Objective: To compare the capacity of silver diamine fluoride (30%) and the bioactive giomer light-curing varnish for arresting ICDAS score 5 non-retentive caries lesions. Material and Methods: An in vitro analytical study was conducted using 36 healthy primary teeth, in which a cavity was created, divided into 3 groups: control (distilled and deionized water), giomer-based light-curing varnish -Barrier Coat, and Silver Diamine Fluoride 30% -Cariestop (SDF). The samples were analyzed for mineral loss as measured by surface microhardness (SMH). The Knoop microhardness test was performed using the HVS-1000 microhardness tester. The data were compared by two-way analysis of variance -treatment and time (before and after treatment) followed by Tukey's post-test. The significance level adopted in all analyzes was 5%. Results: The specimens treated with giomer showed higher SMH compared to the untreated group but were similar to those of the SDF group. The SDF group, on the other hand, showed no statistically significant difference from the control group (p=0.010). Conclusion: The giomer varnish had a remineralizing effect on artificial dentinal caries.