Objective: The study described the incidence of interproximal caries arrest following SDF and fluoride varnish application in the primary dentition. Study design: A retrospective analysis of dental records including radiographs was conducted for interproximal dental caries in pediatric patients treated with SDF applied with woven floss. Bitewing radiographs and ICCMS™ radiographic scoring criteria were used to assess caries depth in primary teeth at baseline and then at 12-month follow-up examination. Results: This study included 185 interproximal carious lesions in 131 patients treated with SDF. Mean baseline ICCMS™ score for all lesions was 1.50, with an average dmft of 2.9. The majority of carious lesions (n=155, 84.0%) showed radiographic evidence of non-progression at 12-month follow-up. There was no statistically significant difference in caries arrest among primary canines, primary first molars, and primary second molars (P=0.61). Furthermore, there was no statistically significant difference in caries arrest in patients with commercial insurance, Medicaid, or no insurance (P=0.27). Conclusions: SDF application with woven floss was associated with interproximal caries arrest in the primary dentition at 12-month follow-up in this sample of low caries risk children. Tooth type and insurance type were not associated with caries arrest.