Which product has been cleared by the FDA as a class II medical device for tooth hypersensitivity and is being fast-tracked as a caries arresting medication?

• A. 38% silver diamine fluoride solution
• B. Silver nitrate solution
• C. Fluoride varnish
• D. Calcium phosphate paste

Answer: (A)

The key idea is that only silver diamine fluoride at 38% has a regulatory path as a device for dentin hypersensitivity while also being studied for caries arrest. This product works by occluding dentinal tubules to reduce sensitivity and by delivering silver ions with fluoride to combat caries—silver provides antimicrobial action and fluoride aids remineralization. That dual action is why it’s being explored as a caries-arresting medication, fitting both parts of the question. The other options don’t have FDA device clearance for hypersensitivity in this context, nor are they being fast-tracked for caries arrest in the same way.