Medical management of caries is a distinct treatment philosophy that employs topical minimally invasive therapies that treat the disease and is not merely prevention. This strategy is justified as an alternative or supplement to traditional care by significant disease recurrence rates following comprehensive operative treatment under general anesthesia. Silver diamine fluoride (SDF) is one agent to enable effective noninvasive treatment. The announcement of breakthrough therapy designation by the Food and Drug Administration (FDA) suggests that SDF may become the first FDA-approved drug for treating caries. Since our systematic review performed in April 2015, 4 clinical trials have been completed, which inform an update to the application protocol and frequency regimen. Suggestions from these studies are to skip the rinsing step due to demonstration of safety in young children, start patients with high disease severity on an intensive regimen of multiple applications over the first few weeks, and continue with semiannual maintenance doses as previously suggested. Breakthroughs in elucidating the impact of SDF on the dental plaque microbiome inform potential opportunities for understanding caries arrest. SDF can be added to the set of evidence-based noninvasive methods to treat caries lesions in primary teeth, such as the Hall crown technique and sealing lesions with accessible margins.

Silver diamine fluoride (SDF) is a brush-on treatment for tooth decay that stops 81% of cavitated caries lesions (dental cavities). Before this innovation, caries was treatable only with operative approaches (dental fillings). SDF-treated lesions harden and become resistant to further decay. We hypothesized that the hardening is due to reaction with silver, rather than classic fluoride-mediated remineralization, because infected dentin is not amenable to remineralization. Using synchrotron microCT with 1.3 μm resolution, we observe filamentous densities up to 500 μm in length and 0.25-7.0 μm in diameter, formed in situ by applying SDF to caries lesions. We show that these “microwires” fill voids in the lesion caused by disease, and permeate through surrounding dentinal tubules. Using spectroscopy, we confirm that the chemical composition of the observed microwires is predominantly silver. To our knowledge, this represents the first structural microscale observations resulting from clinical SDF treatment. These novel observations hint at mechanistic explanations for the first clinical method to harden carious dentin besides remineralization. We hypothesize that SDF may not only achieve its antimicrobial functions by biochemical interactions, but also through its inherent ability to integrate into dentin.