Resin Infiltration with Flowable Resin Composite Sealing for Non-Cavitated Occlusal Caries: A Retrospective Cohort Study

Non-cavitated occlusal pit-and-fissure carious lesions in permanent molars are common among children and adolescents; however, evidence remains limited on whether resin infiltration, combined with flowable resin composite pit-and-fissure sealing, provides superior short-term lesion control compared with sealing alone. This single-center retrospective cohort study included permanent molars with non-cavitated occlusal pit-and-fissure carious lesions, classified according to the International Caries Detection and Assessment System (ICDAS) codes 1-2, in patients aged 6-18 years. The affected tooth served as the unit of analysis. The primary outcome was lesion progression within 12 months, defined as cavitation or localized enamel breakdown, a new radiolucency in dentin, or an operative restoration due to caries progression on the same occlusal surface. A total of 842 patients with 1,117 affected teeth were included, of which 989 teeth had evaluable 12-month outcomes, comprising 330 teeth in the combined-treatment group and 659 teeth in the sealing-alone group. Lesion progression occurred in 6.97% of teeth treated with the combined approach compared with 13.05% of teeth treated with sealing alone, corresponding to an absolute risk reduction of 6.08 percentage points. Modified Poisson regression with generalized estimating equations demonstrated that the combined treatment was associated with a significantly lower 12-month risk of lesion progression after adjustment for prespecified confounders (adjusted RR, 0.52; 95% CI, 0.33-0.82; p = 0.005). Sensitivity analyses, including complete-case analysis, inverse probability of treatment weighting, restriction to baseline ICDAS 2 lesions, and exclusion of partially erupted molars, yielded consistent findings (RRs, 0.51, 0.54, 0.49, and 0.56; p = 0.006, 0.008, 0.009, and 0.022, respectively). These findings suggest that resin infiltration combined with flowable resin composite pit-and-fissure sealing may provide more effective short-term control of lesion progression than sealing alone and may represent a useful microinvasive treatment option for non-cavitated initial occlusal pit-and-fissure carious lesions in permanent molars.