A randomized clinical trial on arresting dentin caries in preschool children by topical fluorides

Abstract

Introduction: Silver diammine fluoride (SDF) has been found to be effective in preventing and arresting dental caries in children. The annual or semi-annual application of SDF may not be practical in migratory populations or effective high caries risk patients. So far, no data are available about the effectiveness of intensive fluoride treatment in arresting dental caries in primary teeth. Objectives: This study aimed to compare the effectiveness of three topical fluoride application protocols in arresting dentin caries in primary teeth of preschool children. Methods: Children aged 3-4 years who had at least one active dental caries lesion were clinically examined by a trained examiner. The visible plaque index (VPI), the dmfs index, extent of carious lesion (ICDAS codes 3-6), color of lesion and presence of plaque on lesion were recorded. After examination, the study children were randomly allocated into three intervention groups: Group 1 – annual application of 30% SDF solution; Group 2 - three applications of 30% SDF solution at weekly intervals; and Group 3 - three applications of 5% sodium fluoride (NaF) varnish at weekly intervals. Information about the children’s background, and oral health related behaviors was collected by a parental questionnaire. The masked examiner carried out follow-up examinations every 6 months. For cavitated dentin lesions (ICDAS code 5 or 6 at baseline), lesions with smooth and hard surfaces were classified as arrested caries. For established carious lesions (ICDAS 3 or 4 at baseline), caries arrest was recorded if they did not progress to cavitated dentin carious lesion. Results: A total of 371 children with 2526 tooth surfaces with active caries lesions received treatment at baseline. After 24 months, 316 children (85%) remained in the study. Of the children remaining, 61% had received only the assigned fluoride treatments provided in the study, while 39% of them had received dental treatments from other dentists. For cavitated dentin lesions, the caries arrest rates among the children receiving only the assigned fluoride treatment were 37%, 35% and 27% for Groups 1, 2 and 3, respectively (p=0.04), while for the children receiving other dental treatments, no significant differences in caries arrest rates between the three groups were observed. The results of multi-level survival analysis showed that the arrest times of dentin caries in both SDF groups were significantly shorter than those of the NaF varnish group. For established carious lesions, the caries arrest rates were 50%, 48% and 54% in Groups 1, 2 and 3, respectively. No statistically significant differences were found among three groups. Presence of plaque on lesion, tooth type, tooth surface and extent of the caries lesion had significant effects on caries arrest rates. Conclusions: For cavitated dentin carious lesions, application of SDF solution, either 3 weekly applications at baseline or annual application, can arrest active dentin caries in primary teeth faster than 3 weekly applications of NaF varnish at baseline. However, for established carious lesions, the three fluoride application protocols are equally efficient in controlling established carious lesions.