Effectiveness of school-based dental sealant programs among children from low-income backgrounds: a pragmatic randomized clinical trial with a follow-up of 3 years

Abstract

Aim: A split-mouth randomized clinical trial was carried out to assess the effectiveness of a school-based dental sealant (SBDS) program for French children from low-income backgrounds within 3 years of follow-up. The secondary objectives were to determine the risk factors for the occurrence of new carious lesions (ICDAS 3-6) on first permanent molars, to evaluate the effectiveness of the program according to risk factors and to assess sealant retention.

Methods: The study included 276 6- to 7-year old pupils (457 pairs of first permanent molars) from Nice. The sealing was performed in first- or second-grade children. The first permanent molars were randomized into two groups: One received resin-based sealant and the other formed a nontreatment group. Carious lesions ICDAS 3-6 on permanent and primary teeth, visible plaque, streptococcus mutans and/or lactobacillus counts were recorded at baseline to assess individual caries risk (ICR). The putative confounders recorded at baseline were sex, grade level, and characteristics of first permanent molars. An intent-to-treat analysis was performed, where the study outcome was the occurrence of new carious lesions within 3 years of follow-up. Univariate and multivariate Cox proportional hazards models (hazard risk, HR) using the procedure PHREG with the option of Covsandwich were performed in SAS to assess the effectiveness of the SBDS program.

Results: At 3 years of follow-up, 228 children (378 tooth pairs) remained in the analysis. The survival analysis showed that first permanent molars that received sealants had 67% (adjusted HR: 0.33; 95% CI: 0.24-0.46) less risk of developing new carious lesions during all the follow-up than molars without sealant. In addition, children with carious lesions ICDAS 3-6 on permanent and primary teeth, that is, high ICR, had three times the risk of having a new carious lesion than others without, independently of the sealant treatment (adjusted HR: 3.00; 95% CI: 1.55-5.75). Effectiveness of the SBDS program at 3 years of follow-up depended on the presence of carious lesions ICDAS 3-6 (HR in 173 children with carious lesions: 0.32; 95% CI: 0.23-0.46) at baseline (HR in 103 children without carious lesions: 0.42; 95% CI: 0.16-1.12). Finally, the overall retention rate was 32.3%.

Conclusion: The effectiveness of the SBDS program was demonstrated in low socioeconomic areas. Selection of schoolchildren according to the presence of carious lesions ICDAS 3-6 should be considered in a SBDS program.

Keywords: clinical trial; school-based dental sealant program; sealant.