Effect of professional application of APF foam on caries reduction in permanent first molars in 6–7-year-old children: 24-month clinical trial

Objectives The purpose of the study was to evaluate the effect of 6-monthly professional application of APF foam on caries reduction in permanent first molars in 6–7-year-old children over 24 months, and to compare the caries-preventive effect between APF foam and APF gel. Methods In a randomised controlled trial, 661 children aged 6–7-years-old were randomly divided into three groups on a school class basis. The foam group and the gel group received 6-monthly APF foam and APF gel application, respectively, and the control group did not receive any treatment. Results The mean caries increment of smooth surfaces of permanent first molars in the foam group was 0.16 while that of the control group was 0.27, resulting in 41% caries reduction (P-value=0.02), but there was no statistically significant difference between the foam group and the gel group (P-value=0.10). No difference was found on the mean caries increment of pit and fissure surfaces or all surfaces among the three groups (ANOVA, P-value=0.89). Conclusion Six-monthly professional application of APF foam could effectively reduce the incidence of dental caries in smooth surfaces of permanent first molars in 6–7-year-old children, which was similar to APF gel.