If your little one stiffens at the sight of a dental chair—or you’re not exactly thrilled to climb into one yourself—there may be a much easier way to deal with certain cavities. A low-cost liquid painted directly onto the tooth can stop decay from spreading without drilling or numbing—and, in many cases, without tears. Now, new U.S. trial data could finally move it closer to FDA approval.
The treatment is called silver diamine fluoride, or SDF, and researchers at the University of Michigan just published the results of a Phase III trial in JAMA Pediatrics. The formula is exactly what it sounds like: silver and fluoride. The silver helps kill the bacteria driving the decay, while the fluoride hardens and remineralizes the damaged tooth. Together, they stopped more than half of the treated cavities from getting worse after a single application.
The trial enrolled 830 children under age 6 across Michigan, New York and Iowa, all of them dealing with serious decay (on average, roughly 11 of their 20 baby teeth were affected). Hygienists painted 38 percent SDF onto the cavities with a small applicator. Six months later, 54 percent of the treated cavities had stopped progressing. In the placebo group, 22.5 percent stopped on their own.
“This is a very effective and safe treatment—even in children as young as 1,” says Margherita Fontana, DDS, PhD, professor of dentistry at the University of Michigan School of Dentistry and the study’s lead investigator.
SDF itself isn’t new. The World Health Organization put it on its essential medicines list in 2021, and dentists here have used it off-label since 2014, when it was cleared as a device for adult tooth sensitivity. Both the American Academy of Pediatric Dentistry and the American Academy of Pediatrics have guidance on using it in kids. What had been missing was a Phase III U.S. trial specifically designed to support FDA approval of SDF as a cavity treatment.
There is, however, one very visible catch: SDF permanently darkens the decayed part of the tooth. And in an exploratory analysis, cavities on front teeth responded better than those on back teeth—about 42 percent were arrested versus 26 percent—likely because they’re easier to keep clean and dry.
The trial focused on young children, but SDF’s potential usefulness may not stop there. Fontana says SDF could still help older adults, people with developmental or physical disabilities, patients with serious dental anxiety and those who can’t easily tolerate or access conventional dental care. For adults, it can buy time until a filling or crown is realistic. Just know the adult research is thinner, concentrated mostly on root decay in older patients.
Cavities remain the most common chronic disease among kids, affecting more than 40 percent of U.S. children ages 2 to 19. Left untreated, they can lead to pain, infection and sometimes surgery under general anesthesia. Against that, a permanent dark spot may not sound so bad.
