Glass Ionomer Sealant versus Fluoride Varnish Application to Prevent Occlusal Caries in Primary Second Molars among Preschool Children: A Randomized Controlled Trial

Fissure sealant is a recommended preventive measure on permanent molars, but its efficacy on primary molars in preschool children is still in doubt. Sodium fluoride varnish (NaFV) enhances remineralization and is effective in preventing caries in smooth surfaces, but limited information is available regarding its use on occlusal surfaces of primary molars. The present study aimed to compare the efficacy of glass ionomer sealant (GIS) versus topical application of 5% NaFV in preventing and arresting occlusal caries in primary second molars among preschool children. One calibrated examiner examined children aged 3–4 years for visible plaque index (VPI), decayed-missing-filled primary surface (dmfs) index, and extent of carious lesions by the International Caries Detection and Assessment System (ICDAS). Subjects with 1 or more primary second molars that were sound or with incipient lesions (ICDAS 0–1), with distinct visual enamel changes (ICDAS 2), or with localized enamel breakdown (ICDAS 3) were recruited. The children were randomly assigned to either NaFV group – application of 5% NaFV at 3-monthly intervals or GIS group – 1 single placement of GIS. A parental questionnaire was used to collect information on the children’s sociodemographic background and oral health-related habits. Two blinded examiners conducted clinical examinations after 6 and 12 months to evaluate the development of occlusal caries and the retention of GIS. Negative binomial regression using generalized estimating equations was employed to adjust for the clustering effect and evaluate the influence of selected variables on the development of occlusal caries into dentin at 12 months. A total of 323 children with 1,159 primary second molars received the respective preventive measures at baseline. At 12 months, 280 children with 989 molars were evaluated. Caries had developed or progressed into dentin in 7.8% and 8.0% of the molars in the NaFV and GIS groups, respectively, with no significant difference between the groups (<i>p</i> = 0.913). The overall retention rates of GIS were 24.6% and 13.5% at 6 and 12 months, respectively. Regression analyses showed only baseline caries experience, and an ICDAS code had a significant association with occlusal caries progression. Quarterly NaFV application and single GIS placement showed similar effectiveness in the prevention of occlusal caries development among preschool children.