fluoride varnish was non-inferior compared to those treated with sealants, ART, and fluoride varnish, although the overall risk was slightly higher. Unfortunately, a high rate of dropout and participant noncompliance was observed, likely due to the impacts of COVID-19 on study procedures. As a result, observed effects may be unreliable beyond the short-term. Trial Registration: NCT03448107