Methods: Children aged 3-4 years who had at least one dentin caries lesion were recruited from 16 kindergartens in Hong Kong and were randomly allocated into three different intervention groups: Group 1 - annual application of 30% silver diammine fluoride (SDF) solution; Group 2 - three applications of 30% SDF solution at weekly interval; and Group 3 - three applications of 5% sodium fluoride (NaF) varnish at weekly interval. Information about the children‘s demographic and socio-economic backgrounds, and oral health related behaviors was collected by a questionnaire completed by their parents. The 12-month follow-up examinations were carried out by a masked examiner to assess whether the treated caries lesions had become arrested.
Results: A total of 325 children with 1824 tooth surfaces with dentin caries received treatment at baseline. After 12 months, 298 children (92%) were examined. The caries arrest rates at tooth surface level were 18%, 26% and 13% for Groups 1, 2 and 3, respectively (p<0.001). In the logistic regression model using Glimmix to adjust for clustering effect, higher caries arrest rates were found in lesions treated in Group 2 (OR=2.1, p=0.047) while lower caries arrest rate in Group 3 were found (OR=0.3, p=0.001), compared to that in Group 1. Other significant variables were tooth type, tooth surface, presence of plaque at lesions, color of lesions at baseline (p<0.05).
Conclusions: The annual or intensive application of SDF solution is more effective in arresting dentin caries than the intensive application of NaF varnish.