Discussion
carious lesions, tooth type, caries
REGRESSION, DISEASE, CARIES, PLAQUE
A PubMed search on 3th December 2022 found no studies on the effectiveness of SDF to prevent approximal caries in primary teeth. This is the first randomized clinical trial to compare the effectiveness of 38% SDF to 5%NaF varnish on approximal surfaces with a control. The results of our study demonstrated no significant differences in preventing approximal caries development among the 3 groups after controlling for cluster effects and confounding factors based on the 18-month follow-up. The results of the present study support a recent systematic review that concluded that fluoride varnish had a modest and uncertain effect on preventing caries development in children [The effectiveness of semi-annual 38% SDF application on preventing caries development was also not observed in our study. Preventing caries development on approximal areas might be more difficult than other surfaces because these areas are more vulnerable to plaque accumulation. Furthermore, approximal areas are difficult to clean and they have restricted salivary access and less fluoride toothpaste exposure compared to other surfaces. The results of the current study were inconsistent with previous studies [Another possibility of the topical fluoride effectiveness being not significantly different from the control group could be the Hawthorne effect [The results of the multi-level logistic regression analysis demonstrated that tooth type and the extent of baseline approximal caries influenced approximal caries development. The first primary molar was more prone to caries development than the canine or second molar in this age group, which was consistent with previous studies [The strengths of this study include sufficient sample size, comprehensive assessment with both clinical and radiographic examinations, as well as using the ICCMS™ scoring system to compare our results to other studies in the future. This study also has limitations. The study was conducted in primary teeth of preschool children with high caries risk in a school-based setting. The results cannot be generalized to other age groups with different caries risks. More research is required regarding the effectiveness of different frequency of professionally applied topical fluorides in preventing and controlling approximal carious lesions.As early childhood caries is a multifactorial disease, preventing new caries development or arresting the progression of carious lesions cannot be accomplished with a single intervention, such as the application of professional topical fluoride, especially in children at high risk for caries. The strategies for preventing ECC in high-risk groups require a combination of individual- and community-level interventions including hand-on tooth brushing with fluoride toothpaste, educating parents / caregivers to improve oral health literacy, promoting school and community to create a healthy dietary environment, and implementing water or milk fluoridation.