OBJECTIVES: Silver diamine fluoride (SDF) is an effective treatment for arresting caries, though its success for interproximal caries varies. This in vitro study aimed to evaluate the delivery of SDF to initial interproximal caries with three delivery methods using a tooth-to-tooth interproximal contact model. METHODS: Extracted permanent premolars were randomly allocated to one of three experimental groups: microbrush, dental floss, Super Floss®, and two control groups. Randomly paired premolars were mounted on a tooth-to-tooth interproximal contact model and artificial carious lesions induced. SDF was delivered with the three delivery methods. The amount and successful delivery of SDF was evaluated with three proxy measures: percentage white spot lesion (WSL) area and depth stained with SDF, and percentage change in mineral density after remineralization. RESULTS: Forty-two premolar pairs were included. The percentage of WSL area stained with SDF in the Super Floss® (93.05 ± 6.52) and dental floss (81.92 ± 20.15) groups were significantly (p <
0.002) higher than the microbrush (33.24 ± 39.01) group
the percentage of WSL depth stained with SDF in the Super Floss® (185.75 ± 51.61) group was significantly (p = 0.007) higher than the microbrush (52.07 ± 81.11) group. There was no difference in the mineral density percentage change between the three groups. CONCLUSION: Effectiveness of SDF delivery to interproximal caries was greatest with Super Floss®, followed by dental floss and then microbrush, with no significant differences between the floss groups. This study serves as a proof of concept prior to validating these methods in clinical settings. CLINICAL SIGNIFICANCE: In this in vitro study, SDF was delivered to initial interproximal caries most effectively using Super Floss®, followed by dental floss and then microbrush. Clinical studies are required to validate the results in clinical settings.