A parent brings a child who has traveled 1.5 hours to the clinic. The child has multiple carious primary teeth and is uncooperative for treatment. The parent requests something quick and non-invasive to arrest the caries until the child can be managed for more extensive treatment. What is the most appropriate initial intervention?

Silver diamine fluoride (SDF) is an ideal caries-arresting agent for uncooperative pediatric patients, patients with complex medical histories, and situations where interim non-invasive management is needed. SDF (38% concentration, e.g., Advantage Arrest) arrests active caries through its antimicrobial properties (silver ions) and remineralizing effects (fluoride). Application requires minimal patient cooperation (a simple brush-on application), no anesthesia, and can be completed quickly. It is particularly valuable when conventional restoration is deferred. The main limitation is that it stains arrested carious dentin black. Fluoride varnish prevents new caries but does not arrest active lesions as effectively as SDF.